If you need to change a stream from unencrypted to crypted after unencrypted traffic has been processed, you use the stream-socket-recvfrom function to read instead of fread when reading the unencrypted traffic. Using fread will cause some of the buffer of the initial CLIENT HELLO message to be read into it's buffers causing the SSL handshake to fail in some situations.

As already mentioned above:

stream_socket_enable_crypto is likely to fail/return zero if the socket is in non-blocking mode.

You may either wait some seconds until all neccessary data has arrived or switch temporary to blocking mode:

<?PHP

  stream_set_blocking ($fd, true);
  stream_socket_enable_crypto ($fd, true, STREAM_CRYPTO_METHOD_TLS_CLIENT);
  stream_set_blocking ($fd, false);

?>

This works very fine for me ;-)

Information to the difference of `crypto_method`

There is `STREAM_CRYPTO_METHOD_*_CLIENT` and `STREAM_CRYPTO_METHOD_*_SERVER`

`STREAM_CRYPTO_METHOD_*_CLIENT` is used for clients, like:
```php
<?php
$client = stream_socket_client("tcp://example.com:443", $errno, $errstr);
stream_socket_enable_crypto($client, true, STREAM_CRYPTO_METHOD_TLS_CLIENT);

//...
?>
```

This code makes a TLS Handshake and the `stream_socket_enable_crypto` sends a `Client HELLO`

`STREAM_CRYPTO_METHOD_*_SERVER` is used for servers, like:
<?php
$server = stream_socket_server("tcp://example.com:443", $errno, $errstr, STREAM_SERVER_BIND | STREAM_SERVER_LISTEN);
stream_context_set_option($server, ["ssl" => [
    "local_cert" => __DIR__."/https.crt",
    "local_pk" => __DIR__."/https.key",
]]);

//...

$client = stream_socket_accept($server);
stream_socket_enable_crypto($client, true, STREAM_CRYPTO_METHOD_TLS_SERVER);

//...
?>

This code makes a TLS Handshake and the `stream_socket_enable_crypto` sends a `Server HELLO` after the client send a `Client HELLO`.

so use `STREAM_CRYPTO_METHOD_*_CLIENT` for requesting data and `STREAM_CRYPTO_METHOD_*_SERVER` for serving data, after accepting a client.

Since PHP 7.2, TLS equates to TLS_ANY, so STREAM_CRYPTO_METHOD_TLS_CLIENT means any TLS versions.