The evil bit is a fictional IPv4 packet header field proposed in RFC 3514, a humorous April Fools' Day RFC from 2003 authored by Steve Bellovin. The RFC recommended that the last remaining unused 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. The evil bit has become a synonym for all attempts to seek simple technical solutions for difficult human social problems, in particular efforts to implement Internet censorship using simple technical solutions.