def METHOD_NAME(username):
    salt = b''
    iterations = 1000
    key = hashlib.pbkdf2_hmac('sha256', salt, salt, iterations, 16)
    aesgcm = AESGCM(key)
    nonce = os.urandom(12)
    username = username.encode()
    ct = aesgcm.encrypt(nonce, username, None)
    cookie = str(binascii.hexlify(nonce), 'ascii') + \
        str(binascii.hexlify(ct), 'ascii')
    return cookie