from tkinter import Tk, simpledialog, messagebox

root = Tk()
root.withdraw()

#считали данные
d = {}
file = open('f.txt','r',encoding='utf-8')
for line in file:
    line = line.rstrip() #line = 'allena,qwerty'
    login, password = line.split(',') # 'allena' 'qwerty'
    d[login] = password
file.close()
print(d)