Class: HMAC::Base

Inherits:
Object
  • Object
show all
Defined in:
lib/hmac.rb

Direct Known Subclasses

MD5, RMD160, SHA1, SHA256, SHA384, SHA512

Instance Method Summary collapse

Constructor Details

#initialize(algorithm, block_size, output_length, key) ⇒ Base

Returns a new instance of Base.



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# File 'lib/hmac.rb', line 23

def initialize(algorithm, block_size, output_length, key)
  @algorithm = algorithm
  @block_size = block_size
  @output_length = output_length
  @initialized = false
  @key_xor_ipad = ''
  @key_xor_opad = ''
  set_key(key) unless key.nil?
end

Instance Method Details

#digest ⇒ Object 



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# File 'lib/hmac.rb', line 82

def digest
  check_status
  @md.digest
end

#hexdigest ⇒ Object 



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# File 'lib/hmac.rb', line 87

def hexdigest
  check_status
  @md.hexdigest
end

#reset_key ⇒ Object 



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# File 'lib/hmac.rb', line 59

def reset_key
  @key_xor_ipad.gsub!(/./, '?')
  @key_xor_opad.gsub!(/./, '?')
  @key_xor_ipad[0..-1] = ''
  @key_xor_opad[0..-1] = ''
  @initialized = false
end

#set_key(key) ⇒ Object 



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# File 'lib/hmac.rb', line 42

def set_key(key)
  # If key is longer than the block size, apply hash function
  # to key and use the result as a real key.
  key = @algorithm.digest(key) if key.size > @block_size
  akey = key.unpack("C*")
  key_xor_ipad = ("\x36" * @block_size).unpack("C*")
  key_xor_opad = ("\x5C" * @block_size).unpack("C*")
  for i in 0 .. akey.size - 1
    key_xor_ipad[i] ^= akey[i]
    key_xor_opad[i] ^= akey[i]
  end
  @key_xor_ipad = key_xor_ipad.pack("C*")
  @key_xor_opad = key_xor_opad.pack("C*")
  @md = @algorithm.new
  @initialized = true
end

#to_s ⇒ Object 



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# File 'lib/hmac.rb', line 91

def hexdigest
  check_status
  @md.hexdigest
end

#update(text) ⇒ Object Also known as: << 



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# File 'lib/hmac.rb', line 67

def update(text)
  check_status
  # perform inner H
  md = @algorithm.new
  md.update(@key_xor_ipad)
  md.update(text)
  str = md.digest
  # perform outer H
  md = @algorithm.new
  md.update(@key_xor_opad)
  md.update(str)
  @md = md
end