Lesson plan

Evil bit

The evil bit is a fictional IPv4 packet header field proposed in a humorous April Fools' Day RFC from 2003, authored by Steve Bellovin. The Request for Comments recommended that the last remaining unused bit, the "Reserved Bit" in the IPv4 packet header, be used to indicate whether a packet had been sent with malicious intent, thus making computer security engineering an easy problem simply ignore any messages with the evil bit set and trust the rest.

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Article summary

The evil bit is a fictional IPv4 packet header field proposed in a humorous April Fools' Day RFC from 2003, authored by Steve Bellovin. The Request for Comments recommended that the last remaining unused bit, the "Reserved Bit" in the IPv4 packet header, be used to indicate whether a packet had been sent with malicious intent, thus making computer security engineering an easy problem simply ignore any messages with the evil bit set and trust the rest.

Key claims

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Discussion questions

  1. Summarise the article in your own words. Which single claim would you verify first, and why?
  2. Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
  3. If two sources disagreed about one of these facts, what would you need in order to trust one over the other?

Bibliography

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Key claims and bibliography are generated from the same tracked claims and sources as the article page.