set_key (HMAC::Base)

    # File lib/hmac/hmac.rb, line 35
        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
          key_xor_ipad = "\x36" * @block_size
          key_xor_opad = "\x5C" * @block_size
          for i in 0 .. key.size - 1
            key_xor_ipad[i] ^= key[i]
            key_xor_opad[i] ^= key[i]
          end
          @key_xor_ipad = key_xor_ipad
          @key_xor_opad = key_xor_opad
          @md = @algorithm.new
          @status = STATUS_INITIALIZED
        end