BSI

Security tip #2: key lengths

In cryptography a key length refers to the digital size of the ‘key’ used to unlock the encryption algorithm. Over time the length of these keys has increased from DES’ modest 64 bit (really 56 bit) key size all the way to the new AES specified key lengths of 128 and 256 bit keys. Each bit increase in in the algorithm doubles the potential number of keys available to use, thus usually making it harder for an adversary to guess the right key.