Bitcoin/address validation: Difference between revisions
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You can use a digest library for [[SHA-256]]. |
You can use a digest library for [[SHA-256]]. |
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''extra credit'': allow your code to deal with [http://bitcoin.stackexchange.com/questions/3059/what-is-a-compressed-bitcoin-key compressed keys] |
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=={{header|Perl}}== |
=={{header|Perl}}== |
Revision as of 03:50, 28 November 2012
Bitcoin/address validation is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.
Write a program that takes a bitcoin address as argument, and checks whether or not this address is valid. The program can either return a boolean value or throw an exception when not valid.
You can use a digest library for SHA-256.
extra credit: allow your code to deal with compressed keys
Perl
<lang 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; my $b58 = qr/[@{[join , @b58]}]/x;
sub decode {
use bigint; shift =~ m/$b58\Z/p ? $b58{${^MATCH}} + 58*decode(${^PREMATCH}) : 0
}
sub check_bitcoin_address {
use Digest::SHA qw(sha256); my $value = decode shift; my @byte; for (1 .. 25) { push @byte, $value % 256; $value /= 256 } @byte = reverse @byte; die unless join(, map { chr } @byte[21..24]) eq substr sha256(sha256 pack 'C*', @byte[0..20]), 0, 4;
}</lang>
Unix shell
<lang bash>base58=({1..9} {A..H} {J..N} {P..Z} {a..k} {m..z}) bitcoinregex="^[$(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
}</lang>