DES key length is commonly 56 bits.

Prepare for the Network Security (NETSEC) 3 Test with flashcards and multiple choice questions. Each question offers hints and explanations. Get exam-ready efficiently!

Multiple Choice

DES key length is commonly 56 bits.

Explanation:
DES uses a 64-bit key input, but eight bits are parity bits and are not used in the encryption process. This leaves 56 bits of actual key material, so the common DES key length is 56 bits. That 56-bit size defines the brute-force search space (2^56 possibilities), which is why DES is considered insecure by modern standards. The other numbers listed aren’t used for DES keys: 40 bits would be unusually small, 100 bits isn’t a DES key length, and 128 bits is a common size for AES and other algorithms but not DES.

DES uses a 64-bit key input, but eight bits are parity bits and are not used in the encryption process. This leaves 56 bits of actual key material, so the common DES key length is 56 bits. That 56-bit size defines the brute-force search space (2^56 possibilities), which is why DES is considered insecure by modern standards. The other numbers listed aren’t used for DES keys: 40 bits would be unusually small, 100 bits isn’t a DES key length, and 128 bits is a common size for AES and other algorithms but not DES.

More Multiple Choice Questions
Subscribe

Get the latest from Passetra

You can unsubscribe at any time. Read our privacy policy