如何在c#中加密和解密字符串?


当前回答

            using System;
            using System.Collections.Generic;
            using System.Text;
            using System.Text.RegularExpressions;  // This is for password validation
            using System.Security.Cryptography;
            using System.Configuration;  // This is where the hash functions reside

            namespace BullyTracker.Common
            {
                public class HashEncryption
                {
                    //public string GenerateHashvalue(string thisPassword)
                    //{
                    //    MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
                    //    byte[] tmpSource;
                    //    byte[] tmpHash;

                    //    tmpSource = ASCIIEncoding.ASCII.GetBytes(thisPassword); // Turn password into byte array
                    //    tmpHash = md5.ComputeHash(tmpSource);

                    //    StringBuilder sOutput = new StringBuilder(tmpHash.Length);
                    //    for (int i = 0; i < tmpHash.Length; i++)
                    //    {
                    //        sOutput.Append(tmpHash[i].ToString("X2"));  // X2 formats to hexadecimal
                    //    }
                    //    return sOutput.ToString();
                    //}
                    //public Boolean VerifyHashPassword(string thisPassword, string thisHash)
                    //{
                    //    Boolean IsValid = false;
                    //    string tmpHash = GenerateHashvalue(thisPassword); // Call the routine on user input
                    //    if (tmpHash == thisHash) IsValid = true;  // Compare to previously generated hash
                    //    return IsValid;
                    //}
                    public string GenerateHashvalue(string toEncrypt, bool useHashing)
                    {
                        byte[] keyArray;
                        byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

                        System.Configuration.AppSettingsReader settingsReader = new AppSettingsReader();
                        // Get the key from config file
                        string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));
                        //System.Windows.Forms.MessageBox.Show(key);
                        if (useHashing)
                        {
                            MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                            keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
                            hashmd5.Clear();
                        }
                        else
                            keyArray = UTF8Encoding.UTF8.GetBytes(key);

                        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
                        tdes.Key = keyArray;
                        tdes.Mode = CipherMode.ECB;
                        tdes.Padding = PaddingMode.PKCS7;

                        ICryptoTransform cTransform = tdes.CreateEncryptor();
                        byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
                        tdes.Clear();
                        return Convert.ToBase64String(resultArray, 0, resultArray.Length);
                    }
                    /// <summary>
                    /// DeCrypt a string using dual encryption method. Return a DeCrypted clear string
                    /// </summary>
                    /// <param name="cipherString">encrypted string</param>
                    /// <param name="useHashing">Did you use hashing to encrypt this data? pass true is yes</param>
                    /// <returns></returns>
                    public string Decrypt(string cipherString, bool useHashing)
                    {
                        byte[] keyArray;
                        byte[] toEncryptArray = Convert.FromBase64String(cipherString);

                        System.Configuration.AppSettingsReader settingsReader = new AppSettingsReader();
                        //Get your key from config file to open the lock!
                        string key = (string)settingsReader.GetValue("SecurityKey", typeof(String));

                        if (useHashing)
                        {
                            MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
                            keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
                            hashmd5.Clear();
                        }
                        else
                            keyArray = UTF8Encoding.UTF8.GetBytes(key);

                        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
                        tdes.Key = keyArray;
                        tdes.Mode = CipherMode.ECB;
                        tdes.Padding = PaddingMode.PKCS7;

                        ICryptoTransform cTransform = tdes.CreateDecryptor();
                        byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

                        tdes.Clear();
                        return UTF8Encoding.UTF8.GetString(resultArray);
                    }


                }

            }

其他回答

很好的例子如何做到这一点使用PGPCore与BouncyCastle,非常简单的解决方案:https://blog.bitscry.com/2018/07/05/pgp-encryption-and-decryption-in-c/

我尝试了不同的解决方案,但这对我来说是最好的,有些bug,但这是完美的。

using (PGP pgp = new PGP())
{
// Generate keys
pgp.GenerateKey(@"C:\TEMP\keys\public.asc", @"C:\TEMP\keys\private.asc", "email@email.com", "password");
// Encrypt file
pgp.EncryptFile(@"C:\TEMP\keys\content.txt", @"C:\TEMP\keys\content__encrypted.pgp", @"C:\TEMP\keys\public.asc", true, true);
// Encrypt and sign file
pgp.EncryptFileAndSign(@"C:\TEMP\keys\content.txt", @"C:\TEMP\keys\content__encrypted_signed.pgp", @"C:\TEMP\keys\public.asc", @"C:\TEMP\keys\private.asc", "password", true, true);
// Decrypt file
pgp.DecryptFile(@"C:\TEMP\keys\content__encrypted.pgp", @"C:\TEMP\keys\content__decrypted.txt", @"C:\TEMP\keys\private.asc", "password");
// Decrypt signed file
pgp.DecryptFile(@"C:\TEMP\keys\content__encrypted_signed.pgp", @"C:\TEMP\keys\content__decrypted_signed.txt", @"C:\TEMP\keys\private.asc", "password");

// Encrypt stream
using (FileStream inputFileStream = new FileStream(@"C:\TEMP\keys\content.txt", FileMode.Open))
using (Stream outputFileStream = File.Create(@"C:\TEMP\keys\content__encrypted2.pgp"))
using (Stream publicKeyStream = new FileStream(@"C:\TEMP\keys\public.asc", FileMode.Open))
    pgp.EncryptStream(inputFileStream, outputFileStream, publicKeyStream, true, true);

// Decrypt stream
using (FileStream inputFileStream = new FileStream(@"C:\TEMP\keys\content__encrypted2.pgp", FileMode.Open))
using (Stream outputFileStream = File.Create(@"C:\TEMP\keys\content__decrypted2.txt"))
using (Stream privateKeyStream = new FileStream(@"C:\TEMP\keys\private.asc", FileMode.Open))
    pgp.DecryptStream(inputFileStream, outputFileStream, privateKeyStream, "password");
}

这是布雷特安排在这里的课程。然而,我做了一个轻微的编辑,因为我在使用URL字符串加密和解密时收到了错误“无效的长度为一个Base-64字符数组”。

public class CryptoURL
{
    private static byte[] _salt = Encoding.ASCII.GetBytes("Catto_Salt_Enter_Any_Value99");

    /// <summary>
    /// Encrypt the given string using AES.  The string can be decrypted using 
    /// DecryptStringAES().  The sharedSecret parameters must match. 
    /// The SharedSecret for the Password Reset that is used is in the next line
    ///  string sharedSecret = "OneUpSharedSecret9";
    /// </summary>
    /// <param name="plainText">The text to encrypt.</param>
    /// <param name="sharedSecret">A password used to generate a key for encryption.</param>
    public static string EncryptString(string plainText, string sharedSecret)
    {
        if (string.IsNullOrEmpty(plainText))
            throw new ArgumentNullException("plainText");
        if (string.IsNullOrEmpty(sharedSecret))
            throw new ArgumentNullException("sharedSecret");

        string outStr = null;                       // Encrypted string to return
        RijndaelManaged aesAlg = null;              // RijndaelManaged object used to encrypt the data.

        try
        {
            // generate the key from the shared secret and the salt
            Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(sharedSecret, _salt);

            // Create a RijndaelManaged object
            aesAlg = new RijndaelManaged();
            aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);

            // Create a decryptor to perform the stream transform.
            ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

            // Create the streams used for encryption.
            using (MemoryStream msEncrypt = new MemoryStream())
            {
                // prepend the IV
                msEncrypt.Write(BitConverter.GetBytes(aesAlg.IV.Length), 0, sizeof(int));
                msEncrypt.Write(aesAlg.IV, 0, aesAlg.IV.Length);
                using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                {
                    using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                    {
                        //Write all data to the stream.
                        swEncrypt.Write(plainText);
                    }
                }

                outStr = HttpServerUtility.UrlTokenEncode(msEncrypt.ToArray());
                //outStr = Convert.ToBase64String(msEncrypt.ToArray());
                // you may need to add a reference. right click reference in solution explorer => "add Reference" => .NET tab => select "System.Web"
            }
        }
        finally
        {
            // Clear the RijndaelManaged object.
            if (aesAlg != null)
                aesAlg.Clear();
        }

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

    /// <summary>
    /// Decrypt the given string.  Assumes the string was encrypted using 
    /// EncryptStringAES(), using an identical sharedSecret.
    /// </summary>
    /// <param name="cipherText">The text to decrypt.</param>
    /// <param name="sharedSecret">A password used to generate a key for decryption.</param>
    public static string DecryptString(string cipherText, string sharedSecret)
    {
        if (string.IsNullOrEmpty(cipherText))
            throw new ArgumentNullException("cipherText");
        if (string.IsNullOrEmpty(sharedSecret))
            throw new ArgumentNullException("sharedSecret");

        // Declare the RijndaelManaged object
        // used to decrypt the data.
        RijndaelManaged aesAlg = null;

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

        byte[] inputByteArray;

        try
        {
            // generate the key from the shared secret and the salt
            Rfc2898DeriveBytes key = new Rfc2898DeriveBytes(sharedSecret, _salt);

            // Create the streams used for decryption.                
            //byte[] bytes = Convert.FromBase64String(cipherText);
            inputByteArray = HttpServerUtility.UrlTokenDecode(cipherText);

            using (MemoryStream msDecrypt = new MemoryStream(inputByteArray))
            {
                // Create a RijndaelManaged object
                // with the specified key and IV.
                aesAlg = new RijndaelManaged();
                aesAlg.Key = key.GetBytes(aesAlg.KeySize / 8);
                // Get the initialization vector from the encrypted stream
                aesAlg.IV = ReadByteArray(msDecrypt);
                // Create a decrytor to perform the stream transform.
                ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);
                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();
                }
            }
        }
        catch (System.Exception ex)
        {
            return "ERROR";
            //throw ex;

        }
        finally
        {
            // Clear the RijndaelManaged object.
            if (aesAlg != null)
                aesAlg.Clear();
        }

        return plaintext;
    }

    static string ConvertStringArrayToString(string[] array)
    {
        //
        // Concatenate all the elements into a StringBuilder.
        //
        StringBuilder builder = new StringBuilder();
        foreach (string value in array)
        {
            builder.Append(value);
            builder.Append('.');
        }
        return builder.ToString();
    }

    private static byte[] ReadByteArray(Stream s)
    {
        byte[] rawLength = new byte[sizeof(int)];
        if (s.Read(rawLength, 0, rawLength.Length) != rawLength.Length)
        {
            throw new SystemException("Stream did not contain properly formatted byte array");
        }

        byte[] buffer = new byte[BitConverter.ToInt32(rawLength, 0)];
        if (s.Read(buffer, 0, buffer.Length) != buffer.Length)
        {
            throw new SystemException("Did not read byte array properly");
        }

        return buffer;
    }

}

下面的示例演示如何加密和解密示例数据:

    // This constant is used to determine the keysize of the encryption algorithm in bits.
    // We divide this by 8 within the code below to get the equivalent number of bytes.
    private const int Keysize = 128;

    // This constant determines the number of iterations for the password bytes generation function.
    private const int DerivationIterations = 1000;

    public static string Encrypt(string plainText, string passPhrase)
    {
        // Salt and IV is randomly generated each time, but is preprended to encrypted cipher text
        // so that the same Salt and IV values can be used when decrypting.  
        var saltStringBytes = GenerateBitsOfRandomEntropy(16);
        var ivStringBytes = GenerateBitsOfRandomEntropy(16);
        var plainTextBytes = Encoding.UTF8.GetBytes(plainText);
        using (var password = new Rfc2898DeriveBytes(passPhrase, saltStringBytes, DerivationIterations))
        {
            var keyBytes = password.GetBytes(Keysize / 8);
            using (var symmetricKey = new RijndaelManaged())
            {
                symmetricKey.BlockSize = 128;
                symmetricKey.Mode = CipherMode.CBC;
                symmetricKey.Padding = PaddingMode.PKCS7;
                using (var encryptor = symmetricKey.CreateEncryptor(keyBytes, ivStringBytes))
                {
                    using (var memoryStream = new MemoryStream())
                    {
                        using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
                        {
                            cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length);
                            cryptoStream.FlushFinalBlock();
                            // Create the final bytes as a concatenation of the random salt bytes, the random iv bytes and the cipher bytes.
                            var cipherTextBytes = saltStringBytes;
                            cipherTextBytes = cipherTextBytes.Concat(ivStringBytes).ToArray();
                            cipherTextBytes = cipherTextBytes.Concat(memoryStream.ToArray()).ToArray();
                            memoryStream.Close();
                            cryptoStream.Close();
                            return Convert.ToBase64String(cipherTextBytes);
                        }
                    }
                }
            }
        }
    }

    public static string Decrypt(string cipherText, string passPhrase)
    {
        // Get the complete stream of bytes that represent:
        // [32 bytes of Salt] + [32 bytes of IV] + [n bytes of CipherText]
        var cipherTextBytesWithSaltAndIv = Convert.FromBase64String(cipherText);
        // Get the saltbytes by extracting the first 32 bytes from the supplied cipherText bytes.
        var saltStringBytes = cipherTextBytesWithSaltAndIv.Take(Keysize / 8).ToArray();
        // Get the IV bytes by extracting the next 32 bytes from the supplied cipherText bytes.
        var ivStringBytes = cipherTextBytesWithSaltAndIv.Skip(Keysize / 8).Take(Keysize / 8).ToArray();
        // Get the actual cipher text bytes by removing the first 64 bytes from the cipherText string.
        var cipherTextBytes = cipherTextBytesWithSaltAndIv.Skip((Keysize / 8) * 2).Take(cipherTextBytesWithSaltAndIv.Length - ((Keysize / 8) * 2)).ToArray();

        using (var password = new Rfc2898DeriveBytes(passPhrase, saltStringBytes, DerivationIterations))
        {
            var keyBytes = password.GetBytes(Keysize / 8);
            using (var symmetricKey = new RijndaelManaged())
            {
                symmetricKey.BlockSize = 128;
                symmetricKey.Mode = CipherMode.CBC;
                symmetricKey.Padding = PaddingMode.PKCS7;
                using (var decryptor = symmetricKey.CreateDecryptor(keyBytes, ivStringBytes))
                {
                    using (var memoryStream = new MemoryStream(cipherTextBytes))
                    {
                        using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
                        {
                            var plainTextBytes = new byte[cipherTextBytes.Length];
                            var decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
                            memoryStream.Close();
                            cryptoStream.Close();
                            return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount);
                        }
                    }
                }
            }
        }
    }

    private static byte[] GenerateBitsOfRandomEntropy(int size)
    {
        // 32 Bytes will give us 256 bits.
        // 16 Bytes will give us 128 bits.
        var randomBytes = new byte[size]; 
        using (var rngCsp = new RNGCryptoServiceProvider())
        {
            // Fill the array with cryptographically secure random bytes.
            rngCsp.GetBytes(randomBytes);
        }
        return randomBytes;
    }

下面是一个使用RSA的例子。

重要:使用RSA加密KeySize - MinimumPadding加密的数据大小是有限制的。例如256字节(假设2048位密钥)- 42字节(最小OEAP填充)= 214字节(最大明文大小)

用RSA密钥替换your_rsa_key。

var provider = new System.Security.Cryptography.RSACryptoServiceProvider();
provider.ImportParameters(your_rsa_key);

var encryptedBytes = provider.Encrypt(
    System.Text.Encoding.UTF8.GetBytes("Hello World!"), true);

string decryptedTest = System.Text.Encoding.UTF8.GetString(
    provider.Decrypt(encryptedBytes, true));

更多信息,请访问MSDN - RSACryptoServiceProvider

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);
}