function verify_market_in_app($signed_data, $signature, $public_key_base64)

{

    $key =  "-----BEGIN PUBLIC KEY-----\n".

        chunk_split($public_key_base64, 64,"\n").

        '-----END PUBLIC KEY-----';  

    //using PHP to create an RSA key

    $key = openssl_get_publickey($key);

    //$signature should be in binary format, but it comes as BASE64.

    //So, I'll convert it.

    $signature = base64_decode($signature);  

    //using PHP's native support to verify the signature

    $result = openssl_verify(

            $signed_data,

            $signature,

            $key,

            OPENSSL_ALGO_SHA1);

    if (0 === $result)

    {

        return false;

    }

    else if (1 !== $result)

    {

        return false;

    }

    else

    {

        return true;

    }

}