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-- adapted from http://lua-users.org/wiki/SecureHashAlgorithm
function ejaSha256(value)
value=tostring(value)
-- 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 = 64 - ((len + 1 + 8) % 64)
len = num2s(8 * len, 8) -- original len in bits, coded
msg = msg .. "\128" .. string.rep("\0", extra) .. len
assert(#msg % 64 == 0)
return msg
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 = bit32.bxor(bit32.rrotate(v, 7), bit32.rrotate(v, 18), bit32.rshift(v, 3))
v = w[j - 2]
local s1 = bit32.bxor(bit32.rrotate(v, 17), bit32.rrotate(v, 19), bit32.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 = bit32.bxor(bit32.rrotate(a, 2), bit32.rrotate(a, 13), bit32.rrotate(a, 22))
local maj = bit32.bxor(bit32.band(a, b), bit32.band(a, c), bit32.band(b, c))
local t2 = s0 + maj
local s1 = bit32.bxor(bit32.rrotate(e, 6), bit32.rrotate(e, 11), bit32.rrotate(e, 25))
local ch = bit32.bxor (bit32.band(e, f), bit32.band(bit32.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] = bit32.band(H[1] + a)
H[2] = bit32.band(H[2] + b)
H[3] = bit32.band(H[3] + c)
H[4] = bit32.band(H[4] + d)
H[5] = bit32.band(H[5] + e)
H[6] = bit32.band(H[6] + f)
H[7] = bit32.band(H[7] + g)
H[8] = bit32.band(H[8] + h)
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
value = preproc(value, #value)
local H = initH256({})
for i = 1, #value, 64 do
digestblock(value, i, H)
end
return finalresult256(H)
end
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