CODEWITHSUNDEEP
phpssl-handshake
MKSOI
MKSOI

Reputation: 59

How to get the list of cipher suits offered by my client?

I am trying to get the list of Cipher Suits offered by my clients when visiting my PHP web page.

I tried checking $_SERVER['SSL_CLIENT_CERT'] or $_SERVER['SSL_CLIENT_CERT_CHAIN_0'], but I am getting the following error

Warning: Undefined array key "SSL_CLIENT_CERT" ..

My webserver is Apache (XAMPP). It seems that the super global variable $_SERVER is not populated with this information. Any idea on how can I get it?

Note: $_SERVER['HTTPS'] is 'on'

Upvotes: 1

Views: 2010

Answers (1)

Digital Alchemist
Digital Alchemist

Reputation: 690

To obtain a list of available cipher methods for your server, use function openssl_get_cipher_methods(). This, however, will not provide you with a list of the cipher suites supported by the client during a specific connection.

To determine the cipher used by the client, inspect the SSL/TLS handshake. Connect to a web server using the command openssl s_client -connect hostname:port to view the details of the handshake, including the negotiated cipher suite or use mod ssl or another Apache module to log the SSL/TLS information in the logs, which will include the negotiated cipher.

$_SERVER is a superglobal variable and its populated based on the configuration of the web server.

Upvotes: 1

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