delphi 字符串加密解密单元

感谢作者：小宇飞刀

unit PwdFunUnit;

interface

uses

SysUtils;

const

C1Key = 12674; // C1 = 52845;

C2Key = 35891; // C2 = 22719;

XXXKey = 'xlinuxx'; //

//-----------对字符串进行加密和解密的极好的函数----------------

Function EncryptionEngine(Src:String; Key:String; Encrypt : Boolean):string;

function EnCrypt(Sour: String):String; //对上一函数的两个引用

function DeCrypt(Sour: String):String;

function EncryptStr(const S: string; Key: Word): string;

function DecryptStr(const S: string; Key: Word): string;

implementation

//-----------对字符串进行加密和解密的极好的函数----------------

Function EncryptionEngine(Src:String; Key:String; Encrypt : Boolean):string;

var

idx :integer;

KeyLen :Integer;

KeyPos :Integer;

offset :Integer;

dest :string;

SrcPos :Integer;

SrcAsc :Integer;

TmpSrcAsc :Integer;

Range :Integer;

begin

try

KeyLen:=Length(Key);

if KeyLen = 0 then key:='xlinuxx';

KeyPos:=0;

SrcPos:=0;

SrcAsc:=0;

Range:=256;

if Encrypt then

begin

Randomize;

offset:=Random(Range);

dest:=format('%1.2x',[offset]);

for SrcPos := 1 to Length(Src) do

begin

SrcAsc:=(Ord(Src[SrcPos]) + offset) MOD 255;

if KeyPos < KeyLen then KeyPos:= KeyPos + 1 else KeyPos:=1;

SrcAsc:= SrcAsc xor Ord(Key[KeyPos]);

dest:=dest + format('%1.2x',[SrcAsc]);

offset:=SrcAsc;

end;

end

else

begin

offset:=StrToInt('$'+ copy(src,1,2));

SrcPos:=3;

repeat

SrcAsc:=StrToInt('$'+ copy(src,SrcPos,2));

if KeyPos < KeyLen Then KeyPos := KeyPos + 1 else KeyPos := 1;

TmpSrcAsc := SrcAsc xor Ord(Key[KeyPos]);

if TmpSrcAsc <= offset then

TmpSrcAsc := 255 + TmpSrcAsc - offset

else

TmpSrcAsc := TmpSrcAsc - offset;

dest := dest + chr(TmpSrcAsc);

offset:=srcAsc;

SrcPos:=SrcPos + 2;

until SrcPos >= Length(Src);

end;

Result:=Dest;

except

Result := '';

end;

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

// ----------- 加密函数 ----------- //

// //

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

function EnCrypt(Sour: String):String;

begin

Result := EncryptionEngine(Sour,XXXKey,True);

end;

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

// ----------- 解密函数 ----------- //

// //

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

function DeCrypt(Sour: String):String;

begin

Result := EncryptionEngine(Sour,XXXKey,False);

end;

{

function EnCrypt(Sour: String):String;

begin

Result := EncryptStr(Sour,110);

end;

function DeCrypt(Sour: String):String;

begin

Result := DecryptStr(Sour,110);

end;

}

function EncryptStr(const S: string; Key: Word): string;

var // 加密

I : Integer;

begin

Result := S;

for I := 1 to Length(S) do

begin

Result[I] := Char(Byte(S[I]) xor (Key shr 8));

Key := (Byte(Result[I]) + Key) * C1Key + C2Key;

end;

function DecryptStr(const S: string; Key: Word): string;

var // 解密

I : Integer;

begin

Result := S;

for I := 1 to Length(S) do

begin

Result[I] := Char(Byte(S[I]) xor (Key shr 8));

Key := (Byte(S[I]) + Key) * C1Key + C2Key;

end;

end.

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