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Python Authentication API

- 1 answer

I'm looking for a python library that will help me to create an authentication method for a desktop app I'm writing. I have found several method in web framework such as django or turbogears.

I just want a kind of username-password association stored into a local file. I can write it by myself, but I'm really it already exists and will be a better solution (I'm not very fluent with encryption).

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Answer

Treat the following as pseudo-code..

try:
    from hashlib import sha as hasher
except ImportError:
    # You could probably exclude the try/except bit,
    # but older Python distros dont have hashlib.
    try:
        import sha as hasher
    except ImportError:
        import md5 as hasher


def hash_password(password):
    """Returns the hashed version of a string
    """
    return hasher.new( str(password) ).hexdigest()

def load_auth_file(path):
    """Loads a comma-seperated file.
    Important: make sure the username
    doesn't contain any commas!
    """
    # Open the file, or return an empty auth list.
    try:
        f = open(path)
    except IOError:
        print "Warning: auth file not found"
        return {}

    ret = {}
    for line in f.readlines():
        split_line = line.split(",")
        if len(split_line) > 2:
            print "Warning: Malformed line:"
            print split_line
            continue # skip it..
        else:
            username, password = split_line
            ret[username] = password
        #end if
    #end for
    return ret

def main():
    auth_file = "/home/blah/.myauth.txt"
    u = raw_input("Username:")
    p = raw_input("Password:") # getpass is probably better..
    if auth_file.has_key(u.strip()):
        if auth_file[u] == hash_password(p):
            # The hash matches the stored one
            print "Welcome, sir!"

Instead of using a comma-separated file, I would recommend using SQLite3 (which could be used for other settings and such.

Also, remember that this isn't very secure - if the application is local, evil users could probably just replace the ~/.myauth.txt file.. Local application auth is difficult to do well. You'll have to encrypt any data it reads using the users password, and generally be very careful.

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source: stackoverflow.com
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