.NET Core 2 Encrypt/Decrypt String

Encryption.cs

public static void Main(string[] args)
{
    var content = "Example test";
    var key = "E546C8DF278CD5931069B522E695D4F2";

    var encrypted = EncryptString(content, key);
    Console.WriteLine(encrypted);

    var decrypted = DecryptString(encrypted, key);
    Console.WriteLine(decrypted);

    Console.ReadLine();
}



public static string EncryptString(string text, string keyString)
{
    var key = Encoding.UTF8.GetBytes(keyString);

    using (var aesAlg = Aes.Create())
    {
        using (var encryptor = aesAlg.CreateEncryptor(key, aesAlg.IV))
        {
            using (var msEncrypt = new MemoryStream())
            {
                using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                using (var swEncrypt = new StreamWriter(csEncrypt))
                {
                    swEncrypt.Write(text);
                }

                var iv = aesAlg.IV;

                var decryptedContent = msEncrypt.ToArray();

                var result = new byte[iv.Length + decryptedContent.Length];

                Buffer.BlockCopy(iv, 0, result, 0, iv.Length);
                Buffer.BlockCopy(decryptedContent, 0, result, iv.Length, decryptedContent.Length);

                return Convert.ToBase64String(result);
            }
        }
    }
}

public static string DecryptString(string cipherText, string keyString)
{
    var fullCipher = Convert.FromBase64String(cipherText);

    var iv = new byte[16];
    var cipher = new byte[16];

    Buffer.BlockCopy(fullCipher, 0, iv, 0, iv.Length);
    Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, iv.Length);
    var key = Encoding.UTF8.GetBytes(keyString);

    using (var aesAlg = Aes.Create())
    {
        using (var decryptor = aesAlg.CreateDecryptor(key, iv))
        {
            string result;
            using (var msDecrypt = new MemoryStream(cipher))
            {
                using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                {
                    using (var srDecrypt = new StreamReader(csDecrypt))
                    {
                        result = srDecrypt.ReadToEnd();
                    }
                }
            }

            return result;
        }
    }
}

Receiving below error when "using (var encryptor = aesAlg.CreateEncryptor(_key, aesAlg.IV))" is executed in EncryptString function.
Error Message: ArgumentException: Specified key is not a valid size for this algorithm. Parameter name: rgbKey

Can anyone help?

Same same

Use this as encryption key: "E546C8DF278CD5931069B522E695D4F2".
It will work for me now after updating key.

The key sizes need to be 128, 192 or 256 bits. Since the code above reads bytes from a UTF8 string min key length is 16 characters, 24 and 32 chars lengths will also work. Anything else will throw an exception