"The Magic Words are Squeamish Ossifrage" was the solution to a challenge ciphertext posed by the inventors of the RSA cipher in 1977.
[1] It was solved in 1993–94 by a large, joint computer project co-ordinated by Derek Atkins, Michael Graff, Arjen Lenstra and Paul Leyland.
Ossifrage ('bone-breaker', from Latin) is an older name for the bearded vulture, a scavenger famous for dropping animal bones and live tortoises on top of rocks to crack them open.
Ron Rivest estimated in 1977 that factoring a 125-digit semiprime would require 40 quadrillion years, using the best algorithm known and the fastest computers of the day.
[6] In their original paper they recommended using 200-digit (663 bit) primes to provide a margin of safety against future developments,[7] though it may have only delayed the solution as a 200-digit semiprime was factored in 2005.