.NET6, Aes 範例, System.Security.Cryptography, Cypher, 加密, Encryption

AesExample.cs

///
/// ref->[Aes 類別](https://docs.microsoft.com/zh-tw/dotnet/api/system.security.cryptography.aes?view=net-6.0)
///

using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json;

class AesExample
{  
    public static void TestGo()
    {
        string original = "Here is 我是中文字 some data to encrypt!";

        // Create a new instance of the Aes
        // class.  This generates a new key and initialization
        // vector (IV).
        using var aesAlg = Aes.Create();

        // Encrypt the string to an array of bytes.
        //byte[] encrypted = EncryptStringToBytes_Aes(original, myAes.Key, myAes.IV);
        byte[] encrypted = DoEncryptData(original, aesAlg);

        // Decrypt the bytes to a string.
        //string roundtrip = DecryptStringFromBytes_Aes(encrypted, myAes.Key, myAes.IV);
        string roundtrip = DoDecryptData(encrypted, aesAlg);

        //Display the original data and the decrypted data.
        Console.WriteLine("Original:   {0}", original);
        Console.WriteLine("Round Trip: {0}", roundtrip);            
    }

    public static void Test2Go()
    {
        TestInfo original = new()
        {
            foo = "我是中文字",
            bar = 9876543210.123456m,
            baz = DateTime.Now
        };

        string cypher = AesSimpleEncrypt(original);

        TestInfo roundtrip = AesSimpleDecrypt<TestInfo>(cypher);

        //Display the original data and the decrypted data.
        Console.WriteLine("Original:   {0}", original);
        Console.WriteLine("Round Trip: {0}", roundtrip);
        Console.WriteLine("Cypher:     {0}", cypher);
    }

    static byte[] EncryptStringToBytes_Aes(string plainText, byte[] Key, byte[] IV)
    {
        // Check arguments.
        if (plainText == null || plainText.Length <= 0)
            throw new ArgumentNullException("plainText");
        if (Key == null || Key.Length <= 0)
            throw new ArgumentNullException("Key");
        if (IV == null || IV.Length <= 0)
            throw new ArgumentNullException("IV");
        byte[] encrypted;

        // Create an Aes object
        // with the specified key and IV.
        using (Aes aesAlg = Aes.Create())
        {
            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);
                    }
                    encrypted = msEncrypt.ToArray();
                }
            }
        }

        // Return the encrypted bytes from the memory stream.
        return encrypted;
    }

    static string DecryptStringFromBytes_Aes(byte[] cipherText, byte[] Key, byte[] IV)
    {
        // Check arguments.
        if (cipherText == null || cipherText.Length <= 0)
            throw new ArgumentNullException("cipherText");
        if (Key == null || Key.Length <= 0)
            throw new ArgumentNullException("Key");
        if (IV == null || IV.Length <= 0)
            throw new ArgumentNullException("IV");

        // Declare the string used to hold
        // the decrypted text.
        string plaintext = null;

        // Create an Aes object
        // with the specified key and IV.
        using (Aes aesAlg = Aes.Create())
        {
            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.
                        plaintext = srDecrypt.ReadToEnd();
                    }
                }
            }
        }

        return plaintext;
    }
    
    static string AesSimpleEncrypt<TObject>(TObject payload)
    {
        return Convert.ToBase64String(DoEncryptData(JsonSerializer.Serialize<TObject>(payload), GenAesKey()));
    }

    static TObject AesSimpleDecrypt<TObject>(string cipherText)
    {
        return JsonSerializer.Deserialize<TObject>(DoDecryptData(Convert.FromBase64String(cipherText), GenAesKey()));
    }

    static byte[] DoEncryptData(string plainText, Aes aesAlg)
    {
        // Create an encryptor to perform the stream transform.
        ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

        // Create the streams used for encryption.
        using var msEncrypt = new MemoryStream();
        using var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write);
        using var swEncrypt = new StreamWriter(csEncrypt);

        //Write all data to the stream.
        swEncrypt.Write(plainText);
        swEncrypt.Close();

        return msEncrypt.ToArray();
    }

    static string DoDecryptData(byte[] cipherText, Aes aesAlg)
    {
        // Create a decryptor to perform the stream transform.
        ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

        // Create the streams used for decryption.
        using var msDecrypt = new MemoryStream(cipherText);
        using var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read);
        using var srDecrypt = new StreamReader(csDecrypt);

        // Read the decrypted bytes from the decrypting stream
        return srDecrypt.ReadToEnd();
    }

    static Aes GenAesKey()
    {
        using var sha = new HMACSHA384(seed);
        string envprops = $"{Environment.MachineName}{Environment.OSVersion}{Environment.ProcessorCount}{DateTime.Today.DayOfYear}9iabcGT%rdX0Ox.y";
        var key48 = sha.ComputeHash(Encoding.ASCII.GetBytes(envprops)).AsSpan();
        Aes aesAlg = Aes.Create();
        aesAlg.Key = key48.Slice(0, 32).ToArray();
        aesAlg.IV = key48.Slice(32, 16).ToArray();
        return aesAlg;
    }

    /// <summary>
    /// only for [JwtSimpleEncode] & [JwtSimpleDecode]
    /// </summary>
    static readonly byte[] seed = { 131, 117, 87, 14, 21, 11, 19, 75, 124, 10, 159, 78, ... };
}

record TestInfo 
{
    public string foo { get; set; }
    public decimal bar { get; set; }
    public DateTime baz { get; set; }
}