68 lines
1.7 KiB
Ruby
68 lines
1.7 KiB
Ruby
require 'stringio'
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# Calculates SHA-1 message digest of _string_. Returns binary digest.
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# For hexadecimal digest, use +*sha1(string).unpack('H*')+.
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#--
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# This is a simple, pure-Ruby implementation of SHA-1, following
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# the algorithm in FIPS 180-1.
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#++
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def sha1(string)
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# functions and constants
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mask = 0xffffffff
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s = proc{|n, x| ((x << n) & mask) | (x >> (32 - n))}
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f = [
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proc {|b, c, d| (b & c) | (b.^(mask) & d)},
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proc {|b, c, d| b ^ c ^ d},
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proc {|b, c, d| (b & c) | (b & d) | (c & d)},
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proc {|b, c, d| b ^ c ^ d},
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].freeze
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k = [0x5a827999, 0x6ed9eba1, 0x8f1bbcdc, 0xca62c1d6].freeze
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# initial hash
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h = [0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476, 0xc3d2e1f0]
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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 >> 32, bit_len & mask].pack("N2")
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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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w = block.unpack("N16")
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# Process block.
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(16..79).each {|t| w[t] = s[1, w[t-3] ^ w[t-8] ^ w[t-14] ^ w[t-16]]}
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a, b, c, d, e = h
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t = 0
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4.times do |i|
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20.times do
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temp = (s[5, a] + f[i][b, c, d] + e + w[t] + k[i]) & mask
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a, b, c, d, e = temp, a, s[30, b], c, d
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t += 1
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end
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end
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[a,b,c,d,e].each_with_index {|x,i| h[i] = (h[i] + x) & mask}
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end
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h.pack("N5")
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end
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if __FILE__ == $0
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# Print some example SHA-1 digests.
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# FIPS 180-1 has correct digests for 'abc' and 'abc...opq'.
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[ 'abc',
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'abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq',
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'Rosetta Code',
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].each {|s| printf("%s:\n %s\n", s, *sha1(s).unpack('H*'))}
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end
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