The code here was originally written by Roberto Ierusalimschy, and is licensed under MIT (see http://lua-users.org/lists/lua-l/2014-08/msg00628.html)
-- SHA-256 code in Lua 5.2; based on the pseudo-code from -- Wikipedia (http://en.wikipedia.org/wiki/SHA-2) local band, rrotate, bxor, rshift, bnot = bit32.band, bit32.rrotate, bit32.bxor, bit32.rshift, bit32.bnot local string, setmetatable, assert = string, setmetatable, assert _ENV = nil -- Initialize table of round constants -- (first 32 bits of the fractional parts of the cube roots of the first -- 64 primes 2..311): local 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, } -- transform a string of bytes in a string of hexadecimal digits local function str2hexa (s) local h = string.gsub(s, ".", function(c) return string.format("%02x", string.byte(c)) end) return h end -- transform number 'l' in a big-endian sequence of 'n' bytes -- (coded as a string) local function num2s (l, n) local s = "" for i = 1, n do local rem = l % 256 s = string.char(rem) .. s l = (l - rem) / 256 end return s end -- transform the big-endian sequence of four bytes starting at -- index 'i' in 's' into a number local function s232num (s, i) local n = 0 for i = i, i + 3 do n = n*256 + string.byte(s, i) end return n end -- append the bit '1' to the message -- append k bits '0', where k is the minimum number >= 0 such that the -- resulting message length (in bits) is congruent to 448 (mod 512) -- append length of message (before pre-processing), in bits, as 64-bit -- big-endian integer local function preproc (msg, len) local extra = -(len + 1 + 8) % 64 len = num2s(8 * len, 8) -- original len in bits, coded msg = msg .. "128円" .. string.rep("0円", extra) .. len assert(#msg % 64 == 0) return msg end local function initH224 (H) -- (second 32 bits of the fractional parts of the square roots of the -- 9th through 16th primes 23..53) H[1] = 0xc1059ed8 H[2] = 0x367cd507 H[3] = 0x3070dd17 H[4] = 0xf70e5939 H[5] = 0xffc00b31 H[6] = 0x68581511 H[7] = 0x64f98fa7 H[8] = 0xbefa4fa4 return H end local function initH256 (H) -- (first 32 bits of the fractional parts of the square roots of the -- first 8 primes 2..19): H[1] = 0x6a09e667 H[2] = 0xbb67ae85 H[3] = 0x3c6ef372 H[4] = 0xa54ff53a H[5] = 0x510e527f H[6] = 0x9b05688c H[7] = 0x1f83d9ab H[8] = 0x5be0cd19 return H end local function digestblock (msg, i, H) -- break chunk into sixteen 32-bit big-endian words w[1..16] local w = {} for j = 1, 16 do w[j] = s232num(msg, i + (j - 1)*4) end -- Extend the sixteen 32-bit words into sixty-four 32-bit words: for j = 17, 64 do local v = w[j - 15] local s0 = bxor(rrotate(v, 7), rrotate(v, 18), rshift(v, 3)) v = w[j - 2] local s1 = bxor(rrotate(v, 17), rrotate(v, 19), rshift(v, 10)) w[j] = w[j - 16] + s0 + w[j - 7] + s1 end -- Initialize hash value for this chunk: local a, b, c, d, e, f, g, h = H[1], H[2], H[3], H[4], H[5], H[6], H[7], H[8] -- Main loop: for i = 1, 64 do local s0 = bxor(rrotate(a, 2), rrotate(a, 13), rrotate(a, 22)) local maj = bxor(band(a, b), band(a, c), band(b, c)) local t2 = s0 + maj local s1 = bxor(rrotate(e, 6), rrotate(e, 11), rrotate(e, 25)) local ch = bxor (band(e, f), band(bnot(e), g)) local t1 = h + s1 + ch + k[i] + w[i] h = g g = f f = e e = d + t1 d = c c = b b = a a = t1 + t2 end -- Add (mod 2^32) this chunk's hash to result so far: H[1] = band(H[1] + a) H[2] = band(H[2] + b) H[3] = band(H[3] + c) H[4] = band(H[4] + d) H[5] = band(H[5] + e) H[6] = band(H[6] + f) H[7] = band(H[7] + g) H[8] = band(H[8] + h) end local function finalresult224 (H) -- Produce the final hash value (big-endian): return str2hexa(num2s(H[1], 4)..num2s(H[2], 4)..num2s(H[3], 4)..num2s(H[4], 4).. num2s(H[5], 4)..num2s(H[6], 4)..num2s(H[7], 4)) end local function finalresult256 (H) -- Produce the final hash value (big-endian): return str2hexa(num2s(H[1], 4)..num2s(H[2], 4)..num2s(H[3], 4)..num2s(H[4], 4).. num2s(H[5], 4)..num2s(H[6], 4)..num2s(H[7], 4)..num2s(H[8], 4)) end ---------------------------------------------------------------------- local HH = {} -- to reuse local function hash224 (msg) msg = preproc(msg, #msg) local H = initH224(HH) -- Process the message in successive 512-bit (64 bytes) chunks: for i = 1, #msg, 64 do digestblock(msg, i, H) end return finalresult224(H) end local function hash256 (msg) msg = preproc(msg, #msg) local H = initH256(HH) -- Process the message in successive 512-bit (64 bytes) chunks: for i = 1, #msg, 64 do digestblock(msg, i, H) end return finalresult256(H) end ---------------------------------------------------------------------- local mt = {} local function new256 () local o = {H = initH256({}), msg = "", len = 0} setmetatable(o, mt) return o end mt.__index = mt function mt:add (m) self.msg = self.msg .. m self.len = self.len + #m local t = 0 while #self.msg - t >= 64 do digestblock(self.msg, t + 1, self.H) t = t + 64 end self.msg = self.msg:sub(t + 1, -1) end function mt:close () self.msg = preproc(self.msg, self.len) self:add("") return finalresult256(self.H) end ---------------------------------------------------------------------- return { hash224 = hash224, hash256 = hash256, new256 = new256, }
The following script performs some basic tests over the previous implementation and shows how to use the library:
-- tests for SHA-2 in Lua 5.2 local sha2 = require 'sha2' -- a few examples from the Web assert(sha2.hash224"The quick brown fox jumps over the lazy dog" == "730e109bd7a8a32b1cb9d9a09aa2325d2430587ddbc0c38bad911525") assert(sha2.hash224"" == "d14a028c2a3a2bc9476102bb288234c415a2b01f828ea62ac5b3e42f") assert(sha2.hash256"The quick brown fox jumps over the lazy dog" == "d7a8fbb307d7809469ca9abcb0082e4f8d5651e46d3cdb762d02d0bf37c9e592") assert(sha2.hash256"The quick brown fox jumps over the lazy cog" == "e4c4d8f3bf76b692de791a173e05321150f7a345b46484fe427f6acc7ecc81be") assert(sha2.hash256"" == "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855") assert(sha2.new256():close() == "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855") assert(sha2.hash256"123456" == "8d969eef6ecad3c29a3a629280e686cf0c3f5d5a86aff3ca12020c923adc6c92") -- most other examples here are checked against a "correct" answer -- given by 'sha224sum'/'sha256sum' -- border cases (sizes around 64 bytes) assert(sha2.hash256(string.rep('a', 62) .. '\n') == "290b30a68148b3ee27ab7b744c297a5d986c1011938a09e73058430593bf83f0") assert(sha2.hash256(string.rep('a', 63) .. '\n') == "a229eaed30f4991d1fcdab77c70b604efd780502c82be0732b310811dc43b2b3") assert(sha2.hash256(string.rep('a', 64) .. '\n') == "44c2336fedab8ff6a85c74c2b94165377b0981f526adb9487895ca6314165e86") assert(sha2.hash256(string.rep('a', 65) .. '\n') == "574883a9977284a46845620eaa55c3fa8209eaa3ebffe44774b6eb2dba2cb325") local x = sha2.new256() for i = 1, 65 do x:add('a') end x:add('\n') assert(x:close() == "574883a9977284a46845620eaa55c3fa8209eaa3ebffe44774b6eb2dba2cb325") -- some large files local function parts (s, j) local x = sha2.new256() local i = 1; j = 1 while i <= #s do x:add(s:sub(i, i + j)) i = i + j + 1 end return x:close() end -- 80 lines of 80 '0's each local s = string.rep('0', 80) .. '\n' s = string.rep(s, 80) assert(parts(s, 70) == "736c7a8b17e2cfd44a3267a844db1a8a3e8988d739e3e95b8dd32678fb599139") assert(parts(s, 7) == "736c7a8b17e2cfd44a3267a844db1a8a3e8988d739e3e95b8dd32678fb599139") assert(parts(s, #s + 10) == "736c7a8b17e2cfd44a3267a844db1a8a3e8988d739e3e95b8dd32678fb599139") -- read a file and prints its hash, if given a file name if arg[1] then local file = assert(io.open (arg[1], 'rb')) local x = sha2.new256() for b in file:lines(2^12) do x:add(b) end file:close() print(x:close()) end print "ok"