(manual) Base64 encryption and decryption

Encryption algorithm

    public static string base64encrypt (string saltstr,string  SOURCESTR)         {             string targetstr = string. Empty;            sourcestr = saltstr  + sourceStr;            if  ( SOURCESTR.LENGTH&NBSP;%&NBSP;3&NBSP;==&NBSP;1)              {sourceStr = sourceStr +  "="  +  "="; }             else if (sourcestr.length%3==2)              { sourceStr = sourceStr +  "=";  }             byte[]&nBsp;sourcebyte = unicodeencoding.unicode.getbytes (SOURCESTR);               int count = sourceByte.Length;                                             List<byte> by = new List<byte> ();             for  (int current = 0; current  < count; current++)              {                by. AddRange (ToBit (sourcebyte[current));             }             byte[] bit8 = new byte[8];                  byte[] bit24 =  new byte[24];    //temp             int i = 0;             Int j = 0;            list<byte > targetByte = new List<byte> ();             foreach  (Byte b in by)              {                 bit24[i] = b;                 if  (i == 23)                  {                     bit24[i] = b;                     targetbyte.addrange (Bit24tobit32 (Bit24));                      i =-1;                 }                i ++;            }             i = 0;             byte[] byy = new byte[targetbyte.count / 8];             foreach  (Byte b in targetbyte)              {                 bit8[i] = b;                 if  (i == 7)                  {                     bit8[7] = b;                     byy[j++]  =  (Byte) tonum (BIT8);                     i = -1;                 }                 i++;            }             targetstr = unicodeencoding.unicode.getstring ( BYY);            return targetstr;         }

decryption algorithm

Public static string base64unencrypt (STRING&NBSP;SALTSTR,STRING&NBSP;SOURCESTR)          {             String targetstr = string. empty;            byte[] temp =  UnicodeEncoding.Unicode.GetBytes (SOURCESTR);   //Turn byte             byte[] sourceByte=new  byte[0];             list<byte> targetbyte = new list<byte > ();            byte[] bit8 =  new byte[8];            int i =  0;            int j = 0;            for  (int m = 0;  m < temp. length; m++)             {                 sourceByte =  Sourcebyte.concat (ToBit (Temp[m])). ToArray ();             }             foreach  (byte b in sourcebyte)              {                 bit8[i] = b;                 if  (i == 7)                  {                     bit8[i] = b;                     targetbyte.addrange (bit8. Tolist<byte> (). GetRange (2,6));                     i = -1;                 }                 i++;            }             i = 0;             byte[] byy=new  byte[targetByte.Count/8];             foreach  (Byte b in targetbyte)              {                 bit8[i] = b;                 if  (i == 7)                  {                     bit8[7] = b;                     byy[j++] =   (byte) tonum (BIT8);                     i = -1;                 }                i ++;            }             targetstr = unicodeencoding.unicode.getstring (BYY);             targetstr = targetstr.trimend (' = ') ;            targetstr =  Targetstr.substring (saltstr.length - 1);             return targetstr;        }

required functions

 public static byte[] bit24tobit32 (BYTE[]&NBSP;BIT24)          {            byte[] bit32 =  new byte[32];            int j  = -1;            for  (int i  = 0; i < 24; i++)              {                 if  (i % 6 == 0)                  {                     bit32[++j] = 0;                     bit32[++j] = 0;                     bit32[++j] =  bit24[i];                 }                else                 {                      bit32[++j] = bit24[i];                 }            }             return bit32;         }  &nBsp;     public static int tonum (Byte[] by)          {            int  num = 0;            int i  = 7;            foreach  (Byte  b in by)             {                 if  (b != 0)                 {                      num = num +  (int) Math.pow (2,i);                 }                     i--;            }             return num;         }        public static byte[] tobit ( BYTE&NBSP;NUM1)         {             byte[] bit = new byte[8];             int num = convert.toint32 (NUM1);             if  (num > -1 | |  num < 128)             {                 for  (int i = 0; i < 8; i++)                 { bit[7  - i] =  (Byte) ((num -  (num = num >> 1)  <<  1)); }            }             else             { throw new indexoutofrangeexception ("Out of range"); }             return bit;         }

test code

            console.writeline ("Input required base64 encrypted string");             string saltstr = string . empty;            string sourcestr =  string. Empty;            console.writeline ("Input add salt string");             saltstr = console.readline () ;             console.writeline ("Input required base64 encrypted string");             sourcestr = console.readline ();            string encryptstr =  Base64encrypt (SALTSTR, SOURCESTR);             consoLe. WriteLine ("Encrypted string" +encryptstr);             Console.WriteLine ("Input Add salt string");             saltstr  = console.readline ();             Console.WriteLine ("Input needs base64 decryption string, character is not lost");             //sourcestr = console.readline ();             string unencryptstr = base64unencrypt (SALTSTR, ENCRYPTSTR);             console.writeline ("String after Encryption"  +  UNENCRYPTSTR);

Test results

(manual) Base64 encryption and decryption