C#•2y ago

CryptoStream decrypt encrypt

I have a class to encrypt and decrypt strings but for some reason i get an exception: System.Security.Cryptography.CryptographicException: 'Padding is invalid and cannot be removed.'

public class BasicEncryption
    {
        public string Encrypt(string rawValue)
        {
            using Aes aes = Aes.Create();
            using ICryptoTransform encryptor = aes.CreateEncryptor();
            using MemoryStream memoryStream = new MemoryStream();
            using CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);
            using StreamWriter swEncrypt = new StreamWriter(cryptoStream);
            swEncrypt.Write(rawValue);
            swEncrypt.Flush();
            var memBytes = memoryStream.ToArray();
            return Convert.ToBase64String(memBytes);
        }

        public string Decrypt(string encryptedValue)
        {
            using Aes aes = Aes.Create();
            byte[] encryptedData = Convert.FromBase64String(encryptedValue);
            using ICryptoTransform decryptor = aes.CreateDecryptor();
            using MemoryStream memoryStream = new MemoryStream(encryptedData);
            using CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
            using StreamReader srDecrypt = new StreamReader(cryptoStream);
            string plaintext = srDecrypt.ReadToEnd();
            return plaintext;
        }
    }

public class BasicEncryption
    {
        public string Encrypt(string rawValue)
        {
            using Aes aes = Aes.Create();
            using ICryptoTransform encryptor = aes.CreateEncryptor();
            using MemoryStream memoryStream = new MemoryStream();
            using CryptoStream cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write);
            using StreamWriter swEncrypt = new StreamWriter(cryptoStream);
            swEncrypt.Write(rawValue);
            swEncrypt.Flush();
            var memBytes = memoryStream.ToArray();
            return Convert.ToBase64String(memBytes);
        }

        public string Decrypt(string encryptedValue)
        {
            using Aes aes = Aes.Create();
            byte[] encryptedData = Convert.FromBase64String(encryptedValue);
            using ICryptoTransform decryptor = aes.CreateDecryptor();
            using MemoryStream memoryStream = new MemoryStream(encryptedData);
            using CryptoStream cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
            using StreamReader srDecrypt = new StreamReader(cryptoStream);
            string plaintext = srDecrypt.ReadToEnd();
            return plaintext;
        }
    }

7 Replies

Unknown User•2y ago

Message Not Public

hippiewho•2y ago

not related

Unknown User•2y ago

Message Not Public

Scratch•2y ago

https://stackoverflow.com/a/8590161

Stack Overflow

Padding is invalid and cannot be removed?

I have looked online for what this exception means in relation to my program but can't seem to find a solution or the reason why it's happening to my specific program. I have been using the example

hippiewho•2y ago

I read this as well... And it does seem to be a padding issue but none of the padding options work... I changed it up a bit and i was able to get the decrypt method to decrypt most of the string.... The last few bits are missing. I ended up adding a few characters to the rawValue string and it decrypted the entire string correctly (with the padding characters I added). Still so lost

Scratch•2y ago

did you set alg.Padding = PaddingMode.PKCS7; on both the encryption and decryption Aes object?

hippiewho•2y ago

Yea I did...

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CryptoStream decrypt encrypt