Text Encoder Decoder

Encoder:

import random

text = input("Please input a text: ")
text = list(text)
print(text)
l = (text.__len__()) * random.randint(10000, 20000) #random-generated characters for each input-text character
print(l)
dec1 = list()
code = list()
i = 0
while i < l:
    dec1.append(random.randchar())
    i = i + 1
print(dec1)
dec = list()
filename = input("Please choose a file name (without file-extension): ")
filedec = open(filename + ".dec", "w")
for i in dec1:
    dec.append(str(i))
pos1 = 0

for i in text:
    pos1 = random.randint(0, l)
    for i2 in dec:
        while str(pos1) in i2:
            pos1 = random.randint(0, l)
    dec[pos1] = i

    code.append(pos1)

decstr = ""
for i in dec:
    decstr = decstr + str(i)
filedec.write(decstr)
filecode = open("Decipher.txt", "w")
filecode.write(str(code))



Decoder:

from ast import literal_eval
datei = input("choose a file to decode (with file-extension): ")
decipher = literal_eval(input("input the decipher.txt: "))
filedec = open(datei, "r")
dec = list(filedec.read())

text = ""
for i in decipher:
    text = text+dec[i]

print(text)