<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_authinfo(request):
 """Get authentication info from the encrypted message."""

    if (("files_iv" not in request.session) or ("files_text" not in request.session) or ("files_key" not in request.COOKIES)):
        return False
    """
        Decrypt the password given the SERVER-side IV, SERVER-side
        ciphertext, and CLIENT-side key.

        See note above on why this is done.
    """

    iv = base64.b64decode(request.session["files_iv"])
    text = base64.b64decode(request.session["files_text"])
    key = base64.b64decode(request.COOKIES["files_key"])

    obj = AES.new(key, AES.MODE_CFB, iv)
    password = obj.decrypt(text)

    username = request.session["filecenter_username"] if "filecenter_username" in request.session else request.user.username

    return {"username": username, "password": password}