csharp_ase_encrypt

gistfile1.txt

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

class Program
{
    static void Main()
    {
        // Define a password, salt, and iteration count for key derivation
        string password = "ThisIsAStrongPassword";
        byte[] salt = Encoding.UTF8.GetBytes("ThisIsASalt");
        int iterations = 10000;

        // Derive a valid key using the password, salt, and iteration count
        byte[] key = DeriveKey(password, salt, iterations);

        // Initialization vector (IV) is also needed for AES encryption
        byte[] iv = GenerateIV();

        string originalText = "Hello, this is a secret message!";

        // Encrypt the original text
        byte[] encryptedBytes = EncryptStringToBytes(originalText, key, iv);

        // Convert the encrypted bytes to a base64 string for easy storage or transmission
        string encryptedText = Convert.ToBase64String(encryptedBytes);
        Console.WriteLine("Encrypted Text: " + encryptedText);

        // Decrypt the encrypted text
        string decryptedText = DecryptStringFromBytes(encryptedBytes, key, iv);
        Console.WriteLine("Decrypted Text: " + decryptedText);

        Console.ReadLine();
    }

    static byte[] DeriveKey(string password, byte[] salt, int iterations)
    {
        using (Rfc2898DeriveBytes derivedBytes = new Rfc2898DeriveBytes(password, salt, iterations))
        {
            return derivedBytes.GetBytes(32); // 32 bytes = 256 bits (valid key size for AES)
        }
    }

    static byte[] GenerateIV()
    {
        using (AesManaged aes = new AesManaged())
        {
            aes.GenerateIV();
            return aes.IV;
        }
    }

    static byte[] EncryptStringToBytes(string plainText, byte[] key, byte[] iv)
    {
        // Create a new instance of the AesManaged class
        using (AesManaged aesAlg = new AesManaged())
        {
            // Set the key and IV
            aesAlg.Key = key;
            aesAlg.IV = iv;

            // Create an encryptor to perform the stream transform
            ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

            // Create the streams used for encryption
            using (MemoryStream msEncrypt = new MemoryStream())
            {
                using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                {
                    using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                    {
                        // Write all data to the stream
                        swEncrypt.Write(plainText);
                    }
                    // Return the encrypted bytes from the memory stream
                    return msEncrypt.ToArray();
                }
            }
        }
    }

    static string DecryptStringFromBytes(byte[] cipherText, byte[] key, byte[] iv)
    {
        // Create a new instance of the AesManaged class
        using (AesManaged aesAlg = new AesManaged())
        {
            // Set the key and IV
            aesAlg.Key = key;
            aesAlg.IV = iv;

            // Create a decryptor to perform the stream transform
            ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

            // Create the streams used for decryption
            using (MemoryStream msDecrypt = new MemoryStream(cipherText))
            {
                using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                {
                    using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                    {
                        // Read the decrypted bytes from the decrypting stream and place them in a string
                        return srDecrypt.ReadToEnd();
                    }
                }
            }
        }
    }
}