AesCryptor Class

Definition

Namespace

Cuemon.Security.Cryptography

Assemblies

Cuemon.Security.Cryptography.dll

Source

src/Cuemon.Security.Cryptography/AesCryptor.cs

Provides an implementation of the Advanced Encryption Standard (AES) symmetric algorithm.

public class AesCryptor

Inheritance

object

AesCryptor

Examples

AesCryptor provides AES encryption and decryption with configurable key size, cipher mode, and padding. This example generates a 256-bit key and 128-bit IV using AesCryptor.GenerateKey() and GenerateInitializationVector(), encrypts "This is a sensitive message that needs encryption.", decrypts the ciphertext, and verifies the round-trip matches the original. It also demonstrates explicit CBC mode with PKCS7 padding via an options delegate, custom key sizes (AesSize.Aes128 and AesSize.Aes192), and the default constructor that generates random credentials automatically. Console output confirms key and IV lengths, base64 ciphertext, round-trip success, and explicit options round-trip verification.

using System;
using System.Security.Cryptography;
using System.Text;
using Cuemon.Security.Cryptography;

namespace MyApp.Security
{
    public class AesCryptorExamples
    {
        public static void Demonstrate()
        {
            // Generate a 256-bit key and 128-bit initialization vector.
            byte[] key = AesCryptor.GenerateKey();
            byte[] iv = AesCryptor.GenerateInitializationVector();

            Console.WriteLine("Key length: {0} bytes ({1} bits)", key.Length, key.Length * 8);
            Console.WriteLine("IV length: {0} bytes ({1} bits)", iv.Length, iv.Length * 8);

            // Create an AesCryptor instance with the generated key and IV.
            var cryptor = new AesCryptor(key, iv);

            // Encrypt a secret message.
            byte[] plaintext = Encoding.UTF8.GetBytes("This is a sensitive message that needs encryption.");
            byte[] ciphertext = cryptor.Encrypt(plaintext);

            Console.WriteLine("Plaintext bytes: {0}", plaintext.Length);
            Console.WriteLine("Ciphertext (base64): {0}", Convert.ToBase64String(ciphertext));

            // Decrypt the ciphertext back to the original message.
            byte[] decrypted = cryptor.Decrypt(ciphertext);
            string roundtrip = Encoding.UTF8.GetString(decrypted);

            Console.WriteLine("Decrypted message: {0}", roundtrip); // matches original

            // Use explicit AES options (CBC mode, PKCS7 padding).
            byte[] ciphertextExplicit = cryptor.Encrypt(plaintext, o =>
            {
                o.Mode = CipherMode.CBC;
                o.Padding = PaddingMode.PKCS7;
            });

            byte[] decryptedExplicit = cryptor.Decrypt(ciphertextExplicit, o =>
            {
                o.Mode = CipherMode.CBC;
                o.Padding = PaddingMode.PKCS7;
            });

            Console.WriteLine("Explicit options roundtrip: {0}",
                Encoding.UTF8.GetString(decryptedExplicit) == roundtrip); // true
        }

        public static void GenerateKeysWithCustomSize()
        {
            // Generate a 128-bit key explicitly.
            byte[] key128 = AesCryptor.GenerateKey(o => o.Size = AesSize.Aes128);
            Console.WriteLine("128-bit key length: {0} bytes", key128.Length); // 16

            // Generate a 192-bit key.
            byte[] key192 = AesCryptor.GenerateKey(o => o.Size = AesSize.Aes192);
            Console.WriteLine("192-bit key length: {0} bytes", key192.Length); // 24

            // Default is 256-bit.
            byte[] key256 = AesCryptor.GenerateKey();
            Console.WriteLine("256-bit key length: {0} bytes", key256.Length); // 32
        }

        public static void UseDefaultConstructor()
        {
            // Default constructor generates a random key and IV.
            var cryptor = new AesCryptor();

            byte[] data = Encoding.UTF8.GetBytes("Hello, world!");
            byte[] encrypted = cryptor.Encrypt(data);
            byte[] decrypted = cryptor.Decrypt(encrypted);

            Console.WriteLine("Default constructor roundtrip: {0}",
                Encoding.UTF8.GetString(decrypted)); // Hello, world!
        }
    }
}

Constructors

Name	Description
AesCryptor()	Initializes a new instance of the AesCryptor class.
AesCryptor(byte[], byte[])	Initializes a new instance of the AesCryptor class.

Fields

Name	Description
BlockSize	Gets the block size (bits) for the Advanced Encryption Standard (AES) symmetric algorithm.

Properties

Name	Description
InitializationVector	Gets the initialization vector (IV) of this instance.
Key	Gets the secret key of this instance.

Methods

Name	Description
Decrypt(byte[], Action<AesCryptorOptions>)	Decrypts the specified value.
Encrypt(byte[], Action<AesCryptorOptions>)	Encrypts the specified value.
GenerateInitializationVector()	Generates a random 128 bit initialization vector (IV).
GenerateKey(Action<AesKeyOptions>)	Generates a secret key from the options defined in setup.