Descifrado AES en Windows 8

Hoy vamos a hablar del bonito mundo del cifrado, ojo no del encriptado (meter en una cripta).

La seguridad es importante, y por eso vamos a ver como cifrar en servidor y descifrar en cliente Windows 8 en aplicaciones Metro.

Para este ejemplo usaremos AES con cifrado de 256 Bytes, (Cifrado militar)

Parte servidora

public string Get()
        {
            //
            String original = "1234567812345678";
            String key = "CLAVEDESEGURIDAD";
            byte[] KeyArr = System.Text.Encoding.ASCII.GetBytes(key);
            String iv = "VECTORINICIALIZACION";
            byte[] IvArr = System.Text.Encoding.ASCII.GetBytes(iv);
            using (AesManaged myAes = new AesManaged())
            {
                return EncryptStringToBytes_Aes(original, KeyArr, IvArr);
            }

        }
        static string EncryptStringToBytes_Aes(string plainText, byte[] Key, byte[] IV)
        {
            byte[] encrypted;
            using (AesManaged aesAlg = new AesManaged())
            {
                ICryptoTransform encryptor = aesAlg.CreateEncryptor(Key, IV);

                using (MemoryStream msEncrypt = new MemoryStream())
                {
                    using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                    {
                        using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                        {
                            swEncrypt.Write(plainText);
                            swEncrypt.Flush();
                            encrypted = msEncrypt.ToArray();
                            return Convert.ToBase64String(encrypted);
                        }
                    }
                }
            }

        }

 Parte de Cliente

 function RunSample(cadenacifradaenbase64) {

	var Algorithm = Windows.Security.Cryptography.Core.SymmetricKeyAlgorithmProvider.openAlgorithm("AES_CBC");
        	var keymaterial2 = Windows.Security.Cryptography.CryptographicBuffer.convertStringToBinary("CLAVEDESEGURIDAD", Windows.Security.Cryptography.BinaryStringEncoding.utf8);
        	var key2;
        	try {
        	    key2 = Algorithm.createSymmetricKey(keymaterial2);

        	}
       	 catch (ex) {
        	    Scenario5Output.textContent += ex.message;
        	    Scenario5Output.textContent += "An invalid key size was selected for the given algorithm.n";
        	    return;
       	 }
	var bufferCifrado = Windows.Security.Cryptography.CryptographicBuffer.decodeFromBase64String(cadenacifradaenbase64);
	var iv = Windows.Security.Cryptography.CryptographicBuffer.convertStringToBinary("VECTORINICIALIZACION", Windows.Security.Cryptography.BinaryStringEncoding.utf8);
	var decrypted = Windows.Security.Cryptography.Core.CryptographicEngine.decrypt(key2, bufferCifrado , iv);        
        var solucion = Windows.Security.Cryptography.CryptographicBuffer.convertBinaryToString(Windows.Security.Cryptography.BinaryStringEncoding.utf8, decrypted);
}

 

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