RSA 是一种非对称加密算法。由于算法特性，加密和解密过程用不同密钥，即公钥和私钥，而被广泛应用于数字证书的安全管理。 在具体应用中，公钥用加密而私钥用于解密，或 私钥用于数字签名而公钥用于签名验证。由于非对称加密算法比价复杂，耗时较长，所以一般在网络环境中RAS 被应用于 签名认证，或小数据传输，如 AES 对称密钥传输。
在.Net 框架中，默认提供的辅助类只能对密钥长度大小相同的数据进行加密解密。 此文提供C# RSA 算法示例一座优化，可以不限数据大小。此实例 仅供交流学习。
RSA 加密
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public string RsaEncrypt(string rawInput, string publicKey) { if (string.IsNullOrEmpty(rawInput)) { return string.Empty; } if(string.IsNullOrWhiteSpace(publicKey)) { throw new ArgumentException("Invalid Public Key"); } using (var rsaProvider = new RSACryptoServiceProvider()) { var inputBytes = Encoding.UTF8.GetBytes(rawInput);//有含义的字符串转化为字节流 rsaProvider.FromXmlString(publicKey);//载入公钥 int bufferSize = (rsaProvider.KeySize / 8) - 11;//单块最大长度 var buffer = new byte[bufferSize]; using (MemoryStream inputStream = new MemoryStream(inputBytes), outputStream = new MemoryStream()) { while (true) { //分段加密 int readSize = inputStream.Read(buffer, 0, bufferSize); if (readSize <= 0) { break; } var temp = new byte[readSize]; Array.Copy(buffer, 0, temp, 0, readSize); var encryptedBytes = rsaProvider.Encrypt(temp, false); outputStream.Write(encryptedBytes, 0, encryptedBytes.Length); } return Convert.ToBase64String(outputStream.ToArray());//转化为字节流方便传输 } } } |
RSA 解密
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public string RsaDecrypt(string encryptedInput, string privateKey) { if (string.IsNullOrEmpty(encryptedInput)) { return string.Empty; } if (string.IsNullOrWhiteSpace(privateKey)) { throw new ArgumentException("Invalid Private Key"); } using (var rsaProvider = new RSACryptoServiceProvider()) { var inputBytes = Convert.FromBase64String(encryptedInput); rsaProvider.FromXmlString(privateKey); int bufferSize = rsaProvider.KeySize / 8; var buffer = new byte[bufferSize]; using (MemoryStream inputStream = new MemoryStream(inputBytes), outputStream = new MemoryStream()) { while (true) { int readSize = inputStream.Read(buffer, 0, bufferSize); if (readSize <= 0) { break; } var temp = new byte[readSize]; Array.Copy(buffer, 0, temp, 0, readSize); var rawBytes = rsaProvider.Decrypt(temp, false); outputStream.Write(rawBytes, 0, rawBytes.Length); } return Encoding.UTF8.GetString(outputStream.ToArray()); } } } |
from:https://blog.csdn.net/hangzhi22/article/details/53089154