Charles Babbage broke the cipher; however, he didn't publish his work.

Slow diffusion rate of the decryption process was immediately exploited to break the cipher.

There have been many attempts to break the remaining cipher(s).

Even when you begin to break the cipher, the information revealed stands for something else, as well.

Perhaps their enemies were able to break the cipher and read their messages.

British scientists could not discover a way to break the cipher.

But to break the cipher would take too long.

Playfair is now regarded as insecure for any purpose, because modern computers could easily break the cipher within seconds.

Kasiski entirely broke the cipher and published the technique in the 19th century.

Even before this, though, some skilled cryptanalysts could occasionally break the cipher in the 16th century.