RSA - System.Security.Cryptography.CryptographicException：“密钥在指定状态下使用无效”

Question

我正在为我的大学在 Visual Studio 中制作一个 C# 项目。我在 RSA 加密方面遇到问题。当尝试解密字符串时，我收到错误

System.Security.Cryptography.CryptographicException: 'Key not valid for use in specified state.

我使用的代码是：

public class RsaEncryptionService
{
    private static RSACryptoServiceProvider csp = new RSACryptoServiceProvider(2048);
    private RSAParameters _privateKey;
    private RSAParameters _publicKey;

    public RsaEncryptionService()
    {
        _privateKey = csp.ExportParameters(true);
        _publicKey = csp.ExportParameters(false);
    }

    public string GetPublicKey()
    {
        var sw = new StringWriter();
        var xmlSerializer = new XmlSerializer(typeof(RSAParameters));
        xmlSerializer.Serialize(sw, _publicKey);
        return sw.ToString();
    }

    public string GetPrivateKey()
    {
        var sw = new StringWriter();
        var xmlSerializer = new XmlSerializer(typeof(RSAParameters));
        xmlSerializer.Serialize(sw, _privateKey);
        return sw.ToString();
    }

    public string Encript(string plainText)
    {
        csp = new RSACryptoServiceProvider();
        csp.ImportParameters(_publicKey);
        var dataBytes = Encoding.Unicode.GetBytes(plainText);
        var cypherData = csp.Encrypt(dataBytes, false);
        return Convert.ToBase64String(cypherData);
    }

    public string Decript(string cypherText)
    {
        var dataBytes = Convert.FromBase64String(cypherText);
        csp.ImportParameters(_privateKey);
        var plaintextBytes = csp.Decrypt(dataBytes, false);
        return Encoding.Unicode.GetString(plaintextBytes);
    }
}

Answer 1

与您的

Encript

 方法一样，您需要在 

csp

 方法的开头将 

RSACryptoServiceProvider

 分配给新的 

Decript

。

RSACryptoServiceProvider 构造函数的 Microsoft 文档有一个实际操作的示例：

public static byte[] RSADecrypt(byte[] DataToDecrypt, RSAParameters RSAKeyInfo, bool DoOAEPPadding)
{
    try
    {
        byte[] decryptedData;
        //Create a new instance of RSACryptoServiceProvider.
        using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider())
        {
            //Import the RSA Key information. This needs
            //to include the private key information.
            RSA.ImportParameters(RSAKeyInfo);

            //Decrypt the passed byte array and specify OAEP padding.  
            //OAEP padding is only available on Microsoft Windows XP or
            //later.  
            decryptedData = RSA.Decrypt(DataToDecrypt, DoOAEPPadding);
        }
        return decryptedData;
    }
    //Catch and display a CryptographicException  
    //to the console.
    catch (CryptographicException e)
    {
        Console.WriteLine(e.ToString());

        return null;
    }
}