test/test_shamir.rb

   1 require 'test/unit'
   2 require 'secretsharing/shamir'
   3
   4 DEFAULT_SECRET_BITLENGTH = 128
   5
   6 class TestShamir < Test::Unit::TestCase
   7         def test_instantiation
   8                 assert_raise( ArgumentError ) { SecretSharing::Shamir.new }
   9                 s1 = SecretSharing::Shamir.new(5)
  10                 assert_equal(s1.n, 5)
  11                 assert_equal(s1.k, 5)
  12                 assert_false(s1.secret_set?)
  13                 s2 = SecretSharing::Shamir.new(5, 3)
  14                 assert_equal(s2.n, 5)
  15                 assert_equal(s2.k, 3)
  16                 assert_false(s2.secret_set?)
  17         end
  18
  19         def test_create_random_secret
  20                 s = SecretSharing::Shamir.new(5)
  21                 s.create_random_secret()
  22                 assert_true(s.secret_set?)
  23                 assert_not_nil(s.secret)
  24                 assert_not_nil(s.shares)
  25                 assert_equal(s.shares.class, Array)
  26                 assert_equal(s.shares.length, 5)
  27                 assert_equal(s.shares[0].class, SecretSharing::Shamir::Share)
  28                 assert_equal(s.secret_bitlength, DEFAULT_SECRET_BITLENGTH)
  29
  30                 # can only be called once
  31                 assert_raise( RunTimeError) { s.create_random_secret() }
  32
  33                 s2 = SecretSharing::Shamir.new(7)
  34                 s2.create_random_secret(256)
  35                 assert_equal(s2.secret_bitlength, 256)
  36         end
  37
  38         def test_recover_secret_k_eq_n
  39                 s = SecretSharing::Shamir.new(5)
  40                 s.create_random_secret()
  41
  42                 s2 = SecretSharing::Shamir.new(5)
  43                 s2.shares << s.shares[0]
  44                 assert_equal(s2.shares.length, 1)
  45                 assert_false(s2.secret_set?)
  46                 assert_nil(s2.secret)
  47                 # adding the same share raises an error
  48                 assert_raise( RunTimeError ) { s2.shares << s.shares[0] }
  49                 # add more shares
  50                 s2.shares << s.shares[1]
  51                 assert_false(s2.secret_set?)
  52                 s2.shares << s.shares[2]
  53                 assert_false(s2.secret_set?)
  54                 s2.shares << s.shares[3]
  55                 assert_false(s2.secret_set?)
  56                 s2.shares << s.shares[4]
  57                 assert_true(s2.secret_set?)
  58                 assert_equal(s.secret, s2.secret)
  59         end
  60
  61         def test_recover_secret_k_le_n
  62                 s = SecretSharing::Shamir.new(5, 3)
  63                 s.create_random_secret()
  64
  65                 s2 = SecretSharing::Shamir.new(5, 3)
  66                 s2.shares << s.shares[0]
  67                 assert_equal(s2.shares.length, 1)
  68                 assert_false(s2.secret_set?)
  69                 assert_nil(s2.secret)
  70                 # add more shares
  71                 s2.shares << s.shares[1]
  72                 assert_false(s2.secret_set?)
  73                 s2.shares << s.shares[2]
  74                 assert_true(s2.secret_set?)
  75                 assert_equal(s.secret, s2.secret)
  76
  77                 # adding more shares than needed raises an error
  78                 assert_raise( RunTimeError ) { s2.shares << s.shares[3] }
  79         end
  80 end