Tag
aes
- Oct 12, 2026 Constructing an S-Box: Field Inversion and Differential Uniformity Why the AES substitution table is an inverse map in GF(2^8) followed by an affine transform, and how differential uniformity bounds the best characteristic. cryptography
- Aug 20, 2026 Key Schedules: Why Subkeys Cannot Be Independent The key expansion that derives a round key from a short master key, the nonlinearity it must add, and the related-key and slide attacks that punish weak expansion. cryptography
- Dec 26, 2025 Diffusion and Branch Numbers in Block Cipher Design How the wide-trail strategy counts active S-boxes across rounds, why a branch number of five bounds a four-round characteristic, and where the bound stops applying. cryptography
- Jan 23, 2025 Constant-Time AES: Removing the Secret-Dependent Table Lookup Why a 256-byte S-box leaks key bits through cache behaviour, and how bit-slicing and vector permutes replace the lookup without changing the cipher. cryptography
- Aug 9, 2023 The AES State Matrix: Byte Ordering, ShiftRows, and MixColumns How sixteen key bytes map onto a four-by-four matrix, why the row shift moves different distances, and what MixColumns does to a column as a polynomial. cryptography