67 lines
1.9 KiB
Ruby
67 lines
1.9 KiB
Ruby
require 'stringio'
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# Calculates MD4 message digest of _string_. Returns binary digest.
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# For hexadecimal digest, use +*md4(str).unpack('H*')+.
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def md4(string)
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# functions
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mask = (1 << 32) - 1
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f = proc {|x, y, z| x & y | x.^(mask) & z}
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g = proc {|x, y, z| x & y | x & z | y & z}
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h = proc {|x, y, z| x ^ y ^ z}
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r = proc {|v, s| (v << s).&(mask) | (v.&(mask) >> (32 - s))}
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# initial hash
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a, b, c, d = 0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476
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bit_len = string.size << 3
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string += "\x80"
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while (string.size % 64) != 56
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string += "\0"
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end
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string = string.force_encoding('ascii-8bit') + [bit_len & mask, bit_len >> 32].pack("V2")
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if string.size % 64 != 0
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fail "failed to pad to correct length"
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end
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io = StringIO.new(string)
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block = ""
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while io.read(64, block)
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x = block.unpack("V16")
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# Process this block.
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aa, bb, cc, dd = a, b, c, d
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[0, 4, 8, 12].each {|i|
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a = r[a + f[b, c, d] + x[i], 3]; i += 1
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d = r[d + f[a, b, c] + x[i], 7]; i += 1
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c = r[c + f[d, a, b] + x[i], 11]; i += 1
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b = r[b + f[c, d, a] + x[i], 19]
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}
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[0, 1, 2, 3].each {|i|
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a = r[a + g[b, c, d] + x[i] + 0x5a827999, 3]; i += 4
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d = r[d + g[a, b, c] + x[i] + 0x5a827999, 5]; i += 4
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c = r[c + g[d, a, b] + x[i] + 0x5a827999, 9]; i += 4
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b = r[b + g[c, d, a] + x[i] + 0x5a827999, 13]
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}
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[0, 2, 1, 3].each {|i|
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a = r[a + h[b, c, d] + x[i] + 0x6ed9eba1, 3]; i += 8
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d = r[d + h[a, b, c] + x[i] + 0x6ed9eba1, 9]; i -= 4
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c = r[c + h[d, a, b] + x[i] + 0x6ed9eba1, 11]; i += 8
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b = r[b + h[c, d, a] + x[i] + 0x6ed9eba1, 15]
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}
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a = (a + aa) & mask
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b = (b + bb) & mask
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c = (c + cc) & mask
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d = (d + dd) & mask
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end
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[a, b, c, d].pack("V4")
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end
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if __FILE__ == $0
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# Print an example MD4 digest.
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str = 'Rosetta Code'
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printf "%s:\n %s\n", str, *md4(str).unpack('H*')
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end
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