AES, block cipher modes, stream ciphers, hash functions, HMAC, salting, key derivation and classical ciphers.
40 cards · basic cards · AI-written, checked twice. Edit anything.
- What is a Caesar cipher?
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A substitution cipher that shifts each letter by a fixed number of positions in the alphabet.- What is a substitution cipher?
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A cipher that replaces each plaintext character with a corresponding ciphertext character using a substitution table.- What is the Vigenère cipher?
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A polyalphabetic substitution cipher that uses a repeating keyword to shift plaintext characters by different amounts.- What is a one-time pad?
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A perfectly secure cipher that uses a random key as long as the plaintext, used exactly once, and XORed with plaintext.- What is a stream cipher?
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A symmetric cipher that encrypts plaintext one bit or byte at a time by XORing it with a keystream generated from a secret key.- What is a keystream in a stream cipher?
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A sequence of pseudorandom bits or bytes generated from a secret key and optional IV, used to encrypt plaintext via XOR.- What is RC4?
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A stream cipher based on key-scheduling and pseudorandom generation algorithms, now considered cryptographically weak.- What is ChaCha20?
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A modern stream cipher designed by Daniel J. Bernstein, based on the ChaCha family, offering good performance and security.- What is a block cipher?
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A symmetric cipher that divides plaintext into fixed-size blocks and encrypts each block independently using the same key.- What is the block size of AES?
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128 bits (16 bytes), fixed for all AES variants.- What are the valid AES key sizes?
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128 bits, 192 bits, or 256 bits (16, 24, or 32 bytes).- How many rounds does AES perform?
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10 rounds for 128-bit keys, 12 for 192-bit keys, 14 for 256-bit keys.- What is the purpose of an S-box in AES?
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A lookup table that performs non-linear byte substitution, providing confusion in the cipher.- What is a Feistel network?
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A symmetric structure that divides a block into two halves, applies a round function to one half with a subkey, and XORs the result with the other half.- What is ECB mode?
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Electronic Codebook mode, which encrypts each plaintext block independently using the same key, producing deterministic ciphertext.
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