参考c#中加密和解密字符串，我找到了一个很好的解决方案:

static readonly string PasswordHash = "P@@Sw0rd";
static readonly string SaltKey = "S@LT&KEY";
static readonly string VIKey = "@1B2c3D4e5F6g7H8";

对于加密

public static string Encrypt(string plainText)
{
    byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);

    byte[] keyBytes = new Rfc2898DeriveBytes(PasswordHash, Encoding.ASCII.GetBytes(SaltKey)).GetBytes(256 / 8);
    var symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC, Padding = PaddingMode.Zeros };
    var encryptor = symmetricKey.CreateEncryptor(keyBytes, Encoding.ASCII.GetBytes(VIKey));

    byte[] cipherTextBytes;

    using (var memoryStream = new MemoryStream())
    {
        using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
        {
            cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
            cryptoStream.FlushFinalBlock();
            cipherTextBytes = memoryStream.ToArray();
            cryptoStream.Close();
        }
        memoryStream.Close();
    }
    return Convert.ToBase64String(cipherTextBytes);
}

对解密

public static string Decrypt(string encryptedText)
{
    byte[] cipherTextBytes = Convert.FromBase64String(encryptedText);
    byte[] keyBytes = new Rfc2898DeriveBytes(PasswordHash, Encoding.ASCII.GetBytes(SaltKey)).GetBytes(256 / 8);
    var symmetricKey = new RijndaelManaged() { Mode = CipherMode.CBC, Padding = PaddingMode.None };

    var decryptor = symmetricKey.CreateDecryptor(keyBytes, Encoding.ASCII.GetBytes(VIKey));
    var memoryStream = new MemoryStream(cipherTextBytes);
    var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read);
    byte[] plainTextBytes = new byte[cipherTextBytes.Length];

    int decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
    memoryStream.Close();
    cryptoStream.Close();
    return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount).TrimEnd("\0".ToCharArray());
}

加密

public string EncryptString(string inputString)
{
    MemoryStream memStream = null;
    try
    {
        byte[] key = { };
        byte[] IV = { 12, 21, 43, 17, 57, 35, 67, 27 };
        string encryptKey = "aXb2uy4z"; // MUST be 8 characters
        key = Encoding.UTF8.GetBytes(encryptKey);
        byte[] byteInput = Encoding.UTF8.GetBytes(inputString);
        DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
        memStream = new MemoryStream();
        ICryptoTransform transform = provider.CreateEncryptor(key, IV);
        CryptoStream cryptoStream = new CryptoStream(memStream, transform, CryptoStreamMode.Write);
        cryptoStream.Write(byteInput, 0, byteInput.Length);
        cryptoStream.FlushFinalBlock();
    }
    catch (Exception ex)
    {
        Response.Write(ex.Message);
    }
    return Convert.ToBase64String(memStream.ToArray());
}

解密:

public string DecryptString(string inputString)
{
    MemoryStream memStream = null;
    try
    {
        byte[] key = { };
        byte[] IV = { 12, 21, 43, 17, 57, 35, 67, 27 };
        string encryptKey = "aXb2uy4z"; // MUST be 8 characters
        key = Encoding.UTF8.GetBytes(encryptKey);
        byte[] byteInput = new byte[inputString.Length];
        byteInput = Convert.FromBase64String(inputString);
        DESCryptoServiceProvider provider = new DESCryptoServiceProvider();
        memStream = new MemoryStream();
        ICryptoTransform transform = provider.CreateDecryptor(key, IV);
        CryptoStream cryptoStream = new CryptoStream(memStream, transform, CryptoStreamMode.Write);
        cryptoStream.Write(byteInput, 0, byteInput.Length);
        cryptoStream.FlushFinalBlock();
    }
    catch (Exception ex)
    {
        Response.Write(ex.Message);
    }

    Encoding encoding1 = Encoding.UTF8;
    return encoding1.GetString(memStream.ToArray());
}

用于AES-GCM加密的BouncyCastle的替代方案是libsodium-net。它包装了libsodium C库。一个很好的优点是它在cpu中使用AES-NI扩展进行非常快速的加密。缺点是，如果CPU没有扩展，它根本无法工作。软件没有退路。

您必须使用System.Security.Cryptography来使用命名空间;usehash是bool类型，true或false。字符串变量“key”对于加密和解密应该是相同的

//Encryption
public string EncryptText(string toEncrypt, bool useHashing)
    {
        try
        {
            byte[] keyArray;
            byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

            string key = "String Key Value"; //Based on this key stirng is encrypting
            //System.Windows.Forms.MessageBox.Show(key);
            //If hashing use get hashcode regards to your key
            if (useHashing)
            {
                MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
                //Always release the resources and flush data
                //of the Cryptographic service provide. Best Practice

                hashmd5.Clear();
            }
            else
                keyArray = UTF8Encoding.UTF8.GetBytes(key);

            TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
            //set the secret key for the tripleDES algorithm
            tdes.Key = keyArray;
            //mode of operation. there are other 4 modes. We choose ECB(Electronic code Book)
            tdes.Mode = CipherMode.ECB;
            //padding mode(if any extra byte added)
            tdes.Padding = PaddingMode.PKCS7;

            ICryptoTransform cTransform = tdes.CreateEncryptor();
            //transform the specified region of bytes array to resultArray
            byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0,          toEncryptArray.Length);
            //Release resources held by TripleDes Encryptor
            tdes.Clear();
            //Return the encrypted data into unreadable string format
            return Convert.ToBase64String(resultArray, 0, resultArray.Length);
        }
        catch (Exception e)
        {
            throw e;
        }
    }

    //Decryption
    public string DecryptText(string cipherString, bool useHashing)
    {

        try
        {
            byte[] keyArray;
            //get the byte code of the string

            byte[] toEncryptArray = Convert.FromBase64String(cipherString);

            string key = "String Key Value"; //Based on this key string is decrypted

            if (useHashing)
            {
                //if hashing was used get the hash code with regards to your key
                MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
                //release any resource held by the MD5CryptoServiceProvider

                hashmd5.Clear();
            }
            else
            {
                //if hashing was not implemented get the byte code of the key
                keyArray = UTF8Encoding.UTF8.GetBytes(key);
            }

            TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
            //set the secret key for the tripleDES algorithm
            tdes.Key = keyArray;
            //mode of operation. there are other 4 modes.
            //We choose ECB(Electronic code Book)

            tdes.Mode = CipherMode.ECB;
            //padding mode(if any extra byte added)
            tdes.Padding = PaddingMode.PKCS7;

            ICryptoTransform cTransform = tdes.CreateDecryptor();
            byte[] resultArray = cTransform.TransformFinalBlock
                    (toEncryptArray, 0, toEncryptArray.Length);
            //Release resources held by TripleDes Encryptor
            tdes.Clear();
            //return the Clear decrypted TEXT
            return UTF8Encoding.UTF8.GetString(resultArray);
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

如果您正在使用ASP。你现在可以使用。Net 4.0以后的内置功能了。

System.Web.Security.MachineKey

. net 4.5有MachineKey.Protect()和MachineKey.Unprotect()。

. net 4.0有MachineKey.Encode()和MachineKey.Decode()。你应该将MachineKeyProtection设置为“All”。

ASP之外。Net这个类似乎在每次应用程序重新启动时都会生成一个新键，所以不起作用。在ILSpy中，如果缺少适当的app.settings，它就会生成自己的默认值。你可以在ASP.Net之外设置。

我还没找到非asp的。系统外的净等值。网络名称空间。

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

public class Program
{
    public static void Main()
    {
        var key = Encoding.UTF8.GetBytes("SUkbqO2ycDo7QwpR25kfgmC7f8CoyrZy");
        var data = Encoding.UTF8.GetBytes("testData");

        //Encrypt data
        var encrypted = CryptoHelper.EncryptData(data,key);

        //Decrypt data
        var decrypted = CryptoHelper.DecryptData(encrypted,key);

        //Display result
        Console.WriteLine(Encoding.UTF8.GetString(decrypted));
    }
}

public static class CryptoHelper
{
    public static byte[] EncryptData(byte[] data, byte[] key)
    {
        using (var aesAlg = Aes.Create())
        {
            aesAlg.Mode = CipherMode.CBC;
            using (var encryptor = aesAlg.CreateEncryptor(key, aesAlg.IV))
            {
                using (var msEncrypt = new MemoryStream())
                {
                    msEncrypt.Write(aesAlg.IV, 0, aesAlg.IV.Length);

                    using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                        csEncrypt.Write(data, 0, data.Length);

                    return msEncrypt.ToArray();
                }
            }
        }

    }

    public static byte[] DecryptData(byte[] encrypted, byte[] key)
    {
        var iv = new byte[16];
        Buffer.BlockCopy(encrypted, 0, iv, 0, iv.Length);
        using (var aesAlg = Aes.Create())
        {
            aesAlg.Mode = CipherMode.CBC;
            using (var decryptor = aesAlg.CreateDecryptor(key, iv))
            {
                using (var msDecrypt = new MemoryStream(encrypted, iv.Length, encrypted.Length - iv.Length))
                {
                    using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                    {
                        using (var resultStream = new MemoryStream())
                        {
                            csDecrypt.CopyTo(resultStream);
                            return resultStream.ToArray();
                        }
                    }
                }
            }
        }
    }
}