本文介绍了md5的纯Lua实现的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
md5 散列算法有纯 lua 实现吗?一个不依赖任何 c 或外部库的?有不依赖于 c 或任何东西的 javascript 实现，所以它应该可以用 lua 实现.谢谢！
Is there a pure lua implementation of the md5 hashing algorithm? One that doesn't rely on any c or external libraries? There's javascript implementations that don't rely on c or anything, so it ought to be possible with lua.Thanks!
推荐答案
我结合了前面提到的需要 bitlib 的 lua MD5 库，并在 LuaBit 中添加，使其成为纯 lua 实现.
I combined the mentioned lua MD5 library that required bitlib and added in LuaBit to make it a pure lua implementation.
作为一个额外的好处，它的结构使其可以在 redis lua 脚本环境中工作.
As an additional benefit it's structured in such a way that it will work inside of the redis lua scripting environment.
请注意，与其他非纯基于 lua 的实现相比，它非常慢.
Please note that it is extremely slow compared to other non pure lua based implementations.
--[[---------------
LuaBit v0.4
-------------------
a bitwise operation lib for lua.
http://luaforge.net/projects/bit/
How to use:
-------------------
bit.bnot(n) -- bitwise not (~n)
bit.band(m, n) -- bitwise and (m & n)
bit.bor(m, n) -- bitwise or (m | n)
bit.bxor(m, n) -- bitwise xor (m ^ n)
bit.brshift(n, bits) -- right shift (n >> bits)
bit.blshift(n, bits) -- left shift (n << bits)
bit.blogic_rshift(n, bits) -- logic right shift(zero fill >>>)
Please note that bit.brshift and bit.blshift only support number within
32 bits.
2 utility functions are provided too:
bit.tobits(n) -- convert n into a bit table(which is a 1/0 sequence)
-- high bits first
bit.tonumb(bit_tbl) -- convert a bit table into a number
-------------------
Under the MIT license.
copyright(c) 2006~2007 hanzhao ([email protected])
--]]---------------
--do
------------------------
-- bit lib implementions
local function check_int(n)
-- checking not float
if(n - math.floor(n) > 0) then
error("trying to use bitwise operation on non-integer!")
end
end
local function tbl_to_number(tbl)
local n = #tbl
local rslt = 0
local power = 1
for i = 1, n do
rslt = rslt + tbl[i]*power
power = power*2
end
return rslt
end
local function expand(tbl_m, tbl_n)
local big = {}
local small = {}
if(#tbl_m > #tbl_n) then
big = tbl_m
small = tbl_n
else
big = tbl_n
small = tbl_m
end
-- expand small
for i = #small + 1, #big do
small[i] = 0
end
end
local to_bits = function () end
local function bit_not(n)
local tbl = to_bits(n)
local size = math.max(#tbl, 32)
for i = 1, size do
if(tbl[i] == 1) then
tbl[i] = 0
else
tbl[i] = 1
end
end
return tbl_to_number(tbl)
end
to_bits = function (n)
check_int(n)
if(n < 0) then
-- negative
return to_bits(bit_not(math.abs(n)) + 1)
end
-- to bits table
local tbl = {}
local cnt = 1
while (n > 0) do
local last = math.mod(n,2)
if(last == 1) then
tbl[cnt] = 1
else
tbl[cnt] = 0
end
n = (n-last)/2
cnt = cnt + 1
end
return tbl
end
local function bit_or(m, n)
local tbl_m = to_bits(m)
local tbl_n = to_bits(n)
expand(tbl_m, tbl_n)
local tbl = {}
local rslt = math.max(#tbl_m, #tbl_n)
for i = 1, rslt do
if(tbl_m[i]== 0 and tbl_n[i] == 0) then
tbl[i] = 0
else
tbl[i] = 1
end
end
return tbl_to_number(tbl)
end
local function bit_and(m, n)
local tbl_m = to_bits(m)
local tbl_n = to_bits(n)
expand(tbl_m, tbl_n)
local tbl = {}
local rslt = math.max(#tbl_m, #tbl_n)
for i = 1, rslt do
if(tbl_m[i]== 0 or tbl_n[i] == 0) then
tbl[i] = 0
else
tbl[i] = 1
end
end
return tbl_to_number(tbl)
end
local function bit_xor(m, n)
local tbl_m = to_bits(m)
local tbl_n = to_bits(n)
expand(tbl_m, tbl_n)
local tbl = {}
local rslt = math.max(#tbl_m, #tbl_n)
for i = 1, rslt do
if(tbl_m[i] ~= tbl_n[i]) then
tbl[i] = 1
else
tbl[i] = 0
end
end
--table.foreach(tbl, print)
return tbl_to_number(tbl)
end
local function bit_rshift(n, bits)
check_int(n)
local high_bit = 0
if(n < 0) then
-- negative
n = bit_not(math.abs(n)) + 1
high_bit = 2147483648 -- 0x80000000
end
for i=1, bits do
n = n/2
n = bit_or(math.floor(n), high_bit)
end
return math.floor(n)
end
-- logic rightshift assures zero filling shift
local function bit_logic_rshift(n, bits)
check_int(n)
if(n < 0) then
-- negative
n = bit_not(math.abs(n)) + 1
end
for i=1, bits do
n = n/2
end
return math.floor(n)
end
local function bit_lshift(n, bits)
check_int(n)
if(n < 0) then
-- negative
n = bit_not(math.abs(n)) + 1
end
for i=1, bits do
n = n*2
end
return bit_and(n, 4294967295) -- 0xFFFFFFFF
end
local function bit_xor2(m, n)
local rhs = bit_or(bit_not(m), bit_not(n))
local lhs = bit_or(m, n)
local rslt = bit_and(lhs, rhs)
return rslt
end
-- An MD5 mplementation in Lua, requires bitlib (hacked to use LuaBit from above, ugh)
-- 10/02/2001 [email protected]
local md5={ff=tonumber('ffffffff',16),consts={}}
string.gsub([[ d76aa478 e8c7b756 242070db c1bdceee
f57c0faf 4787c62a a8304613 fd469501
698098d8 8b44f7af ffff5bb1 895cd7be
6b901122 fd987193 a679438e 49b40821
f61e2562 c040b340 265e5a51 e9b6c7aa
d62f105d 02441453 d8a1e681 e7d3fbc8
21e1cde6 c33707d6 f4d50d87 455a14ed
a9e3e905 fcefa3f8 676f02d9 8d2a4c8a
fffa3942 8771f681 6d9d6122 fde5380c
a4beea44 4bdecfa9 f6bb4b60 bebfbc70
289b7ec6 eaa127fa d4ef3085 04881d05
d9d4d039 e6db99e5 1fa27cf8 c4ac5665
f4292244 432aff97 ab9423a7 fc93a039
655b59c3 8f0ccc92 ffeff47d 85845dd1
6fa87e4f fe2ce6e0 a3014314 4e0811a1
f7537e82 bd3af235 2ad7d2bb eb86d391
67452301 efcdab89 98badcfe 10325476 ]],"(%w+)", function (s) table.insert(md5.consts, tonumber(s,16)) end)
--67452301 efcdab89 98badcfe 10325476 ]],"(%w+)", function (s) tinsert(md5.consts,tonumber(s,16)) end)
function md5.transform(A,B,C,D,X)
local f=function (x,y,z) return bit_or(bit_and(x,y),bit_and(-x-1,z)) end
local g=function (x,y,z) return bit_or(bit_and(x,z),bit_and(y,-z-1)) end
local h=function (x,y,z) return bit_xor(x,bit_xor(y,z)) end
local i=function (x,y,z) return bit_xor(y,bit_or(x,-z-1)) end
local z=function (f,a,b,c,d,x,s,ac)
a=bit_and(a+f(b,c,d)+x+ac,md5.ff)
-- be *very* careful that left shift does not cause rounding!
return bit_or(bit_lshift(bit_and(a,bit_rshift(md5.ff,s)),s),bit_rshift(a,32-s))+b
end
local a,b,c,d=A,B,C,D
local t=md5.consts
a=z(f,a,b,c,d,X[ 0], 7,t[ 1])
d=z(f,d,a,b,c,X[ 1],12,t[ 2])
c=z(f,c,d,a,b,X[ 2],17,t[ 3])
b=z(f,b,c,d,a,X[ 3],22,t[ 4])
a=z(f,a,b,c,d,X[ 4], 7,t[ 5])
d=z(f,d,a,b,c,X[ 5],12,t[ 6])
c=z(f,c,d,a,b,X[ 6],17,t[ 7])
b=z(f,b,c,d,a,X[ 7],22,t[ 8])
a=z(f,a,b,c,d,X[ 8], 7,t[ 9])
d=z(f,d,a,b,c,X[ 9],12,t[10])
c=z(f,c,d,a,b,X[10],17,t[11])
b=z(f,b,c,d,a,X[11],22,t[12])
a=z(f,a,b,c,d,X[12], 7,t[13])
d=z(f,d,a,b,c,X[13],12,t[14])
c=z(f,c,d,a,b,X[14],17,t[15])
b=z(f,b,c,d,a,X[15],22,t[16])
a=z(g,a,b,c,d,X[ 1], 5,t[17])
d=z(g,d,a,b,c,X[ 6], 9,t[18])
c=z(g,c,d,a,b,X[11],14,t[19])
b=z(g,b,c,d,a,X[ 0],20,t[20])
a=z(g,a,b,c,d,X[ 5], 5,t[21])
d=z(g,d,a,b,c,X[10], 9,t[22])
c=z(g,c,d,a,b,X[15],14,t[23])
b=z(g,b,c,d,a,X[ 4],20,t[24])
a=z(g,a,b,c,d,X[ 9], 5,t[25])
d=z(g,d,a,b,c,X[14], 9,t[26])
c=z(g,c,d,a,b,X[ 3],14,t[27])
b=z(g,b,c,d,a,X[ 8],20,t[28])
a=z(g,a,b,c,d,X[13], 5,t[29])
d=z(g,d,a,b,c,X[ 2], 9,t[30])
c=z(g,c,d,a,b,X[ 7],14,t[31])
b=z(g,b,c,d,a,X[12],20,t[32])
a=z(h,a,b,c,d,X[ 5], 4,t[33])
d=z(h,d,a,b,c,X[ 8],11,t[34])
c=z(h,c,d,a,b,X[11],16,t[35])
b=z(h,b,c,d,a,X[14],23,t[36])
a=z(h,a,b,c,d,X[ 1], 4,t[37])
d=z(h,d,a,b,c,X[ 4],11,t[38])
c=z(h,c,d,a,b,X[ 7],16,t[39])
b=z(h,b,c,d,a,X[10],23,t[40])
a=z(h,a,b,c,d,X[13], 4,t[41])
d=z(h,d,a,b,c,X[ 0],11,t[42])
c=z(h,c,d,a,b,X[ 3],16,t[43])
b=z(h,b,c,d,a,X[ 6],23,t[44])
a=z(h,a,b,c,d,X[ 9], 4,t[45])
d=z(h,d,a,b,c,X[12],11,t[46])
c=z(h,c,d,a,b,X[15],16,t[47])
b=z(h,b,c,d,a,X[ 2],23,t[48])
a=z(i,a,b,c,d,X[ 0], 6,t[49])
d=z(i,d,a,b,c,X[ 7],10,t[50])
c=z(i,c,d,a,b,X[14],15,t[51])
b=z(i,b,c,d,a,X[ 5],21,t[52])
a=z(i,a,b,c,d,X[12], 6,t[53])
d=z(i,d,a,b,c,X[ 3],10,t[54])
c=z(i,c,d,a,b,X[10],15,t[55])
b=z(i,b,c,d,a,X[ 1],21,t[56])
a=z(i,a,b,c,d,X[ 8], 6,t[57])
d=z(i,d,a,b,c,X[15],10,t[58])
c=z(i,c,d,a,b,X[ 6],15,t[59])
b=z(i,b,c,d,a,X[13],21,t[60])
a=z(i,a,b,c,d,X[ 4], 6,t[61])
d=z(i,d,a,b,c,X[11],10,t[62])
c=z(i,c,d,a,b,X[ 2],15,t[63])
b=z(i,b,c,d,a,X[ 9],21,t[64])
return A+a,B+b,C+c,D+d
end
-- convert little-endian 32-bit int to a 4-char string
local function leIstr(i)
local f=function (s) return string.char(bit_and(bit_rshift(i,s),255)) end
return f(0)..f(8)..f(16)..f(24)
end
-- convert raw string to big-endian int
local function beInt(s)
local v=0
for i=1,string.len(s) do v=v*256+string.byte(s,i) end
return v
end
-- convert raw string to little-endian int
local function leInt(s)
local v=0
for i=string.len(s),1,-1 do v=v*256+string.byte(s,i) end
return v
end
-- cut up a string in little-endian ints of given size
local function leStrCuts(s,...)
local o,r=1,{}
for i=1,#arg do
table.insert(r,leInt(string.sub(s,o,o+arg[i]-1)))
o=o+arg[i]
end
return r
end
function md5.Calc(s)
local msgLen=string.len(s)
local padLen=56- msgLen % 64
if msgLen % 64 > 56 then padLen=padLen+64 end
if padLen==0 then padLen=64 end
s=s..string.char(128)..string.rep(string.char(0),padLen-1)
s=s..leIstr(8*msgLen)..leIstr(0)
assert(string.len(s) % 64 ==0)
local t=md5.consts
local a,b,c,d=t[65],t[66],t[67],t[68]
for i=1,string.len(s),64 do
local X=leStrCuts(string.sub(s,i,i+63),4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4)
assert(#X==16)
X[0]=table.remove(X,1) -- zero based!
a,b,c,d=md5.transform(a,b,c,d,X)
end
local swap=function (w) return beInt(leIstr(w)) end
return string.format("%08x%08x%08x%08x",swap(a),swap(b),swap(c),swap(d))
end
return md5.Calc("asdf"); -- 912ec803b2ce49e4a541068d495ab570
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