Source URL: https://simonwillison.net/2024/Nov/21/a-warning-about-tiktoken/#atom-everything
Source: Simon Willison’s Weblog
Title: A warning about tiktoken, BPE, and OpenAI models
Feedly Summary: A warning about tiktoken, BPE, and OpenAI models
Tom MacWright warns that OpenAI’s tiktoken Python library has a surprising performance profile: it’s superlinear with the length of input, meaning someone could potentially denial-of-service you by sending you a 100,000 character string if you’re passing that directly to tiktoken.encode().
There’s an open issue about this (now over a year old), so for safety today it’s best to truncate on characters before attempting to count or truncate using tiktoken.
Tags: openai, tom-macwright, security, python
AI Summary and Description: Yes
Summary: The text highlights a critical security vulnerability associated with OpenAI’s tiktoken Python library, indicating that an adversary could exploit performance issues to create denial-of-service (DoS) threats. This information is particularly relevant for professionals managing security in AI systems and applications.
Detailed Description: The warning provided by Tom MacWright addresses a specific flaw within the tiktoken library that can lead to significant performance degradation based on input length. This insight is crucial for AI developers and security professionals who use this library, as it suggests a potential exploit vector that could be leveraged to disrupt services.
– The performance issue is characterized as “superlinear” with respect to input length, which means that the processing time and computational resources required to handle longer inputs increase disproportionately.
– An example provided indicates that a malicious actor could send a 100,000 character string to the `tiktoken.encode()` method, which could severely slow down or crash a system relying on this library.
– There’s an existing open issue that has remained unresolved for over a year, highlighting the need for immediate attention to this security concern.
– To mitigate potential threats, it is advisable to implement truncation on character input before using tiktoken functions to prevent excessive computational load.
This alert serves as a reminder of the importance of evaluating the security implications of third-party libraries in AI applications, particularly how they handle unexpected input sizes. Security teams should prioritize reviewing such libraries to prevent possible exploitation and ensure robust operational resilience.