RSA 解密无法处理不明确的异常

Question

I am trying to encrypt a string of information using RSA in dot net core, the intention is to only encrypt the plain text and send it to a server running PHP/MySQL and store the encrypted information. the server does not send any confirmation or other data in reply, so it is a one-way communication (if I could say). for this purpose I have three methods, one that generates a Keypair of 2048, and stores the information in a List (not the RSAParameter) and returns, the other two methods are encryption and decryption methods. The problem is the Encryption works fine with the public key as modulus and public exponent as an exponent, while at the decryption, with the private key as modulus, public exponent as an exponent, and the private exponent "D" as a private exponent, I am getting the exception " Modulus and Exponents are required fields", if I remove the "D" an exception of "Invalid Data Length for this Key size" is thrown, I am not so good at a mathematical aspect of RSA. I have also tried every method of getting bytes ( Encoding, Covert, etc). Below are the three methods I am using.

Method to Generate Keypair and other Parameters:

public static List<string> RsaKeyGen()
    {
       List<string> keyPair = new List<string>();

       RSA rsa = RSA.Create(2048);
       RSAParameters param = rsa.ExportParameters(true);
        

       keyPair.Add(Convert.ToBase64String(rsa.ExportRSAPrivateKey()));
       keyPair.Add(Convert.ToBase64String(rsa.ExportRSAPublicKey()));
       keyPair.Add(Convert.ToBase64String(param.Exponent));
       keyPair.Add(Convert.ToBase64String(param.D));


       return keyPair;
    }

The Encryption Method

public static string RsaEncrypt(byte[] PUBLIC_KEY ,byte[] EXPONENT, string text)
    {
        RSA rsa = RSA.Create(2048);
     
        RSAParameters param = new RSAParameters();
        param.Modulus = PUBLIC_KEY;
        param.Exponent = EXPONENT;
        rsa.ImportParameters(param);

        return Convert.ToBase64String(rsa.Encrypt(Convert.FromBase64String(text), RSAEncryptionPadding.Pkcs1));
    }

and finally the Decrypt Method:

public static string RsaDecrypt(byte[] PRIVATE_KEY, byte[] EXPONENT, byte[] PEXPO , string DATA)
    {
        RSA rsa = RSA.Create(2048);

        RSAParameters param = new RSAParameters();
        param.Modulus = PRIVATE_KEY;
        param.Exponent = EXPONENT;
        param.D = PEXPO;

        rsa.ImportParameters(param);

        return Convert.ToBase64String(rsa.Decrypt(Convert.FromBase64String(DATA), RSAEncryptionPadding.Pkcs1));
    }

Answer 1

Here is a Minimum Working Example (MWE) using your code as a starting point. As I commented, you just need to import your private/public key. No need to supply Exponent or D .

(by the way, you are converting to-and-from binary and string types all over the place. I suggest you base your whole RSA code on byte[] and only convert back to string if/when you need to. The below code is written to match your supplied signatures)

public class RsaMwe
{
    public static bool Demo()
    {
        var strings = RsaKeyGen();

        var privKey = Convert.FromBase64String(strings[0]);
        var pubKey = Convert.FromBase64String(strings[1]);

        var clearText = "Hello World!";
        var clearText64 = Convert.ToBase64String(Encoding.Default.GetBytes(clearText));

        var encrypted64 = RsaEncrypt(pubKey, clearText64);
        var decrypted64 = RsaDecrypt(privKey, encrypted64);

        return clearText == Encoding.Default.GetString(Convert.FromBase64String(decrypted64));
    }

    public static List<string> RsaKeyGen()
    {
        List<string> keyPair = new List<string>();

        using RSA rsa = RSA.Create(2048);

        keyPair.Add(Convert.ToBase64String(rsa.ExportRSAPrivateKey()));
        keyPair.Add(Convert.ToBase64String(rsa.ExportRSAPublicKey()));

        return keyPair;
    }

    public static string RsaEncrypt(byte[] pubKey, string clearText64)
    {
        using RSA rsa = RSA.Create(2048);
        rsa.ImportRSAPublicKey(pubKey, out _);

        return Convert.ToBase64String(rsa.Encrypt(Convert.FromBase64String(clearText64), RSAEncryptionPadding.Pkcs1));
    }

    public static string RsaDecrypt(byte[] privKey, string cypherText64)
    {
        using RSA rsa = RSA.Create(2048);
        rsa.ImportRSAPrivateKey(privKey, out _);

        return Convert.ToBase64String(rsa.Decrypt(Convert.FromBase64String(cypherText64), RSAEncryptionPadding.Pkcs1));
    }
}

Also don't forget to dispose your RSA objects.