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# frozen_string_literal: true
require "cose/algorithm/base"
require "openssl"
module COSE
module Algorithm
class HMAC < Base
BYTE_LENGTH = 8
attr_reader :hash_function, :tag_length
def initialize(*args, hash_function:, tag_length:)
super(*args)
@hash_function = hash_function
@tag_length = tag_length
end
def mac(key, to_be_signed)
mac = OpenSSL::HMAC.digest(hash_function, key, to_be_signed)
if tag_bytesize && tag_bytesize < mac.bytesize
mac.byteslice(0, tag_bytesize)
else
mac
end
end
private
def tag_bytesize
@tag_bytesize ||=
if tag_length
tag_length / BYTE_LENGTH
end
end
end
end
end
|
