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require 'openssl'
require 'delegate'
module Net::SSH::Transport
#:nodoc:
class OpenSSLAESCTR < SimpleDelegator
def initialize(original)
super
@was_reset = false
end
def block_size
16
end
def self.block_size
16
end
def reset
@was_reset = true
end
def iv=(iv_s)
super unless @was_reset
end
end
#:nodoc:
# Pure-Ruby implementation of Stateful Decryption Counter(SDCTR) Mode
# for Block Ciphers. See RFC4344 for detail.
module CTR
def self.extended(orig)
orig.instance_eval {
@remaining = String.new
@counter = nil
@counter_len = orig.block_size
orig.encrypt
orig.padding = 0
singleton_class.send(:alias_method, :_update, :update)
singleton_class.send(:private, :_update)
singleton_class.send(:undef_method, :update)
def iv
@counter
end
def iv_len
block_size
end
def iv=(iv_s)
@counter = iv_s if @counter.nil?
end
def encrypt
# DO NOTHING (always set to "encrypt")
end
def decrypt
# DO NOTHING (always set to "encrypt")
end
def padding=(pad)
# DO NOTHING (always 0)
end
def reset
@remaining = String.new
end
def update(data)
@remaining += data
encrypted = String.new
offset = 0
while (@remaining.bytesize - offset) >= block_size
encrypted += xor!(@remaining.slice(offset, block_size),
_update(@counter))
increment_counter!
offset += block_size
end
@remaining = @remaining.slice(offset..-1)
encrypted
end
def final
s = @remaining.empty? ? '' : xor!(@remaining, _update(@counter))
@remaining = String.new
s
end
def xor!(s1, s2)
s = []
s1.unpack('Q*').zip(s2.unpack('Q*')) {|a,b| s.push(a ^ b) }
s.pack('Q*')
end
singleton_class.send(:private, :xor!)
def increment_counter!
c = @counter_len
while ((c -= 1) > 0)
if @counter.setbyte(c, (@counter.getbyte(c) + 1) & 0xff) != 0
break
end
end
end
singleton_class.send(:private, :increment_counter!)
}
end
end
end
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