Impersonating Vince

Martin Chorley - @martinjc

PyDiff Lightning Talk Special - 21st March 2017

Evidence

I have evidence!

It is remarkably easy to fake a twitter account...

Ingredients

1. A source of example data
2. An algorithm to create tweets

    
# assume there are more tweets to retrieve
more_tweets = True

# while there are more tweets to retrieve
while(more_tweets):

    # make an api call to get the tweets prior
    # to our earliest retrieved tweet so far
    params = {
        "screen_name": am,
        "count": 200,
        "exclude_replies": "false",
        "max_id": earliest_id
    }

    new_tweets = ta.query_get("statuses", "user_timeline", params)

    # add the newly retrieved tweets to our list
    tweets.extend(new_tweets)

    # find the earliest retrieved tweet
    current_earliest = earliest_id
    for tweet in tweets:
        if tweet["id"] < earliest_id:
            earliest_id = tweet["id"]

    # if the earliest tweet hasn't changed
    # we can't go back any further
    if current_earliest == earliest_id:
        more_tweets=False
    
    

3625 Tweets!

Algorithm

We want to generate realistic looking text

Text that looks like Vince wrote it.

Given a word `A`, what is the probability that Vince uses the word `B` next?

Even Better

Given a sequence `A, B`, what is the probability that Vince uses the word `C` next?

        
data = tweets_file.read()
words = data.split()
words = [word for word in words if word.find('http') < 0 and word.find('@') < 0]
return words
        
    

        
def triples(words):

    if len(words) < 3:
        return

    for i in range(len(words) - 2):
        yield (words[i], words[i+1], words[i+2])

def database(words):
    cache = {}
    for w1, w2, w3 in triples(words):
        key = (w1, w2)
        if key in cache:
            cache[key].append(w3)
        else:
            cache[key] = [w3]
    return cache
        
    

        
def generate_markov_text(size=25, words, cache):
    seed = random.randint(0, len(words)-3)

    seed_word, next_word = words[seed], words[seed+1]
    w1, w2 = seed_word, next_word

    gen_words = []

    for i in range(size):
        gen_words.append(w1)
        w1, w2 = w2, random.choice(cache[(w1, w2)])

    gen_words.append(w2)
    return ' '.join(gen_words)

        
    

Conclusions

The conspiracy is real

All our Twitter accounts are fake