C# 如果我有私钥，如何解密？

Question

我在Python中是这样进行加密的

def encrypt_RSA(public_key_loc, message):
    '''
    param: public_key_loc Path to public key
    param: message String to be encrypted
    return base64 encoded encrypted string
    '''
    from Crypto.PublicKey import RSA
    from Crypto.Cipher import PKCS1_OAEP
    key = open(public_key_loc, "r").read()
    rsakey = RSA.importKey(key)
    rsakey = PKCS1_OAEP.new(rsakey)
    encrypted = rsakey.encrypt(message)
    return encrypted.encode('base64')

我在C#中尝试这样解密，但没有成功

namespace ConsoleApplication1
{

    class Program
    {
        private static string _message = @"gvVweOVn/+IBKNrFV1sb+khVu8PdBC78WusGH7IuCXxK4pEsFo8JbOb68phJAMVM1F8XPoq1PX4D
0VuVPmDFHadOUr59IX0IBbQ72bQ1/BoINimSVOzXRbHOfsNxd0kIEdCv6jNlA7ut7hcoGUz6XzdM
b+k8N2K9Dykjehoo9gZEhaXnws1YiuBVN4B+XyjB1VUrgji9fW60lcpL+0UYZ5mcUvK6T7hS7R9W
9QIf5T02iZJLsp3hxS9j/UxPCvK5Cj6t2h4fRCOYgiQv0L21ZD23nKYWgiGyGEmfArqIswUmZ0h2
I2zMs9vC2JVFIid6FpExHUScItBeuM8qYLA/YQ==";

        static void Main(string[] args)
        {

            Decrypt(_message);

        }

        private static void Decrypt(string text)
        {
            StreamReader sr = new StreamReader("./key.private");
        PemReader pr = new PemReader(sr);
        AsymmetricCipherKeyPair KeyPair = (AsymmetricCipherKeyPair)pr.ReadObject();
        RSAParameters rsa = DotNetUtilities.ToRSAParameters((RsaPrivateCrtKeyParameters)KeyPair.Private);            
        RSACryptoServiceProvider csp = new RSACryptoServiceProvider(2048);
        csp.ImportParameters(rsa);

        var bytesCypherText = Convert.FromBase64String(text);
        var bytesPlainTextData = csp.Decrypt(bytesCypherText, false);
        var plainTextData = System.Text.Encoding.Unicode.GetString(bytesPlainTextData);

        Console.WriteLine(plainTextData);

        }


    }
}

出现了坏数据的异常

在Python这边，我是这样解码的。

def decrypt_RSA(private_key_loc, package):
    '''
    param: public_key_loc Path to your private key
    param: package String to be decrypted
    return decrypted string
    '''
    from Crypto.PublicKey import RSA
    from Crypto.Cipher import PKCS1_OAEP
    from base64 import b64decode
    key = open(private_key_loc, "r").read()
    rsakey = RSA.importKey(key)
    rsakey = PKCS1_OAEP.new(rsakey)
    decrypted = rsakey.decrypt(b64decode(package))
    return decrypted

在这种情况下，私钥是如何影响工作的呢？

提前谢谢你！

Answer 1

var bytesPlainTextData = csp.Decrypt(bytesCypherText, false);

应该是

var bytesPlainTextData = csp.Decrypt(bytesCypherText, true);

因为你在你的Python代码中使用了PKCS1_OAEP填充方式。

Answer 2

在Python这边，你把加密后的字符串进行了base64编码。在用C#解密之前，你需要先把它进行base64解码。此外，你还得确保两边的加密参数（比如块模式、填充方式等）是一样的。