Find the MD4 message digest of a string of octets. Use the ASCII encoded string “Rosetta Code” (without quotes). You may either call an MD4 library, or implement MD4 in your language.

Task
MD4
You are encouraged to solve this task according to the task description, using any language you may know.

MD4 is an obsolete hash function that computes a 128-bit message digest that sometimes appears in obsolete protocols.

RFC 1320 specifies the MD4 algorithm. RFC 6150 declares that MD4 is obsolete.

Ada

Library: CryptAda
with Ada.Text_IO;

with CryptAda.Digests.Message_Digests.MD4;
with CryptAda.Digests.Hashes;
with CryptAda.Pragmatics;
with CryptAda.Utils.Format;

procedure RC_MD4 is
   use CryptAda.Digests.Message_Digests;
   use CryptAda.Digests;
   use CryptAda.Pragmatics;

   function To_Byte_Array (Item : String) return Byte_Array is
      Result : Byte_Array (Item'Range);
   begin
      for I in Result'Range loop
         Result (I) := Byte (Character'Pos (Item (I)));
      end loop;
      return Result;
   end To_Byte_Array;

   Text    : constant String                := "Rosetta Code";
   Bytes   : constant Byte_Array            := To_Byte_Array (Text);
   Handle  : constant Message_Digest_Handle := MD4.Get_Message_Digest_Handle;
   Pointer : constant Message_Digest_Ptr    := Get_Message_Digest_Ptr (Handle);
   Hash    : Hashes.Hash;
begin
   Digest_Start  (Pointer);
   Digest_Update (Pointer, Bytes);
   Digest_End    (Pointer, Hash);

   Ada.Text_IO.Put_Line
     ("""" & Text & """: " & CryptAda.Utils.Format.To_Hex_String (Hashes.Get_Bytes (Hash)));
end RC_MD4;
Output:
"Rosetta Code": A52BCFC6A0D0D300CDC5DDBFBEFE478B

AutoHotkey

Source: MD4 @github by jNizM

str := "Rosetta Code"
MsgBox, % "String:`n" (str) "`n`nMD4:`n" MD4(str)



; MD4 ===============================================================================
MD4(string, encoding = "utf-8")
{
    return CalcStringHash(string, 0x8002, encoding)
}

; CalcAddrHash ======================================================================
CalcAddrHash(addr, length, algid, byref hash = 0, byref hashlength = 0)
{
    static h := [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, "A", "B", "C", "D", "E", "F"]
    static b := h.minIndex()
    o := ""
    if (DllCall("advapi32\CryptAcquireContext", "Ptr*", hProv, "Ptr", 0, "Ptr", 0, "UInt", 24, "UInt", 0xF0000000))
    {
        if (DllCall("advapi32\CryptCreateHash", "Ptr", hProv, "UInt", algid, "UInt", 0, "UInt", 0, "Ptr*", hHash))
        {
            if (DllCall("advapi32\CryptHashData", "Ptr", hHash, "Ptr", addr, "UInt", length, "UInt", 0))
            {
                if (DllCall("advapi32\CryptGetHashParam", "Ptr", hHash, "UInt", 2, "Ptr", 0, "UInt*", hashlength, "UInt", 0))
                {
                    VarSetCapacity(hash, hashlength, 0)
                    if (DllCall("advapi32\CryptGetHashParam", "Ptr", hHash, "UInt", 2, "Ptr", &hash, "UInt*", hashlength, "UInt", 0))
                    {
                        loop, % hashlength
                        {
                            v := NumGet(hash, A_Index - 1, "UChar")
                            o .= h[(v >> 4) + b] h[(v & 0xf) + b]
                        }
                    }
                }
            }
            DllCall("advapi32\CryptDestroyHash", "Ptr", hHash)
        }
        DllCall("advapi32\CryPtreleaseContext", "Ptr", hProv, "UInt", 0)
    }
    return o
}

; CalcStringHash ====================================================================
CalcStringHash(string, algid, encoding = "utf-8", byref hash = 0, byref hashlength = 0)
{
    chrlength := (encoding = "cp1200" || encoding = "utf-16") ? 2 : 1
    length := (StrPut(string, encoding) - 1) * chrlength
    VarSetCapacity(data, length, 0)
    StrPut(string, &data, floor(length / chrlength), encoding)
    return CalcAddrHash(&data, length, algid, hash, hashlength)
}
Output:
String:    Rosetta Code
MD4:       A52BCFC6A0D0D300CDC5DDBFBEFE478B

BASIC

FreeBASIC

' version 19-10-2016
' translation of the (pseudo) code in RFC 1320
' compile with: fbc -s console

Function MD4(test_str As String) As String
  
  Dim As String message = test_str ' string are passed as ByRef

  ' some macro's
  #Macro F(X, Y, Z)
    (((X) And (Y)) Or ((Not(X)) And (Z)))
  #EndMacro

  #Macro G(X, Y, Z)
    (((X) And (Y)) Or (((X) And (Z)) Or ((Y) And (Z))))
  #EndMacro

  #Macro H(X, Y, Z)
    ((X) Xor (Y) Xor (Z))
  #EndMacro
  
  ' a little piece of inline asm to do a rotate left on a 32bit variable
  #Macro ROtate_Left(x, n) ' rotate left
    Asm
      rol dword Ptr [x], n
    End Asm
  #EndMacro
  
  ' #Macro ROtate_left(x, n)
    ' x = x Shl n + x Shr (32 - n)
  ' #EndMacro
  
  Dim As Long i
  Dim As String answer, s1

  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 -8 + i] = ub_ptr[i]
  Next

  ' unsigned 32bit integers only
  Dim As UInteger<32> AA, A = &H67452301
  Dim As UInteger<32> BB, B = &Hefcdab89
  Dim As UInteger<32> CC, C = &H98badcfe
  Dim As UInteger<32> DD, D = &H10325476

  For i = 0 To (l1 -1) \ 64 ' split into 64 byte block

    AA = A : BB = B : CC = C : DD = D

    ' x point to 64 byte block inside the string message
    Dim As UInteger<32> Ptr x = Cast(UInteger<32> Ptr, @message[i*64])

    ' round 1               
    A = A + F(B, C, D) + x[ 0] : ROtate_Left(A,  3)
    D = D + F(A, B, C) + x[ 1] : ROtate_Left(D,  7)
    C = C + F(D, A, B) + x[ 2] : ROtate_Left(C, 11)
    B = B + F(C, D, A) + x[ 3] : ROtate_Left(B, 19)
    A = A + F(B, C, D) + x[ 4] : ROtate_Left(A,  3)
    D = D + F(A, B, C) + x[ 5] : ROtate_Left(D,  7)
    C = C + F(D, A, B) + x[ 6] : ROtate_Left(C, 11)
    B = B + F(C, D, A) + x[ 7] : ROtate_Left(B, 19)
    A = A + F(B, C, D) + x[ 8] : ROtate_Left(A,  3)
    D = D + F(A, B, C) + x[ 9] : ROtate_Left(D,  7)
    C = C + F(D, A, B) + x[10] : ROtate_Left(C, 11)
    B = B + F(C, D, A) + x[11] : ROtate_Left(B, 19)
    A = A + F(B, C, D) + x[12] : ROtate_Left(A,  3)
    D = D + F(A, B, C) + x[13] : ROtate_Left(D,  7)
    C = C + F(D, A, B) + x[14] : ROtate_Left(C, 11)
    B = B + F(C, D, A) + x[15] : ROtate_Left(B, 19)

    ' round 2
    A = A + G(B, C, D) + x[ 0] + &H5A827999 : ROtate_Left(A,  3)
    D = D + G(A, B, C) + x[ 4] + &H5A827999 : ROtate_Left(D,  5)
    C = C + G(D, A, B) + x[ 8] + &H5A827999 : ROtate_Left(C,  9)
    B = B + G(C, D, A) + x[12] + &H5A827999 : ROtate_Left(B, 13)
    A = A + G(B, C, D) + x[ 1] + &H5A827999 : ROtate_Left(A,  3)
    D = D + G(A, B, C) + x[ 5] + &H5A827999 : ROtate_Left(D,  5)
    C = C + G(D, A, B) + x[ 9] + &H5A827999 : ROtate_Left(C,  9)
    B = B + G(C, D, A) + x[13] + &H5A827999 : ROtate_Left(B, 13)
    A = A + G(B, C, D) + x[ 2] + &H5A827999 : ROtate_Left(A,  3)
    D = D + G(A, B, C) + x[ 6] + &H5A827999 : ROtate_Left(D,  5)
    C = C + G(D, A, B) + x[10] + &H5A827999 : ROtate_Left(C,  9)
    B = B + G(C, D, A) + x[14] + &H5A827999 : ROtate_Left(B, 13)
    A = A + G(B, C, D) + x[ 3] + &H5A827999 : ROtate_Left(A,  3)
    D = D + G(A, B, C) + x[ 7] + &H5A827999 : ROtate_Left(D,  5)
    C = C + G(D, A, B) + x[11] + &H5A827999 : ROtate_Left(C,  9)
    B = B + G(C, D, A) + x[15] + &H5A827999 : ROtate_Left(B, 13)

    ' round 3
    A = A + H(B, C, D) + x[ 0] + &H6ED9EBA1 : ROtate_Left(A,  3)
    D = D + H(A, B, C) + x[ 8] + &H6ED9EBA1 : ROtate_Left(D,  9)
    C = C + H(D, A, B) + x[ 4] + &H6ED9EBA1 : ROtate_Left(C, 11)
    B = B + H(C, D, A) + x[12] + &H6ED9EBA1 : ROtate_Left(B, 15)
    A = A + H(B, C, D) + x[ 2] + &H6ED9EBA1 : ROtate_Left(A,  3)
    D = D + H(A, B, C) + x[10] + &H6ED9EBA1 : ROtate_Left(D,  9)
    C = C + H(D, A, B) + x[ 6] + &H6ED9EBA1 : ROtate_Left(C, 11)
    B = B + H(C, D, A) + x[14] + &H6ED9EBA1 : ROtate_Left(B, 15)
    A = A + H(B, C, D) + x[ 1] + &H6ED9EBA1 : ROtate_Left(A,  3)
    D = D + H(A, B, C) + x[ 9] + &H6ED9EBA1 : ROtate_Left(D,  9)
    C = C + H(D, A, B) + x[ 5] + &H6ED9EBA1 : ROtate_Left(C, 11)
    B = B + H(C, D, A) + x[13] + &H6ED9EBA1 : ROtate_Left(B, 15)
    A = A + H(B, C, D) + x[ 3] + &H6ED9EBA1 : ROtate_Left(A,  3)
    D = D + H(A, B, C) + x[11] + &H6ED9EBA1 : ROtate_Left(D,  9)
    C = C + H(D, A, B) + x[ 7] + &H6ED9EBA1 : ROtate_Left(C, 11)
    B = B + H(C, D, A) + x[15] + &H6ED9EBA1 : ROtate_Left(B, 15)

    A += AA : B += BB : C += CC : D += DD

  Next

  ' convert A, B, C and D in hex, then add low order first
  s1 = Hex(A, 8)
  For i = 7 To 1 Step -2 : answer +=Mid(s1, i, 2) : Next
  s1 = Hex(B, 8)
  For i = 7 To 1 Step -2 : answer +=Mid(s1, i, 2) : Next
  s1 = Hex(C, 8)
  For i = 7 To 1 Step -2 : answer +=Mid(s1, i, 2) : Next
  s1 = Hex(D, 8)
  For i = 7 To 1 Step -2 : answer +=Mid(s1, i, 2) : Next

Return LCase(answer)

End Function

' ------=< MAIN >=------

Dim As String test = "Rosetta Code"
Print
Print  test; " => "; MD4(test)


' empty keyboard buffer
While Inkey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End
Output:
Rosetta Code => a52bcfc6a0d0d300cdc5ddbfbefe478b

C

/*
 *
 *      Author: George Mossessian
 *
 *      The MD4 hash algorithm, as described in https://tools.ietf.org/html/rfc1320
 */


#include <stdlib.h>
#include <string.h>
#include <stdint.h>

char *MD4(char *str, int len); //this is the prototype you want to call. Everything else is internal.

typedef struct string{
        char *c;
        int len;
        char sign;
}string;

static uint32_t *MD4Digest(uint32_t *w, int len);
static void setMD4Registers(uint32_t AA, uint32_t BB, uint32_t CC, uint32_t DD);
static uint32_t changeEndianness(uint32_t x);
static void resetMD4Registers(void);
static string stringCat(string first, string second);
static string uint32ToString(uint32_t l);
static uint32_t stringToUint32(string s);

static const char *BASE16 = "0123456789abcdef=";

#define F(X,Y,Z) (((X)&(Y))|((~(X))&(Z)))
#define G(X,Y,Z) (((X)&(Y))|((X)&(Z))|((Y)&(Z)))
#define H(X,Y,Z) ((X)^(Y)^(Z))

#define LEFTROTATE(A,N) ((A)<<(N))|((A)>>(32-(N)))

#define MD4ROUND1(a,b,c,d,x,s) a += F(b,c,d) + x; a = LEFTROTATE(a, s);
#define MD4ROUND2(a,b,c,d,x,s) a += G(b,c,d) + x + (uint32_t)0x5A827999; a = LEFTROTATE(a, s);
#define MD4ROUND3(a,b,c,d,x,s) a += H(b,c,d) + x + (uint32_t)0x6ED9EBA1; a = LEFTROTATE(a, s);

static uint32_t A = 0x67452301;
static uint32_t B = 0xefcdab89;
static uint32_t C = 0x98badcfe;
static uint32_t D = 0x10325476;

string newString(char * c, int t){
	string r;
	int i;
	if(c!=NULL){
		r.len = (t<=0)?strlen(c):t;
		r.c=(char *)malloc(sizeof(char)*(r.len+1));
		for(i=0; i<r.len; i++) r.c[i]=c[i];
		r.c[r.len]='\0';
		return r;
	}
	r.len=t;
	r.c=(char *)malloc(sizeof(char)*(r.len+1));
	memset(r.c,(char)0,sizeof(char)*(t+1));
	r.sign = 1;
	return r;
}

string stringCat(string first, string second){
	string str=newString(NULL, first.len+second.len);
	int i;

	for(i=0; i<first.len; i++){
		str.c[i]=first.c[i];
	}
	for(i=first.len; i<str.len; i++){
		str.c[i]=second.c[i-first.len];
	}
	return str;
}

string base16Encode(string in){
	string out=newString(NULL, in.len*2);
	int i,j;

	j=0;
	for(i=0; i<in.len; i++){
		out.c[j++]=BASE16[((in.c[i] & 0xF0)>>4)];
		out.c[j++]=BASE16[(in.c[i] & 0x0F)];
	}
	out.c[j]='\0';
	return out;
}


string uint32ToString(uint32_t l){
	string s = newString(NULL,4);
	int i;
	for(i=0; i<4; i++){
		s.c[i] = (l >> (8*(3-i))) & 0xFF;
	}
	return s;
}

uint32_t stringToUint32(string s){
	uint32_t l;
	int i;
	l=0;
	for(i=0; i<4; i++){
		l = l|(((uint32_t)((unsigned char)s.c[i]))<<(8*(3-i)));
	}
	return l;
}

char *MD4(char *str, int len){
	string m=newString(str, len);
	string digest;
	uint32_t *w;
	uint32_t *hash;
	uint64_t mlen=m.len;
	unsigned char oneBit = 0x80;
	int i, wlen;


	m=stringCat(m, newString((char *)&oneBit,1));

	//append 0 ≤ k < 512 bits '0', such that the resulting message length in bits
	//	is congruent to −64 ≡ 448 (mod 512)4
	i=((56-m.len)%64);
	if(i<0) i+=64;
	m=stringCat(m,newString(NULL, i));

	w = malloc(sizeof(uint32_t)*(m.len/4+2));

	//append length, in bits (hence <<3), least significant word first
	for(i=0; i<m.len/4; i++){
		w[i]=stringToUint32(newString(&(m.c[4*i]), 4));
	}
	w[i++] = (mlen<<3) & 0xFFFFFFFF;
	w[i++] = (mlen>>29) & 0xFFFFFFFF;

	wlen=i;


	//change endianness, but not for the appended message length, for some reason?
	for(i=0; i<wlen-2; i++){
		w[i]=changeEndianness(w[i]);
	}

	hash = MD4Digest(w,wlen);

	digest=newString(NULL,0);
	for(i=0; i<4; i++){
		hash[i]=changeEndianness(hash[i]);
		digest=stringCat(digest,uint32ToString(hash[i]));
	}

	return base16Encode(digest).c;
}

uint32_t *MD4Digest(uint32_t *w, int len){
	//assumes message.len is a multiple of 64 bytes.
	int i,j;
	uint32_t X[16];
	uint32_t *digest = malloc(sizeof(uint32_t)*4);
	uint32_t AA, BB, CC, DD;

	for(i=0; i<len/16; i++){
		for(j=0; j<16; j++){
			X[j]=w[i*16+j];
		}

		AA=A;
		BB=B;
		CC=C;
		DD=D;

		MD4ROUND1(A,B,C,D,X[0],3);
		MD4ROUND1(D,A,B,C,X[1],7);
		MD4ROUND1(C,D,A,B,X[2],11);
		MD4ROUND1(B,C,D,A,X[3],19);
		MD4ROUND1(A,B,C,D,X[4],3);
		MD4ROUND1(D,A,B,C,X[5],7);
		MD4ROUND1(C,D,A,B,X[6],11);
		MD4ROUND1(B,C,D,A,X[7],19);
		MD4ROUND1(A,B,C,D,X[8],3);
		MD4ROUND1(D,A,B,C,X[9],7);
		MD4ROUND1(C,D,A,B,X[10],11);
		MD4ROUND1(B,C,D,A,X[11],19);
		MD4ROUND1(A,B,C,D,X[12],3);
		MD4ROUND1(D,A,B,C,X[13],7);
		MD4ROUND1(C,D,A,B,X[14],11);
		MD4ROUND1(B,C,D,A,X[15],19);

		MD4ROUND2(A,B,C,D,X[0],3);
		MD4ROUND2(D,A,B,C,X[4],5);
		MD4ROUND2(C,D,A,B,X[8],9);
		MD4ROUND2(B,C,D,A,X[12],13);
		MD4ROUND2(A,B,C,D,X[1],3);
		MD4ROUND2(D,A,B,C,X[5],5);
		MD4ROUND2(C,D,A,B,X[9],9);
		MD4ROUND2(B,C,D,A,X[13],13);
		MD4ROUND2(A,B,C,D,X[2],3);
		MD4ROUND2(D,A,B,C,X[6],5);
		MD4ROUND2(C,D,A,B,X[10],9);
		MD4ROUND2(B,C,D,A,X[14],13);
		MD4ROUND2(A,B,C,D,X[3],3);
		MD4ROUND2(D,A,B,C,X[7],5);
		MD4ROUND2(C,D,A,B,X[11],9);
		MD4ROUND2(B,C,D,A,X[15],13);

		MD4ROUND3(A,B,C,D,X[0],3);
		MD4ROUND3(D,A,B,C,X[8],9);
		MD4ROUND3(C,D,A,B,X[4],11);
		MD4ROUND3(B,C,D,A,X[12],15);
		MD4ROUND3(A,B,C,D,X[2],3);
		MD4ROUND3(D,A,B,C,X[10],9);
		MD4ROUND3(C,D,A,B,X[6],11);
		MD4ROUND3(B,C,D,A,X[14],15);
		MD4ROUND3(A,B,C,D,X[1],3);
		MD4ROUND3(D,A,B,C,X[9],9);
		MD4ROUND3(C,D,A,B,X[5],11);
		MD4ROUND3(B,C,D,A,X[13],15);
		MD4ROUND3(A,B,C,D,X[3],3);
		MD4ROUND3(D,A,B,C,X[11],9);
		MD4ROUND3(C,D,A,B,X[7],11);
		MD4ROUND3(B,C,D,A,X[15],15);

		A+=AA;
		B+=BB;
		C+=CC;
		D+=DD;
	}

	digest[0]=A;
	digest[1]=B;
	digest[2]=C;
	digest[3]=D;
	resetMD4Registers();
	return digest;
}

uint32_t changeEndianness(uint32_t x){
	return ((x & 0xFF) << 24) | ((x & 0xFF00) << 8) | ((x & 0xFF0000) >> 8) | ((x & 0xFF000000) >> 24);
}

void setMD4Registers(uint32_t AA, uint32_t BB, uint32_t CC, uint32_t DD){
	A=AA;
	B=BB;
	C=CC;
	D=DD;
}

void resetMD4Registers(void){
	setMD4Registers(0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476);
}
Output:
printf("%s\n", MD4("Rosetta Code", 12));
a52bcfc6a0d0d300cdc5ddbfbefe478b

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
static class Md4
{
    public static string Md4Hash(this string input)
    {
        // get padded uints from bytes
        List<byte> bytes = Encoding.ASCII.GetBytes(input).ToList();
        uint bitCount = (uint)(bytes.Count) * 8;
        bytes.Add(128);
        while (bytes.Count % 64 != 56) bytes.Add(0);
        var uints = new List<uint>();
        for (int i = 0; i + 3 < bytes.Count; i += 4)
            uints.Add(bytes[i] | (uint)bytes[i + 1] << 8 | (uint)bytes[i + 2] << 16 | (uint)bytes[i + 3] << 24);
        uints.Add(bitCount);
        uints.Add(0);

        // run rounds
        uint a = 0x67452301, b = 0xefcdab89, c = 0x98badcfe, d = 0x10325476;
        Func<uint, uint, uint> rol = (x, y) => x << (int)y | x >> 32 - (int)y;
        for (int q = 0; q + 15 < uints.Count; q += 16)
        {
            var chunk = uints.GetRange(q, 16);
            uint aa = a, bb = b, cc = c, dd = d;
            Action<Func<uint, uint, uint, uint>, uint[]> round = (f, y) =>
            {
                foreach (uint i in new[] { y[0], y[1], y[2], y[3] })
                {
                    a = rol(a + f(b, c, d) + chunk[(int)(i + y[4])] + y[12], y[8]);
                    d = rol(d + f(a, b, c) + chunk[(int)(i + y[5])] + y[12], y[9]);
                    c = rol(c + f(d, a, b) + chunk[(int)(i + y[6])] + y[12], y[10]);
                    b = rol(b + f(c, d, a) + chunk[(int)(i + y[7])] + y[12], y[11]);
                }
            };
            round((x, y, z) => (x & y) | (~x & z), new uint[] { 0, 4, 8, 12, 0, 1, 2, 3, 3, 7, 11, 19, 0 });
            round((x, y, z) => (x & y) | (x & z) | (y & z), new uint[] { 0, 1, 2, 3, 0, 4, 8, 12, 3, 5, 9, 13, 0x5a827999 });
            round((x, y, z) => x ^ y ^ z, new uint[] { 0, 2, 1, 3, 0, 8, 4, 12, 3, 9, 11, 15, 0x6ed9eba1 });
            a += aa; b += bb; c += cc; d += dd;
        }

        // return hex encoded string
        byte[] outBytes = new[] { a, b, c, d }.SelectMany(BitConverter.GetBytes).ToArray();
        return BitConverter.ToString(outBytes).Replace("-", "").ToLower();
    }
    static void Main() { Console.WriteLine("Rosetta Code".Md4Hash()); }
}
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

C++

#include <algorithm>
#include <cstdint>
#include <iomanip>
#include <iostream>
#include <string>
#include <vector>

class MD4 {
public:
	MD4() {
		engine_reset();
	}

	std::vector<int8_t> engine_digest(const std::string& text) {
		engine_update(string_to_byte_vector(text), 0, text.length());

		const int32_t buffer_index = static_cast<int32_t>(count % BLOCK_LENGTH);
		const int32_t padding_length = ( buffer_index < 56 ) ? 56 - buffer_index : 120 - buffer_index;

		std::vector<int8_t> tail(padding_length + 8, 0);
		tail[0] = static_cast<int8_t>(0x80);

		for ( int32_t i = 0; i < 8; ++i ) {
			tail[padding_length + i] = static_cast<int8_t>(unsigned_right_shift(count * 8, 8 * i));
		}

		engine_update(tail, 0, tail.size());

		std::vector<int8_t> result(16, 0);
		for ( int32_t i = 0; i < 4; ++i ) {
			for ( int32_t j = 0; j < 4; ++j ) {
				result[i * 4 + j] = static_cast<int8_t>(unsigned_right_shift(context[i], 8 * j));
			}
		}

		engine_reset();
		return result;
	}

private:
	void engine_update(const std::vector<int8_t>& message_bytes,
					   const int32_t& offset, const int32_t& message_length) {
		if ( offset < 0 || message_length < 0
			|| (int64_t) offset + message_length > (int64_t) message_bytes.size() ) {
			throw std::invalid_argument("Incorrect arguments for function engine_update");
		}

		int32_t buffer_index = static_cast<int32_t>(count % BLOCK_LENGTH);
		count += message_length;
		const int32_t partial_length = BLOCK_LENGTH - buffer_index;
		int32_t i = 0;

		if ( message_length >= partial_length ) {
			for ( int32_t j = 0; j < partial_length; ++j ) {
				buffer[buffer_index + j] = message_bytes[offset + j];
			}
			transform(buffer, 0);
			i = partial_length;
			while ( i + BLOCK_LENGTH - 1 < message_length ) {
				transform(message_bytes, offset + i);
				i += BLOCK_LENGTH;
			}
			buffer_index = 0;
		}

		if ( i < message_length ) {
			for ( int32_t j = 0; j < message_length - i; ++j ) {
				buffer[buffer_index + j] = message_bytes[offset + i + j];
			}
		}
	}

	void transform(const std::vector<int8_t>& buffer, int32_t offset) {
		for ( int32_t i = 0; i < 16; ++i ) {
			extra[i] = ( ( buffer[offset + 0] & 0xff )       ) |
					   ( ( buffer[offset + 1] & 0xff ) << 8  ) |
					   ( ( buffer[offset + 2] & 0xff ) << 16 ) |
					   ( ( buffer[offset + 3] & 0xff ) << 24 );
			offset += 4;
		}

		int32_t a = context[0];
		int32_t b = context[1];
		int32_t c = context[2];
		int32_t d = context[3];

		for ( const int32_t& i : { 0, 4, 8, 12 } ) {
			a = ff(a, b, c, d, extra[i + 0],  3);
			d = ff(d, a, b, c, extra[i + 1],  7);
			c = ff(c, d, a, b, extra[i + 2], 11);
			b = ff(b, c, d, a, extra[i + 3], 19);
		}

		for ( const int32_t& i : { 0, 1, 2, 3 } ) {
			a = gg(a, b, c, d, extra[i + 0],  3);
			d = gg(d, a, b, c, extra[i + 4],  5);
			c = gg(c, d, a, b, extra[i + 8],  9);
			b = gg(b, c, d, a, extra[i + 12], 13);
		}

		for ( const int32_t& i : { 0, 2, 1, 3 } ) {
			a = hh(a, b, c, d, extra[i + 0],  3);
			d = hh(d, a, b, c, extra[i + 8],  9);
			c = hh(c, d, a, b, extra[i + 4], 11);
			b = hh(b, c, d, a, extra[i + 12], 15);
		}

		context[0] += a;
		context[1] += b;
		context[2] += c;
		context[3] += d;
	}

	void engine_reset() {
		count = 0;
		context.assign(4, 0);
		context[0] = 0x67452301;
		context[1] = 0xefcdab89;
		context[2] = 0x98badcfe;
		context[3] = 0x10325476;
		extra.assign(16, 0);
		buffer.assign(BLOCK_LENGTH, 0);
	}

	std::vector<int8_t> string_to_byte_vector(const std::string& text) {
		std::vector<int8_t> bytes;
		bytes.reserve(text.size());

		std::transform(text.begin(), text.end(), std::back_inserter(bytes),
			[](char ch){ return static_cast<int8_t>(ch); });

		return bytes;
	}

	int32_t unsigned_right_shift(const int32_t& base, const int32_t& shift) {
		if ( shift < 0 || shift >= 32 || base == 0 ) {
			return 0;
		}
		return ( base > 0 ) ? base >> shift : static_cast<uint32_t>(base) >> shift;
	}

	int32_t rotate(const int32_t& t, const int32_t& s) {
		return ( t << s ) | unsigned_right_shift(t, 32 - s);
	}

	int32_t ff(const int32_t& a, const int32_t& b, const int32_t& c,
			   const int32_t& d, const int32_t& x, const int32_t& s) {
		return rotate(a + ( ( b & c ) | ( ~b & d ) ) + x, s);
	}

	int32_t gg(const int32_t& a, const int32_t& b, const int32_t& c,
			   const int32_t& d, const int32_t& x, const int32_t& s) {
		return rotate(a + ( ( b & ( c | d ) ) | ( c & d ) ) + x + 0x5A827999, s);
	}

	int32_t hh(const int32_t& a, const int32_t& b, const int32_t& c,
			   const int32_t& d, const int32_t& x, const int32_t& s) {
		return rotate(a + ( b ^ c ^ d ) + x + 0x6ED9EBA1, s);
	}

	uint64_t count;
    std::vector<int32_t> context;
    std::vector<int32_t> extra;
    std::vector<int8_t> buffer;

    const int32_t BLOCK_LENGTH = 64;
};

int main() {
	MD4 md4;
	std::vector<int8_t> result = md4.engine_digest("Rosetta Code");

	for ( const int8_t& bb : result ) {
		std::cout << std::hex << std::setfill('0') << std::setw(2) << ( bb & 0xff );
	}
	std::cout << std::endl;
}
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

Clojure

Library: pandect
(use 'pandect.core)
(md4 "Rosetta Code")
Output:
"a52bcfc6a0d0d300cdc5ddbfbefe478b"

Common Lisp

Library: Ironclad
(ql:quickload 'ironclad)
(defun md4 (str)                                           
  (ironclad:byte-array-to-hex-string
    (ironclad:digest-sequence :md4 
                              (ironclad:ascii-string-to-byte-array str))))

(md4 "Rosetta Code")
Output:
"a52bcfc6a0d0d300cdc5ddbfbefe478b"

D

A short but not efficient implementation.

Translation of: Ruby
import std.stdio, std.string, std.range;

ubyte[16] md4(const(ubyte)[] inData) pure nothrow {
    enum f = (uint x, uint y, uint z) => (x & y) | (~x & z);
    enum g = (uint x, uint y, uint z) => (x & y) | (x & z) | (y & z);
    enum h = (uint x, uint y, uint z) => x ^ y ^ z;
    enum r = (uint v, uint s) => (v << s) | (v >> (32 - s));

    immutable bitLen = ulong(inData.length) << 3;
    inData ~= 0x80;
    while (inData.length % 64 != 56)
        inData ~= 0;
    const data = cast(uint[])inData ~ [uint(bitLen & uint.max), uint(bitLen >> 32)];

    uint a = 0x67452301, b = 0xefcdab89, c = 0x98badcfe, d = 0x10325476;

    foreach (const x; data.chunks(16)) {
        immutable a2 = a, b2 = b, c2 = c, d2 = d;
        foreach (immutable i; [0, 4, 8, 12]) {
            a = r(a + f(b, c, d) + x[i+0],  3);
            d = r(d + f(a, b, c) + x[i+1],  7);
            c = r(c + f(d, a, b) + x[i+2], 11);
            b = r(b + f(c, d, a) + x[i+3], 19);
        }
        foreach (immutable i; [0, 1, 2, 3]) {
            a = r(a + g(b, c, d) + x[i+0] + 0x5a827999,  3);
            d = r(d + g(a, b, c) + x[i+4] + 0x5a827999,  5);
            c = r(c + g(d, a, b) + x[i+8] + 0x5a827999,  9);
            b = r(b + g(c, d, a) + x[i+12] + 0x5a827999, 13);
        }
        foreach (immutable i; [0, 2, 1, 3]) {
            a = r(a + h(b, c, d) + x[i+0] + 0x6ed9eba1,  3);
            d = r(d + h(a, b, c) + x[i+8] + 0x6ed9eba1,  9);
            c = r(c + h(d, a, b) + x[i+4] + 0x6ed9eba1, 11);
            b = r(b + h(c, d, a) + x[i+12] + 0x6ed9eba1, 15);
        }
        a += a2, b += b2, c += c2, d += d2;
    }

    //return cast(ubyte[16])[a, b, c, d];
    immutable uint[4] result = [a, b, c, d];
    return cast(ubyte[16])result;
}

void main() {
    writefln("%(%02x%)", "Rosetta Code".representation.md4);
}
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

Delphi

Library: DCPmd4

Thanks for David Barton for DCPcrypt v2.0 library, and StephenGenusa for store and share in github [1].

program CalcMD4;

{$APPTYPE CONSOLE}

uses
  System.SysUtils,
  DCPmd4;

function MD4(const Str: string): string;
var
  HashDigest: array of byte;
  d: Byte;
begin
  Result := '';
  with TDCP_md4.Create(nil) do
  begin
    Init;
    UpdateStr(Str);
    SetLength(HashDigest, GetHashSize div 8);
    final(HashDigest[0]);
    for d in HashDigest do
      Result := Result + d.ToHexString(2);
    Free;
  end;
end;

begin
  Writeln(MD4('Rosetta Code'));
  readln;
end.
Output:
A52BCFC6A0D0D300CDC5DDBFBEFE478B

Emacs Lisp

md4.el by Taro Kawagishi, originally from FLIM and included in recent Emacs, is an Elisp implementation of the MD4 algorithm. Its md4 function returns the checksum as 16 binary bytes. encode-hex-string from hex-util.el can convert that to a hex string if desired.

(require 'md4)
(require 'hex-util)
(let* ((s  "Rosetta Code")
       (m  (md4 s (length s)))) ;; m = 16 binary bytes
  (encode-hex-string m))
=>
"a52bcfc6a0d0d300cdc5ddbfbefe478b"

Erlang

-module(md4).
-export([md4/0]).

md4() ->
    <<MD4:128>> = crypto:md4("Rosetta Code"),
    io:fwrite("Rosetta Code => ~.16B~n",[MD4]).
Rosetta Code => A52BCFC6A0D0D300CDC5DDBFBEFE478B

Go

package main

import (
    "golang.org/x/crypto/md4"
    "fmt"
)

func main() {
    h := md4.New()
    h.Write([]byte("Rosetta Code"))
    fmt.Printf("%x\n", h.Sum(nil))
}
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

Haskell

Library: Cryptonite
#!/usr/bin/env runhaskell

import Data.ByteString.Char8 (pack)
import System.Environment (getArgs)
import Crypto.Hash

main :: IO ()
main = print . md4 . pack . unwords =<< getArgs
         where md4 x = hash x :: Digest MD4
Output:
$ ./md4.hs Rosetta Code
a52bcfc6a0d0d300cdc5ddbfbefe478b

J

   require 'ide/qt'
   gethash_jqtide_ 'MD4';'Rosetta Code'
a52bcfc6a0d0d300cdc5ddbfbefe478b

Java

Library: BouncyCastle
import org.bouncycastle.crypto.digests.MD4Digest;
import org.bouncycastle.util.encoders.Hex;

public class RosettaMD4
{
    public static void main (String[] argv) throws Exception
    {
        byte[] r = "Rosetta Code".getBytes("US-ASCII");
        MD4Digest d = new MD4Digest();
        d.update (r, 0, r.length);
        byte[] o = new byte[d.getDigestSize()];
        d.doFinal (o, 0);
        Hex.encode (o, System.out);
        System.out.println();
    }
}
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

Without external libraries

import java.util.Arrays;
import java.util.List;

public final class MD4Task {
	
	public static void main(String[] aArgs) {
		String text = "Rosetta Code";
	    
	    MD4 md4 = new MD4();	    
	    byte[] result = md4.engineDigest(text);
	   		
		StringBuilder stringBuilder = new StringBuilder();
	    for ( byte bb : result ) {
            stringBuilder.append(String.format("%02x", bb));
        }
        System.out.println(stringBuilder.toString());
	}
	
}
	
final class MD4 {
	
	public MD4() {
		engineReset();
	}	

	public byte[] engineDigest(String aText) {
		engineUpdate(aText.getBytes(), 0, aText.length());		
		
        final int bufferIndex = (int) ( count % BLOCK_LENGTH );
        final int paddingLength = ( bufferIndex < 56 ) ? 56 - bufferIndex : 120 - bufferIndex;

        byte[] tail = new byte[paddingLength + 8];
        tail[0] = (byte) 0x80;
        
        for ( int i = 0; i < 8; i++ ) {
            tail[paddingLength + i] = (byte) ( ( count * 8 ) >>> ( 8 * i ) );
        }
        
        engineUpdate(tail, 0, tail.length);

        byte[] result = new byte[16];
        for ( int i = 0; i < 4; i++ ) {
            for ( int j = 0; j < 4; j++ ) {
                result[i * 4 + j] = (byte) ( context[i] >>> ( 8 * j ) );
            }
        }

        engineReset();
        return result;
	}
	
	private void engineUpdate(byte[] aMessageBytes, int aOffset, int aMessageLength) {
        if ( aOffset < 0 || aMessageLength < 0 || (long) aOffset + aMessageLength > (long) aMessageBytes.length ) {
            throw new ArrayIndexOutOfBoundsException("Incorrect arguments for method engineUpdate");
        }
        
        int bufferIndex = (int) ( count % BLOCK_LENGTH );
        count += aMessageLength;                                    
        final int partialLength = BLOCK_LENGTH - bufferIndex;
        int i = 0;
        
        if ( aMessageLength >= partialLength ) {
            System.arraycopy(aMessageBytes, aOffset, buffer, bufferIndex, partialLength);
            transform(buffer, 0);	            
            i = partialLength;	            
            while ( i + BLOCK_LENGTH - 1 < aMessageLength ) {
                transform(aMessageBytes, aOffset + i);
                i += BLOCK_LENGTH;
            }
            bufferIndex = 0;
        }
        
        if ( i < aMessageLength ) {
        	System.arraycopy(aMessageBytes, aOffset + i, buffer, bufferIndex, aMessageLength - i);
        }
    }
	
	private void transform (byte[] aBuffer, int aOffset) {
        for ( int i = 0; i < 16; i++ ) { 
            extra[i] = ( ( aBuffer[aOffset++] & 0xff )       ) |
            		   ( ( aBuffer[aOffset++] & 0xff ) << 8  ) |
                       ( ( aBuffer[aOffset++] & 0xff ) << 16 ) |
                       ( ( aBuffer[aOffset++] & 0xff ) << 24 );
        }
        
        int a = context[0];
        int b = context[1];
        int c = context[2];
        int d = context[3];
        
        for ( int i : List.of( 0, 4, 8, 12 ) ) {
        	a = ff(a, b, c, d, extra[i + 0],  3);
	        d = ff(d, a, b, c, extra[i + 1],  7);
	        c = ff(c, d, a, b, extra[i + 2], 11);
	        b = ff(b, c, d, a, extra[i + 3], 19);
        }
        
        for ( int i : List.of( 0, 1, 2, 3 ) ) {
        	a = gg(a, b, c, d, extra[i + 0],  3);
 	        d = gg(d, a, b, c, extra[i + 4],  5);
 	        c = gg(c, d, a, b, extra[i + 8],  9);
 	        b = gg(b, c, d, a, extra[i + 12], 13);
        }
        
        for ( int i : List.of( 0, 2, 1, 3 ) ) {
        	a = hh(a, b, c, d, extra[i + 0],  3);
 	        d = hh(d, a, b, c, extra[i + 8],  9);
 	        c = hh(c, d, a, b, extra[i + 4], 11);
 	        b = hh(b, c, d, a, extra[i + 12], 15);
        }

        context[0] += a;
        context[1] += b;
        context[2] += c;
        context[3] += d;
    }
	
	private void engineReset() {
		count = 0;
        context[0] = 0x67452301;
        context[1] = 0xefcdab89; 
        context[2] = 0x98badcfe;
        context[3] = 0x10325476;
        Arrays.fill(extra, 0);
        Arrays.fill(buffer, (byte) 0);
    }
	
	private static int rotate(int t, int s) {
		return t << s | t >>> ( 32 - s );
	}
	
	private static int ff(int a, int b, int c, int d, int x, int s) {
	    return rotate(a + ( ( b & c ) | ( ~b & d ) ) + x, s);
	}
	
	private static int gg(int a, int b, int c, int d, int x, int s) {
	    return rotate(a + ( ( b & ( c | d ) ) | ( c & d ) ) + x + 0x5A827999, s);
	}
	
	private static int hh(int a, int b, int c, int d, int x, int s) {
	    return rotate(a + ( b ^ c ^ d ) + x + 0x6ED9EBA1, s);
	}
	
	private static final int BLOCK_LENGTH = 64;
	
	private long count;
    private int[] context = new int[4];	 	    
    private int[] extra = new int[16];	
    private byte[] buffer = new byte[BLOCK_LENGTH];

}
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

JavaScript

const md4func = () => {

  const hexcase = 0; /* hex output format. 0 - lowercase; 1 - uppercase    */
  const b64pad = ""; /* base-64 pad character. "=" for strict RFC compliance  */
  const chrsz = 8; /* bits per input character. 8 - ASCII; 16 - Unicode   */

  const tab = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  const hex_tab = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";

  /**
   * Add integers, wrapping at 2^32. This uses 16-bit operations internally
   * to work around bugs in some JS interpreters.
   */
  const safe_add = (x, y) => {
    const lsw = (x & 0xFFFF) + (y & 0xFFFF);
    const msw = (x >> 16) + (y >> 16) + (lsw >> 16);
    return (msw << 16) | (lsw & 0xFFFF);
  };

  /**
   * Bitwise rotate a 32-bit number to the left.
   */
  const rol = (num, cnt) => (num << cnt) | (num >>> (32 - cnt));

  /**
   * Convert a string to an array of little-endian words
   * If chrsz is ASCII, characters >255 have their hi-byte silently ignored.
   */
  const str2binl = str => {
    const bin = Array();
    const mask = (1 << chrsz) - 1;
    for (let i = 0; i < str.length * chrsz; i += chrsz)
      bin[i >> 5] |= (str.charCodeAt(i / chrsz) & mask) << (i % 32);
    return bin;
  };

  /**
   * Convert an array of little-endian words to a string
   */
  const binl2str = bin => {
    let str = "";
    const mask = (1 << chrsz) - 1;
    for (let i = 0; i < bin.length * 32; i += chrsz)
      str += String.fromCharCode((bin[i >> 5] >>> (i % 32)) & mask);
    return str;
  };

  /**
   * Convert an array of little-endian words to a hex string.
   */
  const binl2hex = binarray => {
    let str = "";
    for (let i = 0; i < binarray.length * 4; i++) {
      str += hex_tab.charAt((binarray[i >> 2] >> ((i % 4) * 8 + 4)) & 0xF) +
          hex_tab.charAt((binarray[i >> 2] >> ((i % 4) * 8)) & 0xF);
    }
    return str;
  };

  /**
   * Convert an array of little-endian words to a base-64 string
   */
  const binl2b64 = binarray => {
    let str = "";
    for (let i = 0; i < binarray.length * 4; i += 3) {
      const triplet = (((binarray[i >> 2] >> 8 * (i % 4)) & 0xFF) << 16)
          | (((binarray[i + 1 >> 2] >> 8 * ((i + 1) % 4)) & 0xFF) << 8)
          | ((binarray[i + 2 >> 2] >> 8 * ((i + 2) % 4)) & 0xFF);
      for (let j = 0; j < 4; j++) {
        if (i * 8 + j * 6 > binarray.length * 32) str += b64pad;
        else str += tab.charAt((triplet >> 6 * (3 - j)) & 0x3F);
      }
    }
    return str;
  };


  /**
   * Calculate the MD4 of an array of little-endian words, and a bit length
   */
  const core_md4 = (x, len) => {

    x[len >> 5] |= 0x80 << (len % 32);
    x[(((len + 64) >>> 9) << 4) + 14] = len;
    let a = 1732584193;
    let b = -271733879;
    let c = -1732584194;
    let d = 271733878;

    for (let i = 0; i < x.length; i += 16) {

      const olda = a;
      const oldb = b;
      const oldc = c;
      const oldd = d;

      a = md4_ff(a, b, c, d, x[i], 3);
      d = md4_ff(d, a, b, c, x[i + 1], 7);
      c = md4_ff(c, d, a, b, x[i + 2], 11);
      b = md4_ff(b, c, d, a, x[i + 3], 19);
      a = md4_ff(a, b, c, d, x[i + 4], 3);
      d = md4_ff(d, a, b, c, x[i + 5], 7);
      c = md4_ff(c, d, a, b, x[i + 6], 11);
      b = md4_ff(b, c, d, a, x[i + 7], 19);
      a = md4_ff(a, b, c, d, x[i + 8], 3);
      d = md4_ff(d, a, b, c, x[i + 9], 7);
      c = md4_ff(c, d, a, b, x[i + 10], 11);
      b = md4_ff(b, c, d, a, x[i + 11], 19);
      a = md4_ff(a, b, c, d, x[i + 12], 3);
      d = md4_ff(d, a, b, c, x[i + 13], 7);
      c = md4_ff(c, d, a, b, x[i + 14], 11);
      b = md4_ff(b, c, d, a, x[i + 15], 19);

      a = md4_gg(a, b, c, d, x[i], 3);
      d = md4_gg(d, a, b, c, x[i + 4], 5);
      c = md4_gg(c, d, a, b, x[i + 8], 9);
      b = md4_gg(b, c, d, a, x[i + 12], 13);
      a = md4_gg(a, b, c, d, x[i + 1], 3);
      d = md4_gg(d, a, b, c, x[i + 5], 5);
      c = md4_gg(c, d, a, b, x[i + 9], 9);
      b = md4_gg(b, c, d, a, x[i + 13], 13);
      a = md4_gg(a, b, c, d, x[i + 2], 3);
      d = md4_gg(d, a, b, c, x[i + 6], 5);
      c = md4_gg(c, d, a, b, x[i + 10], 9);
      b = md4_gg(b, c, d, a, x[i + 14], 13);
      a = md4_gg(a, b, c, d, x[i + 3], 3);
      d = md4_gg(d, a, b, c, x[i + 7], 5);
      c = md4_gg(c, d, a, b, x[i + 11], 9);
      b = md4_gg(b, c, d, a, x[i + 15], 13);

      a = md4_hh(a, b, c, d, x[i], 3);
      d = md4_hh(d, a, b, c, x[i + 8], 9);
      c = md4_hh(c, d, a, b, x[i + 4], 11);
      b = md4_hh(b, c, d, a, x[i + 12], 15);
      a = md4_hh(a, b, c, d, x[i + 2], 3);
      d = md4_hh(d, a, b, c, x[i + 10], 9);
      c = md4_hh(c, d, a, b, x[i + 6], 11);
      b = md4_hh(b, c, d, a, x[i + 14], 15);
      a = md4_hh(a, b, c, d, x[i + 1], 3);
      d = md4_hh(d, a, b, c, x[i + 9], 9);
      c = md4_hh(c, d, a, b, x[i + 5], 11);
      b = md4_hh(b, c, d, a, x[i + 13], 15);
      a = md4_hh(a, b, c, d, x[i + 3], 3);
      d = md4_hh(d, a, b, c, x[i + 11], 9);
      c = md4_hh(c, d, a, b, x[i + 7], 11);
      b = md4_hh(b, c, d, a, x[i + 15], 15);

      a = safe_add(a, olda);
      b = safe_add(b, oldb);
      c = safe_add(c, oldc);
      d = safe_add(d, oldd);
    }

    return Array(a, b, c, d);

  };

  /**
   * These functions implement the basic operation for each round of the
   * algorithm.
   */
  const md4_cmn = (q, a, b, x, s, t) => safe_add(
      rol(safe_add(safe_add(a, q), safe_add(x, t)), s), b);

  const md4_ff = (a, b, c, d, x, s) => md4_cmn(
      (b & c) | ((~b) & d), a, 0, x, s, 0);

  const md4_gg = (a, b, c, d, x, s) => md4_cmn(
      (b & c) | (b & d) | (c & d), a, 0, x, s, 1518500249);

  const md4_hh = (a, b, c, d, x, s) => md4_cmn(
      b ^ c ^ d, a, 0, x, s, 1859775393);

  /**
   * Calculate the HMAC-MD4, of a key and some data
   */
  const core_hmac_md4 = (key, data) => {

    let bkey = str2binl(key);
    if (bkey.length > 16) {
      bkey = core_md4(bkey, key.length * chrsz)
    }

    const ipad = Array(16);
    const opad = Array(16);

    for (let i = 0; i < 16; i++) {
      ipad[i] = bkey[i] ^ 0x36363636;
      opad[i] = bkey[i] ^ 0x5C5C5C5C;
    }
    const hash = core_md4(
        ipad.concat(str2binl(data)), 512 + data.length * chrsz);

    return core_md4(opad.concat(hash), 512 + 128);
  };

  /**
   * These are the functions you'll usually want to call
   */
  return {
    hex_md4: s => binl2hex(core_md4(str2binl(s), s.length * chrsz)),
    b64_md4: s => binl2b64(core_md4(str2binl(s), s.length * chrsz)),
    str_md4: s => binl2str(core_md4(str2binl(s), s.length * chrsz)),
    hex_hmac_md4: (key, data) => binl2hex(core_hmac_md4(key, data)),
    b64_hmac_md4: (key, data) => binl2b64(core_hmac_md4(key, data)),
    str_hmac_md4: (key, data) => binl2str(core_hmac_md4(key, data)),
  };

};

const md4 = md4func();
console.log(md4.hex_md4('Rosetta Code'));
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

Julia

Nettle.jl provides a variety of cryptographic functions including the MD4 hash.

using Nettle

msg = "Rosetta Code"

h = HashState(MD4)
update!(h, msg)
h = hexdigest!(h)

println("\"", msg, "\" => ", h)
Output:
"Rosetta Code" => a52bcfc6a0d0d300cdc5ddbfbefe478b

Kotlin

This is a translation of the Java code here. In the interests of conciseness, I have removed the comments from the Kotlin version:

// version 1.0.6

import java.security.MessageDigest

class MD4() : MessageDigest("MD4"), Cloneable {
    private val blockLength = 64
    private var context = IntArray(4)
    private var count = 0L
    private var buffer = ByteArray(blockLength)
    private var x = IntArray(16)
  
    init {
        engineReset()
    }

    private constructor(md: MD4): this() {
        context = md.context.clone()
        buffer = md.buffer.clone()
        count = md.count
    } 

    override fun clone(): Any = MD4(this)

    override fun engineReset() {
        context[0] = 0x67452301
        context[1] = 0xefcdab89.toInt() 
        context[2] = 0x98badcfe.toInt()
        context[3] = 0x10325476
        count = 0L
        for (i in 0 until blockLength) buffer[i] = 0
    }

    override fun engineUpdate(b: Byte) {
        val i = (count % blockLength).toInt()
        count++                                 
        buffer[i] = b
        if (i == blockLength - 1) transform(buffer, 0)
    }

    override fun engineUpdate(input: ByteArray, offset: Int, len: Int) {
        if (offset < 0 || len < 0 || offset.toLong() + len > input.size.toLong())
            throw ArrayIndexOutOfBoundsException()
        var bufferNdx = (count % blockLength).toInt()
        count += len                                    
        val partLen = blockLength - bufferNdx
        var i = 0
        if (len >= partLen) {
            System.arraycopy(input, offset, buffer, bufferNdx, partLen)
            transform(buffer, 0)
            i = partLen
            while (i + blockLength - 1 < len) {
                transform(input, offset + i)
                i += blockLength
            }
            bufferNdx = 0
        }
        if (i < len) System.arraycopy(input, offset + i, buffer, bufferNdx, len - i)
    }

    override fun engineDigest(): ByteArray {
        val bufferNdx = (count % blockLength).toInt()
        val padLen = if (bufferNdx < 56) 56 - bufferNdx else 120 - bufferNdx
        val tail = ByteArray(padLen + 8)
        tail[0] = 0x80.toByte()
        for (i in 0..7) tail[padLen + i] = ((count * 8) ushr (8 * i)).toByte()
        engineUpdate(tail, 0, tail.size)
        val result = ByteArray(16)
        for (i in 0..3)
            for (j in 0..3)
                result[i * 4 + j] = (context[i] ushr (8 * j)).toByte()
        engineReset()
        return result
    }

    private fun transform (block: ByteArray, offset: Int) {
        var offset2 = offset
        for (i in 0..15) 
            x[i] = ((block[offset2++].toInt() and 0xff)       ) or
                   ((block[offset2++].toInt() and 0xff) shl 8 ) or
                   ((block[offset2++].toInt() and 0xff) shl 16) or
                   ((block[offset2++].toInt() and 0xff) shl 24)

        var a = context[0]
        var b = context[1]
        var c = context[2]
        var d = context[3]

        a = ff(a, b, c, d, x[ 0],  3)
        d = ff(d, a, b, c, x[ 1],  7)
        c = ff(c, d, a, b, x[ 2], 11)
        b = ff(b, c, d, a, x[ 3], 19)
        a = ff(a, b, c, d, x[ 4],  3)
        d = ff(d, a, b, c, x[ 5],  7)
        c = ff(c, d, a, b, x[ 6], 11)
        b = ff(b, c, d, a, x[ 7], 19)
        a = ff(a, b, c, d, x[ 8],  3)
        d = ff(d, a, b, c, x[ 9],  7)
        c = ff(c, d, a, b, x[10], 11)
        b = ff(b, c, d, a, x[11], 19)
        a = ff(a, b, c, d, x[12],  3)
        d = ff(d, a, b, c, x[13],  7)
        c = ff(c, d, a, b, x[14], 11)
        b = ff(b, c, d, a, x[15], 19)

        a = gg(a, b, c, d, x[ 0],  3)
        d = gg(d, a, b, c, x[ 4],  5)
        c = gg(c, d, a, b, x[ 8],  9)
        b = gg(b, c, d, a, x[12], 13)
        a = gg(a, b, c, d, x[ 1],  3)
        d = gg(d, a, b, c, x[ 5],  5)
        c = gg(c, d, a, b, x[ 9],  9)
        b = gg(b, c, d, a, x[13], 13)
        a = gg(a, b, c, d, x[ 2],  3)
        d = gg(d, a, b, c, x[ 6],  5)
        c = gg(c, d, a, b, x[10],  9)
        b = gg(b, c, d, a, x[14], 13)
        a = gg(a, b, c, d, x[ 3],  3)
        d = gg(d, a, b, c, x[ 7],  5)
        c = gg(c, d, a, b, x[11],  9)
        b = gg(b, c, d, a, x[15], 13)

        a = hh(a, b, c, d, x[ 0],  3)
        d = hh(d, a, b, c, x[ 8],  9)
        c = hh(c, d, a, b, x[ 4], 11)
        b = hh(b, c, d, a, x[12], 15)
        a = hh(a, b, c, d, x[ 2],  3)
        d = hh(d, a, b, c, x[10],  9)
        c = hh(c, d, a, b, x[ 6], 11)
        b = hh(b, c, d, a, x[14], 15)
        a = hh(a, b, c, d, x[ 1],  3)
        d = hh(d, a, b, c, x[ 9],  9)
        c = hh(c, d, a, b, x[ 5], 11)
        b = hh(b, c, d, a, x[13], 15)
        a = hh(a, b, c, d, x[ 3],  3)
        d = hh(d, a, b, c, x[11],  9)
        c = hh(c, d, a, b, x[ 7], 11)
        b = hh(b, c, d, a, x[15], 15)

        context[0] += a
        context[1] += b
        context[2] += c
        context[3] += d
    }

    private fun ff(a: Int, b: Int, c: Int, d: Int, x: Int, s: Int): Int {
        val t = a + ((b and c) or (b.inv() and d)) + x
        return (t shl s) or (t ushr (32 - s))
    }

    private fun gg(a: Int, b: Int, c: Int, d: Int, x: Int, s: Int): Int {
        val t = a + ((b and (c or d)) or (c and d)) + x + 0x5a827999
        return (t shl s) or (t ushr (32 - s))
    }

    private fun hh(a: Int, b: Int, c: Int, d: Int, x: Int, s: Int): Int {
        val t = a + (b xor c xor d) + x + 0x6ed9eba1 
        return (t shl s) or (t ushr (32 - s))
    }
} 

fun main(args: Array<String>) {
    val text  = "Rosetta Code"
    val bytes = text.toByteArray(Charsets.US_ASCII)
    val md: MessageDigest = MD4()
    val digest = md.digest(bytes)
    for (byte in digest) print("%02x".format(byte))
    println() 
}
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

Lasso

cipher_digest('Rosetta Code', -digest='MD4')->encodeHex->asString
Output:
 A52BCFC6A0D0D300CDC5DDBFBEFE478B 

Lua

Works with: Lua 5.1.4
Library: LuaCrypto

(luarocks install LuaCrypto)

#!/usr/bin/lua

require "crypto"

print(crypto.digest("MD4", "Rosetta Code"))
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

Mathematica /Wolfram Language

Hash["Rosetta Code", "MD4", "HexString"]
a52bcfc6a0d0d300cdc5ddbfbefe478b

Nim

Library: OpenSSL
import strutils

const MD4Len = 16

proc MD4(d: cstring, n: culong, md: cstring = nil): cstring {.cdecl, dynlib: "libssl.so", importc.}

proc MD4(s: string): string =
  result = ""
  var s = MD4(s.cstring, s.len.culong)
  for i in 0 ..< MD4Len:
    result.add s[i].BiggestInt.toHex(2).toLower

echo MD4("Rosetta Code")
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

PARI/GP

Build a MD4 plugin using Linux system library and PARI's function interface. (Linux solution)

#include <pari/pari.h>
#include <openssl/md4.h>

#define HEX(x)  (((x) < 10)? (x)+'0': (x)-10+'a')

/*
 * PARI/GP func: MD4 hash
 *
 * gp code: install("plug_md4", "s", "MD4", "<library path>");
 */
GEN plug_md4(char *text)
{
  char md[MD4_DIGEST_LENGTH];
  char hash[sizeof(md) * 2 + 1];
  int i;

  MD4((unsigned char*)text, strlen(text), (unsigned char*)md);

  for (i = 0; i < sizeof(md); i++) {
    hash[i+i]   = HEX((md[i] >> 4) & 0x0f);
    hash[i+i+1] = HEX(md[i] & 0x0f);
  }

  hash[sizeof(md) * 2] = 0;

  return strtoGENstr(hash);
}

Compile with: gcc -Wall -O2 -fPIC -shared md4.c -o libmd4.so -lcrypt -lpari

Load plugin from your home directory into PARI:

install("plug_md4", "s", "MD4", "~/libmd4.so");

MD4("Rosetta Code")

Output: "a52bcfc6a0d0d300cdc5ddbfbefe478b"

Perl

In-lining code from module Digest::Perl::MD4, lightly edited for clarity.

sub md4 :prototype(@) {
    my @input = grep { defined && length > 0 } split /(.{64})/s, join '', @_;
    push @input, '' if !@input || length($input[$#input]) >= 56;

    my @A = (0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476); # initial regs
    my @T = (0, 0x5A827999, 0x6ED9EBA1);
    my @L = qw(3 7 11 19 3 5 9 13 3 9 11 15);   # left rotate counts
    my @O = (1, 4, 4,                           # x stride for input index
             4, 1, 1,                           # y stride for input index
             0, 0, 1);                          # bitwise reverse both indexes
    my @I = map {
                    my $z   = int $_/16;
                    my $x   = $_%4;
                    my $y   = int $_%16/4;
                    ($x,$y) = (R($x),R($y)) if $O[6+$z];
                    $O[$z] * $x + $O[3+$z] * $y
                } 0..47;

    my ($a,$b,$c,$d);
    my($l,$p) = (0,0);
    foreach (@input) {
        my $r = length($_);
        $l += $r;
        $r++, $_.="\x80" if $r<64 && !$p++;
        my @W = unpack 'V16', $_ . "\0"x7;
        push @W, (0)x16 if @W < 16;
        $W[14] = $l*8 if $r < 57;              # add bit-length in low 32-bits
        ($a,$b,$c,$d) = @A;
        for (0..47) {
            my $z = int $_/16;
            $a = L($L[4*($_>>4) + $_%4],
                 M(&{(sub{$b&$c|~$b&$d},       # F
                      sub{$b&$c|$b&$d|$c&$d},  # G
                      sub{$b^$c^$d}            # H
                     )[$z]}
                   + $a + $W[$I[$_]] + $T[$z]));
            ($a,$b,$c,$d) = ($d,$a,$b,$c);
        }
        my @v = ($a, $b, $c, $d);
        $A[$_] = M($A[$_] + $v[$_]) for 0..3;
    }
    pack 'V4', @A;
}

sub L { # left-rotate
    my ($n, $x) = @_;
    $x<<$n | 2**$n - 1 & $x>>(32-$n);
}

sub M { # mod 2**32
    no integer;
    my ($x) = @_;
    my $m = 1+0xffffffff;
    $x - $m * int $x/$m;
}

sub R { # reverse two bit number
    my $n = pop;
    ($n&1)*2 + ($n&2)/2;
}

sub md4_hex :prototype(@) { # convert to hexadecimal
  unpack 'H*', &md4;
}

print "Rosetta Code => " . md4_hex( "Rosetta Code" ) . "\n";
Output:
Rosetta Code => a52bcfc6a0d0d300cdc5ddbfbefe478b

Phix

Translation of: D
Translation of: Ruby
--
-- demo\rosetta\md4.exw
-- ====================
--
-- Non-optimised. If there is a genuine need for something faster, I can give #ilASM a bash.
-- MD4 is an obsolete hash function that computes a 128-bit message digest that sometimes appears in obsolete protocols.
-- Even the replacement, MD5 is now considered severly comprimised.
--
without js -- (allocate/poke/peek)
function r32(atom a)
    if a<0 then a+=#100000000 end if
    return remainder(a,#100000000)
end function

function rol(atom word, integer bits)
-- left rotate the bits of a 32-bit number by the specified number of bits
    word = r32(word)    -- trim to a 32-bit uint again
    return r32(word*power(2,bits))+floor(word/power(2,32-bits))
end function

function f(atom x,y,z)
    return or_bits(and_bits(x,y),and_bits(not_bits(x),z))
end function

function g(atom x,y,z)
    return or_all({r32(and_bits(x,y)),and_bits(x,z),and_bits(y,z)})
end function

function h(atom x,y,z)
    return xor_bits(r32(xor_bits(x,y)),z)
end function

function md4(sequence data)
    integer bytes_to_add = 64-remainder(length(data)+9,64)
    if bytes_to_add=64 then bytes_to_add = 0 end if
    data = data&#80&repeat(0,bytes_to_add)&
           int_to_bytes(length(data)*8,8)
 
    atom a = 0x67452301, b = 0xefcdab89, c = 0x98badcfe, d = 0x10325476
 
    atom m64 = allocate(64,true)
    integer i
    for x=1 to length(data)-1 by 64 do
        poke(m64,data[x..x+63])
        sequence z = peek4u({m64,16})
        atom a2 = a, b2 = b, c2 = c, d2 = d
        for i=0 to 12 by 4 do
            a = rol(a + f(b, c, d) + z[i+1],  3)
            d = rol(d + f(a, b, c) + z[i+2],  7)
            c = rol(c + f(d, a, b) + z[i+3], 11)
            b = rol(b + f(c, d, a) + z[i+4], 19)
        end for
        for i=1 to 4 do
            a = rol(a + g(b, c, d) + z[i+0]  + 0x5a827999,  3)
            d = rol(d + g(a, b, c) + z[i+4]  + 0x5a827999,  5)
            c = rol(c + g(d, a, b) + z[i+8]  + 0x5a827999,  9)
            b = rol(b + g(c, d, a) + z[i+12] + 0x5a827999, 13)
        end for
        for j=1 to 4 do
            i = {1, 3, 2, 4}[j]
            a = rol(a + h(b, c, d) + z[i+0]  + 0x6ed9eba1,  3)
            d = rol(d + h(a, b, c) + z[i+8]  + 0x6ed9eba1,  9)
            c = rol(c + h(d, a, b) + z[i+4]  + 0x6ed9eba1, 11)
            b = rol(b + h(c, d, a) + z[i+12] + 0x6ed9eba1, 15)
        end for
        a = r32(a+a2)
        b = r32(b+b2)
        c = r32(c+c2)
        d = r32(d+d2)
    end for
    poke4(m64,{a,b,c,d})
    return peek({m64,16})
end function 

function hexify(sequence s)
    for i=1 to length(s) do
        s[i] = sprintf("%02X",s[i])
    end for
    return join(s,"")
end function

?hexify(md4("Rosetta Code"))

{} = wait_key()
Output:
"a52bcfc6a0d0d300cdc5ddbfbefe478b"

PHP

echo hash('md4', "Rosetta Code"), "\n";
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

PicoLisp

Library and implementation.

(de *Md4-W .
   (1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16
   1  5  9 13  2  6 10 14  3  7 11 15  4  8 12 16
   1  9  5 13  3 11  7 15  2 10  6 14  4 12  8 16 .))
(de *Md4-R1 . (3  7 11 19 .))
(de *Md4-R2 . (3  5  9 13 .))
(de *Md4-R3 . (3  9 11 15 .))

(de mod32 (N)
   (& N `(hex "FFFFFFFF")) )
 
(de not32 (N)
   (x| N `(hex "FFFFFFFF")) )
 
(de add32 @
   (mod32 (pass +)) )
   
(de leftRotate (X C)
   (| (mod32 (>> (- C) X)) (>> (- 32 C) X)) )
   
(de md4 (Str)
   (let Len (length Str)
      (setq Str
         (conc
            (need
               (- 8 (* 64 (/ (+ Len 1 8 63) 64)))  # Pad to 64-8 bytes
               (conc
                  (mapcar char (chop Str))   # Works only with ASCII characters
                  (cons `(hex "80")) )       # '1' bit
               0 )                           # Pad with '0'
            (make
               (setq Len (* 8 Len))
               (do 8
                  (link (& Len 255))
                  (setq Len (>> 8 Len )) ) ) ) ) )
   (let
      (H0 `(hex "67452301")
         H1 `(hex "EFCDAB89")
         H2 `(hex "98BADCFE")
         H3 `(hex "10325476") 
         R2 `(hex "5A827999")
         R3 `(hex "6ED9EBA1") )
      (while Str
         (let
            (A H0  B H1  C H2  D H3
               W (make
                    (do 16
                       (link
                          (apply |
                          (mapcar >> (0 -8 -16 -24) (cut 4 'Str)) ) ) ) ) )
            (for I 12
               (cond
                  ((>= 4 I)
                     (setq
                        A (leftRotate
                             (add32
                                A
                                (| (& B C) (& (not32 B) D))
                                (get W (pop '*Md4-W)) )
                             (pop '*Md4-R1) )
                        D (leftRotate
                             (add32
                                D
                                (| (& A B) (& (not32 A) C))
                                (get W (pop '*Md4-W)) )
                             (pop '*Md4-R1) )
                        C (leftRotate
                             (add32
                                C
                                (| (& D A) (& (not32 D) B))
                                (get W (pop '*Md4-W)) )
                             (pop '*Md4-R1) )
                        B (leftRotate
                             (add32
                                B
                                (| (& C D) (& (not32 C) A))
                                (get W (pop '*Md4-W)) )
                             (pop '*Md4-R1) ) ) )
                  ((>= 8 I)
                     (setq
                        A (leftRotate
                             (add32 
                                A
                                (|
                                   (& B (| C D))
                                   (& C D) )
                                (get W (pop '*Md4-W))
                                R2 )
                             (pop '*Md4-R2) )
                        D (leftRotate
                             (add32
                                D
                                (|
                                   (& A (| B C))
                                   (& B C) )
                                (get W (pop '*Md4-W))
                                R2 )       
                             (pop '*Md4-R2) )
                        C (leftRotate
                             (add32 
                                C
                                (|
                                   (& D (| A B))
                                   (& A B) ) 
                                (get W (pop '*Md4-W))
                                R2 )
                             (pop '*Md4-R2) )
                        B (leftRotate
                             (add32 
                                B
                                (|
                                   (& C (| D A))
                                   (& D A) )
                                (get W (pop '*Md4-W))
                                R2 )
                             (pop '*Md4-R2) ) ) )
                  (T
                     (setq
                        A (leftRotate
                             (add32
                                A
                                (x| B C D)
                                (get W (pop '*Md4-W))
                                R3 )
                             (pop '*Md4-R3) )
                        D (leftRotate
                             (add32
                                D
                                (x| A B C)
                                (get W (pop '*Md4-W))
                                R3 )
                             (pop '*Md4-R3) )
                        C (leftRotate
                             (add32
                                C
                                (x| D A B)
                                (get W (pop '*Md4-W))
                                R3 )
                             (pop '*Md4-R3) )
                        B (leftRotate
                             (add32 
                                B
                                (x| C D A)
                                (get W (pop '*Md4-W))
                                R3 )
                             (pop '*Md4-R3) ) ) ) ) )
               (setq
                  H0 (add32 H0 A)
                  H1 (add32 H1 B)
                  H2 (add32 H2 C)
                  H3 (add32 H3 D) ) ) )
      (make
         (for N (list H0 H1 H2 H3)
            (do 4
               (link (& N 255))
               (setq N (>> 8 N)) ) ) ) ) )
  
(let Str "Rosetta Code" 
   (println
      (pack
         (mapcar
            '((B) (pad 2 (hex B)))
            (md4 Str) ) ) )
   (println
      (pack
         (mapcar
            '((B) (pad 2 (hex B)))
            (native 
               "libcrypto.so"
               "MD4"
               '(B . 16)
               Str
               (length Str)
               '(NIL (16)) ) ) ) ) )

(bye)

Python

Depending on how your python was compiled, 'hashlib' from python's standard library may provide md4 hashing.

Library: hashlib
import hashlib
print hashlib.new("md4",raw_input().encode('utf-16le')).hexdigest().upper()

Racket

#lang racket
(require (planet soegaard/digest:1:2/digest))
(md4 #"Rosetta Code")
Output:
"a52bcfc6a0d0d300cdc5ddbfbefe478b"

Raku

(formerly Perl 6)

sub md4($str) {
    my buf8 $buf .= new: $str.encode;
    my $buf-length = $buf.elems;
    $buf.push: 0x80;
    $buf.push: 0 until ($buf - (448 div 8)) %% (512 div 8);
    # raku serializes in little endian by default
    $buf.write-uint64: $buf.elems, $buf-length*8;

    my (&f, &g, &h, &r) = 
      { $^x +& $^y +| +^$x +& $^z },
      { $^x +& $^y +| $x +& $^z +| $y +& $z },
      { $^x +^ $^y +^ $^z },
      # for some reason we have to type v here
      -> uint32 $v, $s { $v +< $s +| $v +> (32 - $s) }

    my uint32 ($a, $b, $c, $d) = 0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476;
 
    loop (my $pos = 0; $pos < $buf.elems; $pos+=64) {
        my ($aa, $bb, $cc, $dd) = $a, $b, $c, $d;
        for 0, 4, 8, 12 -> $i {
            $a = r($a + f($b, $c, $d) + $buf.read-uint32($pos+($i+0)*4),  3);
            $d = r($d + f($a, $b, $c) + $buf.read-uint32($pos+($i+1)*4),  7);
            $c = r($c + f($d, $a, $b) + $buf.read-uint32($pos+($i+2)*4), 11);
            $b = r($b + f($c, $d, $a) + $buf.read-uint32($pos+($i+3)*4), 19);
        }
        for 0, 1, 2, 3 -> $i {
            $a = r($a + g($b, $c, $d) + $buf.read-uint32($pos+($i+0 )*4) + 0x5a827999,  3);
            $d = r($d + g($a, $b, $c) + $buf.read-uint32($pos+($i+4 )*4) + 0x5a827999,  5);
            $c = r($c + g($d, $a, $b) + $buf.read-uint32($pos+($i+8 )*4) + 0x5a827999,  9);
            $b = r($b + g($c, $d, $a) + $buf.read-uint32($pos+($i+12)*4) + 0x5a827999, 13);
        }
        for 0, 2, 1, 3 -> $i {
            $a = r($a + h($b, $c, $d) + $buf.read-uint32($pos+($i+0 )*4) + 0x6ed9eba1,  3);
            $d = r($d + h($a, $b, $c) + $buf.read-uint32($pos+($i+4 )*4) + 0x6ed9eba1,  9);
            $c = r($c + h($d, $a, $b) + $buf.read-uint32($pos+($i+8 )*4) + 0x6ed9eba1, 11);
            $b = r($b + h($c, $d, $a) + $buf.read-uint32($pos+($i+12)*4) + 0x6ed9eba1, 15);
        }
        ($a,$b,$c,$d) Z[+=] ($aa,$bb,$cc,$dd);
    }
 
    reduce { $^buf.write-uint32: $buf.elems, $^x; $buf }, buf8.new, $a, $b, $c, $d; 
}
 
CHECK {
  use Test;
  plan 1;
  is md4('Rosetta Code').list.fmt('%02X'), 'A5 2B CF C6 A0 D0 D3 00 CD C5 DD BF BE FE 47 8B';
}
Output:
1..1
ok 1 - 

Ruby

Use 'openssl' from Ruby's standard library.

Library: OpenSSL
require 'openssl'
puts OpenSSL::Digest::MD4.hexdigest('Rosetta Code')

Implement MD4 in Ruby.

require 'stringio'

# Calculates MD4 message digest of _string_. Returns binary digest.
# For hexadecimal digest, use +*md4(str).unpack('H*')+.
def md4(string)
  # functions
  mask = (1 << 32) - 1
  f = proc {|x, y, z| x & y | x.^(mask) & z}
  g = proc {|x, y, z| x & y | x & z | y & z}
  h = proc {|x, y, z| x ^ y ^ z}
  r = proc {|v, s| (v << s).&(mask) | (v.&(mask) >> (32 - s))}
 
  # initial hash
  a, b, c, d = 0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476
 
  bit_len = string.size << 3
  string += "\x80"
  while (string.size % 64) != 56
    string += "\0"
  end
  string = string.force_encoding('ascii-8bit') + [bit_len & mask, bit_len >> 32].pack("V2")
 
  if string.size % 64 != 0
    fail "failed to pad to correct length"
  end
 
  io = StringIO.new(string)
  block = ""
 
  while io.read(64, block)
    x = block.unpack("V16")
    
    # Process this block.
    aa, bb, cc, dd = a, b, c, d
    [0, 4, 8, 12].each {|i|
      a = r[a + f[b, c, d] + x[i],  3]; i += 1
      d = r[d + f[a, b, c] + x[i],  7]; i += 1
      c = r[c + f[d, a, b] + x[i], 11]; i += 1
      b = r[b + f[c, d, a] + x[i], 19]
    }
    [0, 1, 2, 3].each {|i|
      a = r[a + g[b, c, d] + x[i] + 0x5a827999,  3]; i += 4
      d = r[d + g[a, b, c] + x[i] + 0x5a827999,  5]; i += 4
      c = r[c + g[d, a, b] + x[i] + 0x5a827999,  9]; i += 4
      b = r[b + g[c, d, a] + x[i] + 0x5a827999, 13]
    }
    [0, 2, 1, 3].each {|i|
      a = r[a + h[b, c, d] + x[i] + 0x6ed9eba1,  3]; i += 8
      d = r[d + h[a, b, c] + x[i] + 0x6ed9eba1,  9]; i -= 4
      c = r[c + h[d, a, b] + x[i] + 0x6ed9eba1, 11]; i += 8
      b = r[b + h[c, d, a] + x[i] + 0x6ed9eba1, 15]
    }
    a = (a + aa) & mask
    b = (b + bb) & mask
    c = (c + cc) & mask
    d = (d + dd) & mask
  end
 
  [a, b, c, d].pack("V4")
end

if __FILE__ == $0
  # Print an example MD4 digest.
  str = 'Rosetta Code'
  printf "%s:\n  %s\n", str, *md4(str).unpack('H*')
end
Output:
Rosetta Code:
  a52bcfc6a0d0d300cdc5ddbfbefe478b

Rust

// MD4, based on RFC 1186 and RFC 1320.
//
// https://www.ietf.org/rfc/rfc1186.txt
// https://tools.ietf.org/html/rfc1320
//

use std::fmt::Write;
use std::mem;

// Let not(X) denote the bit-wise complement of X.
// Let X v Y denote the bit-wise OR of X and Y.
// Let X xor Y denote the bit-wise XOR of X and Y.
// Let XY denote the bit-wise AND of X and Y.

// f(X,Y,Z)  =  XY v not(X)Z
fn f(x: u32, y: u32, z: u32) -> u32 {
    (x & y) | (!x & z)
}

// g(X,Y,Z)  =  XY v XZ v YZ
fn g(x: u32, y: u32, z: u32) -> u32 {
    (x & y) | (x & z) | (y & z)
}

// h(X,Y,Z)  =  X xor Y xor Z
fn h(x: u32, y: u32, z: u32) -> u32 {
    x ^ y ^ z
}

// Round 1 macro
// Let [A B C D i s] denote the operation
//   A = (A + f(B,C,D) + X[i]) <<< s
macro_rules! md4round1 {
    ( $a:expr, $b:expr, $c:expr, $d:expr, $i:expr, $s:expr, $x:expr) => {
        {
            // Rust defaults to non-overflowing arithmetic, so we need to specify wrapping add.
            $a = ($a.wrapping_add( f($b, $c, $d) ).wrapping_add( $x[$i] ) ).rotate_left($s);
        }
    };
}

// Round 2 macro
// Let [A B C D i s] denote the operation
//   A = (A + g(B,C,D) + X[i] + 5A827999) <<< s .
macro_rules! md4round2 {
    ( $a:expr, $b:expr, $c:expr, $d:expr, $i:expr, $s:expr, $x:expr) => {
        {
            $a = ($a.wrapping_add( g($b, $c, $d)).wrapping_add($x[$i]).wrapping_add(0x5a827999_u32)).rotate_left($s);
        }
    };
}

// Round 3 macro
// Let [A B C D i s] denote the operation
//   A = (A + h(B,C,D) + X[i] + 6ED9EBA1) <<< s .
macro_rules! md4round3 {
    ( $a:expr, $b:expr, $c:expr, $d:expr, $i:expr, $s:expr, $x:expr) => {
        {
            $a = ($a.wrapping_add(h($b, $c, $d)).wrapping_add($x[$i]).wrapping_add(0x6ed9eba1_u32)).rotate_left($s);
        }
    };
}

fn convert_byte_vec_to_u32(mut bytes: Vec<u8>) -> Vec<u32> {

    bytes.shrink_to_fit();
    let num_bytes = bytes.len();
    let num_words = num_bytes / 4;
    unsafe {
        let words = Vec::from_raw_parts(bytes.as_mut_ptr() as *mut u32, num_words, num_words);
        mem::forget(bytes);
        words
    }
}

// Returns a 128-bit MD4 hash as an array of four 32-bit words.
// Based on RFC 1186 from https://www.ietf.org/rfc/rfc1186.txt
fn md4<T: Into<Vec<u8>>>(input: T) -> [u32; 4] {

    let mut bytes = input.into().to_vec();
    let initial_bit_len = (bytes.len() << 3) as u64;

    // Step 1. Append padding bits
    // Append one '1' bit, then append 0 ≤ k < 512 bits '0', such that the resulting message
    // length in bis is congruent to 448 (mod 512).
    // Since our message is in bytes, we use one byte with a set high-order bit (0x80) plus
    // a variable number of zero bytes.

    // Append zeros
    // Number of padding bytes needed is 448 bits (56 bytes) modulo 512 bits (64 bytes)
    bytes.push(0x80_u8);
    while (bytes.len() % 64) != 56 {
        bytes.push(0_u8);
    }

    // Everything after this operates on 32-bit words, so reinterpret the buffer.
    let mut w = convert_byte_vec_to_u32(bytes);

    // Step 2. Append length
    // A 64-bit representation of b (the length of the message before the padding bits were added)
    // is appended to the result of the previous step, low-order bytes first.
    w.push(initial_bit_len as u32); // Push low-order bytes first
    w.push((initial_bit_len >> 32) as u32);

    // Step 3. Initialize MD buffer
    let mut a = 0x67452301_u32;
    let mut b = 0xefcdab89_u32;
    let mut c = 0x98badcfe_u32;
    let mut d = 0x10325476_u32;

    // Step 4. Process message in 16-word blocks
    let n = w.len();
    for i in 0..n / 16 {

        // Select the next 512-bit (16-word) block to process.
        let x = &w[i * 16..i * 16 + 16];

        let aa = a;
        let bb = b;
        let cc = c;
        let dd = d;

        // [Round 1]
        md4round1!(a, b, c, d, 0, 3, x);  // [A B C D 0 3]
        md4round1!(d, a, b, c, 1, 7, x);  // [D A B C 1 7]
        md4round1!(c, d, a, b, 2, 11, x); // [C D A B 2 11]
        md4round1!(b, c, d, a, 3, 19, x); // [B C D A 3 19]
        md4round1!(a, b, c, d, 4, 3, x);  // [A B C D 4 3]
        md4round1!(d, a, b, c, 5, 7, x);  // [D A B C 5 7]
        md4round1!(c, d, a, b, 6, 11, x); // [C D A B 6 11]
        md4round1!(b, c, d, a, 7, 19, x); // [B C D A 7 19]
        md4round1!(a, b, c, d, 8, 3, x);  // [A B C D 8 3]
        md4round1!(d, a, b, c, 9, 7, x);  // [D A B C 9 7]
        md4round1!(c, d, a, b, 10, 11, x);// [C D A B 10 11]
        md4round1!(b, c, d, a, 11, 19, x);// [B C D A 11 19]
        md4round1!(a, b, c, d, 12, 3, x); // [A B C D 12 3]
        md4round1!(d, a, b, c, 13, 7, x); // [D A B C 13 7]
        md4round1!(c, d, a, b, 14, 11, x);// [C D A B 14 11]
        md4round1!(b, c, d, a, 15, 19, x);// [B C D A 15 19]

        // [Round 2]
        md4round2!(a, b, c, d, 0, 3, x);  //[A B C D 0  3]
        md4round2!(d, a, b, c, 4, 5, x);  //[D A B C 4  5]
        md4round2!(c, d, a, b, 8, 9, x);  //[C D A B 8  9]
        md4round2!(b, c, d, a, 12, 13, x);//[B C D A 12 13]
        md4round2!(a, b, c, d, 1, 3, x);  //[A B C D 1  3]
        md4round2!(d, a, b, c, 5, 5, x);  //[D A B C 5  5]
        md4round2!(c, d, a, b, 9, 9, x);  //[C D A B 9  9]
        md4round2!(b, c, d, a, 13, 13, x);//[B C D A 13 13]
        md4round2!(a, b, c, d, 2, 3, x);  //[A B C D 2  3]
        md4round2!(d, a, b, c, 6, 5, x);  //[D A B C 6  5]
        md4round2!(c, d, a, b, 10, 9, x); //[C D A B 10 9]
        md4round2!(b, c, d, a, 14, 13, x);//[B C D A 14 13]
        md4round2!(a, b, c, d, 3, 3, x);  //[A B C D 3  3]
        md4round2!(d, a, b, c, 7, 5, x);  //[D A B C 7  5]
        md4round2!(c, d, a, b, 11, 9, x); //[C D A B 11 9]
        md4round2!(b, c, d, a, 15, 13, x);//[B C D A 15 13]

        // [Round 3]
        md4round3!(a, b, c, d, 0, 3, x);  //[A B C D 0  3]
        md4round3!(d, a, b, c, 8, 9, x);  //[D A B C 8  9]
        md4round3!(c, d, a, b, 4, 11, x); //[C D A B 4  11]
        md4round3!(b, c, d, a, 12, 15, x);//[B C D A 12 15]
        md4round3!(a, b, c, d, 2, 3, x);  //[A B C D 2  3]
        md4round3!(d, a, b, c, 10, 9, x); //[D A B C 10 9]
        md4round3!(c, d, a, b, 6, 11, x); //[C D A B 6  11]
        md4round3!(b, c, d, a, 14, 15, x);//[B C D A 14 15]
        md4round3!(a, b, c, d, 1, 3, x);  //[A B C D 1  3]
        md4round3!(d, a, b, c, 9, 9, x);  //[D A B C 9  9]
        md4round3!(c, d, a, b, 5, 11, x); //[C D A B 5  11]
        md4round3!(b, c, d, a, 13, 15, x);//[B C D A 13 15]
        md4round3!(a, b, c, d, 3, 3, x);  //[A B C D 3  3]
        md4round3!(d, a, b, c, 11, 9, x); //[D A B C 11 9]
        md4round3!(c, d, a, b, 7, 11, x); //[C D A B 7  11]
        md4round3!(b, c, d, a, 15, 15, x);//[B C D A 15 15]

        a = a.wrapping_add(aa);
        b = b.wrapping_add(bb);
        c = c.wrapping_add(cc);
        d = d.wrapping_add(dd);
    }

    // Step 5. Output
    // The message digest produced as output is A, B, C, D. That is, we begin with the low-order
    // byte of A, and end with the high-order byte of D.
    [u32::from_be(a), u32::from_be(b), u32::from_be(c), u32::from_be(d)]
}

fn digest_to_str(digest: &[u32]) -> String {
    let mut s = String::new();
    for &word in digest {
        write!(&mut s, "{:08x}", word).unwrap();
    }
    s
}

fn main() {
    let val = "Rosetta Code";
    println!("md4(\"{}\") = {}", val, digest_to_str(&md4(val)));
}
Output:
md4("Rosetta Code") = a52bcfc6a0d0d300cdc5ddbfbefe478b

Scala

Library: Scala
import org.bouncycastle.crypto.digests.MD4Digest

object RosettaRIPEMD160 extends App {
  val (raw, messageDigest) = ("Rosetta Code".getBytes("US-ASCII"), new MD4Digest())
  messageDigest.update(raw, 0, raw.length)
  val out = Array.fill[Byte](messageDigest.getDigestSize())(0)
  messageDigest.doFinal(out, 0)

  assert(out.map("%02x".format(_)).mkString == "a52bcfc6a0d0d300cdc5ddbfbefe478b")
  import scala.compat.Platform.currentTime
  println(s"Successfully completed without errors. [total ${currentTime - executionStart} ms]")
}

Seed7

$ include "seed7_05.s7i";
  include "msgdigest.s7i";

const proc: main is func
  begin
    writeln(hex(md4("Rosetta Code")));
  end func;
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

Sidef

Translation of: Perl
var digest = frequire('Digest::MD4');
say digest.md4_hex('Rosetta Code');
Output:
a52bcfc6a0d0d300cdc5ddbfbefe478b

Tcl

Library: Tcllib (Package: md4)
package require md4

# Use -hex option for hexadecimal output instead of binary
puts [md4::md4 -hex "Rosetta Code"]
Output:
A52BCFC6A0D0D300CDC5DDBFBEFE478B

Wren

Translation of: D
Library: Wren-fmt
import "./fmt" for Fmt

var toBytes = Fn.new { |val|
    var bytes = List.filled(4, 0)
    bytes[0] = val         & 255
    bytes[1] = (val >> 8)  & 255
    bytes[2] = (val >> 16) & 255
    bytes[3] = (val >> 24) & 255
    return bytes
}

var toInt = Fn.new { |bytes| bytes[0] | bytes[1] << 8 | bytes[2] << 16 | bytes[3] << 24 }

var md4 = Fn.new { |initMsg|
    var f = Fn.new { |x, y, z| (x & y) | (~x & z) }
    var g = Fn.new { |x, y, z| (x & y) | (x & z) | (y & z) }
    var h = Fn.new { |x, y, z| x ^ y ^ z }
    var r = Fn.new { |v, s| (v << s) | (v >> (32 - s)) }

    var a = 0x67452301
    var b = 0xefcdab89
    var c = 0x98badcfe
    var d = 0x10325476
    var initBytes = initMsg.bytes
    var initLen = initBytes.count
    var newLen = initLen + 1
    while (newLen % 64 != 56) newLen = newLen + 1
    var msg = List.filled(newLen + 8, 0)
    for (i in 0...initLen) msg[i] = initBytes[i]
    msg[initLen] = 0x80 // remaining bytes already 0
    var lenBits = toBytes.call(initLen * 8)
    for (i in newLen...newLen+4) msg[i] = lenBits[i-newLen]
    var extraBits = toBytes.call(initLen >> 29)
    for (i in newLen+4...newLen+8) msg[i] = extraBits[i-newLen-4]
    var offset = 0
    var x = List.filled(16, 0)
    while (offset < newLen) {
        for (i in 0...16) x[i] = toInt.call(msg[offset+i*4...offset + i*4 + 4])
        var a2 = a
        var b2 = b
        var c2 = c
        var d2 = d
        for (i in [0, 4, 8, 12]) {
            a = r.call(a + f.call(b, c, d) + x[i+0],  3)
            d = r.call(d + f.call(a, b, c) + x[i+1],  7)
            c = r.call(c + f.call(d, a, b) + x[i+2], 11)
            b = r.call(b + f.call(c, d, a) + x[i+3], 19)
        }
        for (i in 0..3) {
            a = r.call(a + g.call(b, c, d) + x[i+0]  + 0x5a827999,  3)
            d = r.call(d + g.call(a, b, c) + x[i+4]  + 0x5a827999,  5)
            c = r.call(c + g.call(d, a, b) + x[i+8]  + 0x5a827999,  9)
            b = r.call(b + g.call(c, d, a) + x[i+12] + 0x5a827999, 13)
        }
        for (i in [0, 2, 1, 3]) {
            a = r.call(a + h.call(b, c, d) + x[i+0]  + 0x6ed9eba1,  3)
            d = r.call(d + h.call(a, b, c) + x[i+8]  + 0x6ed9eba1,  9)
            c = r.call(c + h.call(d, a, b) + x[i+4]  + 0x6ed9eba1, 11)
            b = r.call(b + h.call(c, d, a) + x[i+12] + 0x6ed9eba1, 15)
        }
        a = a + a2
        b = b + b2
        c = c + c2
        d = d + d2
        offset = offset + 64
    }
    var digest = List.filled(16, 0)
    var dBytes = toBytes.call(a)
    for (i in 0...4) digest[i] = dBytes[i]
    dBytes = toBytes.call(b)
    for (i in 0...4) digest[i+4] = dBytes[i]
    dBytes = toBytes.call(c)
    for (i in 0...4) digest[i+8] = dBytes[i]
    dBytes = toBytes.call(d)
    for (i in 0...4) digest[i+12] = dBytes[i]
    return digest
}

var strings = [
    "",
    "a",
    "abc",
    "message digest",
    "abcdefghijklmnopqrstuvwxyz",
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",
    "12345678901234567890123456789012345678901234567890123456789012345678901234567890",
    "Rosetta Code"
]

for (s in strings) {
    var digest = md4.call(s)
    Fmt.print("$s <== '$0s'", Fmt.v("xz", 2, digest, 0, "", ""), s)
}
Output:
31d6cfe0d16ae931b73c59d7e0c089c0 <== ''
bde52cb31de33e46245e05fbdbd6fb24 <== 'a'
a448017aaf21d8525fc10ae87aa6729d <== 'abc'
d9130a8164549fe818874806e1c7014b <== 'message digest'
d79e1c308aa5bbcdeea8ed63df412da9 <== 'abcdefghijklmnopqrstuvwxyz'
043f8582f241db351ce627e153e7f0e4 <== 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'
e33b4ddc9c38f2199c3e7b164fcc0536 <== '12345678901234567890123456789012345678901234567890123456789012345678901234567890'
a52bcfc6a0d0d300cdc5ddbfbefe478b <== 'Rosetta Code'