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MD5.pas – 一个Delphi下的MD5算法的实现

2011年4月19日  4,262 views 发表评论 阅读评论

MD5是现在常用的加密算法,可用在程序密码加密上,在注册表或者文件中保存用户密码的MD5值,可以检验用户输入密码的正确性。或者为了程序的安全性,不被别人修改文件,可以对自己的文件进行MD5验证。总之,MD5加密算法是一种十分有用的算法。

通常,我们不关心MD5算法实现的具体过程……我们要的是可以执行的函数,为了节省开发周期,你懂得~下文列出了一个可以直接使用的MD5算法文件的Delphi版本,以后有时间会再转载一些其他语言的版本。

代码如下:

unit MD5;
interface
uses
    SysUtils;
const
    MD5Version         = 102;
    CopyRight : String = ' MD5 Message-Digest (c) 97-98 F. Piette V1.02 ';

{$Q-}
{$R-}

type
    TMD5Context = record
        State: array[0..3] of LongInt;
        Count: array[0..1] of LongInt;
        case Integer of
        0: (BufChar: array[0..63] of Byte);
        1: (BufLong: array[0..15] of LongInt);
    end;
    TMD5Digest = array[0..15] of Char;

procedure MD5Init(var MD5Context: TMD5Context);
procedure MD5Update(var MD5Context: TMD5Context;
                    const Data;
                    Len: Integer);
procedure MD5Transform(var Buf: array of LongInt;
                       const Data: array of LongInt);
procedure MD5UpdateBuffer(var MD5Context: TMD5Context;
                          Buffer: Pointer;
                          BufSize: Integer);
procedure MD5Final(var Digest: TMD5Digest; var MD5Context: TMD5Context);

function GetMD5(Buffer: Pointer; BufSize: Integer): string;
function StrMD5(Buffer : String): string;

implementation

const
    MaxBufSize = 16384;

type
    PMD5Buffer = ^TMD5Buffer;
    TMD5Buffer = array[0..(MaxBufSize - 1)] of Char;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
{ MD5 initialization. Begins an MD5 operation, writing a new context.         }
procedure MD5Init(var MD5Context: TMD5Context);
begin
    FillChar(MD5Context, SizeOf(TMD5Context), #0);
    with MD5Context do begin
        { Load magic initialization constants. }
        State[0] := LongInt($67452301);
        State[1] := LongInt($EFCDAB89);
        State[2] := LongInt($98BADCFE);
        State[3] := LongInt($10325476);
    end
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
{ MD5 block update operation. Continues an MD5 message-digest operation,      }
{ processing another message block, and updating the context.                 }
procedure MD5Update(
    var MD5Context: TMD5Context;            { Context                         }
    const Data;                             { Input block                     }
    Len: Integer);                          { Length of input block           }
type
    TByteArray = array[0..0] of Byte;
var
    Index: Word;
    T: LongInt;
begin
    with MD5Context do begin
        T := Count[0];
        Inc(Count[0], LongInt(Len) shl 3);
        if Count[0] < T then
            Inc(Count[1]);
        Inc(Count[1], Len shr 29);
        T := (T shr 3) and $3F;
        Index := 0;
        if T <> 0 then begin
            Index := T;
            T := 64 - T;
            if Len < T then begin
                Move(Data, BufChar[Index], Len);
                Exit;
            end;
            Move(Data, BufChar[Index], T);
            MD5Transform(State, BufLong);
            Dec(Len, T);
            Index := T; { Wolfgang Klein, 05/06/99 }
        end;
        while Len >= 64 do begin
            Move(TByteArray(Data)[Index], BufChar, 64);
            MD5Transform(State, BufLong);
            Inc(Index, 64);
            Dec(Len, 64);
        end;
        Move(TByteArray(Data)[Index], BufChar, Len);
    end
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
{ MD5 finalization. Ends an MD5 message-digest operation, writing the message }
{ digest and zeroizing the context.                                           }
procedure MD5Final(var Digest: TMD5Digest; var MD5Context: TMD5Context);
var
    Cnt : Word;
    P   : Byte;
begin
    with MD5Context do begin
        Cnt := (Count[0] shr 3) and $3F;
        P := Cnt;
        BufChar[P] := $80;
        Inc(P);
        Cnt := 64 - 1 - Cnt;
        if Cnt < 8 then begin
            FillChar(BufChar[P], Cnt, #0);
            MD5Transform(State, BufLong);
            FillChar(BufChar, 56, #0);
        end
        else
            FillChar(BufChar[P], Cnt - 8, #0);
        BufLong[14] := Count[0];
        BufLong[15] := Count[1];
        MD5Transform(State, BufLong);
        Move(State, Digest, 16)
    end;
    FillChar(MD5Context, SizeOf(TMD5Context), #0)
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
{ MD5 basic transformation. Transforms state based on block.                  }
procedure MD5Transform(
    var Buf: array of LongInt;
    const Data: array of LongInt);
var
    A, B, C, D: LongInt;

    procedure Round1(var W: LongInt; X, Y, Z, Data: LongInt; S: Byte);
    begin
        Inc(W, (Z xor (X and (Y xor Z))) + Data);
        W := (W shl S) or (W shr (32 - S));
        Inc(W, X)
    end;

    procedure Round2(var W: LongInt; X, Y, Z, Data: LongInt; S: Byte);
    begin
        Inc(W, (Y xor (Z and (X xor Y))) + Data);
        W := (W shl S) or (W shr (32 - S));
        Inc(W, X)
    end;

    procedure Round3(var W: LongInt; X, Y, Z, Data: LongInt; S: Byte);
    begin
        Inc(W, (X xor Y xor Z) + Data);
        W := (W shl S) or (W shr (32 - S));
        Inc(W, X)
    end;

    procedure Round4(var W: LongInt; X, Y, Z, Data: LongInt; S: Byte);
    begin
        Inc(W, (Y xor (X or not Z)) + Data);
        W := (W shl S) or (W shr (32 - S));
        Inc(W, X)
    end;
begin
    A := Buf[0];
    B := Buf[1];
    C := Buf[2];
    D := Buf[3];

    Round1(A, B, C, D, Data[ 0] + LongInt($d76aa478), 7);
    Round1(D, A, B, C, Data[ 1] + LongInt($e8c7b756), 12);
    Round1(C, D, A, B, Data[ 2] + LongInt($242070db), 17);
    Round1(B, C, D, A, Data[ 3] + LongInt($c1bdceee), 22);
    Round1(A, B, C, D, Data[ 4] + LongInt($f57c0faf), 7);
    Round1(D, A, B, C, Data[ 5] + LongInt($4787c62a), 12);
    Round1(C, D, A, B, Data[ 6] + LongInt($a8304613), 17);
    Round1(B, C, D, A, Data[ 7] + LongInt($fd469501), 22);
    Round1(A, B, C, D, Data[ 8] + LongInt($698098d8), 7);
    Round1(D, A, B, C, Data[ 9] + LongInt($8b44f7af), 12);
    Round1(C, D, A, B, Data[10] + LongInt($ffff5bb1), 17);
    Round1(B, C, D, A, Data[11] + LongInt($895cd7be), 22);
    Round1(A, B, C, D, Data[12] + LongInt($6b901122), 7);
    Round1(D, A, B, C, Data[13] + LongInt($fd987193), 12);
    Round1(C, D, A, B, Data[14] + LongInt($a679438e), 17);
    Round1(B, C, D, A, Data[15] + LongInt($49b40821), 22);

    Round2(A, B, C, D, Data[ 1] + LongInt($f61e2562), 5);
    Round2(D, A, B, C, Data[ 6] + LongInt($c040b340), 9);
    Round2(C, D, A, B, Data[11] + LongInt($265e5a51), 14);
    Round2(B, C, D, A, Data[ 0] + LongInt($e9b6c7aa), 20);
    Round2(A, B, C, D, Data[ 5] + LongInt($d62f105d), 5);
    Round2(D, A, B, C, Data[10] + LongInt($02441453), 9);
    Round2(C, D, A, B, Data[15] + LongInt($d8a1e681), 14);
    Round2(B, C, D, A, Data[ 4] + LongInt($e7d3fbc8), 20);
    Round2(A, B, C, D, Data[ 9] + LongInt($21e1cde6), 5);
    Round2(D, A, B, C, Data[14] + LongInt($c33707d6), 9);
    Round2(C, D, A, B, Data[ 3] + LongInt($f4d50d87), 14);
    Round2(B, C, D, A, Data[ 8] + LongInt($455a14ed), 20);
    Round2(A, B, C, D, Data[13] + LongInt($a9e3e905), 5);
    Round2(D, A, B, C, Data[ 2] + LongInt($fcefa3f8), 9);
    Round2(C, D, A, B, Data[ 7] + LongInt($676f02d9), 14);
    Round2(B, C, D, A, Data[12] + LongInt($8d2a4c8a), 20);

    Round3(A, B, C, D, Data[ 5] + LongInt($fffa3942), 4);
    Round3(D, A, B, C, Data[ 8] + LongInt($8771f681), 11);
    Round3(C, D, A, B, Data[11] + LongInt($6d9d6122), 16);
    Round3(B, C, D, A, Data[14] + LongInt($fde5380c), 23);
    Round3(A, B, C, D, Data[ 1] + LongInt($a4beea44), 4);
    Round3(D, A, B, C, Data[ 4] + LongInt($4bdecfa9), 11);
    Round3(C, D, A, B, Data[ 7] + LongInt($f6bb4b60), 16);
    Round3(B, C, D, A, Data[10] + LongInt($bebfbc70), 23);
    Round3(A, B, C, D, Data[13] + LongInt($289b7ec6), 4);
    Round3(D, A, B, C, Data[ 0] + LongInt($eaa127fa), 11);
    Round3(C, D, A, B, Data[ 3] + LongInt($d4ef3085), 16);
    Round3(B, C, D, A, Data[ 6] + LongInt($04881d05), 23);
    Round3(A, B, C, D, Data[ 9] + LongInt($d9d4d039), 4);
    Round3(D, A, B, C, Data[12] + LongInt($e6db99e5), 11);
    Round3(C, D, A, B, Data[15] + LongInt($1fa27cf8), 16);
    Round3(B, C, D, A, Data[ 2] + LongInt($c4ac5665), 23);

    Round4(A, B, C, D, Data[ 0] + LongInt($f4292244), 6);
    Round4(D, A, B, C, Data[ 7] + LongInt($432aff97), 10);
    Round4(C, D, A, B, Data[14] + LongInt($ab9423a7), 15);
    Round4(B, C, D, A, Data[ 5] + LongInt($fc93a039), 21);
    Round4(A, B, C, D, Data[12] + LongInt($655b59c3), 6);
    Round4(D, A, B, C, Data[ 3] + LongInt($8f0ccc92), 10);
    Round4(C, D, A, B, Data[10] + LongInt($ffeff47d), 15);
    Round4(B, C, D, A, Data[ 1] + LongInt($85845dd1), 21);
    Round4(A, B, C, D, Data[ 8] + LongInt($6fa87e4f), 6);
    Round4(D, A, B, C, Data[15] + LongInt($fe2ce6e0), 10);
    Round4(C, D, A, B, Data[ 6] + LongInt($a3014314), 15);
    Round4(B, C, D, A, Data[13] + LongInt($4e0811a1), 21);
    Round4(A, B, C, D, Data[ 4] + LongInt($f7537e82), 6);
    Round4(D, A, B, C, Data[11] + LongInt($bd3af235), 10);
    Round4(C, D, A, B, Data[ 2] + LongInt($2ad7d2bb), 15);
    Round4(B, C, D, A, Data[ 9] + LongInt($eb86d391), 21);

    Inc(Buf[0], A);
    Inc(Buf[1], B);
    Inc(Buf[2], C);
    Inc(Buf[3], D);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
procedure MD5UpdateBuffer(
    var MD5Context: TMD5Context;
    Buffer: Pointer;
    BufSize: Integer);
var
    BufTmp : PMD5Buffer;
    BufPtr : PChar;
    Bytes : Word;
begin
    New(BufTmp);
    BufPtr := Buffer;
    try
        repeat
            if BufSize > MaxBufSize then
                Bytes := MaxBufSize
            else
                Bytes := BufSize;
            Move(BufPtr^, BufTmp^, Bytes);
            Inc(BufPtr, Bytes);
            Dec(BufSize, Bytes);
            if Bytes > 0 then
                MD5Update(MD5Context, BufTmp^, Bytes);
        until Bytes < MaxBufSize;
    finally
        Dispose(BufTmp);
    end;
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
function GetMD5(Buffer: Pointer; BufSize: Integer): string;
var
    I          : Integer;
    MD5Digest : TMD5Digest;
    MD5Context : TMD5Context;
begin
    for I := 0 to 15 do
        Byte(MD5Digest[I]) := I + 1;
    MD5Init(MD5Context);
    MD5UpdateBuffer(MD5Context, Buffer, BufSize);
    MD5Final(MD5Digest, MD5Context);
    Result := '';
    for I := 0 to 15 do
        Result := Result + IntToHex(Byte(MD5Digest[I]), 2);
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}
function StrMD5(Buffer : String): string;
begin
    Result := GetMD5(@Buffer[1], Length(Buffer));
end;


{* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *}

end.
  


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    • 你难道没有试过点击一下【一个Delphi下的MD5算法的实现】这行字么……这源码太长了,不折叠这页太长。