new

# File ext/digest/lib/digest/hmac.rb, line 50
    def initialize(key, digester)
      @md = digester.new

      block_len = @md.block_length

      if key.bytesize > block_len
        key = @md.digest(key)
      end

      ipad = Array.new(block_len, 0x36)
      opad = Array.new(block_len, 0x5c)

      key.bytes.each_with_index { |c, i|
        ipad[i] ^= c
        opad[i] ^= c
      }

      @key = key.freeze
      @ipad = ipad.pack('C*').freeze
      @opad = opad.pack('C*').freeze
      @md.update(@ipad)
    end