腾讯云通信UserSig生成.Net实现

腾讯云通信后台生成usersig只有java实现代码。以下是根据java代码转换为net实现，java版github地址：https://github.com/tencentvideocloudmlvbdev/usersig_server_source/blob/master/java/webrtcsigapi.java。

需要使用类库：portable.bouncycastle，sharpziplib，直接从nuget下载安装即可。

另外我正在实现腾讯云im服务端sdk .netcore版本，github地址：https://github.com/yangxuilyx/qcloudim.aspnetcore

 public class tlssignature
    {
        /// <summary>
        /// 获取用户sign
        /// </summary>
        /// <param name="appid">appid</param>
        /// <param name="privatekey">私钥</param>
        /// <param name="userid">用户名</param>
        /// <param name="expire">usersig有效期，出于安全考虑建议为300秒，您可以根据您的业务场景设置其他值。</param>
        /// <returns>生成的usersig</returns>
        public static string genusersig(string appid, string privatekey, string userid, int expire)
        {
            var time = datetime.now.ticks / 1000;
            string serialstring =
                "tls.appid_at_3rd:" + 0 + "\n" +
                "tls.account_type:" + 0 + "\n" +
                "tls.identifier:" + userid + "\n" +
                "tls.sdk_appid:" + appid + "\n" +
                "tls.time:" + time + "\n" +
                "tls.expire_after:" + expire + "\n";

            var sign = convert.tobase64string(sign(privatekey, encoding.utf8.getbytes(serialstring)));

            string jsonstring = "{"
                                + "\"tls.account_type\":\"" + 0 + "\","
                                + "\"tls.identifier\":\"" + userid + "\","
                                + "\"tls.appid_at_3rd\":\"" + 0 + "\","
                                + "\"tls.sdk_appid\":\"" + appid + "\","
                                + "\"tls.expire_after\":\"" + expire + "\","
                                + "\"tls.sig\":\"" + sign + "\","
                                + "\"tls.time\":\"" + time + "\","
                                + "\"tls.version\": \"201512300000\""
                                + "}";

            var compressbytes = compress(encoding.utf8.getbytes(jsonstring));

            var usersign = base64urlencode(compressbytes);
            return usersign;
        }

        private static byte[] compress(byte[] data)
        {
            deflater mdeflater = new deflater();
            mdeflater.setinput(data);
            mdeflater.finish();
            byte[] compressbytes = new byte[512];
            int compressbyteslength = mdeflater.deflate(compressbytes);

            mdeflater.flush();

            return compressbytes.take(compressbyteslength).toarray();
        }

        /// <summary>
        /// ecdsa-sha256签名
        /// </summary>
        /// <param name="privatekey">私钥</param>
        /// <param name="data">需要签名的数据</param>
        /// <returns></returns>
        private static byte[] sign(string privatekey, byte[] data)
        {
            ecprivatekeyparameters privatekeyparam = (ecprivatekeyparameters)privatekeyfactory.createkey(convert.frombase64string(privatekey));

            var signer = signerutilities.getsigner("sha256withecdsa");
            signer.init(true, privatekeyparam);
            signer.blockupdate(data, 0, data.length);

            return signer.generatesignature();
        }

        /// <summary>
        /// 验证ecdsa-sha256签名
        /// </summary>
        /// <param name="publickey">公钥</param>
        /// <param name="data">需要验证的数据原文</param>
        /// <param name="sig">需要验证的签名</param>
        /// <returns>true:验证成功 false:验证失败</returns>
        public static bool verify(string publickey, byte[] data, byte[] sig)
        {
            ecpublickeyparameters publickeyparam = (ecpublickeyparameters)publickeyfactory.createkey(convert.frombase64string(publickey));

            var signer = signerutilities.getsigner("sha256withecdsa");
            signer.init(false, publickeyparam);
            signer.blockupdate(data, 0, data.length);

            return signer.verifysignature(sig);

        }

        private static string base64urlencode(byte[] data)
        {
            return convert.tobase64string(data).replace('+', '*').replace('/', '-')
                 .replace('=', '_');
        }

        private static string base64urldecode(byte[] data)
        {
            return convert.tobase64string(data).replace('*', '+').replace('-', '/')
                .replace('_', '=');
        }
    }