Add constant-time bit-sliced AES engine (TAesBitSlicedEngine) - #158
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Add a table-free, constant-time software AES engine that drops into the existing IBlockCipher/IAesEngine seam alongside the table-based TAesEngine. The engine holds the AES state as eight bit-sliced UInt64 words and realises the S-box as a Boyar-Peralta Boolean circuit, so it performs no data- or key-dependent memory lookups and takes no secret-dependent branch - closing the cache-timing side channel inherent to the table engine. The key schedule is table-free and constant-time as well. Both directions are implemented and are bit-exact with TAesEngine for 128/192/256-bit keys; word rotations go through TBitOperations. The engine is opt-in by construction and is not registered as a default anywhere; paired with the branchless TBasicGcmMultiplier it composes into a constant-time software AES-GCM stack. Tests (TTestAesBitSliced): inherits the standard AES engine battery (known vectors, 10k-iteration Monte Carlo, bad-parameter rejection) and adds FIPS-197 KATs both directions, byte-for-byte parity against TAesEngine over random keys/blocks, encrypt/decrypt round-trips, a CBC round-trip through the mode, and end-to-end AES-GCM through the manual composition.
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Add a table-free, constant-time software AES engine that drops into the existing IBlockCipher/IAesEngine seam alongside the table-based TAesEngine.
The engine holds the AES state as eight bit-sliced UInt64 words and realises the S-box as a Boyar-Peralta Boolean circuit, so it performs no data- or key-dependent memory lookups and takes no secret-dependent branch - closing the cache-timing side channel inherent to the table engine. The key schedule is table-free and constant-time as well. Both directions are implemented and are bit-exact with TAesEngine for 128/192/256-bit keys; word rotations go through TBitOperations. The engine is opt-in by construction and is not registered as a default anywhere; paired with the branchless TBasicGcmMultiplier it composes into a constant-time software AES-GCM stack.
Tests (TTestAesBitSliced): inherits the standard AES engine battery (known vectors, 10k-iteration Monte Carlo, bad-parameter rejection) and adds FIPS-197 KATs both directions, byte-for-byte parity against TAesEngine over random keys/blocks, encrypt/decrypt round-trips, a CBC round-trip through the mode, and end-to-end AES-GCM through the manual composition.