如何在c#中加密和解密字符串?


当前回答

下面是如何使用Bouncy castle包进行AES-GCM加密/解密的示例。

当我在谷歌上搜索从GOlang crypto/aes api解密数据的可能性时,我发现了这个示例:

const (
    gcmBlockSize         = 16 // this is key size
    gcmTagSize           = 16 // this is mac
    gcmStandardNonceSize = 12 // this is nonce
)

func encrypt(data []byte, passphrase string) []byte {
    block, _ := aes.NewCipher([]byte(createHash(passphrase)))
    gcm, err := cipher.NewGCM(block)
    if err != nil {
        panic(err.Error())
    }
    nonce := make([]byte, gcm.NonceSize())
    if _, err = io.ReadFull(rand.Reader, nonce); err != nil {
        panic(err.Error())
    }
    ciphertext := gcm.Seal(nonce, nonce, data, nil)
    return ciphertext
}

. net sample就像一个带有key(256位),mac(128位)和nonce(96位)的咒语。

其他回答

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();
                        }
                    }
                }
            }
        }
    }
}

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。

下面是一个简单的例子,在c#中使用AES CBC模式加密字符串,并使用随机IV和HMAC和密码派生密钥,以显示基本的移动部分:

private byte[] EncryptBytes(byte[] key, byte[] plaintext)
{
    using (var cipher = new RijndaelManaged { Key = key })
    {
        using (var encryptor = cipher.CreateEncryptor())
        {
            var ciphertext = encryptor.TransformFinalBlock(plaintext, 0, plaintext.Length);

            // IV is prepended to ciphertext
            return cipher.IV.Concat(ciphertext).ToArray();
        }
    }
}

private byte[] DecryptBytes(byte[] key, byte[] packed)
{
    using (var cipher = new RijndaelManaged { Key = key })
    {
        int ivSize = cipher.BlockSize / 8;

        cipher.IV = packed.Take(ivSize).ToArray();

        using (var encryptor = cipher.CreateDecryptor())
        {
            return encryptor.TransformFinalBlock(packed, ivSize, packed.Length - ivSize);
        }
    }
}

private byte[] AddMac(byte[] key, byte[] data)
{
    using (var hmac = new HMACSHA256(key))
    {
        var macBytes = hmac.ComputeHash(data);

        // HMAC is appended to data
        return data.Concat(macBytes).ToArray();
    }
}

private bool BadMac(byte[] found, byte[] computed)
{
    int mismatch = 0;

    // Aim for consistent timing regardless of inputs
    for (int i = 0; i < found.Length; i++)
    {
        mismatch += found[i] == computed[i] ? 0 : 1;
    }

    return mismatch != 0;
}

private byte[] RemoveMac(byte[] key, byte[] data)
{
    using (var hmac = new HMACSHA256(key))
    {
        int macSize = hmac.HashSize / 8;

        var packed = data.Take(data.Length - macSize).ToArray();

        var foundMac = data.Skip(packed.Length).ToArray();

        var computedMac = hmac.ComputeHash(packed);

        if (this.BadMac(foundMac, computedMac))
        {
            throw new Exception("Bad MAC");
        }

        return packed;
    }            
}

private List<byte[]> DeriveTwoKeys(string password)
{
    var salt = new byte[] { 1, 2, 3, 4, 5, 6, 7, 8 };

    var kdf = new Rfc2898DeriveBytes(password, salt, 10000);

    var bytes = kdf.GetBytes(32); // Two keys 128 bits each

    return new List<byte[]> { bytes.Take(16).ToArray(), bytes.Skip(16).ToArray() };
}

public byte[] EncryptString(string password, String message)
{
    var keys = this.DeriveTwoKeys(password);

    var plaintext = Encoding.UTF8.GetBytes(message);

    var packed = this.EncryptBytes(keys[0], plaintext);

    return this.AddMac(keys[1], packed);
}

public String DecryptString(string password, byte[] secret)
{
    var keys = this.DeriveTwoKeys(password);

    var packed = this.RemoveMac(keys[1], secret);

    var plaintext = this.DecryptBytes(keys[0], packed);

    return Encoding.UTF8.GetString(plaintext);
}

public void Example()
{
    var password = "correcthorsebatterystaple";

    var secret = this.EncryptString(password, "Hello World");

    Console.WriteLine("secret: " + BitConverter.ToString(secret));

    var recovered = this.DecryptString(password, secret);

    Console.WriteLine(recovered);
}

我想给你我的贡献,与我的代码AES Rfc2898DeriveBytes(这里的文档)算法,写在c#(。NET框架4),并且完全适用于有限的平台,如Windows Phone 7.0+的.NET紧凑框架(不是所有平台都支持.NET框架的每一种编码方法!)

我希望这能帮助到任何人!

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

public static class Crypto
{
    private static readonly byte[] IVa = new byte[] { 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x11, 0x11, 0x12, 0x13, 0x14, 0x0e, 0x16, 0x17 };


    public static string Encrypt(this string text, string salt)
    {
        try
        {
            using (Aes aes = new AesManaged())
            {
                Rfc2898DeriveBytes deriveBytes = new Rfc2898DeriveBytes(Encoding.UTF8.GetString(IVa, 0, IVa.Length), Encoding.UTF8.GetBytes(salt));
                aes.Key = deriveBytes.GetBytes(128 / 8);
                aes.IV = aes.Key;
                using (MemoryStream encryptionStream = new MemoryStream())
                {
                    using (CryptoStream encrypt = new CryptoStream(encryptionStream, aes.CreateEncryptor(), CryptoStreamMode.Write))
                    {
                        byte[] cleanText = Encoding.UTF8.GetBytes(text);
                        encrypt.Write(cleanText, 0, cleanText.Length);
                        encrypt.FlushFinalBlock();
                    }

                    byte[] encryptedData = encryptionStream.ToArray();
                    string encryptedText = Convert.ToBase64String(encryptedData);


                    return encryptedText;
                }
            }
        }
        catch
        {
            return String.Empty;
        }
    }

    public static string Decrypt(this string text, string salt)
    {
        try
        {
            using (Aes aes = new AesManaged())
            {
                Rfc2898DeriveBytes deriveBytes = new Rfc2898DeriveBytes(Encoding.UTF8.GetString(IVa, 0, IVa.Length), Encoding.UTF8.GetBytes(salt));
                aes.Key = deriveBytes.GetBytes(128 / 8);
                aes.IV = aes.Key;

                using (MemoryStream decryptionStream = new MemoryStream())
                {
                    using (CryptoStream decrypt = new CryptoStream(decryptionStream, aes.CreateDecryptor(), CryptoStreamMode.Write))
                    {
                        byte[] encryptedData = Convert.FromBase64String(text);


                        decrypt.Write(encryptedData, 0, encryptedData.Length);
                        decrypt.Flush();
                    }

                    byte[] decryptedData = decryptionStream.ToArray();
                    string decryptedText = Encoding.UTF8.GetString(decryptedData, 0, decryptedData.Length);


                    return decryptedText;
                }
            }
        }
        catch
        {
            return String.Empty;
        }
        }
    }
}

加密是编程中非常常见的问题。我认为最好是安装一个包来为您做这个任务。也许是一个简单的开源NuGet项目 简单Aes加密

密钥在配置文件中,因此很容易在生产环境中更改,而且我没有看到任何缺点。

<MessageEncryption>
  <EncryptionKey KeySize="256" Key="3q2+796tvu/erb7v3q2+796tvu/erb7v3q2+796tvu8="/>
</MessageEncryption>