Invalid length for a Base-64 char array

Question

I'm getting a "Invalid length for a Base-64 char array." inside of the IF(){...} are variations i have tried to get it to work. it fails in the first line without calling decrypt(...) proving it's not that functions problem. i get the same error inside with the first decrypt(...) call. the last one using the encoding.ascii... will get me inside the function, but then it fails inside the function. I'm getting the proper encrypted info from the database to string SSnum. it's value is: 4+mFeTp3tPF

try
{
    string SSnum = dr.GetString(dr.GetOrdinal("Social Security"));
    if (isEncrypted)
    {
      byte[] temp = Convert.FromBase64String(SSnum);
      //SSnum = decrypt(Convert.FromBase64String(SSnum), Key, IV);
      //SSnum = decrypt(Encoding.ASCII.GetBytes(SSnum), Key, IV);
    }
    txt_Social_Security.Text = SSnum;
}
catch { txt_Social_Security.Text = ""; }

I've been told to use the Convert.FromBase64String() and not the ASCII method...so why is it failing, how can i fix it?

Answer 1

Base64 data length should be multiple of 4 and with padding char '=' You can change your data as valid base64 data.

string dummyData = imgData.Trim().Replace(" ", "+");
if (dummyData.Length % 4 > 0)
dummyData = dummyData.PadRight(dummyData.Length + 4 - dummyData.Length % 4, '=');
byte[] byteArray = Convert.FromBase64String(dummyData); 

https://stackoverflow.com/a/9301545/2024022

This will help you , try once. Thanks suribabu.