C# RAS 非对称加密类 支持长字符串

/// <summary>/// [e-mail]/// </summary>abstract class MyRAS { /// <summary> /// RAS加密 /// </summary> /// <param name="xmlPublicKey">公钥</param> /// <param name="EncryptString">明文</param> /// <returns>密文</returns> public static string RSAEncrypt(string xmlPublicKey, string EncryptString) { byte[] PlainTextBArray; byte[] CypherTextBArray; string Result=String.Empty; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPublicKey); int t = (int)(Math.Ceiling((double)EncryptString.Length / (double)50)); //分割明文 for (int i = 0; i <= t-1; i++) { PlainTextBArray = (new UnicodeEncoding()).GetBytes(EncryptString.Substring(i * 50, EncryptString.Length - (i * 50) > 50 ? 50 : EncryptString.Length - (i * 50))); CypherTextBArray = rsa.Encrypt(PlainTextBArray, false); Result += Convert.ToBase64String(CypherTextBArray) + "ThisIsSplit"; } return Result; } /// <summary> /// RAS解密 /// </summary> /// <param name="xmlPrivateKey">私钥</param> /// <param name="DecryptString">密文</param> /// <returns>明文</returns> public static string RSADecrypt(string xmlPrivateKey, string DecryptString) { byte[] PlainTextBArray; byte[] DypherTextBArray; string Result=String.Empty; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); rsa.FromXmlString(xmlPrivateKey); string[] Split = new string[1]; Split[0] = "ThisIsSplit"; //分割密文 string[] mis = DecryptString.Split(Split, StringSplitOptions.RemoveEmptyEntries); for (int i = 0; i < mis.Length; i++) { PlainTextBArray = Convert.FromBase64String(mis[i]); DypherTextBArray = rsa.Decrypt(PlainTextBArray, false); Result += (new UnicodeEncoding()).GetString(DypherTextBArray); } return Result; } /// <summary> /// 产生公钥和私钥对 /// </summary> /// <returns>string[] 0:私钥;1:公钥</returns> public static string[] RSAKey() { string[] keys = new string[2]; System.Security.Cryptography.RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(); keys[0] = rsa.ToXmlString(true); keys[1] = rsa.ToXmlString(false); return keys; } }