用.NET语言写一个RSA加解密字符串的类，具有填充和哈希的功能，可以指定公钥和私钥，每个方法带有出错处理，

以下是.NET语言写的一个RSA加解密字符串的类，具有填充和哈希的功能，可以指定公钥和私钥，每个方法带有出错处理。请注意，为简化代码，以下示例中使用了固定的密钥长度和填充模式，实际使用时应根据需要进行修改。

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

public class RSAHelper
{
    private readonly RSACryptoServiceProvider _rsa;

    public RSAHelper(string publicKey, string privateKey)
    {
        _rsa = new RSACryptoServiceProvider();
        _rsa.FromXmlString(publicKey + privateKey);
    }

    public string Encrypt(string data)
    {
        try
        {
            byte[] bytesToEncrypt = Encoding.UTF8.GetBytes(data);

            // 填充数据
            int maxLength = _rsa.KeySize / 8 - 11;
            if (bytesToEncrypt.Length > maxLength)
            {
                throw new ArgumentException("Data too long for RSA key size");
            }

            byte[] paddedData = new byte[maxLength];
            int dataOffset = 0;
            while (dataOffset < bytesToEncrypt.Length)
            {
                int remainingBytes = bytesToEncrypt.Length - dataOffset;
                int bytesToCopy = Math.Min(remainingBytes, maxLength);
                Array.Copy(bytesToEncrypt, dataOffset, paddedData, 0, bytesToCopy);
                dataOffset += bytesToCopy;

                byte[] encryptedBytes = _rsa.Encrypt(paddedData, false);
                return Convert.ToBase64String(encryptedBytes);
            }
        }
        catch (Exception ex)
        {
            // 处理加密出错
            Console.WriteLine("Encrypt failed: " + ex.Message);
        }

        return null;
    }

    public string Decrypt(string data)
    {
        try
        {
            byte[] bytesToDecrypt = Convert.FromBase64String(data);
            byte[] decryptedBytes = _rsa.Decrypt(bytesToDecrypt, false);
            return Encoding.UTF8.GetString(decryptedBytes);
        }
        catch (Exception ex)
        {
            // 处理解密出错
            Console.WriteLine("Decrypt failed: " + ex.Message);
        }

        return null;
    }

    public string Sign(string data)
    {
        try
        {
            byte[] bytesToSign = Encoding.UTF8.GetBytes(data);
            byte[] hash = SHA256.Create().ComputeHash(bytesToSign);
            byte[] signature = _rsa.SignHash(hash, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
            return Convert.ToBase64String(signature);
        }
        catch (Exception ex)
        {
            // 处理签名出错
            Console.WriteLine("Sign failed: " + ex.Message);
        }

        return null;
    }

    public bool Verify(string data, string signature)
    {
        try
        {
            byte[] bytesToVerify = Encoding.UTF8.GetBytes(data);
            byte[] hash = SHA256.Create().ComputeHash(bytesToVerify);
            byte[] signatureBytes = Convert.FromBase64String(signature);
            return _rsa.VerifyHash(hash, signatureBytes, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
        }
        catch (Exception ex)
        {
            // 处理验签出错
            Console.WriteLine("Verify failed: " + ex.Message);
        }

        return false;
    }
}

使用示例：

string publicKey = "<RSAKeyValue><Modulus>...</Modulus><Exponent>...</Exponent></RSAKeyValue>";
string privateKey = "<RSAKeyValue><Modulus>...</Modulus><Exponent>...</Exponent><P>...</P><Q>...</Q><DP>...</DP><DQ>...</DQ><InverseQ>...</InverseQ><D>...</D></RSAKeyValue>";
RSAHelper rsa = new RSAHelper(publicKey, privateKey);
string data = "Hello, RSA!";
string encryptedData = rsa.Encrypt(data);
string decryptedData = rsa.Decrypt(encryptedData);
string signature = rsa.Sign(data);
bool verified = rsa.Verify(data, signature);