Bitcoin/address validation
You are encouraged to solve this task according to the task description, using any language you may know.
- Task
Write a program that takes a bitcoin address as argument, and checks whether or not this address is valid.
A bitcoin address uses a base58 encoding, which uses an alphabet of the characters 0 .. 9, A ..Z, a .. z, but without the four characters:
- 0 zero
- O uppercase oh
- I uppercase eye
- l lowercase ell
With this encoding, a bitcoin address encodes 25 bytes:
- the first byte is the version number, which will be zero for this task ;
- the next twenty bytes are a RIPEMD-160 digest, but you don't have to know that for this task: you can consider them a pure arbitrary data ;
- the last four bytes are a checksum check. They are the first four bytes of a double SHA-256 digest of the previous 21 bytes.
To check the bitcoin address, you must read the first twenty-one bytes, compute the checksum, and check that it corresponds to the last four bytes.
The program can either return a boolean value or throw an exception when not valid.
You can use a digest library for SHA-256.
- Example of a bitcoin address
1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i
It doesn't belong to anyone and is part of the test suite of the bitcoin software.
You can change a few characters in this string and check that it'll fail the test.
Ada
with Ada.Exceptions, Interfaces;
with Ada.Streams;
use Ada.Exceptions, Interfaces;
use Ada.Streams;
package Bitcoin is
subtype BT_Raw_Addr is Stream_Element_Array(1..25);
subtype BT_Checksum is Stream_Element_Array(1..4);
subtype BT_Addr is String(1..34);
subtype Sha256String is String(1..64);
Invalid_Address_Error : Exception;
function Double_Sha256(S : Stream_Element_Array) return BT_Checksum;
function Is_Valid(A : BT_Raw_Addr) return Boolean;
procedure Base58_Decode(S : BT_Addr; A : out BT_Raw_Addr) ;
private
Base58 : constant String := "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
function Hex_Val (C, C2 : Character) return Stream_Element;
end Bitcoin;
with GNAT.SHA256, Ada.Strings.Fixed;
use GNAT.SHA256, Ada.Strings.Fixed;
package body Bitcoin is
function Hex_Val (C, C2 : Character) return Stream_Element is
subtype Nibble is Integer range 0..15;
HEX : array (0..255) of Nibble := (
48=>0, 49=>1, 50=>2, 51=>3, 52=>4, 53=>5, 54=>6, 55=>7, 56=>8, 57=>9
, 65=>10, 66=>11, 67=>12, 68 =>13, 69 =>14, 70 =>15
, 97=>10, 98=>11, 99=>12, 100=>13, 101=>14, 102=>15
, Others=>0
);
begin
return Stream_Element(HEX(Character'Pos(C)) * 16 + HEX(Character'Pos(C2)));
end Hex_Val;
function Double_Sha256(S : Stream_Element_Array) return BT_Checksum is
Ctx : Context := Initial_Context;
D : Message_Digest;
S2 : Stream_Element_Array(1..32);
Ctx2 : Context := Initial_Context;
C : BT_Checksum;
begin
Update(Ctx, S);
D := Digest(Ctx);
for I in S2'Range loop
S2(I) := Hex_Val(D(Integer(I)*2-1), D(Integer(I)*2));
end loop;
Update(Ctx2, S2);
D := Digest(Ctx2);
for I in C'Range loop
C(I) := Hex_Val(D(Integer(I)*2-1), D(Integer(I)*2));
end loop;
return C;
end Double_Sha256;
--------------------------------------------------------------------------------
-- Summary of Base58: --
-- We decode S into a 200 bit unsigned integer. --
-- We could use a BigNum library, but choose to go without. --
--------------------------------------------------------------------------------
procedure Base58_Decode(S : BT_Addr; A : out BT_Raw_Addr) is
begin
A := (Others => 0);
for I in S'Range loop
declare
P : Natural := Index(Base58, String(S(I..I)));
C : Natural;
begin
if P = 0 then
raise Invalid_Address_Error;
end if;
C := P - 1;
for J in reverse A'Range loop
C := C + Natural(A(J)) * 58;
A(J) := Stream_Element(Unsigned_32(C) and 255); -- 0x00FF
C := Natural(Shift_Right(Unsigned_32(C),8) and 255); -- 0xFF00
end loop;
if C /= 0 then
raise Invalid_Address_Error;
end if;
end;
end loop;
end Base58_Decode;
function Is_Valid(A : BT_Raw_Addr) return Boolean is
begin
return A(1) = 0 and A(22..25) = Double_Sha256(A(1..21));
end Is_Valid;
end Bitcoin;
with Ada.Text_IO, Bitcoin;
use Ada.Text_IO, Bitcoin;
procedure Bitcoin_Addr_Validate is
begin
declare
BTs : array (positive range <>) of BT_Addr := (
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" -- VALID
, "1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9" -- VALID
, "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X" -- checksum changed, original data.
, "1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" -- data changed, original checksum.
, "1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" -- invalid chars
);
begin
for I in Bts'Range loop
declare
A : BT_Raw_Addr;
Valid : Boolean;
begin
Put(BTs(I) & " validity: ");
Base58_Decode(BTs(I), A);
Valid := Is_Valid(A);
Put_Line(Boolean'Image(Valid));
exception
when E : Invalid_Address_Error =>
Put_Line ("*** Error: Invalid BT address.");
end;
end loop;
end;
end Bitcoin_Addr_Validate;
- Output:
1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i validity: TRUE 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9 validity: TRUE 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X validity: FALSE 1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i validity: FALSE 1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i validity: *** Error: Invalid BT address.
C
#include <stdio.h>
#include <string.h>
#include <openssl/sha.h>
const char *coin_err;
#define bail(s) { coin_err = s; return 0; }
int unbase58(const char *s, unsigned char *out) {
static const char *tmpl = "123456789"
"ABCDEFGHJKLMNPQRSTUVWXYZ"
"abcdefghijkmnopqrstuvwxyz";
int i, j, c;
const char *p;
memset(out, 0, 25);
for (i = 0; s[i]; i++) {
if (!(p = strchr(tmpl, s[i])))
bail("bad char");
c = p - tmpl;
for (j = 25; j--; ) {
c += 58 * out[j];
out[j] = c % 256;
c /= 256;
}
if (c) bail("address too long");
}
return 1;
}
int valid(const char *s) {
unsigned char dec[32], d1[SHA256_DIGEST_LENGTH], d2[SHA256_DIGEST_LENGTH];
coin_err = "";
if (!unbase58(s, dec)) return 0;
SHA256(SHA256(dec, 21, d1), SHA256_DIGEST_LENGTH, d2);
if (memcmp(dec + 21, d2, 4))
bail("bad digest");
return 1;
}
int main (void) {
const char *s[] = {
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I",
0 };
int i;
for (i = 0; s[i]; i++) {
int status = valid(s[i]);
printf("%s: %s\n", s[i], status ? "Ok" : coin_err);
}
return 0;
}
Compile with -lcrypto
- Output:
1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9: Ok 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i: Ok 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9: bad digest 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I: bad char
C#
This requires NUnit package to compile.
using System;
using System.Linq;
using System.Security.Cryptography;
using NUnit.Framework;
namespace BitcoinValidator
{
public class ValidateTest
{
[TestCase]
public void ValidateBitcoinAddressTest()
{
Assert.IsTrue(ValidateBitcoinAddress("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i")); // VALID
Assert.IsTrue(ValidateBitcoinAddress("1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9")); // VALID
Assert.Throws<Exception>(() => ValidateBitcoinAddress("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X")); // checksum changed, original data
Assert.Throws<Exception>(() => ValidateBitcoinAddress("1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i")); // data changed, original checksum
Assert.Throws<Exception>(() => ValidateBitcoinAddress("1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i")); // invalid chars
Assert.Throws<Exception>(() => ValidateBitcoinAddress("BZbvjr")); // checksum is fine, address too short
}
public static bool ValidateBitcoinAddress(string address)
{
if (address.Length < 26 || address.Length > 35) throw new Exception("wrong length");
var decoded = DecodeBase58(address);
var d1 = Hash(decoded.SubArray(0, 21));
var d2 = Hash(d1);
if (!decoded.SubArray(21, 4).SequenceEqual(d2.SubArray(0, 4))) throw new Exception("bad digest");
return true;
}
const string Alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
const int Size = 25;
private static byte[] DecodeBase58(string input)
{
var output = new byte[Size];
foreach (var t in input)
{
var p = Alphabet.IndexOf(t);
if (p == -1) throw new Exception("invalid character found");
var j = Size;
while (--j > 0)
{
p += 58 * output[j];
output[j] = (byte)(p % 256);
p /= 256;
}
if (p != 0) throw new Exception("address too long");
}
return output;
}
private static byte[] Hash(byte[] bytes)
{
var hasher = new SHA256Managed();
return hasher.ComputeHash(bytes);
}
}
public static class ArrayExtensions
{
public static T[] SubArray<T>(this T[] data, int index, int length)
{
var result = new T[length];
Array.Copy(data, index, result, 0, length);
return result;
}
}
}
C++
This example uses the C++ code from the SHA-256 task. This slightly complicates the code because the previous task was designed to hash a string of ASCII characters rather than a byte array.
#include <algorithm>
#include <cstdint>
#include <iostream>
#include <map>
#include <stdexcept>
#include <string>
#include <vector>
#include "SHA256.cpp"
SHA256 sha256{ };
const std::string ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
std::map<char, uint32_t> base_map =
{ { '0', 0 }, { '1', 1 }, { '2', 2 }, { '3', 3 }, { '4', 4 }, { '5', 5 }, { '6', 6 }, { '7', 7 },
{ '8', 8 }, { '9', 9 }, { 'a', 10 }, { 'b', 11 }, { 'c', 12 }, { 'd', 13 }, { 'e', 14 }, { 'f', 15 },
{ 'A', 10 }, { 'B', 11 }, { 'C', 12 }, { 'D', 13 }, { 'E', 14 }, { 'F', 15 } };
std::vector<uint32_t> hex_to_bytes(const std::string& text) {
std::vector<uint32_t> bytes(text.size() / 2, 0);
for ( uint64_t i = 0; i < text.size(); i += 2 ) {
const uint32_t first_digit = base_map[text[i]];
const uint32_t second_digit = base_map[text[i + 1]];
bytes[i / 2] = ( first_digit << 4 ) + second_digit;
}
return bytes;
}
std::string vector_to_ascii_string(const std::vector<uint32_t>& bytes) {
std::string result = "";
for ( uint32_t i = 0; i < bytes.size(); ++i ) {
result += static_cast<char>(bytes[i]);
}
return result;
}
std::vector<uint32_t> decode_base_58(const std::string& text) {
std::vector<uint32_t> result(25, 0);
for ( const char& ch : text ) {
std::string::size_type index = ALPHABET.find(ch);
if ( index == static_cast<uint64_t>(-1) ) {
throw std::invalid_argument("Invalid character found in bitcoin address");
}
for ( uint64_t i = result.size() - 1; i > 0; i-- ) {
index += 58 * result[i];
result[i] = index & 0xFF;
index >>= 8;
}
if ( index != 0 ) {
throw std::invalid_argument("Bitcoin address is too long");
}
}
return result;
}
bool is_valid(const std::string& address) {
if ( address.size() < 26 || address.size() > 35 ) {
throw std::invalid_argument("Invalid length of bitcoin address");
}
std::vector<uint32_t> decoded = decode_base_58(address);
std::vector first21(decoded.begin(), decoded.begin() + 21);
// Convert the 'first21' into a suitable ASCII string for the first SHA256 hash
std::string text = vector_to_ascii_string(first21);
std::string hash_1 = sha256.message_digest(text);
// Convert 'hashOne' into a suitable ASCII string for the second SHA256 hash
std::vector<uint32_t> bytes_1 = hex_to_bytes(hash_1);
std::string ascii_1 = vector_to_ascii_string(bytes_1);
std::string hash_2 = sha256.message_digest(ascii_1);
std::vector<uint32_t> bytes_2 = hex_to_bytes(hash_2);
std::vector<uint32_t> checksum(bytes_2.begin(), bytes_2.begin() + 4);
std::vector<uint32_t> last4(decoded.begin() + 21, decoded.begin() + 25);
return checksum == last4;
}
int main() {
const std::vector<std::string> addresses = { "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j",
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X",
"1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" };
for ( const std::string& address : addresses ) {
std::cout << address << " : " << std::boolalpha << is_valid(address) << std::endl;
}
}
- Output:
1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i : true 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j : false 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9 : true 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X : false 1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i : false
D
This requires the D module from the SHA-256 Task.
import std.stdio, std.algorithm, std.array, std.string, sha_256_2;
struct A25 {
// Type for a 25 ubyte (not base58 encoded) bitcoin address.
ubyte[25] enc;
ubyte bitcoinVersion() const pure nothrow @safe @nogc {
return enc[0];
}
ubyte[4] embeddedChecksum() return const pure nothrow @safe @nogc {
return enc[$ - 4 .. $];
}
/** Computes a double sha256 hash of the first 21 bytes of
the address. Returns the full 32 ubyte sha256 hash. */
ubyte[32] doubleSHA256() const pure nothrow @nogc {
return SHA256.digest(SHA256.digest(enc[0 .. 21]));
}
/** Returns a four ubyte checksum computed from the first 21
bytes of the address. */
ubyte[4] computeChecksum() const pure nothrow @nogc {
return doubleSHA256[0 .. 4];
}
/** Takes a base58 encoded address and decodes it into the
receiver. Errors are returned if the argument is not valid base58
or if the decoded value does not fit in the 25 ubyte address.
The address is not otherwise checked for validity. */
string set58(in ubyte[] s) pure nothrow @safe @nogc {
static immutable digits =
"123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
.representation;
static assert(digits.length == 58);
foreach (immutable char s1; s) {
immutable c = digits.countUntil(s1);
if (c < 0)
return "found a bad char in the Bitcoin address.";
// Currently the D type system can't see c as nonegative.
uint uc = (c < 0) ? 0 : c;
foreach_reverse (ref aj; enc) {
uc += digits.length * aj;
aj = uc % 256;
uc /= 256;
}
if (uc > 0)
return "too long Bitcoin address.";
}
return null;
}
}
/** Validates a base58 encoded bitcoin address. An address is valid
if it can be decoded into a 25 ubyte address, the Version number is 0,
and the checksum validates. Return value ok will be true for valid
addresses. If ok is false, the address is invalid and the error value
may indicate why. */
string isValidA58(in ubyte[] a58) pure nothrow @nogc {
A25 a;
immutable err = a.set58(a58);
if (!err.empty)
return err;
if (a.bitcoinVersion != 0)
return "not Bitcoin version 0.";
return (a.embeddedChecksum == a.computeChecksum) ? null :
"checksums don't match.";
}
void main() {
immutable tests = ["1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz"];
foreach (immutable test; tests) {
immutable err = test.representation.isValidA58;
writefln(`"%s": %s`, test, err.empty ? "OK." : err);
}
}
- Output:
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i": OK. "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j": checksums don't match. "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!": found a bad char in the Bitcoin address. "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz": not Bitcoin version 0. "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz": too long Bitcoin address.
Dart
This requires Crypto package to compile.
import 'package:crypto/crypto.dart';
class Bitcoin {
final String ALPHABET =
"123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
List<int> bigIntToByteArray(BigInt data) {
String str;
bool neg = false;
if (data < BigInt.zero) {
str = (~data).toRadixString(16);
neg = true;
} else str = data.toRadixString(16);
int p = 0;
int len = str.length;
int blen = (len + 1) ~/ 2;
int boff = 0;
List bytes;
if (neg) {
if (len & 1 == 1) {
p = -1;
}
int byte0 = ~int.parse(str.substring(0, p + 2), radix: 16);
if (byte0 < -128) byte0 += 256;
if (byte0 >= 0) {
boff = 1;
bytes = new List<int>(blen + 1);
bytes[0] = -1;
bytes[1] = byte0;
} else {
bytes = new List<int>(blen);
bytes[0] = byte0;
}
for (int i = 1; i < blen; ++i) {
int byte = ~int.parse(str.substring(p + (i << 1), p + (i << 1) + 2),
radix: 16);
if (byte < -128) byte += 256;
bytes[i + boff] = byte;
}
} else {
if (len & 1 == 1) {
p = -1;
}
int byte0 = int.parse(str.substring(0, p + 2), radix: 16);
if (byte0 > 127) byte0 -= 256;
if (byte0 < 0) {
boff = 1;
bytes = new List<int>(blen + 1);
bytes[0] = 0;
bytes[1] = byte0;
} else {
bytes = new List<int>(blen);
bytes[0] = byte0;
}
for (int i = 1; i < blen; ++i) {
int byte =
int.parse(str.substring(p + (i << 1), p + (i << 1) + 2), radix: 16);
if (byte > 127) byte -= 256;
bytes[i + boff] = byte;
}
}
return bytes;
}
List<int> arrayCopy(bytes, srcOffset, result, destOffset, bytesLength) {
for (int i = srcOffset; i < bytesLength; i++) {
result[destOffset + i] = bytes[i];
}
return result;
}
List<int> decodeBase58To25Bytes(String input) {
BigInt number = BigInt.zero;
for (String t in input.split('')) {
int p = ALPHABET.indexOf(t);
if (p == (-1))
return null;
number = number * (BigInt.from(58)) + (BigInt.from(p));
}
List<int> result = new List<int>(24);
List<int> numBytes = bigIntToByteArray(number);
return arrayCopy(
numBytes, 0, result, result.length - numBytes.length, numBytes.length);
}
validateAddress(String address) {
List<int> decoded = new List.from(decodeBase58To25Bytes(address));
List<int> temp = new List<int>.from(decoded);
temp.insert(0, 0);
List<int> hash1 = sha256.convert(temp.sublist(0, 21)).bytes;
List<int> hash2 = sha256.convert(hash1).bytes;
if (hash2[0] != decoded[20] ||
hash2[1] != decoded[21] ||
hash2[2] != decoded[22] ||
hash2[3] != decoded[23]) return false;
return true;
}
}
- Output:
"1BNGaR29FmfAqidXmD9HLwsGv9p5WVvvhq" true "1BNGaR29FmfAqidXmD9HLws" false
Delphi
This requires DCPcrypt library to compile.
uses
DCPsha256;
type
TByteArray = array of Byte;
function HashSHA256(const Input: TByteArray): TByteArray;
var
Hasher: TDCP_sha256;
begin
Hasher := TDCP_sha256.Create(nil);
try
Hasher.Init;
Hasher.Update(Input[0], Length(Input));
SetLength(Result, Hasher.HashSize div 8);
Hasher.Final(Result[0]);
finally
Hasher.Free;
end;
end;
function DecodeBase58(const Input: string): TByteArray;
const
Size = 25;
Alphabet = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz';
var
C: Char;
I, J: Integer;
begin
SetLength(Result, Size);
for C in Input do
begin
I := Pos(C, Alphabet) - 1;
if I = -1 then
raise Exception.CreateFmt('Invalid character found: %s', [C]);
for J := High(Result) downto 0 do
begin
I := I + (58 * Result[J]);
Result[J] := I mod 256;
I := I div 256;
end;
if I <> 0 then
raise Exception.Create('Address too long');
end;
end;
procedure ValidateBitcoinAddress(const Address: string);
var
Hashed: TByteArray;
Decoded: TByteArray;
begin
if (Length(Address) < 26) or (Length(Address) > 35) then
raise Exception.Create('Wrong length');
Decoded := DecodeBase58(Address);
Hashed := HashSHA256(HashSHA256(Copy(Decoded, 0, 21)));
if not CompareMem(@Decoded[21], @Hashed[0], 4) then
raise Exception.Create('Bad digest');
end;
Erlang
Using base58 module from http://github.com/titan098/erl-base58.git.
-module( bitcoin_address ).
-export( [task/0, validate/1] ).
task() ->
io:fwrite( "Validate ~p~n", ["1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i"] ),
io:fwrite( "~p~n", [validate("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i")] ),
io:fwrite( "Validate ~p~n", ["1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW622"] ),
io:fwrite( "~p~n", [validate("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW622")] ).
validate( String ) ->
{length_25, <<Address:21/binary, Checksum:4/binary>>} = {length_25, base58:base58_to_binary( String )},
<<Version:1/binary, _/binary>> = Address,
{version_0, <<0>>} = {version_0, Version},
<<Four_bytes:4/binary, _T/binary>> = crypto:hash( sha256, crypto:hash(sha256, Address) ),
{checksum, Checksum} = {checksum, Four_bytes},
ok.
- Output:
17> bitcoin_address:task().
Validate "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i"
ok
Validate "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW622"
** exception error: no match of right hand side value {checksum,<<"ÀF²ÿ">>}
in function bitcoin_address:validate/1 (src/bitcoin_address.erl, line 16)
in call from bitcoin_address:task/0 (src/bitcoin_address.erl, line 9)
Factor
USING: byte-arrays checksums checksums.sha io.binary kernel math
math.parser sequences ;
IN: rosetta-code.bitcoin.validation
CONSTANT: ALPHABET "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
: base58>bigint ( str -- n )
[ ALPHABET index ]
[ [ 58 * ] [ + ] bi* ] map-reduce ;
: base58> ( str -- bytes ) base58>bigint 25 >be ;
: btc-checksum ( bytes -- checksum-bytes )
21 head 2 [ sha-256 checksum-bytes ] times 4 head ;
: btc-valid? ( str -- ? ) base58> [ btc-checksum ] [ 4 tail* ] bi = ;
- Output:
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" btc-valid? . ! t, VALID "1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9" btc-valid? . ! t, VALID "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X" btc-valid? . ! f, checksum changed, original data. "1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" btc-valid? . ! f, data changed, original checksum.
FreeBASIC
' version 05-04-2017
' compile with: fbc -s console
' function adapted from the SHA-256 task
Function SHA_256(test_str As String, bitcoin As ULong = 0) As String
#Macro Ch (x, y, z)
(((x) And (y)) Xor ((Not (x)) And z))
#EndMacro
#Macro Maj (x, y, z)
(((x) And (y)) Xor ((x) And (z)) Xor ((y) And (z)))
#EndMacro
#Macro sigma0 (x)
(((x) Shr 2 Or (x) Shl 30) Xor ((x) Shr 13 Or (x) Shl 19) Xor ((x) Shr 22 Or (x) Shl 10))
#EndMacro
#Macro sigma1 (x)
(((x) Shr 6 Or (x) Shl 26) Xor ((x) Shr 11 Or (x) Shl 21) Xor ((x) Shr 25 Or (x) Shl 7))
#EndMacro
#Macro sigma2 (x)
(((x) Shr 7 Or (x) Shl 25) Xor ((x) Shr 18 Or (x) Shl 14) Xor ((x) Shr 3))
#EndMacro
#Macro sigma3 (x)
(((x) Shr 17 Or (x) Shl 15) Xor ((x) Shr 19 Or (x) Shl 13) Xor ((x) Shr 10))
#EndMacro
Dim As String message = test_str ' strings are passed as ByRef's
Dim As Long i, j
Dim As UByte Ptr ww1
Dim As UInteger<32> Ptr ww4
Do
Dim As ULongInt l = Len(message)
' set the first bit after the message to 1
message = message + Chr(1 Shl 7)
' add one char to the length
Dim As ULong padding = 64 - ((l +1) Mod (512 \ 8)) ' 512 \ 8 = 64 char.
' check if we have enough room for inserting the length
If padding < 8 Then padding = padding + 64
message = message + String(padding, Chr(0)) ' adjust length
Dim As ULong l1 = Len(message) ' new length
l = l * 8 ' orignal length in bits
' create ubyte ptr to point to l ( = length in bits)
Dim As UByte Ptr ub_ptr = Cast(UByte Ptr, @l)
For i = 0 To 7 'copy length of message to the last 8 bytes
message[l1 -1 - i] = ub_ptr[i]
Next
'table of constants
Dim As UInteger<32> K(0 To ...) = _
{ &H428a2f98, &H71374491, &Hb5c0fbcf, &He9b5dba5, &H3956c25b, &H59f111f1, _
&H923f82a4, &Hab1c5ed5, &Hd807aa98, &H12835b01, &H243185be, &H550c7dc3, _
&H72be5d74, &H80deb1fe, &H9bdc06a7, &Hc19bf174, &He49b69c1, &Hefbe4786, _
&H0fc19dc6, &H240ca1cc, &H2de92c6f, &H4a7484aa, &H5cb0a9dc, &H76f988da, _
&H983e5152, &Ha831c66d, &Hb00327c8, &Hbf597fc7, &Hc6e00bf3, &Hd5a79147, _
&H06ca6351, &H14292967, &H27b70a85, &H2e1b2138, &H4d2c6dfc, &H53380d13, _
&H650a7354, &H766a0abb, &H81c2c92e, &H92722c85, &Ha2bfe8a1, &Ha81a664b, _
&Hc24b8b70, &Hc76c51a3, &Hd192e819, &Hd6990624, &Hf40e3585, &H106aa070, _
&H19a4c116, &H1e376c08, &H2748774c, &H34b0bcb5, &H391c0cb3, &H4ed8aa4a, _
&H5b9cca4f, &H682e6ff3, &H748f82ee, &H78a5636f, &H84c87814, &H8cc70208, _
&H90befffa, &Ha4506ceb, &Hbef9a3f7, &Hc67178f2 }
Dim As UInteger<32> h0 = &H6a09e667
Dim As UInteger<32> h1 = &Hbb67ae85
Dim As UInteger<32> h2 = &H3c6ef372
Dim As UInteger<32> h3 = &Ha54ff53a
Dim As UInteger<32> h4 = &H510e527f
Dim As UInteger<32> h5 = &H9b05688c
Dim As UInteger<32> h6 = &H1f83d9ab
Dim As UInteger<32> h7 = &H5be0cd19
Dim As UInteger<32> a, b, c, d, e, f, g, h
Dim As UInteger<32> t1, t2, w(0 To 63)
For j = 0 To (l1 -1) \ 64 ' split into block of 64 bytes
ww1 = Cast(UByte Ptr, @message[j * 64])
ww4 = Cast(UInteger<32> Ptr, @message[j * 64])
For i = 0 To 60 Step 4 'little endian -> big endian
Swap ww1[i ], ww1[i +3]
Swap ww1[i +1], ww1[i +2]
Next
For i = 0 To 15 ' copy the 16 32bit block into the array
W(i) = ww4[i]
Next
For i = 16 To 63 ' fill the rest of the array
w(i) = sigma3(W(i -2)) + W(i -7) + sigma2(W(i -15)) + W(i -16)
Next
a = h0 : b = h1 : c = h2 : d = h3 : e = h4 : f = h5 : g = h6 : h = h7
For i = 0 To 63
t1 = h + sigma1(e) + Ch(e, f, g) + K(i) + W(i)
t2 = sigma0(a) + Maj(a, b, c)
h = g : g = f : f = e
e = d + t1
d = c : c = b : b = a
a = t1 + t2
Next
h0 += a : h1 += b : h2 += c : h3 += d
h4 += e : h5 += f : h6 += g : h7 += h
Next j
Dim As String answer = Hex(h0, 8) + Hex(h1, 8) + Hex(h2, 8) + Hex(h3, 8) _
+ Hex(h4, 8) + Hex(h5, 8) + Hex(h6, 8) + Hex(h7, 8)
If bitcoin = 0 Then
Return LCase(answer)
Else 'conver hex value's to integer value's
message = String(32,0)
For i = 0 To 31
message[i] = Val("&h" + Mid(answer, i * 2 + 1, 2))
Next
bitcoin = 0
End If
Loop
End Function
Function conv_base58(bitcoin_address As String) As String
Dim As String base58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
Dim As String tmp = String(24, 0)
Dim As Long x, y, z
For x = 1 To Len(bitcoin_address) -1
z = InStr(base58, Chr(bitcoin_address[x])) -1
If z = -1 Then
Print " bitcoin address contains illegal character"
Return ""
End If
For y = 23 To 0 Step -1
z = z + tmp[y] * 58
tmp[y] = z And 255 ' test_str[y] = z Mod 256
z Shr= 8 ' z \= 256
Next
If z <> 0 Then
Print " bitcoin address is to long"
Return ""
End If
Next
z = InStr(base58, Chr(bitcoin_address[0])) -1
Return Chr(z) + tmp
End Function
' ------=< MAIN >=------
Data "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" ' original
Data "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j" ' checksum changed
Data "1NAGa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" ' address changed
Data "0AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" ' only 1 or 3 as first char. allowed
Data "1AGNa15ZQXAZUgFlqJ2i7Z2DPU2J6hW62i" ' illegal character in address
Dim As String tmp, result, checksum, bitcoin_address
Dim As Long i, j
For i = 1 To 5
Read bitcoin_address
Print "Bitcoin address: "; bitcoin_address;
tmp = Left(bitcoin_address,1)
If tmp <> "1" And tmp <> "3" Then
Print " first character is not 1 or 3"
Continue For
End If
' convert bitcoinaddress
tmp = conv_base58(bitcoin_address)
If tmp = "" Then Continue For
' get the checksum, last 4 digits
For j As Long = 21 To 24
checksum = checksum + LCase(Hex(tmp[j], 2))
Next
' send the first 21 characters to the SHA 256 routine
result = SHA_256(Left(tmp, 21), 2)
result = Left(result, 8) ' get the checksum (the first 8 digits (hex))
If checksum = result Then ' test the found checksum against
Print " is valid" ' the one from the address
Else
Print " is not valid, checksum fails"
End If
Next
' empty keyboard buffer
While InKey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End
- Output:
Bitcoin address: 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i is valid Bitcoin address: 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j is not valid, checksum fails Bitcoin address: 1NAGa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i is not valid, checksum fails Bitcoin address: 0AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i first character is not 1 or 3 Bitcoin address: 1AGNa15ZQXAZUgFlqJ2i7Z2DPU2J6hW62i bitcoin address contains illegal character
Go
package main
import (
"bytes"
"crypto/sha256"
"errors"
"os"
)
// With at least one other bitcoin RC task, this source is styled more like
// a package to show how functions of the two tasks might be combined into
// a single package. It turns out there's not really that much shared code,
// just the A25 type and doubleSHA256 method, but it's enough to suggest how
// the code might be organized. Types, methods, and functions are capitalized
// where they might be exported from a package.
// A25 is a type for a 25 byte (not base58 encoded) bitcoin address.
type A25 [25]byte
func (a *A25) Version() byte {
return a[0]
}
func (a *A25) EmbeddedChecksum() (c [4]byte) {
copy(c[:], a[21:])
return
}
// DoubleSHA256 computes a double sha256 hash of the first 21 bytes of the
// address. This is the one function shared with the other bitcoin RC task.
// Returned is the full 32 byte sha256 hash. (The bitcoin checksum will be
// the first four bytes of the slice.)
func (a *A25) doubleSHA256() []byte {
h := sha256.New()
h.Write(a[:21])
d := h.Sum([]byte{})
h = sha256.New()
h.Write(d)
return h.Sum(d[:0])
}
// ComputeChecksum returns a four byte checksum computed from the first 21
// bytes of the address. The embedded checksum is not updated.
func (a *A25) ComputeChecksum() (c [4]byte) {
copy(c[:], a.doubleSHA256())
return
}/* {{header|Go}} */
// Tmpl and Set58 are adapted from the C solution.
// Go has big integers but this techinique seems better.
var tmpl = []byte("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")
// Set58 takes a base58 encoded address and decodes it into the receiver.
// Errors are returned if the argument is not valid base58 or if the decoded
// value does not fit in the 25 byte address. The address is not otherwise
// checked for validity.
func (a *A25) Set58(s []byte) error {
for _, s1 := range s {
c := bytes.IndexByte(tmpl, s1)
if c < 0 {
return errors.New("bad char")
}
for j := 24; j >= 0; j-- {
c += 58 * int(a[j])
a[j] = byte(c % 256)
c /= 256
}
if c > 0 {
return errors.New("too long")
}
}
return nil
}
// ValidA58 validates a base58 encoded bitcoin address. An address is valid
// if it can be decoded into a 25 byte address, the version number is 0,
// and the checksum validates. Return value ok will be true for valid
// addresses. If ok is false, the address is invalid and the error value
// may indicate why.
func ValidA58(a58 []byte) (ok bool, err error) {
var a A25
if err := a.Set58(a58); err != nil {
return false, err
}
if a.Version() != 0 {
return false, errors.New("not version 0")
}
return a.EmbeddedChecksum() == a.ComputeChecksum(), nil
}
// Program returns exit code 0 with valid address and produces no output.
// Otherwise exit code is 1 and a message is written to stderr.
func main() {
if len(os.Args) != 2 {
errorExit("Usage: valid <base58 address>")
}
switch ok, err := ValidA58([]byte(os.Args[1])); {
case ok:
case err == nil:
errorExit("Invalid")
default:
errorExit(err.Error())
}
}
func errorExit(m string) {
os.Stderr.WriteString(m + "\n")
os.Exit(1)
}
- Output:
Command line usage examples showing program exit status.
> valid ; echo $status Usage: valid <base58 address> 1 > valid 1 1 ; echo $status Usage: valid <base58 address> 1 > valid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i ; echo $status 0 > valid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j ; echo $status Invalid 1 > valid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62! ; echo $status bad char 1 > valid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz ; echo $status not version 0 1 > valid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz ; echo $status too long 1
Haskell
import Control.Monad (when)
import Data.List (elemIndex)
import Data.Monoid ((<>))
import qualified Data.ByteString as BS
import Data.ByteString (ByteString)
import Crypto.Hash.SHA256 (hash) -- from package cryptohash
-- Convert from base58 encoded value to Integer
decode58 :: String -> Maybe Integer
decode58 = fmap combine . traverse parseDigit
where
combine = foldl (\acc digit -> 58 * acc + digit) 0 -- should be foldl', but this trips up the highlighting
parseDigit char = toInteger <$> elemIndex char c58
c58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
-- Convert from base58 encoded value to bytes
toBytes :: Integer -> ByteString
toBytes = BS.reverse . BS.pack . map (fromIntegral . (`mod` 256)) . takeWhile (> 0) . iterate (`div` 256)
-- Check if the hash of the first 21 (padded) bytes matches the last 4 bytes
checksumValid :: ByteString -> Bool
checksumValid address =
let (value, checksum) = BS.splitAt 21 $ leftPad address
in and $ BS.zipWith (==) checksum $ hash $ hash $ value
where
leftPad bs = BS.replicate (25 - BS.length bs) 0 <> bs
-- utility
withError :: e -> Maybe a -> Either e a
withError e = maybe (Left e) Right
-- Check validity of base58 encoded bitcoin address.
-- Result is either an error string (Left) or unit (Right ()).
validityCheck :: String -> Either String ()
validityCheck encoded = do
num <- withError "Invalid base 58 encoding" $ decode58 encoded
let address = toBytes num
when (BS.length address > 25) $ Left "Address length exceeds 25 bytes"
when (BS.length address < 4) $ Left "Address length less than 4 bytes"
when (not $ checksumValid address) $ Left "Invalid checksum"
-- Run one validity check and display results.
validate :: String -> IO ()
validate encodedAddress = do
let result = either show (const "Valid") $ validityCheck encodedAddress
putStrLn $ show encodedAddress ++ " -> " ++ result
-- Run some validity check tests.
main :: IO ()
main = do
validate "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" -- VALID
validate "1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9" -- VALID
validate "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X" -- checksum changed, original data.
validate "1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" -- data changed, original checksum.
validate "1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" -- invalid chars
validate "1ANa55215ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" -- too long
validate "i55j" -- too short
- Output:
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" -> Valid "1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9" -> Valid "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X" -> Invalid "1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" -> Invalid "1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" -> "Invalid base 58 encoding" "1ANa55215ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" -> "Address length exceeds 25 bytes" "i55j" -> "Address length less than 4 bytes"
Java
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
public class BitcoinAddressValidator {
private static final String ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
public static boolean validateBitcoinAddress(String addr) {
if (addr.length() < 26 || addr.length() > 35)
return false;
byte[] decoded = decodeBase58To25Bytes(addr);
if (decoded == null)
return false;
byte[] hash1 = sha256(Arrays.copyOfRange(decoded, 0, 21));
byte[] hash2 = sha256(hash1);
return Arrays.equals(Arrays.copyOfRange(hash2, 0, 4), Arrays.copyOfRange(decoded, 21, 25));
}
private static byte[] decodeBase58To25Bytes(String input) {
BigInteger num = BigInteger.ZERO;
for (char t : input.toCharArray()) {
int p = ALPHABET.indexOf(t);
if (p == -1)
return null;
num = num.multiply(BigInteger.valueOf(58)).add(BigInteger.valueOf(p));
}
byte[] result = new byte[25];
byte[] numBytes = num.toByteArray();
System.arraycopy(numBytes, 0, result, result.length - numBytes.length, numBytes.length);
return result;
}
private static byte[] sha256(byte[] data) {
try {
MessageDigest md = MessageDigest.getInstance("SHA-256");
md.update(data);
return md.digest();
} catch (NoSuchAlgorithmException e) {
throw new IllegalStateException(e);
}
}
public static void main(String[] args) {
assertBitcoin("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", true);
assertBitcoin("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j", false);
assertBitcoin("1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9", true);
assertBitcoin("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X", false);
assertBitcoin("1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", false);
assertBitcoin("1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", false);
assertBitcoin("BZbvjr", false);
assertBitcoin("i55j", false);
assertBitcoin("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!", false);
assertBitcoin("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz", false);
assertBitcoin("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz", false);
assertBitcoin("1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9", false);
assertBitcoin("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I", false);
}
private static void assertBitcoin(String address, boolean expected) {
boolean actual = validateBitcoinAddress(address);
if (actual != expected)
throw new AssertionError(String.format("Expected %s for %s, but got %s.", expected, address, actual));
}
}
Alternative Version
This example uses the Java code from the SHA-256 task as an alternative to using Java's built-in SHA256 method. It also decodes Base58 without using Java's built-in BigInteger class.
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.List;
public final class BitcoinAddressValidation {
public static void main(String[] args) {
List<String> addresses = List.of ( "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j",
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X",
"1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" );
for ( String address : addresses ) {
System.out.println(address + " : " + isValid(address));
}
}
private static boolean isValid(String address) {
if ( address.length() < 26 || address.length() > 35 ) {
throw new AssertionError("Invalid length of bitcoin address");
}
byte[] decoded = decodeBase58(address);
byte[] first21 = Arrays.copyOfRange(decoded, 0, 21);
// Convert 'first21' into an ASCII string for the first SHA256 hash
String text = new String(first21, StandardCharsets.ISO_8859_1);
String hashOne = SHA256.messageDigest(text);
// Convert 'hashOne' into an ASCII string for the second SHA256 hash
byte[] bytesOne = hexToBytes(hashOne);
String asciiOne = new String(bytesOne, StandardCharsets.ISO_8859_1);
String hashTwo = SHA256.messageDigest(asciiOne);
byte[] bytesTwo = hexToBytes(hashTwo);
byte[] checksum = Arrays.copyOfRange(bytesTwo, 0, 4);
byte[] last4 = Arrays.copyOfRange(decoded, 21, 25);
return Arrays.equals(last4, checksum);
}
private static byte[] decodeBase58(String text) {
byte[] result = new byte[25];
for ( char ch : text.toCharArray() ) {
int index = ALPHABET.indexOf(ch);
if ( index == -1 ) {
throw new AssertionError("Invalid character found in bitcoin address: " + ch);
}
for ( int i = result.length - 1; i > 0; i-- ) {
index += 58 * (int) ( result[i] & 0xFF );
result[i] = (byte) ( index & 0xFF );
index >>= 8;
}
if ( index != 0 ) {
throw new AssertionError("Bitcoin address is too long");
}
}
return result;
}
private static byte[] hexToBytes(String text) {
byte[] bytes = new byte[text.length() / 2];
for ( int i = 0; i < text.length(); i += 2 ) {
final int firstDigit = Character.digit(text.charAt(i), 16);
final int secondDigit = Character.digit(text.charAt(i + 1), 16);
bytes[i / 2] = (byte) ( ( firstDigit << 4 ) + secondDigit );
}
return bytes;
}
private static final String ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
}
- Output:
1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i : true 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j : false 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9 : true 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X : false 1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i : false
Julia
using SHA
bytes(n::Integer, l::Int) = collect(UInt8, (n >> 8i) & 0xFF for i in l-1:-1:0)
function decodebase58(bc::String, l::Int)
digits = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
num = big(0)
for c in bc
num = num * 58 + search(digits, c) - 1
end
return bytes(num, l)
end
function checkbcaddress(addr::String)
if !(25 ≤ length(addr) ≤ 35) return false end
bcbytes = decodebase58(addr, 25)
sha = sha256(sha256(bcbytes[1:end-4]))
return bcbytes[end-3:end] == sha[1:4]
end
const addresses = Dict(
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" => true,
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j" => false,
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9" => true,
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X" => true,
"1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" => false,
"1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" => false,
"BZbvjr" => false,
"i55j" => false,
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!" => false,
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz" => false,
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz" => false,
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9" => false,
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I" => false)
for (addr, corr) in addresses
println("Address: $addr\nExpected: $corr\tChecked: ", checkbcaddress(addr))
end
- Output:
Address: 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X Expected: true Checked: false Address: 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i Expected: true Checked: true Address: 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j Expected: false Checked: false Address: 1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i Expected: false Checked: false Address: 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9 Expected: true Checked: true Address: BZbvjr Expected: false Checked: false Address: 1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i Expected: false Checked: false Address: i55j Expected: false Checked: false Address: 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz Expected: false Checked: false Address: 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9 Expected: false Checked: false Address: 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62! Expected: false Checked: false Address: 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I Expected: false Checked: false Address: 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz Expected: false Checked: false
Kotlin
import java.security.MessageDigest
object Bitcoin {
private const val ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
private fun ByteArray.contentEquals(other: ByteArray): Boolean {
if (this.size != other.size) return false
return (0 until this.size).none { this[it] != other[it] }
}
private fun decodeBase58(input: String): ByteArray? {
val output = ByteArray(25)
for (c in input) {
var p = ALPHABET.indexOf(c)
if (p == -1) return null
for (j in 24 downTo 1) {
p += 58 * (output[j].toInt() and 0xff)
output[j] = (p % 256).toByte()
p = p shr 8
}
if (p != 0) return null
}
return output
}
private fun sha256(data: ByteArray, start: Int, len: Int, recursion: Int): ByteArray {
if (recursion == 0) return data
val md = MessageDigest.getInstance("SHA-256")
md.update(data.sliceArray(start until start + len))
return sha256(md.digest(), 0, 32, recursion - 1)
}
fun validateAddress(address: String): Boolean {
if (address.length !in 26..35) return false
val decoded = decodeBase58(address)
if (decoded == null) return false
val hash = sha256(decoded, 0, 21, 2)
return hash.sliceArray(0..3).contentEquals(decoded.sliceArray(21..24))
}
}
fun main(args: Array<String>) {
val addresses = arrayOf(
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j",
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X",
"1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"BZbvjr",
"i55j",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz",
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I"
)
for (address in addresses)
println("${address.padEnd(36)} -> ${if (Bitcoin.validateAddress(address)) "valid" else "invalid"}")
}
- Output:
1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i -> valid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j -> invalid 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9 -> valid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X -> invalid 1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i -> invalid 1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i -> invalid BZbvjr -> invalid i55j -> invalid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62! -> invalid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz -> invalid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz -> invalid 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9 -> invalid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I -> invalid
Mathematica / Wolfram Language
chars = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"; data =
IntegerDigits[
FromDigits[
StringPosition[chars, #][[1]] - 1 & /@ Characters[InputString[]],
58], 256, 25];
data[[-4 ;;]] ==
IntegerDigits[
Hash[FromCharacterCode[
IntegerDigits[Hash[FromCharacterCode[data[[;; -5]]], "SHA256"],
256, 32]], "SHA256"], 256, 32][[;; 4]]
- Input:
1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i 2AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i
- Output:
True False
Nim
Tests on first digit character and on address length have been added to detect wrong addresses such as "BZbvjr".
Using “libssl”
import algorithm
const SHA256Len = 32
const AddrLen = 25
const AddrMsgLen = 21
const AddrChecksumOffset = 21
const AddrChecksumLen = 4
proc SHA256(d: pointer, n: culong, md: pointer = nil): cstring {.cdecl, dynlib: "libssl.so", importc.}
proc decodeBase58(inStr: string, outArray: var openarray[uint8]) =
let base = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
outArray.fill(0)
for aChar in inStr:
var accum = base.find(aChar)
if accum < 0:
raise newException(ValueError, "Invalid character: " & $aChar)
for outIndex in countDown((AddrLen - 1), 0):
accum += 58 * outArray[outIndex].int
outArray[outIndex] = (accum mod 256).uint8
accum = accum div 256
if accum != 0:
raise newException(ValueError, "Address string too long")
proc verifyChecksum(addrData: openarray[uint8]) : bool =
let doubleHash = SHA256(SHA256(cast[ptr uint8](addrData), AddrMsgLen), SHA256Len)
for ii in 0 ..< AddrChecksumLen:
if doubleHash[ii].uint8 != addrData[AddrChecksumOffset + ii]:
return false
return true
proc main() =
let
testVectors : seq[string] = @[
"3yQ",
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62ix",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62ixx",
"17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j",
"1badbadbadbadbadbadbadbadbadbadbad",
"16UwLL9Risc3QfPqBUvKofHmBQ7wMtjvM",
"1111111111111111111114oLvT2",
"BZbvjr",
]
var
buf: array[AddrLen, uint8]
astr: string
for vector in testVectors:
stdout.write(vector & " : ")
try:
if vector[0] notin {'1', '3'}:
raise newException(ValueError, "invalid starting character")
if vector.len < 26:
raise newException(ValueError, "address too short")
decodeBase58(vector, buf)
if buf[0] != 0:
stdout.write("NG - invalid version number\n")
elif verifyChecksum(buf):
stdout.write("OK\n")
else:
stdout.write("NG - checksum invalid\n")
except:
stdout.write("NG - " & getCurrentExceptionMsg() & "\n")
main()
- Output:
3yQ : NG - address too short 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9 : OK 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i : OK 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9 : NG - checksum invalid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I : NG - Invalid character: I 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62ix : NG - invalid version number 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62ixx : NG - Address string too long 17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j : OK 1badbadbadbadbadbadbadbadbadbadbad : NG - invalid version number 16UwLL9Risc3QfPqBUvKofHmBQ7wMtjvM : OK 1111111111111111111114oLvT2 : OK BZbvjr : NG - invalid starting character
Using “nimcrypto”
import nimcrypto
import strformat
const
DecodedLength = 25 # Decoded address length.
CheckSumLength = 4 # Checksum length in address.
# Representation of a decoded address.
type Bytes25 = array[DecodedLength, byte]
#---------------------------------------------------------------------------------------------------
proc base58Decode(input: string): Bytes25 =
## Decode a base58 encoded bitcoin address.
const Base = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
for ch in input:
var n = Base.find(ch)
if n < 0:
raise newException(ValueError, "invalid character: " & ch)
for i in countdown(result.high, 0):
n += 58 * result[i].int
result[i] = byte(n and 255)
n = n div 256
if n != 0:
raise newException(ValueError, "decoded address is too long")
#---------------------------------------------------------------------------------------------------
proc verifyChecksum(data: Bytes25) =
## Verify that data has the expected checksum.
var digest = sha256.digest(data.toOpenArray(0, data.high - CheckSumLength))
digest = sha256.digest(digest.data)
if digest.data[0..<CheckSumLength] != data[^CheckSumLength..^1]:
raise newException(ValueError, "wrong checksum")
#---------------------------------------------------------------------------------------------------
proc checkValidity(address: string) =
## Check the validity of a bitcoin address.
try:
if address[0] notin {'1', '3'}:
raise newException(ValueError, "starting character is not 1 or 3")
if address.len < 26:
raise newException(ValueError, "address too short")
address.base58Decode().verifyChecksum()
echo fmt"Address “{address}” is valid."
except ValueError:
echo fmt"Address “{address}” is invalid ({getCurrentExceptionMsg()})."
#———————————————————————————————————————————————————————————————————————————————————————————————————
const testVectors : seq[string] = @[
"3yQ", # Invalid.
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9", # Valid.
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", # Valid.
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9", # Invalid.
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I", # Invalid.
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62ix", # Invalid.
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62ixx", # Invalid.
"17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j", # Valid.
"1badbadbadbadbadbadbadbadbadbadbad", # Invalid.
"16UwLL9Risc3QfPqBUvKofHmBQ7wMtjvM", # Valid.
"1111111111111111111114oLvT2", # Valid.
"BZbvjr"] # Invalid.
for vector in testVectors:
vector.checkValidity()
- Output:
Address “3yQ” is invalid (address too short). Address “1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9” is valid. Address “1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i” is valid. Address “1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9” is invalid (wrong checksum). Address “1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I” is invalid (invalid character: I). Address “1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62ix” is invalid (wrong checksum). Address “1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62ixx” is invalid (decoded address is too long). Address “17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j” is valid. Address “1badbadbadbadbadbadbadbadbadbadbad” is invalid (wrong checksum). Address “16UwLL9Risc3QfPqBUvKofHmBQ7wMtjvM” is valid. Address “1111111111111111111114oLvT2” is valid. Address “BZbvjr” is invalid (starting character is not 1 or 3).
Oberon-2
MODULE BitcoinAddress;
IMPORT
Object,
NPCT:Tools,
Crypto:SHA256,
S := SYSTEM,
Out;
CONST
BASE58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
TYPE
BC_RAW = ARRAY 25 OF CHAR;
SHA256_HASH = ARRAY 32 OF CHAR;
VAR
b58: Object.CharsLatin1;
PROCEDURE IndexOfB58Char(c: CHAR): INTEGER;
VAR
i: INTEGER;
BEGIN
i := 0;
WHILE (b58[i] # 0X) & (b58[i] # c) DO INC(i) END;
IF b58[i] = 0X THEN RETURN -1 ELSE RETURN i END
END IndexOfB58Char;
PROCEDURE DecodeB58(s [NO_COPY]: ARRAY OF CHAR;VAR out: BC_RAW): BOOLEAN;
VAR
i,j,k: LONGINT;
BEGIN
FOR i := 0 TO LEN(out) - 1 DO; out[i] := CHR(0) END;
i := 0;
WHILE (s[i] # 0X) DO;
k := IndexOfB58Char(s[i]);
IF k < 0 THEN
Out.String("Error: Bad base58 character");Out.Ln;
RETURN FALSE
END;
FOR j := LEN(out) - 1 TO 0 BY -1 DO
k := k + 58 * ORD(out[j]);
out[j] := CHR(k MOD 256);
k := k DIV 256;
END;
IF k # 0 THEN Out.String("Error: Address to long");Out.Ln; RETURN FALSE END;
INC(i)
END;
RETURN TRUE
END DecodeB58;
PROCEDURE Valid(s [NO_COPY]: ARRAY OF CHAR): BOOLEAN;
VAR
dec: BC_RAW;
d1, d2: SHA256.Hash;
d1Str, d2Str: SHA256_HASH;
x,y: LONGINT;
BEGIN
Out.String(s);Out.String(" is valid? ");
IF ~DecodeB58(s,dec) THEN RETURN FALSE END;
d1 := SHA256.NewHash();d1.Initialize();
d2 := SHA256.NewHash();d2.Initialize();
d1.Update(dec,0,21);d1.GetHash(d1Str,0);
d2.Update(d1Str,0,d1.size);d2.GetHash(d2Str,0);
S.MOVE(S.ADR(dec) + 21,S.ADR(x),4);
S.MOVE(S.ADR(d2Str),S.ADR(y),4);
RETURN (x = y)
END Valid;
BEGIN
b58 := Tools.AsString(BASE58);
Out.Bool(Valid("1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9"));Out.Ln;
Out.Bool(Valid("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i"));Out.Ln;
Out.Bool(Valid("1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9"));Out.Ln;
Out.Bool(Valid("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I"));Out.Ln
END BitcoinAddress.
- Output:
1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9 is valid? TRUE 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i is valid? TRUE 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9 is valid? FALSE 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I is valid? Error: Bad base58 character FALSE
Perl
my @b58 = qw{
1 2 3 4 5 6 7 8 9
A B C D E F G H J K L M N P Q R S T U V W X Y Z
a b c d e f g h i j k m n o p q r s t u v w x y z
};
my %b58 = map { $b58[$_] => $_ } 0 .. 57;
sub unbase58 {
use integer;
my @out;
my $azeroes = length($1) if $_[0] =~ /^(1*)/;
for my $c ( map { $b58{$_} } $_[0] =~ /./g ) {
for (my $j = 25; $j--; ) {
$c += 58 * ($out[$j] // 0);
$out[$j] = $c % 256;
$c /= 256;
}
}
my $bzeroes = length($1) if join('', @out) =~ /^(0*)/;
die "not a 25 byte address\n" if $bzeroes != $azeroes;
return @out;
}
sub check_bitcoin_address {
# Does nothing if address is valid
# dies otherwise
use Digest::SHA qw(sha256);
my @byte = unbase58 shift;
die "wrong checksum\n" unless
(pack 'C*', @byte[21..24]) eq
substr sha256(sha256 pack 'C*', @byte[0..20]), 0, 4;
}
Phix
-- -- demo\rosetta\bitcoin_address_validation.exw -- =========================================== -- with javascript_semantics include builtins\sha256.e constant b58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz" string charmap = "" function valid(string s, bool expected) bool res := (expected==false) if charmap="" then charmap = repeat('\0',256) for i=1 to length(b58) do charmap[b58[i]] = i end for end if -- not at all sure about this: -- if length(s)!=34 then -- return {expected==false,"bad length"} -- end if if not find(s[1],"13") then return {res,"first character is not 1 or 3"} end if string out = repeat('\0',25) for i=1 to length(s) do integer c = charmap[s[i]] if c=0 then return {res,"bad char"} end if c -= 1 for j=25 to 1 by -1 do c += 58 * out[j]; out[j] = and_bits(c,#FF) c = floor(c/#100) end for if c!=0 then return {res,"address too long"} end if end for if out[1]!='\0' then return {res,"not version 0"} end if if out[22..$]!=sha256(sha256(out[1..21]))[1..4] then return {res,"bad digest"} end if res := (expected==true) return {res,"OK"} end function constant tests = {{"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9",true}, -- OK {"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9",false}, -- bad digest {"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",true}, -- OK {"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j",false}, -- bad disgest {"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X",false}, -- bad digest (checksum changed, original data.) {"1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",false}, -- bad digest (data changed, original checksum.) {"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz",false}, -- not version 0 {"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz",false}, -- address too long {"1BGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",false}, -- bad digest {"1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",false}, -- bad char {"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I",false}, -- bad char {"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!",false}, -- bad char {"1AGNa15ZQXAZUgFiqJ3i7Z2DPU2J6hW62i",false}, -- bad digest {"1111111111111111111114oLvT2", true}, -- OK {"17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j",true}, -- OK {"1badbadbadbadbadbadbadbadbadbadbad",false}, -- not version 0 {"BZbvjr",false}, -- first character is not 1 or 3 (checksum is fine, address too short) {"i55j",false}, -- first character is not 1 or 3 (checksum is fine, address too short) {"16UwLL9Risc3QfPqBUvKofHmBQ7wMtjvM", true}, -- OK (from public_point_to_address) $} for i=1 to length(tests) do {string ti, bool expected} = tests[i] {bool res, string coin_err} = valid(ti,expected) if not res then printf(1,"%s: %s\n", {ti, coin_err}) {} = wait_key() end if end for ?"done" {} = wait_key()
(No output other than "done" since all tests pass)
PHP
function validate($address){
$decoded = decodeBase58($address);
$d1 = hash("sha256", substr($decoded,0,21), true);
$d2 = hash("sha256", $d1, true);
if(substr_compare($decoded, $d2, 21, 4)){
throw new \Exception("bad digest");
}
return true;
}
function decodeBase58($input) {
$alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
$out = array_fill(0, 25, 0);
for($i=0;$i<strlen($input);$i++){
if(($p=strpos($alphabet, $input[$i]))===false){
throw new \Exception("invalid character found");
}
$c = $p;
for ($j = 25; $j--; ) {
$c += (int)(58 * $out[$j]);
$out[$j] = (int)($c % 256);
$c /= 256;
$c = (int)$c;
}
if($c != 0){
throw new \Exception("address too long");
}
}
$result = "";
foreach($out as $val){
$result .= chr($val);
}
return $result;
}
function main () {
$s = array(
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I",
);
foreach($s as $btc){
$message = "OK";
try{
validate($btc);
}catch(\Exception $e){ $message = $e->getMessage(); }
echo "$btc: $message\n";
}
}
main();
- Output:
1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9: OK 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i: OK 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9: bad digest 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I: invalid character found
PicoLisp
(load "sha256.l")
(setq *Alphabet
(chop "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz") )
(de unbase58 (Str)
(let (Str (chop Str) Lst (need 25 0) C)
(while (setq C (dec (index (pop 'Str) *Alphabet)))
(for (L Lst L)
(set
L (& (inc 'C (* 58 (car L))) 255)
'C (/ C 256) )
(pop 'L) ) )
(flip Lst) ) )
(de valid (Str)
(and
(setq @@ (unbase58 Str))
(=
(head 4 (sha256 (sha256 (head 21 @@))))
(tail 4 @@) ) ) )
(test
T
(valid "17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j") )
(test
T
(=
NIL
(valid "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j")
(valid "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!")
(valid "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz")
(valid "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz") ) )PureBasic
; using PureBasic 5.50 (x64)
EnableExplicit
Macro IsValid(expression)
If expression
PrintN("Valid")
Else
PrintN("Invalid")
EndIf
EndMacro
Procedure.i DecodeBase58(Address$, Array result.a(1))
Protected i, j, p
Protected charSet$ = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
Protected c$
For i = 1 To Len(Address$)
c$ = Mid(Address$, i, 1)
p = FindString(charSet$, c$) - 1
If p = -1 : ProcedureReturn #False : EndIf; Address contains invalid Base58 character
For j = 24 To 1 Step -1
p + 58 * result(j)
result(j) = p % 256
p / 256
Next j
If p <> 0 : ProcedureReturn #False : EndIf ; Address is too long
Next i
ProcedureReturn #True
EndProcedure
Procedure HexToBytes(hex$, Array result.a(1))
Protected i
For i = 1 To Len(hex$) - 1 Step 2
result(i/2) = Val("$" + Mid(hex$, i, 2))
Next
EndProcedure
Procedure.i IsBitcoinAddressValid(Address$)
Protected format$, digest$
Protected i, isValid
Protected Dim result.a(24)
Protected Dim result2.a(31)
Protected result$, result2$
; Address length must be between 26 and 35 - see 'https://en.bitcoin.it/wiki/Address'
If Len(Address$) < 26 Or Len(Address$) > 35 : ProcedureReturn #False : EndIf
; and begin with either 1 or 3 which is the format number
format$ = Left(Address$, 1)
If format$ <> "1" And format$ <> "3" : ProcedureReturn #False : EndIf
isValid = DecodeBase58(Address$, result())
If Not isValid : ProcedureReturn #False : EndIf
UseSHA2Fingerprint(); Using functions from PB's built-in Cipher library
digest$ = Fingerprint(@result(), 21, #PB_Cipher_SHA2, 256); apply SHA2-256 to first 21 bytes
HexToBytes(digest$, result2()); change hex string to ascii array
digest$ = Fingerprint(@result2(), 32, #PB_Cipher_SHA2, 256); apply SHA2-256 again to all 32 bytes
HexToBytes(digest$, result2())
result$ = PeekS(@result() + 21, 4, #PB_Ascii); last 4 bytes
result2$ = PeekS(@result2(), 4, #PB_Ascii); first 4 bytes
If result$ <> result2$ : ProcedureReturn #False : EndIf
ProcedureReturn #True
EndProcedure
If OpenConsole()
Define address$ = "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i"
Define address2$ = "1BGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i"
Define address3$ = "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I"
Print(address$ + " -> ")
IsValid(IsBitcoinAddressValid(address$))
Print(address2$ + " -> ")
IsValid(IsBitcoinAddressValid(address2$))
Print(address3$ + " -> ")
IsValid(IsBitcoinAddressValid(address3$))
PrintN("")
PrintN("Press any key to close the console")
Repeat: Delay(10) : Until Inkey() <> ""
CloseConsole()
EndIf
- Output:
1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i -> Valid 1BGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i -> Invalid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I -> Invalid
Python
from hashlib import sha256
digits58 = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
def decode_base58(bc, length):
n = 0
for char in bc:
n = n * 58 + digits58.index(char)
return n.to_bytes(length, 'big')
def check_bc(bc):
try:
bcbytes = decode_base58(bc, 25)
return bcbytes[-4:] == sha256(sha256(bcbytes[:-4]).digest()).digest()[:4]
except Exception:
return False
print(check_bc('1AGNa15ZQXAZUgFiqJ3i7Z2DPU2J6hW62i'))
print(check_bc("17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j"))
- Output:
Returns:
- False
- True
- Help
- Yuuki-chan edit: Delete this help if it's not needed anymore
- For those looking at examples here to try and work out what is required, the
n.to_bytes()call is equivalent to this code which converts a (long) integer into individual bytes of a byte array in a particular order: >>> n = 2491969579123783355964723219455906992268673266682165637887 >>> length = 25 >>> list( reversed(range(length)) ) [24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0] >>> assert n.to_bytes(length, 'big') == bytes( (n >> i*8) & 0xff for i in reversed(range(length))) >>>
Racket
#lang racket/base
;; Same sha-256 interface as the same-named task
(require ffi/unsafe ffi/unsafe/define openssl/libcrypto)
(define-ffi-definer defcrypto libcrypto)
(defcrypto SHA256_Init (_fun _pointer -> _int))
(defcrypto SHA256_Update (_fun _pointer _pointer _long -> _int))
(defcrypto SHA256_Final (_fun _pointer _pointer -> _int))
(define (sha256 bytes)
(define ctx (malloc 128))
(define result (make-bytes 32))
(SHA256_Init ctx)
(SHA256_Update ctx bytes (bytes-length bytes))
(SHA256_Final result ctx)
result)
;; base58 decoding
(define base58-digits
(let ([v (make-vector 128 #f)])
(for ([i (in-naturals)]
[c "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"])
(vector-set! v (char->integer c) i))
v))
(define (base58->integer str)
(for/fold ([n 0]) ([c str])
(+ (* n 58) (vector-ref base58-digits (char->integer c)))))
(define (int->bytes n digits)
(list->bytes (let loop ([n n] [digits digits] [acc '()])
(if (zero? digits) acc
(let-values ([(q r) (quotient/remainder n 256)])
(loop q (sub1 digits) (cons r acc)))))))
(define (validate-bitcoin-address str)
(define bs (int->bytes (base58->integer str) 25))
(equal? (subbytes (sha256 (sha256 (subbytes bs 0 21))) 0 4)
(subbytes bs 21)))
;; additional tests taken from the other solutions
(validate-bitcoin-address "1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i") ; => #t
(validate-bitcoin-address "1111111111111111111114oLvT2") ; => #t
(validate-bitcoin-address "17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j") ; => #t
(validate-bitcoin-address "1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9") ; => #t
(validate-bitcoin-address "1badbadbadbadbadbadbadbadbadbadbad") ; => #f
Raku
(formerly Perl 6)
sub sha256(blob8 $b) returns blob8 {
given run <openssl dgst -sha256 -binary>, :in, :out, :bin {
.in.write: $b;
.in.close;
return .out.slurp;
}
}
my $bitcoin-address = rx/
<< <+alnum-[0IOl]> ** 26..* >> # an address is at least 26 characters long
<?{
.subbuf(21, 4) eq sha256(sha256 .subbuf(0, 21)).subbuf(0, 4) given
blob8.new: <
1 2 3 4 5 6 7 8 9
A B C D E F G H J K L M N P Q R S T U V W X Y Z
a b c d e f g h i j k m n o p q r s t u v w x y z
>.pairs.invert.hash{$/.comb}
.reduce(* * 58 + *)
.polymod(256 xx 24)
.reverse;
}>
/;
say "Here is a bitcoin address: 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i" ~~ $bitcoin-address;
- Output:
｢1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i｣
Ruby
# Validate Bitcoin address
#
# Nigel_Galloway
# October 13th., 2014
require 'digest/sha2'
def convert g
i,e = '',[]
(0...g.length/2).each{|n| e[n] = g[n+=n]+g[n+1]; i+='H2'}
e.pack(i)
end
N = [0,1,2,3,4,5,6,7,8,nil,nil,nil,nil,nil,nil,nil,9,10,11,12,13,14,15,16,nil,17,18,19,20,21,nil,22,23,24,25,26,27,28,29,30,31,32,nil,nil,nil,nil,nil,nil,33,34,35,36,37,38,39,40,41,42,43,nil,44,45,46,47,48,49,50,51,52,53,54,55,56,57]
A = '1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62x'
g = A.bytes.inject(0){|g,n| g*58+N[n-49]}.to_s(16) # A small and interesting piece of code to do the decoding of base58-encoded data.
n = g.slice!(0..-9)
(n.length...42).each{n.insert(0,'0')}
puts "I think the checksum should be #{g}\nI calculate that it is #{Digest::SHA256.hexdigest(Digest::SHA256.digest(convert(n)))[0,8]}"
- Output:
With A = '1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i'
I think the checksum should be c046b2ff I calculate that it is c046b2ff
With A = '1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62x' (final digit i corrupted to x).
I think the checksum should be c046b30d I calculate that it is c046b2ff
Rust
This requires the rust-crypto crate for sha256.
extern crate crypto;
use crypto::digest::Digest;
use crypto::sha2::Sha256;
const DIGITS58: [char; 58] = ['1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z'];
fn main() {
println!("{}", validate_address("1AGNa15ZQXAZUgFiqJ3i7Z2DPU2J6hW62i"));
println!("{}", validate_address("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i"));
println!("{}", validate_address("17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j"));
println!("{}", validate_address("17NdbrSGoUotzeGCcMMC?nFkEvLymoou9j"));
}
fn validate_address(address: &str) -> bool {
let decoded = match from_base58(address, 25) {
Ok(x) => x,
Err(_) => return false
};
if decoded[0] != 0 {
return false;
}
let mut sha = Sha256::new();
sha.input(&decoded[0..21]);
let mut first_round = vec![0u8; sha.output_bytes()];
sha.result(&mut first_round);
sha.reset();
sha.input(&first_round);
let mut second_round = vec![0u8; sha.output_bytes()];
sha.result(&mut second_round);
if second_round[0..4] != decoded[21..25] {
return false
}
true
}
fn from_base58(encoded: &str, size: usize) -> Result<Vec<u8>, String> {
let mut res: Vec<u8> = vec![0; size];
for base58_value in encoded.chars() {
let mut value: u32 = match DIGITS58
.iter()
.position(|x| *x == base58_value){
Some(x) => x as u32,
None => return Err(String::from("Invalid character found in encoded string."))
};
for result_index in (0..size).rev() {
value += 58 * res[result_index] as u32;
res[result_index] = (value % 256) as u8;
value /= 256;
}
}
Ok(res)
}
- Output:
false true true false
Scala
import java.security.MessageDigest
import java.util.Arrays.copyOfRange
import scala.annotation.tailrec
import scala.math.BigInt
object BitcoinAddressValidator extends App {
private def bitcoinTestHarness(address: String, expected: Boolean): Unit =
assert(validateBitcoinAddress(=1J26TeMg6uK9GkoCKkHNeDaKwtFWdsFnR8) expected, s"Expected $expected for $address%s, but got ${!expected}.")
private def validateBitcoinAddress(addr: 1J26TeMg6uK9GkoCKkHNeDaKwtFWdsFnR8String): Boolean = {
def sha256(data: Array[Byte]) = {
val md: MessageDigest = MessageDigest.getInstance("SHA-256")
md.update(data)
md.digest
}
def decodeBase58To25Bytes(input: String): Option[Array[Byte]] = {
def ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
@tailrec
def loop(s: String, accu: BigInt): BigInt = {
if (s.isEmpty) accu
else {
val p = ALPHABET.indexOf(s.head)
if (p >= 0) loop(s.tail, accu * 58 + p)
else -1
}
}
val num = loop(input, 0)
if (num >= 0) {
val (result, numBytes) = (new Array[Byte](25), num.toByteArray)
System.arraycopy(numBytes, 0, result, result.length - numBytes.length, numBytes.length)
Some(result)
}
else None
}
if (27 to 34 contains addr.length) {
val decoded = decodeBase58To25Bytes(addr)
if (decoded.isEmpty) false
else {
val hash1 = sha256(copyOfRange(decoded.get, 0, 21))
copyOfRange(sha256(hash1), 0, 4)
.sameElements(copyOfRange(decoded.get, 21, 25))
}
} else false
} // validateBitcoinAddress
bitcoinTestHarness("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", true)
bitcoinTestHarness("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j", false)
bitcoinTestHarness("1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9", true)
bitcoinTestHarness("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X", false)
bitcoinTestHarness("1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", false)
bitcoinTestHarness("1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", false)
bitcoinTestHarness("BZbvjr", false)
bitcoinTestHarness("i55j", false)
bitcoinTestHarness("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!", false)
bitcoinTestHarness("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz", false)
bitcoinTestHarness("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz", false)
bitcoinTestHarness("1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9", false)
bitcoinTestHarness("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I", false)
println(s"Successfully completed without errors. [total ${scala.compat.Platform.currentTime - executionStart}ms]")
}
Seed7
The Seed7 library encoding.s7i defines the function fromBase58, which decodes a Base58 encoded string. The Seed7 library msgdigest.s7i defines the function sha256, which computes a SHA-256 message digest. No external library is needed.
$ include "seed7_05.s7i";
include "msgdigest.s7i";
include "encoding.s7i";
const func boolean: validBitcoinAddress (in string: address) is func
result
var boolean: isValid is FALSE;
local
var string: decoded is "";
begin
if succeeds(decoded := fromBase58(address)) and
length(decoded) = 25 and decoded[1] = '\0;' and
sha256(sha256(decoded[.. 21]))[.. 4] = decoded[22 ..] then
isValid := TRUE;
end if;
end func;
const proc: checkValidationFunction (in string: address, in boolean: expected) is func
local
var boolean: isValid is FALSE;
begin
isValid := validBitcoinAddress(address);
writeln((address <& ": ") rpad 37 <& isValid);
if isValid <> expected then
writeln(" *** Expected " <& expected <& " for " <& address <& ", but got " <& isValid <& ".");
end if;
end func;
const proc: main is func
begin
checkValidationFunction("1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9", TRUE); # okay
checkValidationFunction("1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9", FALSE); # bad digest
checkValidationFunction("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", TRUE); # okay
checkValidationFunction("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j", FALSE); # bad digest
checkValidationFunction("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X", FALSE); # bad digest
checkValidationFunction("1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", FALSE); # bad digest
checkValidationFunction("oMRDCDfyQhEerkaSmwCfSPqf3MLgBwNvs", FALSE); # not version 0
checkValidationFunction("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz", FALSE); # wrong length
checkValidationFunction("1BGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", FALSE); # bad digest
checkValidationFunction("1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", FALSE); # bad char
checkValidationFunction("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I", FALSE); # bad char
checkValidationFunction("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!", FALSE); # bad char
checkValidationFunction("1AGNa15ZQXAZUgFiqJ3i7Z2DPU2J6hW62i", FALSE); # bad digest
checkValidationFunction("1111111111111111111114oLvT2", TRUE); # okay
checkValidationFunction("17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j", TRUE); # okay
checkValidationFunction("1badbadbadbadbadbadbadbadbadbadbad", FALSE); # wrong length
checkValidationFunction("BZbvjr", FALSE); # wrong length
checkValidationFunction("i55j", FALSE); # wrong length
checkValidationFunction("16UwLL9Risc3QfPqBUvKofHmBQ7wMtjvM", TRUE); # okay
end func;- Output:
1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9: TRUE 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9: FALSE 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i: TRUE 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j: FALSE 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X: FALSE 1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i: FALSE oMRDCDfyQhEerkaSmwCfSPqf3MLgBwNvs: FALSE 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz: FALSE 1BGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i: FALSE 1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i: FALSE 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I: FALSE 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!: FALSE 1AGNa15ZQXAZUgFiqJ3i7Z2DPU2J6hW62i: FALSE 1111111111111111111114oLvT2: TRUE 17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j: TRUE 1badbadbadbadbadbadbadbadbadbadbad: FALSE BZbvjr: FALSE i55j: FALSE 16UwLL9Risc3QfPqBUvKofHmBQ7wMtjvM: TRUE
Tcl
package require sha256
# Generate a large and boring piece of code to do the decoding of
# base58-encoded data.
apply {{} {
set chars "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
set i -1
foreach c [split $chars ""] {
lappend map $c "return -level 0 [incr i]"
}
lappend map default {return -code error "bad character \"$c\""}
proc base58decode str [string map [list @BODY@ [list $map]] {
set num 0
set count [expr {ceil(log(58**[string length $str])/log(256))}]
foreach c [split $str {}] {
set num [expr {$num*58+[switch $c @BODY@]}]
}
for {set i 0} {$i < $count} {incr i} {
append result [binary format c [expr {$num & 255}]]
set num [expr {$num >> 8}]
}
return [string reverse $result]
}]
}}
# How to check bitcoin address validity
proc bitcoin_addressValid {address} {
set a [base58decode $address]
set ck [sha2::sha256 -bin [sha2::sha256 -bin [string range $a 0 end-4]]]
if {[string range $a end-3 end] ne [string range $ck 0 3]} {
return -code error "signature does not match"
}
return "$address is ok"
}
Testing if it works
puts [bitcoin_addressValid 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9]
puts [bitcoin_addressValid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i]
- Output:
1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9 is ok 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i is ok
UNIX Shell
base58=({1..9} {A..H} {J..N} {P..Z} {a..k} {m..z})
bitcoinregex="^[$(printf "%s" "${base58[@]}")]{34}$"
decodeBase58() {
local s=$1
for i in {0..57}
do s="${s//${base58[i]}/ $i}"
done
dc <<< "16o0d${s// /+58*}+f"
}
checksum() {
xxd -p -r <<<"$1" |
openssl dgst -sha256 -binary |
openssl dgst -sha256 -binary |
xxd -p -c 80 |
head -c 8
}
checkBitcoinAddress() {
if [[ "$1" =~ $bitcoinregex ]]
then
h=$(decodeBase58 "$1")
checksum "00${h::${#h}-8}" |
grep -qi "^${h: -8}$"
else return 2
fi
}
Wren
import "./crypto" for Sha256
import "./str" for Str
import "./fmt" for Conv, Fmt
class Bitcoin {
static alphabet_ { "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz" }
static contentEquals_(ba1, ba2) {
if (ba1.count != ba2.count) return false
return !(0...ba1.count).any { |i| ba1[i] != ba2[i] }
}
static decodeBase58_(input) {
var output = List.filled(25, 0)
for (c in input) {
var p = alphabet_.indexOf(c)
if (p == -1) return null
for (j in 24..1) {
p = p + 58 * output[j]
output[j] = p % 256
p = p >> 8
}
if (p != 0) return null
}
return output
}
static sha256_(data, start, len, recursion) {
if (recursion == 0) return data
var md = Sha256.digest(data[start...start+len])
md = Str.chunks(md, 2).map { |x| Conv.atoi(x, 16) }.toList
return sha256_(md, 0, 32, recursion-1)
}
static validateAddress(address) {
var len = address.count
if (len < 26 || len > 35) return false
var decoded = decodeBase58_(address)
if (!decoded) return false
var hash = sha256_(decoded, 0, 21, 2)
return contentEquals_(hash[0..3], decoded[21..24])
}
}
var addresses = [
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j",
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X",
"1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i",
"BZbvjr",
"i55j",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62!",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz",
"1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I"
]
for (address in addresses) {
Fmt.print("$-36s -> $s", address, Bitcoin.validateAddress(address) ? "valid" : "invalid")
}
- Output:
1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i -> valid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62j -> invalid 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9 -> valid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X -> invalid 1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i -> invalid 1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i -> invalid BZbvjr -> invalid i55j -> invalid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62! -> invalid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62iz -> invalid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz -> invalid 1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nJ9 -> invalid 1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62I -> invalid
zkl
Uses shared library zklMsgHash.
var [const] MsgHash=Import("zklMsgHash"); // SHA-256, etc
const symbols="123456789" // 58 characters: no cap i,o; ell, zero
"ABCDEFGHJKLMNPQRSTUVWXYZ"
"abcdefghijkmnopqrstuvwxyz";
fcn unbase58(str){ // --> Data (byte bucket)
out:=Data().fill(0,25);
str.pump(Void,symbols.index,'wrap(n){ // throws on out of range
[24..0,-1].reduce('wrap(c,idx){
c+=58*out[idx]; // throws if not enough data
out[idx]=c;
c/256; // should be zero when done
},n) : if(_) throw(Exception.ValueError("address too long"));
});
out;
}
fcn coinValide(addr){
reg dec,chkSum;
try{ dec=unbase58(addr) }catch{ return(False) }
chkSum=dec[-4,*]; dec.del(21,*);
// hash then hash the hash --> binary hash (instead of hex string)
(2).reduce(MsgHash.SHA256.fp1(1,dec),dec); // dec is i/o buffer
dec[0,4]==chkSum;
}T("1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i","1Q1pE5vPGEEMqRcVRMbtBK842Y6Pzo6nK9",
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62X", // checksum changed, original data.
"1ANNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", // data changed, original checksum.
"1A Na15ZQXAZUgFiqJ2i7Z2DPU2J6hW62i", // invalid chars
"1AGNa15ZQXAZUgFiqJ2i7Z2DPU2J6hW62izz", // too long
).apply(coinValide).println();- Output:
L(True,True,False,False,False,False)
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