Moo! Wrapper

Moo! Wrapper is a BOINC-native wrapper around distributed.net's RC5-72 challenge: a brute-force search for the 72-bit symmetric-encryption key specified in RSA Laboratories' original Secret-Key Challenge. That challenge began in the 1990s — when exports of strong cryptography were still restricted — to empirically demonstrate that 56- and 64-bit keys were insecure and that 72-bit keys were on their way out. RSA formally retired the Secret-Key Challenge in May 2007, but distributed.net has kept the RC5-72 search going ever since as a community-run effort. Moo! Wrapper brings this continuing effort into the BOINC ecosystem, letting volunteers contribute with the same client they use for science projects.

The mathematics is simple and brutal: check every 2⁷² possible keys until one correctly decrypts the challenge ciphertext. On paper the search space is astronomical (4.7 × 10²¹ keys), but in practice distributed.net has been grinding through it since 2002. As of 2026, 15.7 % of the keyspace has been searched; at current rates the remainder could take another ~36 years, or could end any day if a participant hits the key.

Moo! Wrapper supports both CPU and GPU computation, with modern OpenCL applications providing a huge throughput advantage. It's also a regular participant in Formula BOINC sprints, the competitive series between BOINC teams, making it popular among community-minded volunteers.

Why is this meaningful beyond the competition? RC5 was the algorithm used to establish the modern understanding of symmetric cipher key-size security; every retired key-length from this challenge has become empirical evidence in cryptographic policy. Every work unit continues that legacy.