Module: JOSE::JWA::SHA3

Extended by:
SHA3
Included in:
SHA3
Defined in:
lib/jose/jwa/sha3.rb

Constant Summary collapse

ROUNDS5 = 
(0...5).to_a.freeze
ROUNDS23 = 
(0...23).to_a.freeze
ROUNDS24 = 
(0...24).to_a.freeze
ROUNDS25 = 
(0...25).to_a.freeze
ROUNDSBY5 = 
[0, 5, 10, 15, 20].freeze
ROTATIONS = 
[
  0,1,62,28,27,36,44,6,55,20,3,10,43,25,39,41,45,15,
  21,8,18,2,61,56,14
].freeze
PERMUTATION = 
[
  1,6,9,22,14,20,2,12,13,19,23,15,4,24,21,8,16,5,3,
  18,17,11,7,10
].freeze
RC = 
[
  0x0000000000000001,0x0000000000008082,0x800000000000808a,
  0x8000000080008000,0x000000000000808b,0x0000000080000001,
  0x8000000080008081,0x8000000000008009,0x000000000000008a,
  0x0000000000000088,0x0000000080008009,0x000000008000000a,
  0x000000008000808b,0x800000000000008b,0x8000000000008089,
  0x8000000000008003,0x8000000000008002,0x8000000000000080,
  0x000000000000800a,0x800000008000000a,0x8000000080008081,
  0x8000000000008080,0x0000000080000001,0x8000000080008008
].freeze

Instance Method Summary collapse

Instance Method Details

#reinterpret_to_octets(w) ⇒ Object

Reinterpret word array w to octet array and return it.



86
87
88
89
90
91
92
 
# File 'lib/jose/jwa/sha3.rb', line 86

def reinterpret_to_octets(w)
  mp = ''.force_encoding('BINARY')
  (0...(w.length)).each do |j|
    mp << OpenSSL::BN.new(w[j]).to_s(2).rjust(8, JOSE::JWA::ZERO_PAD).reverse
  end
  return mp
end

#reinterpret_to_words_and_xor(s, b) ⇒ Object

Reinterpret octet array b to word array and XOR it to state s.



76
77
78
79
80
81
82
83
 
# File 'lib/jose/jwa/sha3.rb', line 76

def reinterpret_to_words_and_xor(s, b)
  (0...(b.length/8)).each do |j|
    block = b[(8*j)..-1][0...8]
    block = block.pack(JOSE::JWA::UCHAR_PACK) if block.is_a?(Array)
    s[j] ^= OpenSSL::BN.new(block.reverse, 2).to_i
  end
  return s
end

#rol(x, b) ⇒ Object

Rotate a word x by b places to the left.



33
34
35
 
# File 'lib/jose/jwa/sha3.rb', line 33

def rol(x, b)
  return ((x << b) | (x >> (64 - b))) & (2**64-1)
end

#sha3_224(msg) ⇒ Object

Implementations of actual SHA-3 functions.



126
127
128
 
# File 'lib/jose/jwa/sha3.rb', line 126

def sha3_224(msg)
  return sha3_raw(msg,18,6,28)
end

#sha3_256(msg) ⇒ Object 



130
131
132
 
# File 'lib/jose/jwa/sha3.rb', line 130

def sha3_256(msg)
  return sha3_raw(msg,17,6,32)
end

#sha3_384(msg) ⇒ Object 



134
135
136
 
# File 'lib/jose/jwa/sha3.rb', line 134

def sha3_384(msg)
  return sha3_raw(msg,13,6,48)
end

#sha3_512(msg) ⇒ Object 



138
139
140
 
# File 'lib/jose/jwa/sha3.rb', line 138

def sha3_512(msg)
  return sha3_raw(msg,9,6,64)
end

#sha3_raw(msg, r_w, o_p, e_b) ⇒ Object

(semi-)generic SHA-3 implementation



95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
 
# File 'lib/jose/jwa/sha3.rb', line 95

def sha3_raw(msg, r_w, o_p, e_b)
  r_b = 8 * r_w
  s = [0]*25
  # Handle whole blocks.
  idx = 0
  blocks = msg.bytesize / r_b
  (0...blocks).each do |i|
    reinterpret_to_words_and_xor(s, msg[idx..-1][0...r_b])
    idx += r_b
    sha3_transform(s)
  end
  # Handle last block padding.
  m = msg[idx..-1].unpack(JOSE::JWA::UCHAR_PACK)
  m.push(o_p)
  while m.length < r_b
    m.push(0)
  end
  m[-1] |= 128
  # Handle padded last block.
  reinterpret_to_words_and_xor(s, m)
  sha3_transform(s)
  # Output.
  out = ''.force_encoding('BINARY')
  while out.length < e_b
    out << reinterpret_to_octets(s[0...r_w])
    sha3_transform(s)
  end
  return out[0...e_b]
end

#sha3_transform(s) ⇒ Object

Do the SHA-3 state transform on state s.



38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
 
# File 'lib/jose/jwa/sha3.rb', line 38

def sha3_transform(s)
  ROUNDS24.each do |rnd|
    # AddColumnParity (Theta)
    c = [0]*5
    d = [0]*5
    ROUNDS25.each do |i|
      c[i % 5] ^= s[i]
    end
    ROUNDS5.each do |i|
      d[i] = c[(i+4) % 5] ^ rol(c[(i+1) % 5], 1)
    end
    ROUNDS25.each do |i|
      s[i] ^= d[i % 5]
    end
    # RotateWords (Rho).
    ROUNDS25.each do |i|
      s[i] = rol(s[i], ROTATIONS[i])
    end
    # PermuteWords (Pi)
    t = s[PERMUTATION[0]]
    ROUNDS23.each do |i|
      s[PERMUTATION[i]] = s[PERMUTATION[i+1]]
    end
    s[PERMUTATION[-1]] = t
    # NonlinearMixRows (Chi)
    ROUNDSBY5.each do |i|
      t = [s[i],s[i+1],s[i+2],s[i+3],s[i+4],s[i],s[i+1]]
      ROUNDS5.each do |j|
        s[i+j] = t[j]^((~t[j+1])&(t[j+2]))
      end
    end
    # AddRoundConstant (Iota)
    s[0] ^= RC[rnd]
  end
  return s
end

#shake128(msg, olen) ⇒ Object 



142
143
144
 
# File 'lib/jose/jwa/sha3.rb', line 142

def shake128(msg,olen)
  return sha3_raw(msg,21,31,olen)
end

#shake256(msg, olen) ⇒ Object 



146
147
148
 
# File 'lib/jose/jwa/sha3.rb', line 146

def shake256(msg,olen)
  return sha3_raw(msg,17,31,olen)
end