module Net::SSH::Transport::KeyExpander

  1. lib/net/ssh/transport/key_expander.rb
Parent: Transport

Methods

Public Class

  1. expand_key

Public Class methods

expand_key (bytes, start, options={})

Generate a key value in accordance with the SSH2 specification. (RFC4253 7.2. "Output from Key Exchange")

[show source] 
# File lib/net/ssh/transport/key_expander.rb, line 6
def self.expand_key(bytes, start, options={})
  if bytes == 0
    return ""
  end

  k = start[0, bytes]

  digester = options[:digester] or raise 'No digester supplied'
  shared   = options[:shared] or raise 'No shared secret supplied'
  hash     = options[:hash] or raise 'No hash supplied'

  while k.length < bytes
    step = digester.digest(shared + hash + k)
    bytes_needed = bytes - k.length
    k << step[0, bytes_needed]
  end

  return k
end