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Ard Biesheuvel authored
For the final round, avoid the expanded and padded lookup tables exported by the generic AES driver. Instead, for encryption, we can perform byte loads from the same table we used for the inner rounds, which will still be hot in the caches. For decryption, use the inverse AES Sbox directly, which is 4x smaller than the inverse lookup table exported by the generic driver. This should significantly reduce the Dcache footprint of our code, which makes the code more robust against timing attacks. It does not introduce any additional module dependencies, given that we already rely on the core AES module for the shared key expansion routines. Signed-off-by:
Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by:
Herbert Xu <herbert@gondor.apana.org.au>
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