AES Fundamentals Quiz

The most commonly used symmetric cipher globally, securing data across various applications.

A US government agency responsible for setting and maintaining standards for cryptography, including the selection of AES.

The fundamental building block of AES, operating on 128-bit blocks of data to transform them into scrambled ciphertext.

The size of the input and output data that the AES algorithm processes. For AES, it is always 128 bits, meaning it can encrypt 16 bytes at a time.

The length of the secret key used for encryption and decryption. AES supports 128, 192, and 256-bit key lengths, offering varying levels of security.

The process of changing the ciphertext generated by AES back into the original plaintext using the correct key.

The series of transformations that AES applies to the data to encrypt it, involving steps such as byte substitution, diffusion, and key addition.

A process of generating a sequence of round keys from the original key used in each round of the encryption process.

The process of transforming ciphertext back into plaintext using the same algorithm but with reverse operations.

The inverse of the MixColumns operation used in AES encryption, achieved by multiplying each column of the state matrix with the inverse of a specific matrix.

A 4x4 matrix used in Inv MixColumns to reverse the mixing of columns during the decryption process. Its elements are specific hexadecimal values.

The process of shifting the rows of the state matrix in the opposite direction of the ShiftRows operation during encryption. Each row is shifted a specific number of positions to the right.

A lookup table used to perform the reverse byte substitution during decryption, undoing the original byte substitution done in encryption.

A mathematical structure used to define operations on elements, used extensively in AES. Operations in GF(2⁸) are based on modular arithmetic with a specific polynomial.

A method of performing arithmetic operations on elements within a Galois Field. It involves modulo operations with a specified irreducible polynomial.

The fundamental building block used in AES, providing a mechanism for combining a state matrix and a round key.

This layer aims to ensure that each byte in the cipher text depends on all bytes of the plaintext. This is done by taking the XOR of each byte in the state with a corresponding byte in the key.

A technique that provides confusion, essentially making the output of the ciphertext appear random and unpredictable.

The AES algorithm uses a different number of rounds for different key lengths, ensuring a higher level of security for longer keys.

Each round in AES is made up of several layers, each with unique operations, that work together to encrypt the data.

The Diffusion Layer in AES is crucial as it spreads the influence of each byte across the entire state, strengthening the encryption process.

The ShiftRows layer rearranges rows of the state matrix, introducing complexity and disrupting patterns in the data.

The MixColumn layer combines blocks of four bytes through matrix multiplication, further blurring the relationship between input and output.

The Key Schedule in AES generates round keys from the original key throughout the encryption process, ensuring key-dependent encryption.

The Key Schedule for 128-bit AES uses a function called "g" to generate various round keys, ensuring the secrecy of the encryption process.

The round coefficient RC in AES is a special variable within the key schedule that increases with each round, further enhancing the security of the algorithm.

AES, being highly secure, has different key lengths (128/192/256 bits) offering different levels of security with longer keys providing greater protection.

AES is a block cipher, where data gets divided into 128-bit blocks, each block is treated as a unique 4x4 matrix for processing.

The state matrix in AES is used to visualize and manipulate the data during the encryption process, representing the current state of the encryption.

The AES round function consists of a cascade of different operations like Byte Substitution, ShiftRows, MixColumns, and Key Addition, applied iteratively over the data.

The AES algorithm was selected as the Advanced Encryption Standard in 2001 because of its security, efficiency, and adaptability to different platforms.

Subkeys are used in reverse order compared to encryption. In practice, the same key schedule is used for both encryption and decryption, requiring all subkeys to be computed before the first block's encryption can begin.

A table-based approach where all round functions are combined into a single look-up, leading to four tables with 256 entries each, enabling fast round computation using 16 table look-ups.

AES employs a sequence of transformations, including byte substitution, diffusion, and key addition.

The process of generating a sequence of round keys from the original key, used in each round of the encryption process.

While AES itself is secure, potential weaknesses can arise from its implementation, making it vulnerable to side-channel attacks that exploit information leakage during processing.

AES is a modern block cipher exceptionally resistant to known analytical attacks and brute-force attempts, providing robust long-term security.