An SSLContext is used to set various options regarding certificates, algorithms, verification, session caching, etc. The SSLContext is used to create an SSLSocket.

All attributes must be set before creating an SSLSocket as the SSLContext will be frozen afterward.

The following attributes are available but don’t show up in rdoc:

Constants
No documentation available
No documentation available
No documentation available

No session caching for client or server

Client sessions are added to the session cache

Server sessions are added to the session cache

Both client and server sessions are added to the session cache

Normally the session cache is checked for expired sessions every 255 connections. Since this may lead to a delay that cannot be controlled, the automatic flushing may be disabled and flush_sessions can be called explicitly.

Always perform external lookups of sessions even if they are in the internal cache.

This flag has no effect on clients

Never automatically store sessions in the internal store.

The list of available SSL/TLS methods

Attributes
Read & Write

A callback invoked when DH parameters are required.

The callback is invoked with the Session for the key exchange, an flag indicating the use of an export cipher and the keylength required.

The callback must return an OpenSSL::PKey::DH instance of the correct key length.

Read & Write

Context certificate

key

Read & Write

Context private key

Read & Write

A certificate or Array of certificates that will be sent to the client.

Read & Write

The path to a file containing a PEM-format CA certificate

Read & Write

The path to a directory containing CA certificates in PEM format.

Files are looked up by subject’s X509 name’s hash value.

Read & Write

Maximum session lifetime.

Read & Write

Maximum session lifetime.

Read & Write

Session verification mode.

Valid modes are VERIFY_NONE, VERIFY_PEER, VERIFY_CLIENT_ONCE, VERIFY_FAIL_IF_NO_PEER_CERT and defined on OpenSSL::SSL

Read & Write

Number of CA certificates to walk when verifying a certificate chain.

Read & Write

A callback for additional certificate verification. The callback is invoked for each certificate in the chain.

The callback is invoked with two values. preverify_ok indicates indicates if the verification was passed (true) or not (false). store_context is an OpenSSL::X509::StoreContext containing the context used for certificate verification.

If the callback returns false verification is stopped.

Read & Write

An OpenSSL::X509::Store used for certificate verification

Read & Write

An Array of extra X509 certificates to be added to the certificate chain.

Read & Write

A callback invoked when a client certificate is requested by a server and no certificate has been set.

The callback is invoked with a Session and must return an Array containing an OpenSSL::X509::Certificate and an OpenSSL::PKey. If any other value is returned the handshake is suspended.

Read & Write

A callback invoked when ECDH parameters are required.

The callback is invoked with the Session for the key exchange, an flag indicating the use of an export cipher and the keylength required.

The callback must return an OpenSSL::PKey::EC instance of the correct key length.

Read & Write

Sets the context in which a session can be reused. This allows sessions for multiple applications to be distinguished, for example, by name.

Read & Write

A callback invoked on a server when a session is proposed by the client but the session could not be found in the server’s internal cache.

The callback is invoked with the SSLSocket and session id. The callback may return a Session from an external cache.

Read & Write

A callback invoked when a new session was negotiated.

The callback is invoked with an SSLSocket. If false is returned the session will be removed from the internal cache.

Read & Write

A callback invoked when a session is removed from the internal cache.

The callback is invoked with an SSLContext and a Session.

Read & Write

A callback invoked whenever a new handshake is initiated. May be used to disable renegotiation entirely.

The callback is invoked with the active SSLSocket. The callback’s return value is irrelevant, normal return indicates “approval” of the renegotiation and will continue the process. To forbid renegotiation and to cancel the process, an Error may be raised within the callback.

Disable client renegotiation

When running a server, it is often desirable to disable client renegotiation entirely. You may use a callback as follows to implement this feature:

num_handshakes = 0
ctx.renegotiation_cb = lambda do |ssl|
  num_handshakes += 1
  raise RuntimeError.new("Client renegotiation disabled") if num_handshakes > 1
end
Read & Write

An Enumerable of Strings. Each String represents a protocol to be advertised as the list of supported protocols for Next Protocol Negotiation. Supported in OpenSSL 1.0.1 and higher. Has no effect on the client side. If not set explicitly, the NPN extension will not be sent by the server in the handshake.

Example

ctx.npn_protocols = ["http/1.1", "spdy/2"]
Read & Write

A callback invoked on the client side when the client needs to select a protocol from the list sent by the server. Supported in OpenSSL 1.0.1 and higher. The client MUST select a protocol of those advertised by the server. If none is acceptable, raising an error in the callback will cause the handshake to fail. Not setting this callback explicitly means not supporting the NPN extension on the client - any protocols advertised by the server will be ignored.

Example

ctx.npn_select_cb = lambda do |protocols|
  #inspect the protocols and select one
  protocols.first
end
Read & Write

An Enumerable of Strings. Each String represents a protocol to be advertised as the list of supported protocols for Application-Layer Protocol Negotiation. Supported in OpenSSL 1.0.1 and higher. Has no effect on the client side. If not set explicitly, the NPN extension will not be sent by the server in the handshake.

Example

ctx.alpn_protocols = ["http/1.1", "spdy/2", "h2"]
Read & Write

A callback invoked on the server side when the server needs to select a protocol from the list sent by the client. Supported in OpenSSL 1.0.2 and higher. The server MUST select a protocol of those advertised by the client. If none is acceptable, raising an error in the callback will cause the handshake to fail. Not setting this callback explicitly means not supporting the ALPN extension on the client - any protocols advertised by the server will be ignored.

Example

ctx.alpn_select_cb = lambda do |protocols|
  #inspect the protocols and select one
  protocols.first
end
Class Methods

You can get a list of valid methods with OpenSSL::SSL::SSLContext::METHODS

Instance Methods

The list of ciphers configured for this context.

Sets the list of available ciphers for this context. Note in a server context some ciphers require the appropriate certificates. For example, an RSA cipher can only be chosen when an RSA certificate is available.

See also OpenSSL::Cipher and OpenSSL::Cipher::ciphers

Removes sessions in the internal cache that have expired at time.

Gets various OpenSSL options.

Sets various OpenSSL options.

Adds session to the session cache

The current session cache mode.

Sets the SSL session cache mode. Bitwise-or together the desired SESSION_CACHE_* constants to set. See SSL_CTX_set_session_cache_mode(3) for details.

Returns the current session cache size. Zero is used to represent an unlimited cache size.

Sets the session cache size. Returns the previously valid session cache size. Zero is used to represent an unlimited session cache size.

Returns a Hash containing the following keys:

:accept

Number of started SSL/TLS handshakes in server mode

:accept_good

Number of established SSL/TLS sessions in server mode

:accept_renegotiate

Number of start renegotiations in server mode

:cache_full

Number of sessions that were removed due to cache overflow

:cache_hits

Number of successfully reused connections

:cache_misses

Number of sessions proposed by clients that were not found in the cache

:cache_num

Number of sessions in the internal session cache

:cb_hits

Number of sessions retrieved from the external cache in server mode

:connect

Number of started SSL/TLS handshakes in client mode

:connect_good

Number of established SSL/TLS sessions in client mode

:connect_renegotiate

Number of start renegotiations in client mode

:timeouts

Number of sessions proposed by clients that were found in the cache but had expired due to timeouts

Removes session from the session cache

Sets the parameters for this SSL context to the values in params. The keys in params must be assignment methods on SSLContext.

If the verify_mode is not VERIFY_NONE and ca_file, ca_path and cert_store are not set then the system default certificate store is used.

This method is called automatically when a new SSLSocket is created. However, it is not thread-safe and must be called before creating SSLSocket objects in a multi-threaded program.

You can get a list of valid versions with OpenSSL::SSL::SSLContext::METHODS