System.Security.Cryptography.CryptographicException: 'The input data is not a complete block.' C#

Question

I have C# code that is writing to a text file where the password inputted by the user gets encrypted through AES using EasyEncryption. I have both key and iv set to 128bit and encryption works fine. However, when I try to decrypt the password, I keep getting the incomplete block message.

        //PASSWORD IS BEING ENCRYPTED BEFORE SAVING TO TEXT FILE
        var keyValue = "/A?D(G+KbPeShVkY";
        var ivValue = "*G-KaPdSgVkYp3s5";
        var pEncryption = EasyEncryption.AES.Encrypt(PASSWORD, keyValue, ivValue);
        Console.WriteLine("\nPassword encrypted= " + pEncryption);
        file.WriteLine("password=" + pEncryption);

This is the decryption part that gives me the block error

        //PASSWORD DECRYPTION
        var keyValue = "/A?D(G+KbPeShVkY";
        var ivValue = "*G-KaPdSgVkYp3s5";
        var dcryPassword = EasyEncryption.AES.Decrypt(data["password"],keyValue, ivValue);

Does this: https://stackoverflow.com/questions/19614178/aes-encryption-error-the-input-data-is-not-a-complete-block help? — Athanasios Kataras, Feb 22 '20 at 08:23
Try with the code that @Charles shared and if it works, check where your data["password"] is converted along the way like the example in my other comment. — Athanasios Kataras, Feb 22 '20 at 08:25

score 0 · Answer 1 · answered Feb 22 '20 at 06:59

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i have faced similar issue, and resolved by observingthe input text for decryt() method some time it is malformed.

you can also check the same.

answered Feb 22 '20 at 06:59

Krishna Bhanu Singh

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score 0 · Answer 2 · answered Feb 22 '20 at 20:41

Okay, I finally figured out a solution. I was attempting to decrypt the password straight from a notepad file which reads by default UTF8. I read the encrypted password using a string called rpass (read password) and then used rpass to be decrypted. Works as it should now.

//Need to read from text UTF8 before trying to decrypt, == is padding
            string rpass = data["password"] + "==";
            Console.WriteLine(rpass);
            string dpass = Decrypt(rpass);
            Console.WriteLine("decryption= " + dpass);

The +== is to add the padding. My text file that is being read is separates the values with =. — Joshua Jaynes, Feb 22 '20 at 20:42

System.Security.Cryptography.CryptographicException: 'The input data is not a complete block.' C#

2 Answers2