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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