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

public static class NetworkValideRsa2Sdk
{
    public static string EncryptData(string rawData, string publicKeyPem)
    {
        using (var rsa = RSA.Create())
        {
            rsa.ImportFromPem(publicKeyPem.ToCharArray());
            int chunkSize = rsa.KeySize / 8 - 11;
            byte[] source = Encoding.UTF8.GetBytes(rawData);
            using (var ms = new System.IO.MemoryStream())
            {
                for (int i = 0; i < source.Length; i += chunkSize)
                {
                    int len = Math.Min(chunkSize, source.Length - i);
                    byte[] chunk = new byte[len];
                    Buffer.BlockCopy(source, i, chunk, 0, len);
                    byte[] enc = rsa.Encrypt(chunk, RSAEncryptionPadding.Pkcs1);
                    ms.Write(enc, 0, enc.Length);
                }
                return Convert.ToBase64String(ms.ToArray());
            }
        }
    }

    public static string DecryptMsg(string msg, string publicKeyPem)
    {
        using (var rsa = RSA.Create())
        {
            rsa.ImportFromPem(publicKeyPem.ToCharArray());
            byte[] source = Convert.FromBase64String(msg);
            int chunkSize = rsa.KeySize / 8;
            using (var ms = new System.IO.MemoryStream())
            {
                for (int i = 0; i < source.Length; i += chunkSize)
                {
                    byte[] chunk = new byte[chunkSize];
                    Buffer.BlockCopy(source, i, chunk, 0, chunkSize);
                    byte[] dec = rsa.Decrypt(chunk, RSAEncryptionPadding.Pkcs1);
                    ms.Write(dec, 0, dec.Length);
                }
                return Encoding.UTF8.GetString(ms.ToArray());
            }
        }
    }

    public static string MakeSign(string data, string appKey)
    {
        using (var md5 = MD5.Create())
        {
            var bytes = md5.ComputeHash(Encoding.UTF8.GetBytes(data + appKey));
            return BitConverter.ToString(bytes).Replace("-", "").ToLowerInvariant();
        }
    }
}