lua rc4算法实现

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由于项目需要，用python django写restful接口遇到瓶颈，python django+uwsgi处理请求是会阻塞的，

如果阻塞请求不及时处理，会卡住越来越多的其它的请求，导致越来越多的502。所以将请求处理频繁的，会阻

塞长时间的接口用lua实现，lua放在nginx里跑，还是很快的。

呵呵，费话少说了！

项目因用到rc4加密算法，但网上实现lua rc4算法的很少，有的要依赖lua第三方库，很不方便。根据wiki实

现自己的算法:

-- RC4
-- http://en.wikipedia.org/wiki/RC4function KSA(key)
local key_len = string.len(key)
local S = {}
local key_byte = {} for i = , do
S[i] = i
end for i = , key_len do
key_byte[i-] = string.byte(key, i, i)
end local j =
for i = , do
j = (j + S[i] + key_byte[i % key_len]) %
S[i], S[j] = S[j], S[i]
end
return S
endfunction PRGA(S, text_len)
local i =
local j =
local K = {} for n = , text_len do i = (i + ) %
j = (j + S[i]) % S[i], S[j] = S[j], S[i]
K[n] = S[(S[i] + S[j]) % ]
end
return K
endfunction RC4(key, text)
local text_len = string.len(text) local S = KSA(key)
local K = PRGA(S, text_len)
return output(K, text)
endfunction output(S, text)
local len = string.len(text)
local c = nil
local res = {}
for i = , len do
c = string.byte(text, i, i)
res[i] = string.char(bxor(S[i], c))
end
return table.concat(res)
end-------------------------------
-------------bit wise-----------
-------------------------------local bit_op = {}
function bit_op.cond_and(r_a, r_b)
return (r_a + r_b == ) and or
endfunction bit_op.cond_xor(r_a, r_b)
return (r_a + r_b == ) and or
endfunction bit_op.cond_or(r_a, r_b)
return (r_a + r_b > ) and or
endfunction bit_op.base(op_cond, a, b)
-- bit operation
if a < b then
a, b = b, a
end
local res =
local shift =
while a ~= do
r_a = a %
r_b = b % res = shift * bit_op[op_cond](r_a, r_b) + res
shift = shift * a = math.modf(a / )
b = math.modf(b / )
end
return res
endfunction bxor(a, b)
return bit_op.base('cond_xor', a, b)
endfunction band(a, b)
return bit_op.base('cond_and', a, b)
endfunction bor(a, b)
return bit_op.base('cond_or', a, b)
end--key = "Key"
--text = "Plaintext"
--K = RC4(key, text)
--print (K)
--text = RC4(key, K)
--print (text)
--
--key = "Wiki"
--text = "pedia"
--K = RC4(key, text)
--print (K)
--
--key = "Secret"
--text = "Attack at dawn"
--K = RC4(key, text)
--print (K)