An invalid length for a base-64 char array error occurred in the encrypted URL.

The class is transferred from: http://forums.asp.net/t/1222829.aspx. However, I have some questions. Now I want to share the answer, which is very simple.

Using System;
Using System. IO;
Using System. xml;
Using System. text;
Using System. Security. cryptography;


/**/ /// <Summary>
///Summary Description for encryption64
/// </Summary>
Public   Class Encryption64
{
Const   String Administrative ey =   " Aqwsedrf " ;
Const   String Desiv =   " Hgfedcba " ;

Public   Static   String Desdecrypt ( String Stringtodecrypt) // Decrypt the content
{

Byte [] Key;
Byte [] IV;

Byte [] Inputbytearray;
Try
{

Key = Convert2bytearray (distribuey );

IV = Convert2bytearray (desiv );

Int Len = Stringtodecrypt. length;

// Stringtodecrypt = stringtodecrypt. Replace ("", "+ ");
Inputbytearray = Convert. frombase64string (stringtodecrypt );


Descryptoserviceprovider des =   New Descryptoserviceprovider ();

Memorystream MS =   New Memorystream ();

Cryptostream CS =   New Cryptostream (MS, Des. createdecryptor (Key, IV), cryptostreammode. Write );
CS. Write (inputbytearray, 0 , Inputbytearray. Length );

CS. flushfinalblock ();

Encoding = Encoding. utf8; Return Encoding. getstring (Ms. toarray ());
}

Catch (System. Exception ex)
{

ThrowEx;
}
}

Public   Static   String Desencrypt ( String Stringtoencrypt) // Encrypt the content
{

Byte [] Key;
Byte [] IV;

Byte [] Inputbytearray;
Try
{

Key = Convert2bytearray (distribuey );

IV = Convert2bytearray (desiv );

Inputbytearray = Encoding. utf8.getbytes (stringtoencrypt );
Descryptoserviceprovider des =   New Descryptoserviceprovider ();

Memorystream MS =   New Memorystream (); cryptostream CS =   New Cryptostream (MS, Des. createencryptor (Key, IV), cryptostreammode. Write );
CS. Write (inputbytearray, 0 , Inputbytearray. Length );

CS. flushfinalblock ();

String Value = Convert. tobase64string (Ms. toarray ());
// Value = value. Replace ("+ ","");

Return Value;
}

Catch (System. Exception ex)
{

ThrowEx;
}

}

Static   Byte [] Convert2bytearray ( String Strinput)
{

Int Intcounter; Char [] Arrchar;
Arrchar = Strinput. tochararray ();

Byte [] Arrbyte =   New   Byte [Arrchar. Length];

For (Intcounter =   0 ; Intcounter <= Arrbyte. Length -   1 ; Intcounter ++ )
Arrbyte [intcounter] = Convert. tobyte (arrchar [intcounter]);

Return Arrbyte;
}



}

AboveCodeIt runs normally most of the time, but if the encrypted string contains "+", it is received using request. querystring, and the "+" character will be missed,
During decryption, an invalid length for a base-64 char array exception is reported.

String Value = Convert. tobase64string (Ms. toarray ());
Value = Value. Replace ( " + " , "   " );

Should be replaced when decryptionStringtodecrypt=Stringtodecrypt. Replace (" ","+");
Inputbytearray=Convert. frombase64string (stringtodecrypt );

it takes a long time to discover it, hoping it will be helpful to you...