高分求一加密算法：两个可见字符串(长度可能不等)-------->一个密文可见字符串(就是可见的ASCII码)各位！帮忙呀！（为什么没人帮忙呀？太忙了？高

高分求一加密算法：两个可见字符串(长度可能不等)--------&gt;一个密文可见字符串(就是可见的ASCII码)各位！帮忙呀！（为什么没人帮忙呀？太忙了？高手去哪啦！！！救命呀！我加分，全部家当：900分，快呀！（分已经发了：id=1535790,1535788）） (300分)<br />高分求一加密算法：两个可见字符串(长度可能不等)--------&gt;一个密文可见字符串(就是可见的ASCII码)
您就写出来吧，我急用，，，，，，

我有！等会发给你吧，email？

可逆吗.

不用可逆！！！只要校验就好了！！！

//加密

FUNCTION EnKey(Msg1: STRING; EnKeyNo: integer): STRING;
VAR
ResultStr: STRING;
Temp: char;
I: integer;
BEGIN
ResultStr := '';
FOR I := 1 TO length(Msg1) DO
BEGIN
Temp := Chr(Ord(Msg1) + EnKeyNo);
ResultStr := ResultStr + Temp;
END;
EnKey := ResultStr;
END;

//解密

FUNCTION DisKey(Msg1: STRING; DisKeyNo: integer): STRING;
VAR
ResultStr: STRING;
Temp: char;
I: integer;
BEGIN
ResultStr := '';
FOR I := 1 TO length(Msg1) DO
BEGIN
Temp := Chr(Ord(Msg1) - DisKeyNo);
ResultStr := ResultStr + Temp;
END;
DisKey := ResultStr;
END;

這是我做系統登錄的時候所用的加密解密算法,不知道是否適合你!

//不可逆
FUNCTION entypePass(strA: String;strB: String):String;
var l_Str : String;
l_ret : String;
I,l_Cnt,J,K : Integer;
BEGIN
if length(strA) &lt; length(strB) then
begin
l_str := strA;
strA := strB;
strB := l_str;
end;
l_str := '';
FOR I := Length(strB) DOWNTO 1 DO
l_str := l_str + Copy(strB,I,1);
strB := l_str;
l_str := strA;
I := 1;
l_Cnt := 1;
WHILE True DO BEGIN
l_Str := Copy(l_str,1,I)+Copy(strB,l_Cnt,1)+ Copy(l_str,I+1,Length(l_str)-I);
l_Cnt := l_Cnt + 1; I := I + 3;
IF I &gt;= Length(l_str) THEN I := Length(l_str) MOD 4 ;
IF l_Cnt &gt;= Length(strB) THEN Break;
END;
J := Length(Trim(l_Str));
FOR I := 1 TO J DO
BEGIN
l_Cnt := Ord(l_str);
K := l_Cnt+Ord(l_str[(J MOD I)+1])+I;
l_ret := l_ret + Chr(K);
END;
Result := l_Ret;
END;

gz

来晚了，混点分

晚了,晚了
up一下

晚了,晚了

贴出符合要求代码都有分！最少200！
Up也有！：）

好像你们的算法都忽略了有些字符可能加密后都在键盘用普通方法打不出来

说明了就是不在'0'-'9','a'-'z','A'-'Z'之间了

基本都是一次加密的普通算法。
顶

up

不明白“两个可见字符串(长度可能不等)--------&gt;一个密文可见字符串”这个是什么意思。
这两个字符串的其中一个是要 加密的明文，另一个是密钥吗？
用md5可以为任意长度的字符串或文件生成固定长度散列值，不会重复，不过不可逆；
利用如DES等的加密算法，可以生成ASCII密文。
而诸如BlowFish,IDEA等加密算法，网上有，你可以看看这个：
http://www.cityinthesky.co.uk/cryptography.html

//标准des算法的pas程序
unit WNDES;

interface

uses
Windows, Messages, ShlObj, WinSock, IniFiles, ActiveX, SysUtils,
Classes, Graphics, Controls, Forms, Dialogs;

type
TKeyByte = array[0..5] of Byte;
TDesMode = (dmEncry, dmDESry);
const
BitIP: array[0..63] of Byte =
(57, 49, 41, 33, 25, 17, 9, 1,
59, 51, 43, 35, 27, 19, 11, 3,
61, 53, 45, 37, 29, 21, 13, 5,
63, 55, 47, 39, 31, 23, 15, 7,
56, 48, 40, 32, 24, 16, 8, 0,
58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6);

BitCP: array[0..63] of Byte =
(39, 7, 47, 15, 55, 23, 63, 31,
38, 6, 46, 14, 54, 22, 62, 30,
37, 5, 45, 13, 53, 21, 61, 29,
36, 4, 44, 12, 52, 20, 60, 28,
35, 3, 43, 11, 51, 19, 59, 27,
34, 2, 42, 10, 50, 18, 58, 26,
33, 1, 41, 9, 49, 17, 57, 25,
32, 0, 40, 8, 48, 16, 56, 24);

BitExp: array[0..47] of Integer =
(31, 0, 1, 2, 3, 4, 3, 4, 5, 6, 7, 8, 7, 8, 9, 10,
11, 12, 11, 12, 13, 14, 15, 16, 15, 16, 17, 18, 19, 20, 19, 20,
21, 22, 23, 24, 23, 24, 25, 26, 27, 28, 27, 28, 29, 30, 31, 0);

BitPM: array[0..31] of Byte =
(15, 6, 19, 20, 28, 11, 27, 16, 0, 14, 22, 25, 4, 17, 30, 9,
1, 7, 23, 13, 31, 26, 2, 8, 18, 12, 29, 5, 21, 10, 3, 24);

sBox: array[0..7] of array[0..63] of Byte =
((14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13),

(15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9),

(10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12),

(7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14),

(2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3),

(12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13),

(4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12),

(13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11));

BitPMC1: array[0..55] of Byte =
(56, 48, 40, 32, 24, 16, 8,
0, 57, 49, 41, 33, 25, 17,
9, 1, 58, 50, 42, 34, 26,
18, 10, 2, 59, 51, 43, 35,
62, 54, 46, 38, 30, 22, 14,
6, 61, 53, 45, 37, 29, 21,
13, 5, 60, 52, 44, 36, 28,
20, 12, 4, 27, 19, 11, 3);

BitPMC2: array[0..47] of Byte =
(13, 16, 10, 23, 0, 4,
2, 27, 14, 5, 20, 9,
22, 18, 11, 3, 25, 7,
15, 6, 26, 19, 12, 1,
40, 51, 30, 36, 46, 54,
29, 39, 50, 44, 32, 47,
43, 48, 38, 55, 33, 52,
45, 41, 49, 35, 28, 31);
//////////////////DES加密算法////////////////////////////
function EncryStr(Str, Key: string): string; //加密
function EncryStrHex(Str, Key: string): string; //以十六进制加密(有些时侯加密的密文含有特殊字符文本框不能显示、数据库文本字段也不能存储。以十六进制形式表示可保证绝对不会出现该种情况)
function DESryStr(Str, Key: string): string; //解密
function DESryStrHex(StrHex, Key: string): string; //解密十六进制加密的密文

var
subKey: array[0..15] of TKeyByte;
implementation



procedure initPermutation(var inData: array of Byte);
var
newData: array[0..7] of Byte;
i: Integer;
begin
FillChar(newData, 8, 0);
for i := 0 to 63 do
if (inData[BitIP shr 3] and (1 shl (7 - (BitIP and $07)))) &lt;&gt; 0 then
newData[i shr 3] := newData[i shr 3] or (1 shl (7 - (i and $07)));
for i := 0 to 7 do inData := newData;
end;

procedure conversePermutation(var inData: array of Byte);
var
newData: array[0..7] of Byte;
i: Integer;
begin
FillChar(newData, 8, 0);
for i := 0 to 63 do
if (inData[BitCP shr 3] and (1 shl (7 - (BitCP and $07)))) &lt;&gt; 0 then
newData[i shr 3] := newData[i shr 3] or (1 shl (7 - (i and $07)));
for i := 0 to 7 do inData := newData;
end;

procedure expand(inData: array of Byte; var outData: array of Byte);
var
i: Integer;
begin
FillChar(outData, 6, 0);
for i := 0 to 47 do
if (inData[BitExp shr 3] and (1 shl (7 - (BitExp and $07)))) &lt;&gt; 0 then
outData[i shr 3] := outData[i shr 3] or (1 shl (7 - (i and $07)));
end;

procedure permutation(var inData: array of Byte);
var
newData: array[0..3] of Byte;
i: Integer;
begin
FillChar(newData, 4, 0);
for i := 0 to 31 do
if (inData[BitPM shr 3] and (1 shl (7 - (BitPM and $07)))) &lt;&gt; 0 then
newData[i shr 3] := newData[i shr 3] or (1 shl (7 - (i and $07)));
for i := 0 to 3 do inData := newData;
end;

function si(s, inByte: Byte): Byte;
var
c: Byte;
begin
c := (inByte and $20) or ((inByte and $1E) shr 1) or
((inByte and $01) shl 4);
Result := (sBox[c] and $0F);
end;

procedure permutationChoose1(inData: array of Byte;
var outData: array of Byte);
var
i: Integer;
begin
FillChar(outData, 7, 0);
for i := 0 to 55 do
if (inData[BitPMC1 shr 3] and (1 shl (7 - (BitPMC1 and $07)))) &lt;&gt; 0 then
outData[i shr 3] := outData[i shr 3] or (1 shl (7 - (i and $07)));
end;

procedure permutationChoose2(inData: array of Byte;
var outData: array of Byte);
var
i: Integer;
begin
FillChar(outData, 6, 0);
for i := 0 to 47 do
if (inData[BitPMC2 shr 3] and (1 shl (7 - (BitPMC2 and $07)))) &lt;&gt; 0 then
outData[i shr 3] := outData[i shr 3] or (1 shl (7 - (i and $07)));
end;


procedure cycleMove(var inData: array of Byte; bitMove: Byte);
var
i: Integer;
begin
for i := 0 to bitMove - 1 do
begin
inData[0] := (inData[0] shl 1) or (inData[1] shr 7);
inData[1] := (inData[1] shl 1) or (inData[2] shr 7);
inData[2] := (inData[2] shl 1) or (inData[3] shr 7);
inData[3] := (inData[3] shl 1) or ((inData[0] and $10) shr 4);
inData[0] := (inData[0] and $0F);
end;
end;

procedure makeKey(inKey: array of Byte; var outKey: array of TKeyByte);
const
bitDisplace: array[0..15] of Byte =
(1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1);
var
outData56: array[0..6] of Byte;
key28l: array[0..3] of Byte;
key28r: array[0..3] of Byte;
key56o: array[0..6] of Byte;
i: Integer;
begin
permutationChoose1(inKey, outData56);

key28l[0] := outData56[0] shr 4;
key28l[1] := (outData56[0] shl 4) or (outData56[1] shr 4);
key28l[2] := (outData56[1] shl 4) or (outData56[2] shr 4);
key28l[3] := (outData56[2] shl 4) or (outData56[3] shr 4);
key28r[0] := outData56[3] and $0F;
key28r[1] := outData56[4];
key28r[2] := outData56[5];
key28r[3] := outData56[6];

for i := 0 to 15 do
begin
cycleMove(key28l, bitDisplace);
cycleMove(key28r, bitDisplace);
key56o[0] := (key28l[0] shl 4) or (key28l[1] shr 4);
key56o[1] := (key28l[1] shl 4) or (key28l[2] shr 4);
key56o[2] := (key28l[2] shl 4) or (key28l[3] shr 4);
key56o[3] := (key28l[3] shl 4) or (key28r[0]);
key56o[4] := key28r[1];
key56o[5] := key28r[2];
key56o[6] := key28r[3];
permutationChoose2(key56o, outKey);
end;
end;

procedure encry(inData, subKey: array of Byte;
var outData: array of Byte);
var
outBuf: array[0..5] of Byte;
buf: array[0..7] of Byte;
i: Integer;
begin
expand(inData, outBuf);
for i := 0 to 5 do outBuf := outBuf xor subKey;
// outBuf xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx xxxxxxxx
buf[0] := outBuf[0] shr 2; //xxxxxx -&gt; 2
buf[1] := ((outBuf[0] and $03) shl 4) or (outBuf[1] shr 4); // 4 &lt;- xx xxxx -&gt; 4
buf[2] := ((outBuf[1] and $0F) shl 2) or (outBuf[2] shr 6); // 2 &lt;- xxxx xx -&gt; 6
buf[3] := outBuf[2] and $3F; // xxxxxx
buf[4] := outBuf[3] shr 2; // xxxxxx
buf[5] := ((outBuf[3] and $03) shl 4) or (outBuf[4] shr 4); // xx xxxx
buf[6] := ((outBuf[4] and $0F) shl 2) or (outBuf[5] shr 6); // xxxx xx
buf[7] := outBuf[5] and $3F; // xxxxxx
for i := 0 to 7 do buf := si(i, buf);
for i := 0 to 3 do outBuf := (buf[i * 2] shl 4) or buf[i * 2 + 1];
permutation(outBuf);
for i := 0 to 3 do outData := outBuf;
end;

procedure desData(desMode: TDesMode;
inData: array of Byte; var outData: array of Byte);
// inData, outData 都为8Bytes，否则出错
var
i, j: Integer;
temp, buf: array[0..3] of Byte;
begin
for i := 0 to 7 do outData := inData;
initPermutation(outData);
if desMode = dmEncry then
begin
for i := 0 to 15 do
begin
for j := 0 to 3 do temp[j] := outData[j]; //temp = Ln
for j := 0 to 3 do outData[j] := outData[j + 4]; //Ln+1 = Rn
encry(outData, subKey, buf); //Rn ==Kn==&gt; buf
for j := 0 to 3 do outData[j + 4] := temp[j] xor buf[j]; //Rn+1 = Ln^buf
end;

for j := 0 to 3 do temp[j] := outData[j + 4];
for j := 0 to 3 do outData[j + 4] := outData[j];
for j := 0 to 3 do outData[j] := temp[j];
end
else if desMode = dmDESry then
begin
for i := 15 downto 0 do
begin
for j := 0 to 3 do temp[j] := outData[j];
for j := 0 to 3 do outData[j] := outData[j + 4];
encry(outData, subKey, buf);
for j := 0 to 3 do outData[j + 4] := temp[j] xor buf[j];
end;
for j := 0 to 3 do temp[j] := outData[j + 4];
for j := 0 to 3 do outData[j + 4] := outData[j];
for j := 0 to 3 do outData[j] := temp[j];
end;
conversePermutation(outData);
end;

function EncryStr(Str, Key: string): string;
var
StrByte, OutByte, KeyByte: array[0..7] of Byte;
StrResult: string;
I, J: Integer;
begin
if (Length(Str) &gt; 0) and (Ord(Str[Length(Str)]) = 0) then
raise Exception.Create('Error: the last char is NULL char.');
if Length(Key) &lt; 8 then
while Length(Key) &lt; 8 do Key := Key + Chr(0);
while Length(Str) mod 8 &lt;&gt; 0 do Str := Str + Chr(0);

for J := 0 to 7 do KeyByte[J] := Ord(Key[J + 1]);
makeKey(keyByte, subKey);

StrResult := '';

for I := 0 to Length(Str) div 8 - 1 do
begin
for J := 0 to 7 do
StrByte[J] := Ord(Str[I * 8 + J + 1]);
desData(dmEncry, StrByte, OutByte);
for J := 0 to 7 do
StrResult := StrResult + Chr(OutByte[J]);
end;

Result := StrResult;
end;

function DESryStr(Str, Key: string): string;
var
StrByte, OutByte, KeyByte: array[0..7] of Byte;
StrResult: string;
I, J: Integer;
begin
if Length(Key) &lt; 8 then
while Length(Key) &lt; 8 do Key := Key + Chr(0);

for J := 0 to 7 do KeyByte[J] := Ord(Key[J + 1]);
makeKey(keyByte, subKey);

StrResult := '';

for I := 0 to Length(Str) div 8 - 1 do
begin
for J := 0 to 7 do StrByte[J] := Ord(Str[I * 8 + J + 1]);
desData(dmDESry, StrByte, OutByte);
for J := 0 to 7 do
StrResult := StrResult + Chr(OutByte[J]);
end;
while (Length(StrResult) &gt; 0) and
(Ord(StrResult[Length(StrResult)]) = 0) do
Delete(StrResult, Length(StrResult), 1);
Result := StrResult;
end;

///////////////////////////////////////////////////////////

function EncryStrHex(Str, Key: string): string;
var
StrResult, TempResult, Temp: string;
I: Integer;
begin
TempResult := EncryStr(Str, Key);
StrResult := '';
for I := 0 to Length(TempResult) - 1 do
begin
Temp := Format('%x', [Ord(TempResult[I + 1])]);
if Length(Temp) = 1 then Temp := '0' + Temp;
StrResult := StrResult + Temp;
end;
Result := StrResult;
end;

function DESryStrHex(StrHex, Key: string): string;
function HexToInt(Hex: string): Integer;
var
I, Res: Integer;
ch: Char;
begin
Res := 0;
for I := 0 to Length(Hex) - 1 do
begin
ch := Hex[I + 1];
if (ch &gt;= '0') and (ch &lt;= '9') then
Res := Res * 16 + Ord(ch) - Ord('0')
else if (ch &gt;= 'A') and (ch &lt;= 'F') then
Res := Res * 16 + Ord(ch) - Ord('A') + 10
else if (ch &gt;= 'a') and (ch &lt;= 'f') then
Res := Res * 16 + Ord(ch) - Ord('a') + 10
else raise Exception.Create('Error: not a Hex String');
end;
Result := Res;
end;

var
Str, Temp: string;
I: Integer;
begin
Str := '';
for I := 0 to Length(StrHex) div 2 - 1 do
begin
Temp := Copy(StrHex, I * 2 + 1, 2);
Str := Str + Chr(HexToInt(Temp));
end;
Result := DESryStr(Str, Key);
end;

end.

up

////////////////////加密模块///////////////////////////////////////////////////////////////
const AlphabetLength = 64;
Alphabet:string[AlphabetLength]='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
Pad = '=';

constructor TBase64.Create;
begin
inherited Create;
ffilterdecodeinput:=true;
end;
function TBase64.ValueToCharacter(value:Byte;var character:char):boolean;
begin
Result:=true;
if (value&gt;AlphabetLength-1) then Result:=false
else character:=Alphabet[value+1];
end;

//******************************************************************
// converts a character to a value in the range of 0..AlphabetLength-1
// returns true if the character exists in the alphabet
//******************************************************************
function TBase64.CharacterToValue(character:char;var value:byte):boolean;
begin
Result:=true;
value:=Pos(character,Alphabet);
if value=0 then Result:=false
else value:=value-1;
end;


//******************************************************************
// Encodes a string to its base64 representation in ASCII Format
// returns BASE64_OK if conversion was done without errors
//******************************************************************
function TBase64.EncodeData(InputData:string;var OutputData:string):Byte;
var i:integer;
currentb,prevb:Byte;
c:Byte;
s:char;
InputLength:integer;

begin
OutPutData:='';
InputLength:=Length(InputData);
i:=1;
if (InputLength=0) then begin Result:=BASE64_OK;exit;end;

repeat
// process first group
currentb:=ord(InputData);
i:=i+1;
InputLength:=InputLength-1;
c:=(currentb shr 2);
if not ValueToCharacter(c,s) then begin Result:=BASE64_ERROR;exit;end;
OutPutData:=OutPutData+s;
prevb:=currentb;

// process second group
if InputLength=0 then currentb:=0
else begin
currentb:=ord(InputData);
i:=i+1;
end;
InputLength:=InputLength-1;
c:=(prevb and $03) shl 4 + (currentb shr 4);
if not ValueToCharacter(c,s) then begin Result:=BASE64_ERROR;exit;end;
OutPutData:=OutPutData+s;
prevb:=currentb;

// process third group
if InputLength&lt;0 then s:=pad
else
begin
if InputLength=0 then currentb:=0
else begin
currentb:=ord(InputData);
i:=i+1;
end;
InputLength:=InputLength-1;
c:=(prevb and $0F) shl 2 + (currentb shr 6);
if not ValueToCharacter(c,s) then begin Result:=BASE64_ERROR;exit;end;
end;
OutPutData:=OutPutData+s;

// process fourth group
if InputLength&lt;0 then s:=pad
else
begin
c:=(currentb and $3F);
if not ValueToCharacter(c,s) then begin Result:=BASE64_ERROR;exit;end;
end;
OutPutData:=OutPutData+s;

until InputLength&lt;=0;

result:=BASE64_OK;
end;



//******************************************************************
// ignores all characters not in base64 alphabet
// and returns the filtered string
//******************************************************************
function TBase64.filterLine(InputData:string):string;
var f:byte;
i:integer;
begin
result:='';
for i:= 1 to Length(InputData) do
if CharacterToValue(inputData,f) or (InputData=Pad) then result:=Result+InputData;
end;



//******************************************************************
// Decodes a base64 representation in ASCII format into a string
// returns BASE64_OK if conversion was done without errors
//******************************************************************
function TBase64.DecodeData(InputData:string;var OutputData:string):Byte;
var i:integer;
InputLength:integer;
currentb,prevb:Byte;
c:Byte;
s:char;

begin
if (InputData='') then begin result:=BASE64_OK;exit;end;
OutPutData:='';

if filterdecodeinput then InputData:=FilterLine(InputData);

InputLength:=Length(InputData);
if InputLength mod 4&lt;&gt;0 then begin Result:=BASE64_LENGTH;exit;end;

i:=0;
repeat
// process first byte
i:=i+1;s:=InputData; if not CharacterToValue(s,currentb) then begin Result:=BASE64_INVALID;exit;end;
i:=i+1;s:=InputData; if not CharacterToValue(s,prevb) then begin Result:=BASE64_INVALID;exit;end;

c:=(currentb shl 2)+(prevb shr 4);
OutPutData:=OutPutData+chr(c);

// process second Byte
i:=i+1;s:=InputData;
if s=pad then
begin
if (i&lt;&gt;InputLength-1) then begin Result:=BASE64_DATALEFT;exit;end // too much data left
else if InputData[i+1]&lt;&gt;pad then begin Result:=BASE64_PADDING;exit;end; // last char has to be a pad
end
else
begin
if not CharacterToValue(s,currentb) then begin Result:=BASE64_INVALID;exit;end;
c:=(prevb shl 4)+(currentb shr 2);
OutPutData:=OutPutData+chr(c);
end;

// process third Byte
i:=i+1;s:=InputData;
if s=pad then
begin
if (i&lt;&gt;InputLength) then begin Result:=BASE64_DATALEFT;exit;end; // too much data Left
end
else
begin
if not CharacterToValue(s,prevb) then begin Result:=BASE64_INVALID;exit;end;
c:=(currentb shl 6)+(prevb);
OutPutData:=OutPutData+chr(c);
end;

until (i&gt;=InputLength);
result:=BASE64_OK;
end;

用MD5吧，这个用的人最多。好像没有办法破解的

来学习的啦 []