Question

我需要实现AES 256加密/解密，但我找不到能够正常工作的示例。

MSDN建议我使用AES类。

Rijndael类是Aes算法的前身。您应该使用Aes算法而不是Rijndael。有关更多信息，请参阅.NET安全博客中的条目The Differences Between Rijndael and AES。

有人能指出我使用AES类的AES256的好例子吗？

添加更多清晰度：

我有一个包含共享密钥和一串加密文本的密码文件。我需要解密文本然后验证它。

我见过的所有示例都希望至少有2个参数来执行加密/解密。

我是否能够从密码文件中的文本推断出初始化向量和密钥？

这是我的密码文件中保存的文本示例：

ÊÚá¸±Ìráƒ@†²;Ä;öDWnªóª©¨¨L

Answer 1

也许这个列出here的例子可以帮到你。作者的陈述

大约24行加密代码，23行解密

Answer 2

一旦我发现了我的客户端如何处理加密/解密的所有信息，就可以直接使用dtb建议的AesManaged example。

最终实现的代码如下所示：

    try
    {
        // Create a new instance of the AesManaged class.  This generates a new key and initialization vector (IV).
        AesManaged myAes = new AesManaged();

        // Override the cipher mode, key and IV
        myAes.Mode = CipherMode.ECB;
        myAes.IV = new byte[16] { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }; // CRB mode uses an empty IV
        myAes.Key = CipherKey;  // Byte array representing the key
        myAes.Padding = PaddingMode.None;

        // Create a encryption object to perform the stream transform.
        ICryptoTransform encryptor = myAes.CreateEncryptor();

        // TODO: perform the encryption / decryption as required...

    }
    catch (Exception ex)
    {
        // TODO: Log the error 
        throw ex;
    }

Answer 3

尝试here中的示例。

运行良好。

class Aes256CbcEncrypter
    {
        private static readonly Encoding encoding = Encoding.UTF8;

        public static string Encrypt(string plainText, string key)
        {
            try
            {
                RijndaelManaged aes = new RijndaelManaged();
                aes.KeySize = 256;
                aes.BlockSize = 128;
                aes.Padding = PaddingMode.PKCS7;
                aes.Mode = CipherMode.CBC;

                aes.Key = encoding.GetBytes(key);
                aes.GenerateIV();

                ICryptoTransform AESEncrypt = aes.CreateEncryptor(aes.Key, aes.IV);
                byte[] buffer = encoding.GetBytes(plainText);

                string encryptedText = Convert.ToBase64String(AESEncrypt.TransformFinalBlock(buffer, 0, buffer.Length));

                String mac = "";

                mac = BitConverter.ToString(HmacSHA256(Convert.ToBase64String(aes.IV) + encryptedText, key)).Replace("-", "").ToLower();

                var keyValues = new Dictionary<string, object>
                {
                    { "iv", Convert.ToBase64String(aes.IV) },
                    { "value", encryptedText },
                    { "mac", mac },
                };

                JavaScriptSerializer serializer = new JavaScriptSerializer();

                return Convert.ToBase64String(encoding.GetBytes(serializer.Serialize(keyValues)));
            }
            catch (Exception e)
            {
                throw new Exception("Error encrypting: " + e.Message);
            }
        }

        public static string Decrypt(string plainText, string key)
        {
            try
            {
                RijndaelManaged aes = new RijndaelManaged();
                aes.KeySize = 256;
                aes.BlockSize = 128;
                aes.Padding = PaddingMode.PKCS7;
                aes.Mode = CipherMode.CBC;
                aes.Key = encoding.GetBytes(key);

                // Base 64 decode
                byte[] base64Decoded = Convert.FromBase64String(plainText);
                string base64DecodedStr = encoding.GetString(base64Decoded);

                // JSON Decode base64Str
                JavaScriptSerializer ser = new JavaScriptSerializer();
                var payload = ser.Deserialize<Dictionary<string, string>>(base64DecodedStr);

                aes.IV = Convert.FromBase64String(payload["iv"]);

                ICryptoTransform AESDecrypt = aes.CreateDecryptor(aes.Key, aes.IV);
                byte[] buffer = Convert.FromBase64String(payload["value"]);

                return encoding.GetString(AESDecrypt.TransformFinalBlock(buffer, 0, buffer.Length));
            }
            catch (Exception e)
            {
                throw new Exception("Error decrypting: " + e.Message);
            }
        }

        static byte[] HmacSHA256(String data, String key)
        {
            using (HMACSHA256 hmac = new HMACSHA256(encoding.GetBytes(key)))
            {
                return hmac.ComputeHash(encoding.GetBytes(data));
            }
        }
    }
}

Answer 4

public class AesCryptoService
{
    private static byte[] Key = Encoding.ASCII.GetBytes(@"qwr{@^h`h&_`50/ja9!'dcmh3!uw<&=?");
    private static byte[] IV = Encoding.ASCII.GetBytes(@"9/\~V).A,lY&=t2b");


    public static string EncryptStringToBytes_Aes(string plainText)
    {
        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;


        using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
        {
            aesAlg.Key = Key;
            aesAlg.IV = IV;
            aesAlg.Mode = CipherMode.CBC;
            aesAlg.Padding = PaddingMode.PKCS7;

            ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

            using (MemoryStream msEncrypt = new MemoryStream())
            {
                using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                {
                    using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                    {
                        swEncrypt.Write(plainText);
                    }
                    encrypted = msEncrypt.ToArray();
                }
            }
        }
        
        return Convert.ToBase64String(encrypted);
    }


    
    public static string DecryptStringFromBytes_Aes(string Text)
    {
        if (Text == null || Text.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");

        string plaintext = null;
        byte[] cipherText = Convert.FromBase64String(Text.Replace(' ', '+'));

        using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
        {
            aesAlg.Key = Key;
            aesAlg.IV = IV;
            aesAlg.Mode = CipherMode.CBC;
            aesAlg.Padding = PaddingMode.PKCS7;


            ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

            using (MemoryStream msDecrypt = new MemoryStream(cipherText))
            {
                using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                {
                    using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                    {
                        plaintext = srDecrypt.ReadToEnd();
                    }
                }
            }

        }

        return plaintext;
    }
}

C＃使用System.Security.Cryptography.Aes进行AES256加密的示例

4 个答案: