...
Excerpt |
---|
There are lots of way can encrypt a text string based on a key. By the approach, you can use a single numerical key, or text string. In terms of security's point of view, text string-based key has better security performance. |
Below example shows the method encrypting a text string based on a numerical keycode is an example of string encryption module.
Code Block | ||
---|---|---|
| ||
function Encrypt(const CKEY1 = 53761 InString:string; Salt:string): string; var i : Byte; StartKey, MultKey, AddKey: Word; begin Result := ''; if (Salt = CKEY2 = 32618; function EncryptStr(const S :WideString; Key: Word): String; var i :Integer'') then begin Result := InString; end else begin StartKey := Length(Salt); MultKey := Ord(Salt[1]); AddKey := 0; for i := 1 to Length(Salt) - 1 do AddKey := AddKey + Ord(Salt[i]); for i := 1 to Length(InString) do begin Result := Result + CHAR(Byte(InString[i]) xor (StartKey shr 8)); RStrStartKey := (Byte(Result[i]) + StartKey) * MultKey + :RawByteStringAddKey; end; RStrB :TBytes Absolute RStrend; end; function Decrypt(const InString:string; Salt:string): string; var i : Byte; StartKey, MultKey, AddKey: Word; begin Result := ''; RStrif (Salt = '') then begin Result := InString; end else begin StartKey := Ord(Salt[1]); MultKey := UTF8EncodeLength(SSalt); AddKey := 0; for i := 01 to Length(RStrSalt) - 1 do begin AddKey := AddKey + RStrBOrd(Salt[i]); for i := 1 to Length(InString) do begin Result := RStrB Result + CHAR(Byte(InString[i]) xor (KeyStartKey shr 8)); Key StartKey := (Byte(RStrBInString[i]) + KeyStartKey) * CKEY1MultKey + CKEY2AddKey; end; end; end; |
By the way, above was not helpful for me - I use multibyte character, and below code was so helpful even though I can't use any key on the documentation
Code Block |
---|
uses IdCoder, IdCoderMIME, IdGlobal; .. .. begin // encode string sMasterXML.Text i := 0 to Length(RStr)-1 do beginTIdEncoderMIME.EncodeString(sMasterXML.Text, IndyTextEncoding_UTF8); // deocde string ResultsMasterXML.Text := TIdDecoderMIME.DecodeString(sMasterXML.Text, IndyTextEncoding_UTF8); end; |
Below is combined encryption algorithm which provides much better secure results.
Code Block | ||
---|---|---|
| ||
uses IdCoder, IdCoderMIME, IdGlobal; . . . const CK_ENC_VAR_RANGE=10Result + IntToHex(RStrB[i], 2); end; end; function DecryptStrCKEncrypt(const SSource: Stringstring; KeySalt: Wordstring): Stringstring; var i, tmpKeylenSalt, key, keyWeight:Integer Word; InString: string; begin Result RStr :RawByteString:= ''; if (Salt = '') RStrBthen begin Result :TBytes= Absolute RStrSource; end else begin tmpStr InString := :stringTIdEncoderMIME.EncodeString(Source, IndyTextEncoding_UTF8); begin lenSalt tmpStr:= UpperCaseLength(SSalt); SetLength(RStr, Length(tmpStr) div 2); i:= 1; try keyWeight := 0; for i := 1 to lenSalt do keyWeight := keyWeight + ord(Salt[i]); keyWeight := keyWeight mod CK_ENC_VAR_RANGE; whilefor (i < := 1 to Length(tmpStrInString)) do begin RStrB[i div 2]:= StrToInt('$' + tmpStr[i] + tmpStr[i+1] key := ( ord(Salt[(i mod lenSalt) + 1]) mod CK_ENC_VAR_RANGE); Result := Result + CHAR(Byte(InString[i]) + key - keyWeight); end; Inc(i, 2);end; end; function CKDecrypt(const InString:string; Salt:string): string; var i, endlenSalt, key, keyWeight: Word; exceptTarget: string; begin if (Salt Result:= '') then begin Target := InString; end else begin Exit; endlenSalt := Length(Salt); keyWeight := 0; for i := 01 to Length(RStr)-1 do begin tmpKey:= RStrB[i] lenSalt do keyWeight := keyWeight + ord(Salt[i]); keyWeight := keyWeight mod CK_ENC_VAR_RANGE; Target := ''; RStrB[i]for i := 1 to Length(InString) do begin key := ( RStrBord(Salt[(i] xor (Key shr 8 mod lenSalt) + 1]) mod CK_ENC_VAR_RANGE); Key Target := (tmpKeyTarget + KeyCHAR(Byte(InString[i]) *- CKEY1key + CKEY2keyWeight); end; Result := UTF8Decode(RStr)TIdDecoderMIME.DecodeString(Target, IndyTextEncoding_UTF8); end; end; |
Example
Code Block |
---|
{ Testng } procedure TForm1.btn1ClickButton1Click(Sender: TObject); begin txt2Memo2.Text := EncryptStrCKEncrypt(txt1Memo1.Text, 223'foo'); lbl1Memo3.CaptionText := DecryptStrCKDecrypt(txt2Memo2.Text, 223'foo'); end; |
...