break

To successfully perform cryptanalysis and thus succeed in decrypting data or performing some other cryptographic function, without initially having knowledge of the key that the function requires. (See: penetrate, strength, work factor.)

Usage: This term applies to encrypted data or, more generally, to a cryptographic algorithm or cryptographic system. Also, while the most common use is to refer to completely breaking an algorithm, the term is also used when a method is found that substantially reduces the work factor.