Martin Gardner:

   "A new kind of cipher that would take millions of years to break"

Scientific American, August 1977

This trapdoor ciphers column introduced RSA cryptography, a new
“public key” method of secret communication previously not believed
possible. It was based on an MIT memo by Ron Rivest, Adi Shamir and
Leonard Adleman from April 1977, which they sent to Gardner. He was so
impressed that he broke his usual rule of planning his column several
months in advance, and quickly wrote it up for publication.

The basic idea is to secretly take two very large prime numbers (p, q)
at least 40 digits long each, and form their product r=pq, assuming
that it would be an insurmountable task for an outsider to factor
r. It’s considered safe to reveal r, as well as a related odd number
s, to all and sundry; that's the public key. Anyone wishing to send a
secret numerical “word” w to the person who selected p and q does the
following: find the remainder e when ws is divided by r, and
communicate e openly. An easy mathematical trick allows a person who
knows e to reconstruct w from it provided they know the factors p and
q of n, but it seems unlikely that somebody not knowing p and q would
have a chance.

To prove the point, the RSA team provided Gardner with a 128-digit
coded message e, computed using a specified 129-digit n, which was the
product of mysterious top-secret, 64-digit and 65-digit primes p and
q, respectively. They also indicated that s = 9007. A prize of $100
was offered for anyone who could recover the original message w from
which e had been computed. Given the title of the column, it was
assumed that no one would crack it anytime soon. In fact, Gardner
hedged his bets and prefaced the piece with an Edgar Allan Poe quote:
“Yet it may be roundly asserted that human ingenuity cannot concoct a
cipher which human ingenuity cannot resolve.”

RSA cryptography became an industry standard and variations of it are
still in use today, though in recent times the question of how secure
it is has been revisited. Despite the groundbreaking nature of
Gardner’s column, it didn't quite live up to its title. The challenge
message posed in it was successfully decoded as early as April 1994.