# abstract class OpenSSL::SSL::Context

- OpenSSL::SSL::Context
- Reference
- Object

##
Overview

An `SSL::Context` represents a generic secure socket protocol configuration.

For both server and client applications exist more specialized subclassses `SSL::Context::Server` and `SSL::Context::Client` which need to be instantiated appropriately.

##
Direct Known Subclasses

- OpenSSL::SSL::Context::Client
- OpenSSL::SSL::Context::Server

##
Defined in:

openssl/ssl/context.cr
openssl/ssl/defaults.cr

##
Constant Summary

CIPHER_SUITES_INTERMEDIATE = `"TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256"`

  The list of secure ciphersuites on intermediate compatibility level as per Mozilla recommendations.

  The oldest clients supported by this configuration are:

  - Firefox 27
  - Android 4.4.2
  - Chrome 31
  - Edge
  - IE 11 on Windows 7
  - Java 8u31
  - OpenSSL 1.0.1
  - Opera 20
  - Safari 9

  This list represents version 5.7 of the intermediate configuration available at https://ssl-config.mozilla.org/guidelines/5.7.json.

  See https://wiki.mozilla.org/Security/Server_Side_TLS for details.

CIPHER_SUITES_MODERN = `"TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256"`

  The list of secure ciphersuites on modern compatibility level as per Mozilla recommendations.

  The oldest clients supported by this configuration are:

  - Firefox 63
  - Android 10.0
  - Chrome 70
  - Edge 75
  - Java 11
  - OpenSSL 1.1.1
  - Opera 57
  - Safari 12.1

  This list represents version 5.7 of the modern configuration available at https://ssl-config.mozilla.org/guidelines/5.7.json.

  See https://wiki.mozilla.org/Security/Server_Side_TLS for details.

CIPHER_SUITES_OLD = `"TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256"`

  The list of secure ciphersuites on old compatibility level as per Mozilla recommendations.

  The oldest clients supported by this configuration are:

  - Firefox 1
  - Android 2.3
  - Chrome 1
  - Edge 12
  - IE8 on Windows XP
  - Java 6
  - OpenSSL 0.9.8
  - Opera 5
  - Safari 1

  This list represents version 5.7 of the old configuration available at https://ssl-config.mozilla.org/guidelines/5.7.json.

  See https://wiki.mozilla.org/Security/Server_Side_TLS for details.

CIPHERS_INTERMEDIATE = `"TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-CHACHA20-POLY1305:!RC4:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS"`

  The list of secure ciphers on intermediate compatibility level as per Mozilla recommendations.

  The oldest clients supported by this configuration are:

  - Firefox 27
  - Android 4.4.2
  - Chrome 31
  - Edge
  - IE 11 on Windows 7
  - Java 8u31
  - OpenSSL 1.0.1
  - Opera 20
  - Safari 9

  This list represents version 5.7 of the intermediate configuration available at https://ssl-config.mozilla.org/guidelines/5.7.json.

  See https://wiki.mozilla.org/Security/Server_Side_TLS for details.

CIPHERS_MODERN = `"TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:!RC4:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS"`

  The list of secure ciphers on modern compatibility level as per Mozilla recommendations.

  The oldest clients supported by this configuration are:

  - Firefox 63
  - Android 10.0
  - Chrome 70
  - Edge 75
  - Java 11
  - OpenSSL 1.1.1
  - Opera 57
  - Safari 12.1

  This list represents version 5.7 of the modern configuration available at https://ssl-config.mozilla.org/guidelines/5.7.json.

  See https://wiki.mozilla.org/Security/Server_Side_TLS for details.

CIPHERS_OLD = `"TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA256:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!RC4:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!SRP:!DSS"`

  The list of secure ciphers on old compatibility level as per Mozilla recommendations.

  The oldest clients supported by this configuration are:

  - Firefox 1
  - Android 2.3
  - Chrome 1
  - Edge 12
  - IE8 on Windows XP
  - Java 6
  - OpenSSL 0.9.8
  - Opera 5
  - Safari 1

  This list represents version 5.7 of the old configuration available at https://ssl-config.mozilla.org/guidelines/5.7.json.

  See https://wiki.mozilla.org/Security/Server_Side_TLS for details.

##
Instance Method Summary

- #add_modes(mode : OpenSSL::SSL::Modes)

  Adds modes to the TLS context.

- #add_options(options : OpenSSL::SSL::Options)

  Adds options to the TLS context.

- #add_x509_verify_flags(flags : OpenSSL::SSL::X509VerifyFlags)

  Sets the given `OpenSSL::SSL::X509VerifyFlags` in this context, additionally to the already set ones.

- #alpn_protocol=(protocol : String)

  Specifies an ALPN protocol to negotiate with the remote endpoint.

- #ca_certificates=(file_path : String)

  Sets the path to a file containing all CA certificates, in PEM format, used to validate the peers certificate.

- #ca_certificates_path=(dir_path : String)

  Sets the path to a directory containing all CA certificates used to validate the peers certificate.

- #certificate_chain=(file_path : String)

  Specify the path to the certificate chain file to use.

- #cipher_suites=(cipher_suites : String)

  Specify a list of TLS ciphersuites to use or discard for TLSv1.3.

- #ciphers=(ciphers : String)

  Specify a list of TLS ciphers to use or discard for TLSv1.2 and below.

- #default_verify_param=(name : String)

  Sets this context verify param to the default one of the given name.

- #finalize
- #modes : LibSSL::Modes

  Returns the current modes set on the TLS context.

- #options : LibSSL::Options

  Returns the current options set on the TLS context.

- #private_key=(file_path : String)

  Specify the path to the private key to use.

- #remove_modes(mode : OpenSSL::SSL::Modes)

  Removes modes from the TLS context.

- #remove_options(options : OpenSSL::SSL::Options)

  Removes options from the TLS context.

- #security_level : Int32

  Returns the security level used by this TLS context.

- #security_level=(value : Int32)

  Sets the security level used by this TLS context.

- #set_default_verify_paths

  Sets the default paths for `#ca_certificates=` and `#ca_certificates_path=`.

- #set_intermediate_ciphers

  Sets the current ciphers and ciphers suites to intermediate compatibility level as per Mozilla recommendations.

- #set_modern_ciphers

  Sets the current ciphers and ciphers suites to modern compatibility level as per Mozilla recommendations.

- #set_old_ciphers

  Sets the current ciphers and ciphers suites to old compatibility level as per Mozilla recommendations.

- #set_tmp_ecdh_key(curve = LibCrypto::NID_X9_62_prime256v1) : Nil

  Adds a temporary ECDH key curve to the TLS context.

- #to_unsafe : LibSSL::SSLContext
- #verify_mode : LibSSL::VerifyMode

  Returns the current verify mode.

- #verify_mode=(mode : OpenSSL::SSL::VerifyMode)

  Sets the verify mode.

### Instance methods inherited from class `Reference`

==(other : self)
==(other : JSON::Any)
==(other : YAML::Any)
==(other) ==, dup dup, hash(hasher) hash, initialize initialize, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference) : Bool
same?(other : Nil) same?, to_s(io : IO) : Nil to_s

### Constructor methods inherited from class `Reference`

new new, unsafe_construct(address : Pointer, *args, **opts) : self unsafe_construct

### Class methods inherited from class `Reference`

pre_initialize(address : Pointer) pre_initialize

### Instance methods inherited from class `Object`

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?, inspect(io : IO) : Nil
inspect : String inspect, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil!(message)
not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String to_json, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json, to_s(io : IO) : Nil
to_s : String to_s, to_yaml(io : IO) : Nil
to_yaml : String to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

### Class methods inherited from class `Object`

from_json(string_or_io, root : String)
from_json(string_or_io) from_json, from_yaml(string_or_io : String | IO) from_yaml

### Macros inherited from class `Object`

class_getter(*names, &block) class_getter, class_getter!(*names) class_getter!, class_getter?(*names, &block) class_getter?, class_property(*names, &block) class_property, class_property!(*names) class_property!, class_property?(*names, &block) class_property?, class_setter(*names) class_setter, def_clone def_clone, def_equals(*fields) def_equals, def_equals_and_hash(*fields) def_equals_and_hash, def_hash(*fields) def_hash, delegate(*methods, to object) delegate, forward_missing_to(delegate) forward_missing_to, getter(*names, &block) getter, getter!(*names) getter!, getter?(*names, &block) getter?, property(*names, &block) property, property!(*names) property!, property?(*names, &block) property?, setter(*names) setter

##
Instance Method Detail

def add_modes(mode : OpenSSL::SSL::Modes) #

Adds modes to the TLS context.

def add_options(options : OpenSSL::SSL::Options) #

Adds options to the TLS context.

Example:

    context.add_options(
      OpenSSL::SSL::Options::ALL |       # various workarounds
      OpenSSL::SSL::Options::NO_SSL_V2 | # disable overly deprecated SSLv2
      OpenSSL::SSL::Options::NO_SSL_V3   # disable deprecated SSLv3
    )

def add_x509_verify_flags(flags : OpenSSL::SSL::X509VerifyFlags) #

Sets the given `OpenSSL::SSL::X509VerifyFlags` in this context, additionally to the already set ones.

def alpn_protocol=(protocol : String) #

Specifies an ALPN protocol to negotiate with the remote endpoint. This is required to negotiate HTTP/2 with browsers, since browser vendors decided not to implement HTTP/2 over insecure connections.

Example:

    context.alpn_protocol = "h2"

def ca_certificates=(file_path : String) #

Sets the path to a file containing all CA certificates, in PEM format, used to validate the peers certificate.

def ca_certificates_path=(dir_path : String) #

Sets the path to a directory containing all CA certificates used to validate the peers certificate. The certificates should be in PEM format and the `c_rehash(1)` utility must have been run in the directory.

def certificate_chain=(file_path : String) #

Specify the path to the certificate chain file to use. In server mode this is presented to the client, in client mode this used as client certificate.

def cipher_suites=(cipher_suites : String) #

Specify a list of TLS ciphersuites to use or discard for TLSv1.3.

See `#security_level=` for some sensible system configuration.

NOTE The ciphersuites available to an application are determined by the linked version of the system SSL library. A comprehensive list of ciphersuites can be found in the OpenSSL Cipher documentation.

def ciphers=(ciphers : String) #

Specify a list of TLS ciphers to use or discard for TLSv1.2 and below.

See `#security_level=` for some sensible system configuration.

This method does not impact TLSv1.3 ciphersuites. Use `#cipher_suites=` to configure those.

NOTE The ciphers available to an application are determined by the linked version of the system SSL library. A comprehensive list of ciphers can be found in the OpenSSL Cipher documentation.

def default_verify_param=(name : String) #

Sets this context verify param to the default one of the given name.

Depending on the OpenSSL version, the available defaults are `default`, `pkcs7`, `smime_sign`, `ssl_client` and `ssl_server`.

def finalize #
def modes : LibSSL::Modes #

Returns the current modes set on the TLS context.

def options : LibSSL::Options #

Returns the current options set on the TLS context.

def private_key=(file_path : String) #

Specify the path to the private key to use. The key must in PEM format. The key must correspond to the entity certificate set by `#certificate_chain=`.

def remove_modes(mode : OpenSSL::SSL::Modes) #

Removes modes from the TLS context.

def remove_options(options : OpenSSL::SSL::Options) #

Removes options from the TLS context.

Example:

    context.remove_options(OpenSSL::SSL::Options::NO_SSL_V3)

def security_level : Int32 #

Returns the security level used by this TLS context.

def security_level=(value : Int32) #

Sets the security level used by this TLS context. The default system security level might disable some ciphers.

- https://www.openssl.org/docs/man1.1.1/man3/SSL_CTX_set_security_level.html
- https://wiki.debian.org/ContinuousIntegration/TriagingTips/openssl-1.1.1

def set_default_verify_paths #

Sets the default paths for `#ca_certificates=` and `#ca_certificates_path=`.

def set_intermediate_ciphers #

Sets the current ciphers and ciphers suites to intermediate compatibility level as per Mozilla recommendations. See `CIPHERS_INTERMEDIATE` and `CIPHER_SUITES_INTERMEDIATE`. See `#security_level=` for some sensible system configuration.

def set_modern_ciphers #

Sets the current ciphers and ciphers suites to modern compatibility level as per Mozilla recommendations. See `CIPHERS_MODERN` and `CIPHER_SUITES_MODERN`. See `#security_level=` for some sensible system configuration.

def set_old_ciphers #

Sets the current ciphers and ciphers suites to old compatibility level as per Mozilla recommendations. See `CIPHERS_OLD` and `CIPHER_SUITES_OLD`. See `#security_level=` for some sensible system configuration.

def set_tmp_ecdh_key(curve = LibCrypto::NID_X9_62_prime256v1) : Nil #

Adds a temporary ECDH key curve to the TLS context. This is required to enable the EECDH cipher suites. By default the prime256 curve will be used.

def to_unsafe : LibSSL::SSLContext #
def verify_mode : LibSSL::VerifyMode #

Returns the current verify mode. See the `SSL_CTX_set_verify(3)` manpage for more details.

def verify_mode=(mode : OpenSSL::SSL::VerifyMode) #

Sets the verify mode. See the `SSL_CTX_set_verify(3)` manpage for more details.