To decrypt a double transposition, construct a block with the right number of rows under the keyword, blocking off the short columns. Write the cipher in by columns, and read it out by rows.

Cryptanalyst Jim Gillogly created them using the Playfair, Double Playfair, and Double Transposition ciphers, respectively.

Zodiac Killer cipher is cracked after eluding sleuths for 51 years Northern California serial murderer sent encoded messages that went uncracked until now.

It’s Math Monday! In this third post in a series on columnar transposition ciphers, we look at a formula for the underlying permutation of a CTC and specialize it to the rail fence cipher.

Oranchak, a 46-year-old software developer in Virginia, said the 340 is what’s known as a transposition cipher. Most ciphers used today by computers rely on mathematics to scramble messages.

Experts believed it was a transposition cipher but were mystified by the arrangement of strange markings.