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", "3des-ctr" => "des-ede3", "blowfish-ctr" => "bf-ecb", "aes256-ctr" => ::OpenSSL::Cipher.ciphers.include?("aes-256-ctr") ? "aes-256-ctr" : "aes-256-ecb", "aes192-ctr" => ::OpenSSL::Cipher.ciphers.include?("aes-192-ctr") ? "aes-192-ctr" : "aes-192-ecb", "aes128-ctr" => ::OpenSSL::Cipher.ciphers.include?("aes-128-ctr") ? "aes-128-ctr" : "aes-128-ecb", 'cast128-ctr' => 'cast5-ecb', 'none' => 'none' }
- SSH_TO_CLASS =
if Net::SSH::Transport::ChaCha20Poly1305CipherLoader::LOADED { '[email protected]' => Net::SSH::Transport::ChaCha20Poly1305Cipher } else { } end
Class Method Summary collapse
-
.get(name, options = {}) ⇒ Object
Retrieves a new instance of the named algorithm.
-
.get_lengths(name, options = {}) ⇒ 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 60 def self.get(name, = {}) klass = SSH_TO_CLASS[name] unless klass.nil? key_len = klass.key_length key = Net::SSH::Transport::KeyExpander.(key_len, [:key], ) return klass.new(encrypt: [:encrypt], key: key) end ossl_name = SSH_TO_OSSL[name] or raise NotImplementedError, "unimplemented cipher `#{name}'" return IdentityCipher if ossl_name == "none" cipher = OpenSSL::Cipher.new(ossl_name) cipher.send([:encrypt] ? :encrypt : :decrypt) cipher.padding = 0 cipher.extend(Net::SSH::Transport::OpenSSLCipherExtensions) if name =~ /-ctr(@openssh.org)?$/ if ossl_name !~ /-ctr/ cipher.extend(Net::SSH::Transport::CTR) else cipher = Net::SSH::Transport::OpenSSLAESCTR.new(cipher) end end cipher.iv = Net::SSH::Transport::KeyExpander.(cipher.iv_len, [:iv], ) key_len = cipher.key_len cipher.key_len = key_len cipher.key = Net::SSH::Transport::KeyExpander.(key_len, [:key], ) return cipher end |
.get_lengths(name, options = {}) ⇒ 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. if :iv_len option is supplied the third return value will be ivlen
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# File 'lib/net/ssh/transport/cipher_factory.rb', line 99 def self.get_lengths(name, = {}) klass = SSH_TO_CLASS[name] return [klass.key_length, klass.block_size] unless klass.nil? ossl_name = SSH_TO_OSSL[name] if ossl_name.nil? || ossl_name == "none" result = [0, 0] result << 0 if [:iv_len] else cipher = OpenSSL::Cipher.new(ossl_name) key_len = cipher.key_len cipher.key_len = key_len block_size = case ossl_name when /\-ctr/ Net::SSH::Transport::OpenSSLAESCTR.block_size else cipher.block_size end result = [key_len, block_size] result << cipher.iv_len if [:iv_len] end result 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 46 def self.supported?(name) return true if SSH_TO_CLASS.key?(name) ossl_name = SSH_TO_OSSL[name] or raise NotImplementedError, "unimplemented cipher `#{name}'" return true if ossl_name == "none" return SSH_TO_CLASS.key?(name) || OpenSSL::Cipher.ciphers.include?(ossl_name) end |