From 5a41cad6e4047f5e3dfc17b7414e8e551f1e770b Mon Sep 17 00:00:00 2001
From: Ale2610 <ale.proto00@gmail.com>
Date: Fri, 31 Jul 2015 20:29:07 +0200
Subject: [PATCH] Create sha256.lua

---
 src/apis/sha256.lua | 183 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 183 insertions(+)
 create mode 100644 src/apis/sha256.lua

diff --git a/src/apis/sha256.lua b/src/apis/sha256.lua
new file mode 100644
index 0000000..89d0489
--- /dev/null
+++ b/src/apis/sha256.lua
@@ -0,0 +1,183 @@
+local MOD = 2^32
+local MODM = MOD-1
+ 
+local function memoize(f)
+        local mt = {}
+        local t = setmetatable({}, mt)
+        function mt:__index(k)
+                local v = f(k)
+                t[k] = v
+                return v
+        end
+        return t
+end
+ 
+local function make_bitop_uncached(t, m)
+        local function bitop(a, b)
+                local res,p = 0,1
+                while a ~= 0 and b ~= 0 do
+                        local am, bm = a % m, b % m
+                        res = res + t[am][bm] * p
+                        a = (a - am) / m
+                        b = (b - bm) / m
+                        p = p*m
+                end
+                res = res + (a + b) * p
+                return res
+        end
+        return bitop
+end
+ 
+local function make_bitop(t)
+        local op1 = make_bitop_uncached(t,2^1)
+        local op2 = memoize(function(a) return memoize(function(b) return op1(a, b) end) end)
+        return make_bitop_uncached(op2, 2 ^ (t.n or 1))
+end
+ 
+local bxor1 = make_bitop({[0] = {[0] = 0,[1] = 1}, [1] = {[0] = 1, [1] = 0}, n = 4})
+ 
+local function bxor(a, b, c, ...)
+        local z = nil
+        if b then
+                a = a % MOD
+                b = b % MOD
+                z = bxor1(a, b)
+                if c then z = bxor(z, c, ...) end
+                return z
+        elseif a then return a % MOD
+        else return 0 end
+end
+ 
+local function band(a, b, c, ...)
+        local z
+        if b then
+                a = a % MOD
+                b = b % MOD
+                z = ((a + b) - bxor1(a,b)) / 2
+                if c then z = bit32_band(z, c, ...) end
+                return z
+        elseif a then return a % MOD
+        else return MODM end
+end
+ 
+local function bnot(x) return (-1 - x) % MOD end
+ 
+local function rshift1(a, disp)
+        if disp < 0 then return lshift(a,-disp) end
+        return math.floor(a % 2 ^ 32 / 2 ^ disp)
+end
+ 
+local function rshift(x, disp)
+        if disp > 31 or disp < -31 then return 0 end
+        return rshift1(x % MOD, disp)
+end
+ 
+local function lshift(a, disp)
+        if disp < 0 then return rshift(a,-disp) end
+        return (a * 2 ^ disp) % 2 ^ 32
+end
+ 
+local function rrotate(x, disp)
+    x = x % MOD
+    disp = disp % 32
+    local low = band(x, 2 ^ disp - 1)
+    return rshift(x, disp) + lshift(low, 32 - disp)
+end
+ 
+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,
+}
+ 
+local function str2hexa(s)
+        return (string.gsub(s, ".", function(c) return string.format("%02x", string.byte(c)) end))
+end
+ 
+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
+ 
+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
+ 
+local function preproc(msg, len)
+        local extra = 64 - ((len + 9) % 64)
+        len = num2s(8 * len, 8)
+        msg = msg .. "\128" .. string.rep("\0", extra) .. len
+        assert(#msg % 64 == 0)
+        return msg
+end
+ 
+local function initH256(H)
+        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)
+        local w = {}
+        for j = 1, 16 do w[j] = s232num(msg, i + (j - 1)*4) end
+        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]
+                w[j] = w[j - 16] + s0 + w[j - 7] + bxor(rrotate(v, 17), rrotate(v, 19), rshift(v, 10))
+        end
+ 
+        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]
+        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, f, e, d, c, b, a = g, f, e, d + t1, c, b, a, t1 + t2
+        end
+ 
+        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
+ 
+function sha256(msg)
+        msg = preproc(msg, string.len(msg))
+        local H = initH256({})
+        for i = 1, #msg, 64 do digestblock(msg, i, H) end
+        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