CyberCertPrepSecurity FundamentalsCryptography FundamentalsEASYFree question
What is the key difference between a block cipher and a stream cipher?
- A.A. Block ciphers are faster than stream ciphers
- B.C. Stream ciphers use asymmetric keys
- C.B. Block ciphers encrypt fixed-size blocks of data; stream ciphers encrypt data one bit or byte at a time
- D.D. Block ciphers cannot be used with modes of operation
Why C is correct
Block ciphers (like AES) encrypt data in fixed-size blocks (e.g., 128 bits). Stream ciphers (like ChaCha20) encrypt data continuously, one bit or byte at a time, by XORing plaintext with a pseudorandom keystream. Stream ciphers are often faster for real-time data.
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