Delphi字符串加密/解密

unit uEncrypt_Decrypt;

 

interface

 

uses SysUtils;

 

const XorKey: array[0..7] of Byte = ($B2, $09, $AA, $55, $93, $6D, $84, $47);

 

//通过密钥Key加密

function EncryptString(Source, Key: string): string;

function UnEncryptString(Source, Key: string): string;

 

//异或加密

function Enc(str: string): string;

function Dec(str: string): string;

 

 

implementation

 

function EncryptString(Source, Key: string): string;

var

  KeyLen,KeyPos,Offset,SrcPos,SrcAsc,Range: integer;

  Dest: string;

begin

  KeyLen := Length(Key);

  if KeyLen = 0 then

    Key := 'delphi';

  KeyPos := 0;

  Range := 256;

  randomize;

  Offset := random(Range);

  Dest := format('%1.2x', [Offset]);

  for SrcPos := 1 to Length(Source) do

  begin

    SrcAsc := (Ord(Source[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;

  result := Dest;

end;

 

function UnEncryptString(Source, Key: string): string;

var

  KeyLen,KeyPos,Offset,SrcPos,SrcAsc,TmpSrcAsc: integer;

  Dest: string;

begin

  KeyLen := Length(Key);

  if KeyLen = 0 then

    Key := 'delphi';

  KeyPos := 0;

  Offset := strtoint('$' + copy(Source, 1, 2));

  SrcPos := 3;

  repeat

    SrcAsc := strtoint('$' + copy(Source, 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(Source);

  result := Dest;

end;

 

function Enc(str: string): string;

var

  i, j: Integer;

begin

  Result := '';

  j := 0;

  for i := 1 to Length(str) do

  begin

    Result := Result + IntToHex(Byte(str[i]) xor XorKey[j], 2);

    j := (j + 1) mod 8;

  end;

end;

 

function Dec(str: string): string;

var

  i, j: Integer;

begin

  Result := '';

  j := 0;

  for i := 1 to Length(str) div 2 do

  begin

    Result := Result + Char(StrToInt('$' + Copy(str, i * 2 - 1, 2)) xor

    XorKey[j]);

    j := (j + 1) mod 8;

  end;

end;

 

end.

 

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基于DES加密解密:  http://blog.csdn.net/warrially/article/details/8089041