Delphi String Encryption/Decryption

Unit uencrypt_decrypt; interface uses Sysutils; const xorkey:array[0..7] of Byte = ($B 2, $09, $AA, $55, $9 3, $6d, $84, $47);  //through key key encryption function encryptstring (source, key:string): String;function unencryptstring (source , key:string): string; //XOR/Cryptographic 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]) + OFFSE T) mod 255;    If Keypos < Keylen then      Keypos: = Keypos + 1    else  &nbsp ;   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  &nb Sp Key: = ' Delphi ';  keypos: = 0;  Offset: = Strtoint (' $ ' + copy (Source, 1, 2));  Srcpos: = 3;  repeat&nb Sp   SRCASC: = Strtoint (' $ ' + copy (Source, Srcpos, 2));    If Keypos < Keylen then      KEYP OS: = Keypos + 1    else      Keypos: = 1;    TMPSRCASC: = Srcasc xor Ord (Key[keypos]);     If TMPSRCASC <= Offset then      TMPSRCASC: = 255 + tmpsrcasc-offset    ELSE&N Bsp     TMPSRCASC: = tmpsrcasc-offset;    Dest: = Dest + chr (TMPSRCASC);    Offset: = srcasc;& nbsp   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&NB Sp   XORKEY[J]);    J: = (j + 1) mod 8;  end;end; end. ====================================== ======-based DES encryption and decryption:  http://blog.csdn.net/warrially/article/details/8089041

Delphi String Encryption/decryption