CryptographicEngine.EncryptAndAuthenticate | encryptAndAuthenticate method

var encryptedAndAuthenticatedData = Windows.Security.Cryptography.Core.CryptographicEngine.encryptAndAuthenticate(key, data, nonce, authenticatedData);

public EncryptedAndAuthenticatedData AuthenticatedEncryption(
    String strMsg,
    String strAlgName,
    UInt32 keyLength,
    out BinaryStringEncoding encoding,
    out IBuffer buffNonce,
    out CryptographicKey key)
{
    // Open a SymmetricKeyAlgorithmProvider object for the specified algorithm.
    SymmetricKeyAlgorithmProvider objAlgProv = SymmetricKeyAlgorithmProvider.OpenAlgorithm(strAlgName);

    // Create a buffer that contains the data to be encrypted.
    encoding = BinaryStringEncoding.Utf8;
    IBuffer buffMsg = CryptographicBuffer.ConvertStringToBinary(strMsg, encoding);

    // Generate a symmetric key.
    IBuffer keyMaterial = CryptographicBuffer.GenerateRandom(keyLength);
    key = objAlgProv.CreateSymmetricKey(keyMaterial);

    // Generate a new nonce value.
    buffNonce = GetNonce();

    // Encrypt and authenticate the message.
    EncryptedAndAuthenticatedData objEncrypted = CryptographicEngine.EncryptAndAuthenticate(
        key,
        buffMsg,
        buffNonce,
        null);

    return objEncrypted;

}

IBuffer GetNonce()
{
    // Security best practises require that an ecryption operation not
    // be called more than once with the same nonce for the same key.
    // A nonce value can be predictable, but must be unique for each
    // secure session.

    NonceBytes[0]++;
    for (int i = 0; i < NonceBytes.Length - 1; i++)
    {
        if (NonceBytes[i] == 255)
        {
            NonceBytes[i + 1]++;
        }
    }

    return CryptographicBuffer.CreateFromByteArray(NonceBytes);
}