C# RSA 非对称加密

代码：

RSAHelper.cs(RSA加密工具类)：

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

namespace Utils
{
    /// <summary>
    /// RSA加密工具类
    /// </summary>
    public class RSAHelper
    {
        /// <summary>
        /// RSA加密
        /// </summary>
        public static string RSAEncrypt_LongContent(string publicKey, string content)
        {
            byte[] bytes = Encoding.UTF8.GetBytes(content);


            int pageSize = 117;
            int pageCount = (bytes.Length - 1) / pageSize + 1;

            StringBuilder result = new StringBuilder();
            for (int page = 1; page <= pageCount; page++)
            {
                int start = pageSize * (page - 1);

                byte[] subBytes = page == pageCount ? new byte[bytes.Length - start] : new byte[pageSize];

                Array.Copy(bytes, start, subBytes, 0, subBytes.Length);

                string strEncrypted = RSAEncrypt(publicKey, Encoding.UTF8.GetString(subBytes));
                result.Append(strEncrypted);
            }

            return result.ToString();
        }

        /// <summary>
        /// RSA解密
        /// </summary>
        public static string RSADecrypt_LongContent(string privateKey, string content)
        {
            int pageSize = 172;
            int pageCount = (content.Length - 1) / pageSize + 1;

            StringBuilder result = new StringBuilder();
            for (int page = 1; page <= pageCount; page++)
            {
                int start = pageSize * (page - 1);

                string subContent = null;
                if (page != pageCount)
                {
                    subContent = content.Substring(start, pageSize);
                }
                else
                {
                    subContent = content.Substring(start, content.Length - start);
                }

                string strEncrypted = RSADecrypt(privateKey, subContent);
                result.Append(strEncrypted);
            }

            return result.ToString();
        }

        /// <summary>
        /// RSA加密
        /// </summary>
        public static string RSAEncrypt(string publicKey, string content)
        {
            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
            rsa.FromXmlString(publicKey);
            byte[] cipherBytes = rsa.Encrypt(Encoding.UTF8.GetBytes(content), false);

            return Convert.ToBase64String(cipherBytes);
        }

        /// <summary>
        /// RSA解密
        /// </summary>
        public static string RSADecrypt(string privateKey, string content)
        {
            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
            rsa.FromXmlString(privateKey);
            byte[] cipherBytes = rsa.Decrypt(Convert.FromBase64String(content), false);

            return Encoding.UTF8.GetString(cipherBytes);
        }

        /// <summary>
        /// 创建公钥私钥
        /// </summary>
        public static RSAKey CreateKey()
        {
            RSAKey rsaKey = new RSAKey();

            using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
            {
                rsaKey.PublicKey_NET = rsa.ToXmlString(false); // 公钥
                rsaKey.PrivateKey_NET = rsa.ToXmlString(true); // 私钥

                rsaKey.PublicKey_Java = RSAKeyConvert.RSAPublicKeyDotNet2Java(rsaKey.PublicKey_NET);
                rsaKey.PrivateKey_Java = RSAKeyConvert.RSAPrivateKeyDotNet2Java(rsaKey.PrivateKey_NET);
            }

            return rsaKey;
        }
    }

    public class RSAKey
    {
        public string PublicKey_NET { get; set; }

        public string PrivateKey_NET { get; set; }

        public string PublicKey_Java { get; set; }

        public string PrivateKey_Java { get; set; }
    }
}

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