uencrypt.pas

传奇假人登陆器 原代码 不完全 但是可以拿来研究

unit uEncrypt; 
interface 

function Decrypt(const S: AnsiString; Key: Word): AnsiString; 
function Encrypt(const S: AnsiString; Key: Word): AnsiString; 

implementation 

const 
C1 = 52845; 
C2 = 22719; 

function Decode(const S: AnsiString): AnsiString; 
const 
Map: array[Char] of Byte = (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 62, 0, 0, 0, 63, 52, 53, 
54, 55, 56, 57, 58, 59, 60, 61, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 
3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 
20, 21, 22, 23, 24, 25, 0, 0, 0, 0, 0, 0, 26, 27, 28, 29, 30, 
31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 
46, 47, 48, 49, 50, 51, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0); 
var 
I: LongInt; 
begin 
case Length(S) of 
2: 
begin 
I := Map[S[1]] + (Map[S[2]] shl 6); 
SetLength(Result, 1); 
Move(I, Result[1], Length(Result)) 
end; 
3: 
begin 
I := Map[S[1]] + (Map[S[2]] shl 6) + (Map[S[3]] shl 12); 
SetLength(Result, 2); 
Move(I, Result[1], Length(Result)) 
end; 
4: 
begin 
I := Map[S[1]] + (Map[S[2]] shl 6) + (Map[S[3]] shl 12) + 
(Map[S[4]] shl 18); 
SetLength(Result, 3); 
Move(I, Result[1], Length(Result)) 
end 
end 
end; 

function PreProcess(const S: AnsiString): AnsiString; 
var 
SS: AnsiString; 
begin 
SS := S; 
Result := ''; 
while SS <> '' do 
begin 
Result := Result + Decode(Copy(SS, 1, 4)); 
Delete(SS, 1, 4) 
end 
end; 

function InternalDecrypt(const S: AnsiString; Key: Word): AnsiString; 
var 
I: Word; 
Seed: Word; 
begin 
Result := S; 
Seed := Key; 
for I := 1 to Length(Result) do 
begin 
Result[I] := Char(Byte(Result[I]) xor (Seed shr 8)); 
Seed := (Byte(S[I]) + Seed) * Word(C1) + Word(C2) 
end 
end; 

function Decrypt(const S: AnsiString; Key: Word): AnsiString; 
begin 
Result := InternalDecrypt(PreProcess(S), Key) 
end; 

function Encode(const S: AnsiString): AnsiString; 
const 
Map: array[0..63] of Char = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ' + 
'abcdefghijklmnopqrstuvwxyz0123456789+/'; 
var 
I: LongInt; 
begin 
I := 0; 
Move(S[1], I, Length(S)); 
case Length(S) of 
1: 
Result := Map[I mod 64] + Map[(I shr 6) mod 64]; 
2: 
Result := Map[I mod 64] + Map[(I shr 6) mod 64] + 
Map[(I shr 12) mod 64]; 
3: 
Result := Map[I mod 64] + Map[(I shr 6) mod 64] + 
Map[(I shr 12) mod 64] + Map[(I shr 18) mod 64] 
end 
end; 

function PostProcess(const S: AnsiString): AnsiString; 
var 
SS: AnsiString; 
begin 
SS := S; 
Result := ''; 
while SS <> '' do 
begin 
Result := Result + Encode(Copy(SS, 1, 3)); 
Delete(SS, 1, 3) 
end 
end; 

function InternalEncrypt(const S: AnsiString; Key: Word): AnsiString; 
var 
I: Word; 
Seed: Word; 
begin 
Result := S; 
Seed := Key; 
for I := 1 to Length(Result) do 
begin 
Result[I] := Char(Byte(Result[I]) xor (Seed shr 8)); 
Seed := (Byte(Result[I]) + Seed) * Word(C1) + Word(C2) 
end 
end; 

function Encrypt(const S: AnsiString; Key: Word): AnsiString; 
begin 
Result := PostProcess(InternalEncrypt(S, Key)) 
end; 

end.