SHAmwow/shamwow.rb

101 lines
3.1 KiB
Ruby

#!/usr/local/bin/ruby
def chunker(string, chunk_size)
return (string.length / chunk_size).times.collect { |i| string[i * chunk_size, chunk_size] }
end
# treat all numbers as if they are 32-bit integers
def ror(num, shift)
((num >> shift) | (num << (32-shift)) & ((2 ** 32) - 1))
end
def sha2(message)
# Implementation taken from https://en.wikipedia.org/wiki/SHA-2#Pseudocode
message_in_bits = message.unpack("B*")[0]
# first 32 bits of the fractional parts of the square roots of the first 8 primes 2 through 19:
h0 = 0x6a09e667
h1 = 0xbb67ae85
h2 = 0x3c6ef372
h3 = 0xa54ff53a
h4 = 0x510e527f
h5 = 0x9b05688c
h6 = 0x1f83d9ab
h7 = 0x5be0cd19
# first 32 bits of the fractional parts of the cube roots of the first 64 primes 2 through 311:
k = [
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
]
len = message_in_bits.length
bits = message_in_bits
bits << "1"
bits << "0" * (512 - ((bits.length + 64) % 512))
bits << "%064b" % len
chunked = chunker(bits, 512)
i = 0
while i < chunked.length
m = []
message = chunker(chunked[i], 32)
message.each_with_index { |word, index| m[index] = word.to_i(2) } # here's where we pass from strings of 1s and 0s back to numbers
(16..63).each { |word|
s0 = ror(m[word-15], 7) ^ ror(m[word-15], 18) ^ (m[word-15] >> 3)
s1 = ror(m[word-2], 17) ^ ror(m[word-2], 19) ^ (m[word-2] >> 10)
m[word] = (m[word-16] + s0 + m[word-7] + s1) & 0xFFFFFFFF
}
a = h0
b = h1
c = h2
d = h3
e = h4
f = h5
g = h6
h = h7
(0..63).each { |word|
s1 = ror(e, 6) ^ ror(e, 11) ^ ror(e, 25)
ch = (e & f) ^ (~(e) & g)
temp1 = (h + s1 + ch + k[word] + m[word]) & 0xFFFFFFFF
s0 = ror(a, 2) ^ ror(a, 13) ^ ror(a, 22)
maj = (a & b) ^ (a & c) ^ (b & c)
temp2 = (s0 + maj) & 0xFFFFFFFF
h = g
g = f
f = e
e = (d + temp1) & 0xFFFFFFFF
d = c
c = b
b = a
a = (temp1 + temp2) & 0xFFFFFFFF
}
h0 = (h0 + a) & 0xFFFFFFFF
h1 = (h1 + b) & 0xFFFFFFFF
h2 = (h2 + c) & 0xFFFFFFFF
h3 = (h3 + d) & 0xFFFFFFFF
h4 = (h4 + e) & 0xFFFFFFFF
h5 = (h5 + f) & 0xFFFFFFFF
h6 = (h6 + g) & 0xFFFFFFFF
h7 = (h7 + h) & 0xFFFFFFFF
i = i + 1
end
("%08x" % h0).concat("%08x" % h1).concat("%08x" % h2).concat("%08x" % h3).concat("%08x" % h4).concat("%08x" % h5).concat("%08x" % h6).concat("%08x" % h7)
end