3 ms·
My understanding is that fast implementations in software require look up tables which are susceptible to timing attacks.
by tel 13y ago
My understanding is that fast implementations in software require look up tables which are susceptible to timing attacks.
- sweis 13y agoOpenSSL has a GCM implementation which is very fast and I believe is not susceptible to timing attacks due to using vpclmulqdq: http://git.openssl.org/gitweb/?p=openssl.git;a=blob;f=crypto/modes/asm/aesni-gcm-x86_64.pl;h=3781933917227dd127352fa8d7d066804dacba13;hb=HEAD http://git.openssl.org/gitweb/?p=openssl.git;a=blob;f=crypto... You can debate whether it's a "software implementation" since it's using AESNI and PCLMULQDQ.
- tptacek 13y agoI think PCLMULQDQ is noncontroversial, but also considered "hardware supported".
- mentat 13y agoSo cache timing attacks increasing with table size? I thought the table was only for the authentication section. I guess that would be reversible to the key. Are there any papers on this?
- nightcracker 13y agoI'm not exactly sure on the details of AES-GCM, but in general if you use secret data to influence either the data path (indexing tables), code path (branches) or timing (either branches or non-constant instructions) then your secret data should be considered compromised in a model allowing side channel attacks.