using System;
namespace Shared.Encryption
{
    public class RSA
    {
        /// <summary>
        /// 用指定的密匙加密 
        /// </summary>
        /// <param name="source">明文</param>
        /// <param name="e">可以是RSACryptoServiceProvider生成的E</param>
        /// <param name="n">可以是RSACryptoServiceProvider生成的Modulus</param>
        /// <returns>返回密文</returns>
        public static string EncryptString(string source, BigInteger e, BigInteger n)
        {
            int len = source.Length;
            int len1 = 0;
            int blockLen = 0;
            if ((len % 128) == 0)
                len1 = len / 128;
            else
                len1 = len / 128 + 1;
            string block = "";
            var result = new System.Text.StringBuilder();
            for (int i = 0; i < len1; i++)
            {
                if (len >= 128)
                    blockLen = 128;
                else
                    blockLen = len;
                block = source.Substring(i * 128, blockLen);
                byte[] oText = System.Text.Encoding.UTF8.GetBytes(block);
                var biText = new BigInteger(oText);
                var biEnText = biText.modPow(e, n);
                var temp = biEnText.ToHexString();
                result.Append(temp).Append("@");
                len -= blockLen;
            }
            return result.ToString().TrimEnd('@');
        }

    }
}