Constants added in PHP 5.6 :
STREAM_CRYPTO_METHOD_ANY_CLIENT
STREAM_CRYPTO_METHOD_TLSv1_0_CLIENT
STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT
STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT
STREAM_CRYPTO_METHOD_ANY_SERVER
STREAM_CRYPTO_METHOD_TLSv1_0_SERVER
STREAM_CRYPTO_METHOD_TLSv1_1_SERVER
STREAM_CRYPTO_METHOD_TLSv1_2_SERVER
Now, be careful because since PHP 5.6.7, STREAM_CRYPTO_METHOD_TLS_CLIENT (same for _SERVER) no longer means any tls version but tls 1.0 only (for "backward compatibility"...).
Before PHP 5.6.7 :
STREAM_CRYPTO_METHOD_SSLv23_CLIENT = STREAM_CRYPTO_METHOD_SSLv2_CLIENT|STREAM_CRYPTO_METHOD_SSLv3_CLIENT
STREAM_CRYPTO_METHOD_TLS_CLIENT = STREAM_CRYPTO_METHOD_TLSv1_0_CLIENT|STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT|STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT
PHP >= 5.6.7
STREAM_CRYPTO_METHOD_SSLv23_CLIENT = STREAM_CRYPTO_METHOD_TLSv1_0_CLIENT|STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT|STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT
STREAM_CRYPTO_METHOD_TLS_CLIENT = STREAM_CRYPTO_METHOD_TLSv1_0_CLIENT
PHP bug : https://bugs.php.net/bug.php?id=69195
Commit : https://github.com/php/php-src/commit/10bc5fd4c4c8e1dd57bd911b086e9872a56300a0
STREAM_CRYPTO_METHOD_SSLv23_CLIENT is not safe to use because before php 5.6.7, it means sslv2 or sslv3. So, you should do this :
<?php
$crypto_method = STREAM_CRYPTO_METHOD_TLS_CLIENT;
if (defined('STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT')) {
$crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT;
$crypto_method |= STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT;
}
stream_socket_enable_crypto($socket, true, $crypto_method);
?>