Class: Net::SSH::Transport::CipherFactory
- Inherits:
-
Object
- Object
- Net::SSH::Transport::CipherFactory
- Defined in:
- lib/net/ssh/transport/cipher_factory.rb
Overview
Implements a factory of OpenSSL cipher algorithms.
Constant Summary collapse
- SSH_TO_OSSL =
Maps the SSH name of a cipher to it’s corresponding OpenSSL name
{ "3des-cbc" => "des-ede3-cbc", "blowfish-cbc" => "bf-cbc", "aes256-cbc" => "aes-256-cbc", "aes192-cbc" => "aes-192-cbc", "aes128-cbc" => "aes-128-cbc", "idea-cbc" => "idea-cbc", "cast128-cbc" => "cast-cbc", "[email protected]" => "aes-256-cbc", "arcfour128" => "rc4", "arcfour256" => "rc4", "arcfour512" => "rc4", "none" => "none" }
Class Method Summary collapse
-
.get(name, options = {}) ⇒ Object
Retrieves a new instance of the named algorithm.
-
.get_lengths(name) ⇒ Object
Returns a two-element array containing the [ key-length, block-size ] for the named cipher algorithm.
-
.supported?(name) ⇒ Boolean
Returns true if the underlying OpenSSL library supports the given cipher, and false otherwise.
Class Method Details
.get(name, options = {}) ⇒ Object
Retrieves a new instance of the named algorithm. The new instance will be initialized using an iv and key generated from the given iv, key, shared, hash and digester values. Additionally, the cipher will be put into encryption or decryption mode, based on the value of the encrypt
parameter.
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# File 'lib/net/ssh/transport/cipher_factory.rb', line 37 def self.get(name, ={}) ossl_name = SSH_TO_OSSL[name] or raise NotImplementedError, "unimplemented cipher `#{name}'" return IdentityCipher if ossl_name == "none" cipher = OpenSSL::Cipher::Cipher.new(ossl_name) cipher.send([:encrypt] ? :encrypt : :decrypt) cipher.padding = 0 cipher.iv = make_key(cipher.iv_len, [:iv], ) if ossl_name != "rc4" key_len = cipher.key_len cipher.key_len = key_len = 32 if name == "arcfour256" cipher.key_len = key_len = 64 if name == "arcfour512" cipher.key = make_key(key_len, [:key], ) cipher.update(" " * 1536) if ossl_name == "rc4" return cipher end |
.get_lengths(name) ⇒ Object
Returns a two-element array containing the [ key-length, block-size ] for the named cipher algorithm. If the cipher algorithm is unknown, or is “none”, 0 is returned for both elements of the tuple.
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# File 'lib/net/ssh/transport/cipher_factory.rb', line 59 def self.get_lengths(name) ossl_name = SSH_TO_OSSL[name] return [0, 0] if ossl_name.nil? || ossl_name == "none" cipher = OpenSSL::Cipher::Cipher.new(ossl_name) key_len = cipher.key_len key_len = 32 if name == "arcfour256" key_len = 64 if name == "arcfour512" return [key_len, ossl_name=="rc4" ? 8 : cipher.block_size] end |
.supported?(name) ⇒ Boolean
Returns true if the underlying OpenSSL library supports the given cipher, and false otherwise.
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# File 'lib/net/ssh/transport/cipher_factory.rb', line 26 def self.supported?(name) ossl_name = SSH_TO_OSSL[name] or raise NotImplementedError, "unimplemented cipher `#{name}'" return true if ossl_name == "none" return OpenSSL::Cipher.ciphers.include?(ossl_name) end |