C# 字符串和文件加解密 使用Cryptography

public class EncryptionAndDecryption
    {

        /// <summary>
        /// 加密文件
        /// </summary>
        /// <param name="bytesToBeEncrypted"></param>
        /// <param name="passwordBytes"></param>
        /// <returns></returns>
        public byte[] AES_Encrypt(byte[] bytesToBeEncrypted, byte[] passwordBytes)
        {
            byte[] encryptedBytes = null;

            //把盐放在这里，换成符合你口味的：
            //salt字节必须至少为8个字节。
            byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };

            using (MemoryStream ms = new MemoryStream())
            {
                using (RijndaelManaged AES = new RijndaelManaged())
                {
                    AES.KeySize = 256;
                    AES.BlockSize = 128;

                    var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
                    AES.Key = key.GetBytes(AES.KeySize / 8);
                    AES.IV = key.GetBytes(AES.BlockSize / 8);

                    AES.Mode = CipherMode.CBC;

                    using (var cs = new CryptoStream(ms, AES.CreateEncryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(bytesToBeEncrypted, 0, bytesToBeEncrypted.Length);
                        cs.Close();
                    }
                    encryptedBytes = ms.ToArray();
                }
            }

            return encryptedBytes;
        }
        /// <summary>
        /// 解密文件
        /// </summary>
        /// <param name="bytesToBeDecrypted"></param>
        /// <param name="passwordBytes"></param>
        /// <returns></returns>
        public byte[] AES_Decrypt(byte[] bytesToBeDecrypted, byte[] passwordBytes)
        {
            byte[] decryptedBytes = null;

            //把盐放在这里，换成符合你口味的：
            //salt字节必须至少为8个字节。
            byte[] saltBytes = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };

            using (MemoryStream ms = new MemoryStream())
            {
                using (RijndaelManaged AES = new RijndaelManaged())
                {
                    AES.KeySize = 256;
                    AES.BlockSize = 128;

                    var key = new Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);
                    AES.Key = key.GetBytes(AES.KeySize / 8);
                    AES.IV = key.GetBytes(AES.BlockSize / 8);

                    AES.Mode = CipherMode.CBC;

                    using (var cs = new CryptoStream(ms, AES.CreateDecryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(bytesToBeDecrypted, 0, bytesToBeDecrypted.Length);
                        cs.Close();
                    }
                    decryptedBytes = ms.ToArray();
                }
            }

            return decryptedBytes;
        }
        /// <summary>
        /// 字符串加密
        /// </summary>
        /// <param name="input"></param>
        /// <param name="password"></param>
        /// <returns></returns>
        public string EncryptText(string input, string password)
        {
            // Get the bytes of the string 获取字符串的字节数
            byte[] bytesToBeEncrypted = Encoding.UTF8.GetBytes(input);
            byte[] passwordBytes = Encoding.UTF8.GetBytes(password);

            // Hash the password with SHA256 用SHA256散列密码
            passwordBytes = SHA256.Create().ComputeHash(passwordBytes);

            byte[] bytesEncrypted = AES_Encrypt(bytesToBeEncrypted, passwordBytes);

            string result = Convert.ToBase64String(bytesEncrypted);

            return result;
        }

        /// <summary>
        /// 字符串解密
        /// </summary>
        /// <param name="input"></param>
        /// <param name="password"></param>
        /// <returns></returns>
        public string DecryptText(string input, string password)
        {
            // Get the bytes of the string 获取字符串的字节数
            byte[] bytesToBeDecrypted = Convert.FromBase64String(input);
            byte[] passwordBytes = Encoding.UTF8.GetBytes(password);
            passwordBytes = SHA256.Create().ComputeHash(passwordBytes);

            byte[] bytesDecrypted = AES_Decrypt(bytesToBeDecrypted, passwordBytes);

            string result = Encoding.UTF8.GetString(bytesDecrypted);

            return result;
        }
    }

调用class，加密字符串，页面上可以看到效果

            EncryptionAndDecryption ed = new EncryptionAndDecryption();
            //加密 123456abc，key是111aaa
            var str = ed.EncryptText("123456abc","111aaa");
            //加密过后的字符串
            ViewBag.encryptStr = str;
            //解密后得到 123456abc
            ViewBag.decryptStr = ed.DecryptText(str,"111aaa");

 <div>加密：@ViewBag.encryptStr<br />解密：@ViewBag.decryptStr</div>