Problem with Encryption decryption

Question

I am using this source code to encrypt and decrypt the password

public static string EncodePasswordToBase64(string password) 
{
   try 
   {
      byte[] encData_byte = new byte[password.Length]; 
      encData_byte = System.Text.Encoding.UTF8.GetBytes(password); 
      string encodedData = Convert.ToBase64String(encData_byte); 
      return encodedData; 
   } 
   catch (Exception ex) 
   { 
      throw new Exception("Error in base64Encode" + ex.Message); 
   } 
}
//this function Convert to Decord your Password
public string DecodeFrom64(string encodedData) 
{
   System.Text.UTF8Encoding encoder = new System.Text.UTF8Encoding(); 
   System.Text.Decoder utf8Decode = encoder.GetDecoder();
   byte[] todecode_byte = Convert.FromBase64String(encodedData); 
   int charCount = utf8Decode.GetCharCount(todecode_byte, 0, todecode_byte.Length); 
   char[] decoded_char = new char[charCount]; 
   utf8Decode.GetChars(todecode_byte, 0, todecode_byte.Length, decoded_char, 0); 
   string result = new String(decoded_char); 
   return result;
}

When I implement it.

string password = DecodeFrom64(txtPassword.Text.Trim());

I am coming across this error.

The input is not a valid Base-64 string as it contains a non-base 64 character

How can I resolve this issue

Answer 1

Hi @Adeel Mirza ,

The input is not a valid Base-64 string as it contains a non-base 64 character

The exact reason you're getting such an error is because it's not a valid Base64 string.
The Convert.FromBase64String(String) method converts the specified string to an equivalent array of 8-bit unsigned integers that encodes binary data as base-64 numbers.
FormatException
The length of string, ignoring white-space characters, is not zero or a multiple of 4.
The solution is that you need a string length divisible by 4, otherwise you pad it with equal signs.

 if (encodedData.Length % 4 != 0)  
      encodedData += new String('=', 4 - encodedData.Length % 4);  

-or-
The format of string is invalid. string contains a non-base-64 character, more than two padding characters, or a non-white space-character among the padding characters.

encodedData = encodedData.Replace('#', '=');  

If there are special characters that need to be replaced, note that there can only be at most two padding characters
Best regards,
Lan Huang

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