Caesar_RSA.lua

os.loadAPI("/Primes.lua")
os.loadAPI("/TableInt.lua")

function GetNew(_bitLength)
    local k = {}
    k.p = Primes.GetBetween(19,2^_bitLength)
    k.q = Primes.GetBetween(19,2^_bitLength)
    k.n = k.p * k.q
    k.phi_n = (k.p-1) * (k.q-1)
    local eTable = {}
    local e = 2
    for i = 1, 4 do
        while Primes.GCD2(e,k.phi_n) ~= 1 or Primes.GCD2(e,k.n) ~= 1 do
            e = e + 1
        end
        eTable[i] = e
    end
    k.e = eTable[math.random(1,#eTable)]
    local dTable = {}
    local d = 2
    for i = 1, 4 do
        while (d * k.e) % k.phi_n ~= 1 do
            d = d + 1
        end
        dTable[i] = d
    end
    k.d = dTable[math.random(1,#dTable)]
    local pb = {k.e,k.n}
    pb.e = k.e
    pb.n = k.n
    local pv = {k.d,k.n}
    pv.d = k.d
    pv.n = k.n
    k.public = pb
    k.private = pv
    return k
end

function PrintKey(_key)
    print("p = ".._key.p)
    print("q = ".._key.q)
    print("n = ".._key.n)
    print("phi_n = ".._key.phi_n)
    print("e = ".._key.e)
    print("d = ".._key.d)
end

function Encrypt(_message,_pair)
    local cipher = ""
    for i = 1, #_message do
        cipher = cipher .. TableInt.Mod(TableInt.Pow(_message:sub(i,i):byte(),_pair[1],'s'),_pair[2]) .. ' '
    end
    return cipher
end

function Decrypt(_cipher,_pair)
    local message = ""
    local i = 1
    while i < #_cipher do
        local mChar = ""
        while _cipher:sub(i,i) ~= ' ' do
            mChar = mChar .. _cipher:sub(i,i)
            i = i + 1
        end
        message = message .. string.char(TableInt.Mod(TableInt.Pow(tonumber(mChar),_pair[1],'s'),_pair[2]))
        i = i + 1
    end
    return message
end