Length limits of encauth etc. #216

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opened 2017-05-11 08:35:45 -05:00 by sjaeckel · 1 comment

sjaeckel commented

2017-05-11 08:35:45 -05:00

(Migrated from github.com)

As @karel-m pointed out in https://github.com/libtom/libtomcrypt/pull/211/files#r115594690 we have a possible issue in chacha20poly1305

Now when I am looking at the implementation the max length of our chacha20poly1305 is 2^64 bytes; however, in theory chacha20poly1305 has max length limit 2^70 bytes. The potentioal trouble might occur due to the fact that we do not check for reaching 2^64.

We should verify the existing implementations regarding such limitations.

The following encauth implementations exist, they should be marked as resolved after their implementation has been verified and/or fixed

ccm
chacha20poly1305
eax
gcm fixed in #129
ocb
ocb3

Should this list contain further elements, e.g. MAC's?

As @karel-m pointed out in https://github.com/libtom/libtomcrypt/pull/211/files#r115594690 we have a possible issue in `chacha20poly1305` > Now when I am looking at the implementation the max length of our `chacha20poly1305` is `2^64` bytes; however, in theory `chacha20poly1305` has max length limit `2^70` bytes. The potentioal trouble might occur due to the fact that we do not check for reaching `2^64`. We should verify the existing implementations regarding such limitations. The following encauth implementations exist, they should be marked as resolved after their implementation has been verified and/or fixed - [ ] `ccm` - [ ] `chacha20poly1305` - [ ] `eax` - [x] `gcm` fixed in #129 - [ ] `ocb` - [ ] `ocb3` Should this list contain further elements, e.g. MAC's?

sjaeckel commented

2025-10-07 03:38:56 -05:00

(Migrated from github.com)

CFRG is working on defining those limits in https://datatracker.ietf.org/doc/draft-irtf-cfrg-aead-limits/

Integration will be postponed until the RFC is finished.

CFRG is working on defining those limits in https://datatracker.ietf.org/doc/draft-irtf-cfrg-aead-limits/ Integration will be postponed until the RFC is finished.