// 加密方法一(通过密钥加密解密)
function EncryptString(Source, Key: string): string;
function UnEncryptString(Source, Key: string): string;
//加密方法二(通过移位加密解密)
function Encode(Str: string): string;
function Decode(Str: string): string;
//加密方法三（异或加密解密）
function Enc(str: string): string;
function Dec(str: string): string;

－－－－－－－－－－－－－－－

function TFrmRegister.EncryptString(Source, Key: string): string;
// 对字符串加密(Source:源 Key:密匙)
var
KeyLen: integer;
KeyPos: integer;
Offset: integer;
Dest: string;
SrcPos: integer;
SrcAsc: integer;
Range: integer;
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 TFrmRegister.UnEncryptString(Source, Key: string): string;
// 对字符串解密(Src:源 Key:密匙)
var
KeyLen: integer;
KeyPos: integer;
Offset: integer;
Dest: string;
SrcPos: integer;
SrcAsc: integer;
TmpSrcAsc: integer;
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 TFrmRegister.Decode(Str: string): string;
var
TmpChr: AnsiChar;
i, Len: Integer;
begin
Result := Str;
len := Length(Result);
TmpChr := result[len];
for i := Len downto 2 do
begin
Result[i] := result[i - 1];
Result[1] := TmpChr;
end;
end;

function TFrmRegister.Encode(Str: string): string;
var
TmpChr: AnsiChar;
i, Len: Integer;
begin
Result := Str;
len := Length(Result);
TmpChr := result[1];
for i := 1 to len - 1 do
begin
Result[i] := result[i + 1];
Result[len] := TmpChr;
end;
end;

---------

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

function TFrmRegister.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 TFrmRegister.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;