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tianxing78
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关于md5，请教一下md5对一字符串加密后，是不是一个长度为32的16进制码？比如我对1进行加密后的字符串为c4ca4238a0b923820dcc509a6f75849b，是不是这个字符串中永远不会出现像g,h,i,j,k等一类的代码？只会是数字及abcdef？下面是我用的delphi的md5源程序：unit md5;// ----------------------------------------------------------------------------------------------- INTERFACE // ----------------------------------------------------------------------------------------------- usesWindows; type MD5Count = array[0..1] of DWORD; MD5State = array[0..3] of DWORD; MD5Block = array[0..15] of DWORD; MD5CBits = array[0..7] of byte; MD5Digest = array[0..15] of byte; MD5Buffer = array[0..63] of byte; MD5Context = record State: MD5State; Count: MD5Count; Buffer: MD5Buffer; end; procedure MD5Init(var Context: MD5Context); procedure MD5Update(var Context: MD5Context; Input: pChar; Length: longword); procedure MD5Final(var Context: MD5Context; var Digest: MD5Digest); function MD5String(M: string): MD5Digest; function MD5File(N: string): MD5Digest; function MD5Print(D: MD5Digest): string; function MD5Match(D1, D2: MD5Digest): boolean; // ----------------------------------------------------------------------------------------------- IMPLEMENTATION // ----------------------------------------------------------------------------------------------- var PADDING: MD5Buffer = ( $80, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00, $00 ); function F(x, y, z: DWORD): DWORD; begin Result := (x and y) or ((not x) and z); end; function G(x, y, z: DWORD): DWORD; begin Result := (x and z) or (y and (not z)); end; function H(x, y, z: DWORD): DWORD; begin Result := x xor y xor z; end; function I(x, y, z: DWORD): DWORD; begin Result := y xor (x or (not z)); end; procedure rot(var x: DWORD; n: BYTE); begin x := (x shl n) or (x shr (32 - n)); end; procedure FF(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD); begin inc(a, F(b, c, d) + x + ac); rot(a, s); inc(a, b); end; procedure GG(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD); begin inc(a, G(b, c, d) + x + ac); rot(a, s); inc(a, b); end; procedure HH(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD); begin inc(a, H(b, c, d) + x + ac); rot(a, s); inc(a, b); end; procedure II(var a: DWORD; b, c, d, x: DWORD; s: BYTE; ac: DWORD); begin inc(a, I(b, c, d) + x + ac); rot(a, s); inc(a, b); end; // ----------------------------------------------------------------------------------------------- // Encode Count bytes at Source into (Count / 4) DWORDs at Target procedure Encode(Source, Target: pointer; Count: longword); var S: PByte; T: PDWORD; I: longword; begin S := Source; T := Target; for I := 1 to Count div 4 do begin T^ := S^; inc(S); T^ := T^ or (S^ shl 8); inc(S); T^ := T^ or (S^ shl 16); inc(S); T^ := T^ or (S^ shl 24); inc(S); inc(T); end; end; // Decode Count DWORDs at Source into (Count * 4) Bytes at Target procedure Decode(Source, Target: pointer; Count: longword); var S: PDWORD; T: PByte; I: longword; begin S := Source; T := Target; for I := 1 to Count do begin T^ := S^ and $ff; inc(T); T^ := (S^ shr 8) and $ff; inc(T); T^ := (S^ shr 16) and $ff; inc(T); T^ := (S^ shr 24) and $ff; inc(T); inc(S); end; end; // Transform State according to first 64 bytes at Buffer procedure Transform(Buffer: pointer; var State: MD5State); var a, b, c, d: DWORD; Block: MD5Block; begin Encode(Buffer, @Block, 64); a := State[0]; b := State[1]; c := State[2]; d := State[3]; FF (a, b, c, d, Block[ 0], 7, $d76aa478); FF (d, a, b, c, Block[ 1], 12, $e8c7b756); FF (c, d, a, b, Block[ 2], 17, $242070db); FF (b, c, d, a, Block[ 3], 22, $c1bdceee); FF (a, b, c, d, Block[ 4], 7, $f57c0faf); FF (d, a, b, c, Block[ 5], 12, $4787c62a); FF (c, d, a, b, Block[ 6], 17, $a8304613); FF (b, c, d, a, Block[ 7], 22, $fd469501); FF (a, b, c, d, Block[ 8], 7, $698098d8); FF (d, a, b, c, Block[ 9], 12, $8b44f7af); FF (c, d, a, b, Block[10], 17, $ffff5bb1); FF (b, c, d, a, Block[11], 22, $895cd7be); FF (a, b, c, d, Block[12], 7, $6b901122); FF (d, a, b, c, Block[13], 12, $fd987193); FF (c, d, a, b, Block[14], 17, $a679438e); FF (b, c, d, a, Block[15], 22, $49b40821); GG (a, b, c, d, Block[ 1], 5, $f61e2562); GG (d, a, b, c, Block[ 6], 9, $c040b340); GG (c, d, a, b, Block[11], 14, $265e5a51); GG (b, c, d, a, Block[ 0], 20, $e9b6c7aa); GG (a, b, c, d, Block[ 5], 5, $d62f105d); GG (d, a, b, c, Block[10], 9, $2441453); GG (c, d, a, b, Block[15], 14, $d8a1e681); GG (b, c, d, a, Block[ 4], 20, $e7d3fbc8); GG (a, b, c, d, Block[ 9], 5, $21e1cde6); GG (d, a, b, c, Block[14], 9, $c33707d6); GG (c, d, a, b, Block[ 3], 14, $f4d50d87); GG (b, c, d, a, Block[ 8], 20, $455a14ed); GG (a, b, c, d, Block[13], 5, $a9e3e905); GG (d, a, b, c, Block[ 2], 9, $fcefa3f8); GG (c, d, a, b, Block[ 7], 14, $676f02d9); GG (b, c, d, a, Block[12], 20, $8d2a4c8a); HH (a, b, c, d, Block[ 5], 4, $fffa3942); HH (d, a, b, c, Block[ 8], 11, $8771f681); HH (c, d, a, b, Block[11], 16, $6d9d6122); HH (b, c, d, a, Block[14], 23, $fde5380c); HH (a, b, c, d, Block[ 1], 4, $a4beea44); HH (d, a, b, c, Block[ 4], 11, $4bdecfa9); HH (c, d, a, b, Block[ 7], 16, $f6bb4b60); HH (b, c, d, a, Block[10], 23, $bebfbc70); HH (a, b, c, d, Block[13], 4, $289b7ec6); HH (d, a, b, c, Block[ 0], 11, $eaa127fa); HH (c, d, a, b, Block[ 3], 16, $d4ef3085); HH (b, c, d, a, Block[ 6], 23, $4881d05); HH (a, b, c, d, Block[ 9], 4, $d9d4d039); HH (d, a, b, c, Block[12], 11, $e6db99e5); HH (c, d, a, b, Block[15], 16, $1fa27cf8); HH (b, c, d, a, Block[ 2], 23, $c4ac5665); II (a, b, c, d, Block[ 0], 6, $f4292244); II (d, a, b, c, Block[ 7], 10, $432aff97); II (c, d, a, b, Block[14], 15, $ab9423a7); II (b, c, d, a, Block[ 5], 21, $fc93a039); II (a, b, c, d, Block[12], 6, $655b59c3); II (d, a, b, c, Block[ 3], 10, $8f0ccc92); II (c, d, a, b, Block[10], 15, $ffeff47d); II (b, c, d, a, Block[ 1], 21, $85845dd1); II (a, b, c, d, Block[ 8], 6, $6fa87e4f); II (d, a, b, c, Block[15], 10, $fe2ce6e0); II (c, d, a, b, Block[ 6], 15, $a3014314); II (b, c, d, a, Block[13], 21, $4e0811a1); II (a, b, c, d, Block[ 4], 6, $f7537e82); II (d, a, b, c, Block[11], 10, $bd3af235); II (c, d, a, b, Block[ 2], 15, $2ad7d2bb); II (b, c, d, a, Block[ 9], 21, $eb86d391); inc(State[0], a); inc(State[1], b); inc(State[2], c); inc(State[3], d); end; // ----------------------------------------------------------------------------------------------- // Initialize given Context procedure MD5Init(var Context: MD5Context); begin with Context do begin State[0] := $67452301; State[1] := $efcdab89; State[2] := $98badcfe; State[3] := $10325476; Count[0] := 0; Count[1] := 0; ZeroMemory(@Buffer, SizeOf(MD5Buffer)); end; end; // Update given Context to include Length bytes of Input procedure MD5Update(var Context: MD5Context; Input: pChar; Length: longword); var Index: longword; PartLen: longword; I: longword; begin with Context do begin Index := (Count[0] shr 3) and $3f; inc(Count[0], Length shl 3); if Count[0] < (Length shl 3) then inc(Count[1]); inc(Count[1], Length shr 29); end; PartLen := 64 - Index; if Length >= PartLen then begin CopyMemory(@Context.Buffer[Index], Input, PartLen); Transform(@Context.Buffer, Context.State); I := PartLen; while I + 63 < Length do begin Transform(@Input, Context.State); inc(I, 64); end; Index := 0; end else I := 0; CopyMemory(@Context.Buffer[Index], @Input, Length - I); end; // Finalize given Context, create Digest and zeroize Context procedure MD5Final(var Context: MD5Context; var Digest: MD5Digest); var Bits: MD5CBits; Index: longword; PadLen: longword; begin Decode(@Context.Count, @Bits, 2); Index := (Context.Count[0] shr 3) and $3f; if Index < 56 then PadLen := 56 - Index else PadLen := 120 - Index; MD5Update(Context, @PADDING, PadLen); MD5Update(Context, @Bits, 8); Decode(@Context.State, @Digest, 4); ZeroMemory(@Context, SizeOf(MD5Context)); end; // ----------------------------------------------------------------------------------------------- // Create digest of given Message function MD5String(M: string): MD5Digest; var Context: MD5Context; begin MD5Init(Context); MD5Update(Context, pChar(M), length(M)); MD5Final(Context, Result); end; // Create digest of file with given Name function MD5File(N: string): MD5Digest; var FileHandle: THandle; MapHandle: THandle; ViewPointer: pointer; Context: MD5Context; begin MD5Init(Context); FileHandle := CreateFile(pChar(N), GENERIC_READ, FILE_SHARE_READ or FILE_SHARE_WRITE, nil, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL or FILE_FLAG_SEQUENTIAL_SCAN, 0); if FileHandle <> INVALID_HANDLE_value then try MapHandle := CreateFileMapping(FileHandle, nil, PAGE_READONLY, 0, 0, nil); if MapHandle <> 0 then try ViewPointer := MapViewOfFile(MapHandle, FILE_MAP_READ, 0, 0, 0); if ViewPointer <> nil then try MD5Update(Context, ViewPointer, GetFileSize(FileHandle, nil)); finally UnmapViewOfFile(ViewPointer); end; finally CloseHandle(MapHandle); end; finally CloseHandle(FileHandle); end; MD5Final(Context, Result); end; // Create hex representation of given Digest function MD5Print(D: MD5Digest): string; var I: byte; const Digits: array[0..15] of char = ('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'); begin Result := '';for I := 0 to 15 do Result := Result + Digits[(D shr 4) and $0f] + Digits[D and $0f]; end; // ----------------------------------------------------------------------------------------------- // Compare two Digests function MD5Match(D1, D2: MD5Digest): boolean; var I: byte; begin I := 0; Result := TRUE; while Result and (I < 16) do begin Result := D1 = D2; inc(I); end; end; end.