Triple DES has replaced DES. It uses block encryption. The basic algorithmic principles have not changed, however in Triple DES data blocks are encrypted with three different keys. Thus, Triple DES uses a 168-bit key. Later, a vulnerability lessened the time required to crack a 168-bit key to the time required to crack a 108-bit key. Basically, a 108-bit key is sufficient for quite reliable encryption today. However, in the future, it will be insufficient. One more disadvantage of this algorithm is its low processing speed.