C# / Generate a 1024 bits symmetric key for HMAC-SHA256

Here is the way to generate a symmetric key for HMAC-SHA256 encryption, that is needed, for example, in using JWT Security Tokens when providing a REST API :

        private static void GenerateEncryptionKey()
        {
            RNGCryptoServiceProvider cryptoProvider = new RNGCryptoServiceProvider();
            byte[] keyForHmacSha256 = new byte[64];
            cryptoProvider.GetNonZeroBytes(keyForHmacSha256);
            StringBuilder hex = new StringBuilder(keyForHmacSha256.Length * 2);
            foreach (byte b in keyForHmacSha256)
            {
                hex.AppendFormat("{0:x2}", b);
            }
            Console.WriteLine(hex.ToString());
        }

An example of output is composed of 128 bytes, that means 128x8 bits, so 1024 bits :
"401b09eab3c013c48a54922bb802bec8fd531819211125f201d8b3727429090fb337591abd3e44453b954555b7a0812e1081c39b740293f765eae731f59d3ed1"

You could then copy and paste this generated key into your Token Validation Handler if needed for this purpose...

Android Retrofit2 Image Upload Example (to RESTful API server)

If you need to use Retrofit 2 in your Android application source code, then you can check the following example on GitHub :

https://github.com/reuniware/AndroidRetrofit2ImageUpload

Extension Facebook "Je Suis Suivi" pour Google Chrome

Voici le lien d'installation de l'extension :

http://app.getresponse.com/click.html?x=a62b&lc=BvUFaM&mc=JK&s=5E7lzR&u=hVZ3B&y=d&