240 lines
6.1 KiB
Lua
240 lines
6.1 KiB
Lua
-- SHA-256 code in Lua 5.2; based on the pseudo-code from
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-- Wikipedia (http://en.wikipedia.org/wiki/SHA-2)
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-- from http://lua-users.org/wiki/SecureHashAlgorithm
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local band, rrotate, bxor, rshift, bnot =
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bit32.band, bit32.rrotate, bit32.bxor, bit32.rshift, bit32.bnot
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local string, setmetatable, assert = string, setmetatable, assert
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-- Initialize table of round constants
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-- (first 32 bits of the fractional parts of the cube roots of the first
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-- 64 primes 2..311):
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local k = {
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0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
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0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
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0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
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0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
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0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
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0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
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0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
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0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
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0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
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0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
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0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
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0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
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0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
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0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
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0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
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0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
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}
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-- transform a string of bytes in a string of hexadecimal digits
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local function str2hexa (s)
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local h = string.gsub(s, ".", function(c)
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return string.format("%02x", string.byte(c))
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end)
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return h
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end
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-- transform number 'l' in a big-endian sequence of 'n' bytes
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-- (coded as a string)
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local function num2s (l, n)
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local s = ""
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for i = 1, n do
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local rem = l % 256
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s = string.char(rem) .. s
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l = (l - rem) / 256
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end
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return s
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end
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-- transform the big-endian sequence of four bytes starting at
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-- index 'i' in 's' into a number
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local function s232num (s, i)
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local n = 0
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for i = i, i + 3 do
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n = n*256 + string.byte(s, i)
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end
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return n
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end
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-- append the bit '1' to the message
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-- append k bits '0', where k is the minimum number >= 0 such that the
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-- resulting message length (in bits) is congruent to 448 (mod 512)
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-- append length of message (before pre-processing), in bits, as 64-bit
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-- big-endian integer
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local function preproc (msg, len)
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local extra = 64 - ((len + 1 + 8) % 64)
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len = num2s(8 * len, 8) -- original len in bits, coded
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msg = msg .. "\128" .. string.rep("\0", extra) .. len
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assert(#msg % 64 == 0)
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return msg
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end
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local function initH224 (H)
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-- (second 32 bits of the fractional parts of the square roots of the
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-- 9th through 16th primes 23..53)
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H[1] = 0xc1059ed8
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H[2] = 0x367cd507
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H[3] = 0x3070dd17
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H[4] = 0xf70e5939
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H[5] = 0xffc00b31
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H[6] = 0x68581511
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H[7] = 0x64f98fa7
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H[8] = 0xbefa4fa4
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return H
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end
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local function initH256 (H)
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-- (first 32 bits of the fractional parts of the square roots of the
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-- first 8 primes 2..19):
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H[1] = 0x6a09e667
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H[2] = 0xbb67ae85
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H[3] = 0x3c6ef372
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H[4] = 0xa54ff53a
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H[5] = 0x510e527f
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H[6] = 0x9b05688c
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H[7] = 0x1f83d9ab
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H[8] = 0x5be0cd19
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return H
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end
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local function digestblock (msg, i, H)
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-- break chunk into sixteen 32-bit big-endian words w[1..16]
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local w = {}
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for j = 1, 16 do
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w[j] = s232num(msg, i + (j - 1)*4)
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end
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-- Extend the sixteen 32-bit words into sixty-four 32-bit words:
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for j = 17, 64 do
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local v = w[j - 15]
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local s0 = bxor(rrotate(v, 7), rrotate(v, 18), rshift(v, 3))
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v = w[j - 2]
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local s1 = bxor(rrotate(v, 17), rrotate(v, 19), rshift(v, 10))
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w[j] = w[j - 16] + s0 + w[j - 7] + s1
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end
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-- Initialize hash value for this chunk:
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local a, b, c, d, e, f, g, h =
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H[1], H[2], H[3], H[4], H[5], H[6], H[7], H[8]
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-- Main loop:
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for i = 1, 64 do
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local s0 = bxor(rrotate(a, 2), rrotate(a, 13), rrotate(a, 22))
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local maj = bxor(band(a, b), band(a, c), band(b, c))
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local t2 = s0 + maj
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local s1 = bxor(rrotate(e, 6), rrotate(e, 11), rrotate(e, 25))
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local ch = bxor (band(e, f), band(bnot(e), g))
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local t1 = h + s1 + ch + k[i] + w[i]
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h = g
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g = f
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f = e
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e = d + t1
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d = c
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c = b
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b = a
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a = t1 + t2
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end
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-- Add (mod 2^32) this chunk's hash to result so far:
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H[1] = band(H[1] + a)
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H[2] = band(H[2] + b)
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H[3] = band(H[3] + c)
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H[4] = band(H[4] + d)
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H[5] = band(H[5] + e)
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H[6] = band(H[6] + f)
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H[7] = band(H[7] + g)
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H[8] = band(H[8] + h)
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end
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local function finalresult224 (H)
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-- Produce the final hash value (big-endian):
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return
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str2hexa(num2s(H[1], 4)..num2s(H[2], 4)..num2s(H[3], 4)..num2s(H[4], 4)..
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num2s(H[5], 4)..num2s(H[6], 4)..num2s(H[7], 4))
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end
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local function finalresult256 (H)
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-- Produce the final hash value (big-endian):
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return
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str2hexa(num2s(H[1], 4)..num2s(H[2], 4)..num2s(H[3], 4)..num2s(H[4], 4)..
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num2s(H[5], 4)..num2s(H[6], 4)..num2s(H[7], 4)..num2s(H[8], 4))
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end
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----------------------------------------------------------------------
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local HH = {} -- to reuse
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local function hash224 (msg)
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msg = preproc(msg, #msg)
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local H = initH224(HH)
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-- Process the message in successive 512-bit (64 bytes) chunks:
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for i = 1, #msg, 64 do
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digestblock(msg, i, H)
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end
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return finalresult224(H)
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end
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local function hash256 (msg)
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msg = preproc(msg, #msg)
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local H = initH256(HH)
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-- Process the message in successive 512-bit (64 bytes) chunks:
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for i = 1, #msg, 64 do
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digestblock(msg, i, H)
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end
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return finalresult256(H)
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end
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----------------------------------------------------------------------
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local mt = {}
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local function new256 ()
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local o = {H = initH256({}), msg = "", len = 0}
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setmetatable(o, mt)
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return o
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end
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mt.__index = mt
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function mt:add (m)
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self.msg = self.msg .. m
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self.len = self.len + #m
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local t = 0
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while #self.msg - t >= 64 do
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digestblock(self.msg, t + 1, self.H)
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t = t + 64
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end
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self.msg = self.msg:sub(t + 1, -1)
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end
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function mt:close ()
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self.msg = preproc(self.msg, self.len)
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self:add("")
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return finalresult256(self.H)
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end
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----------------------------------------------------------------------
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return {
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hash224 = hash224,
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hash256 = hash256,
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new256 = new256,
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}
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