nettle-bugs February 2017

nettle-bugs@lists.lysator.liu.se

4 participants
4 discussions

Is the gitlab being used or not?
by Gustavo Serra Scalet 09 Apr '17

09 Apr '17

Hi, I noticed there is no merging/update activities on the gitlab website: https://git.lysator.liu.se/nettle/nettle/merge_requests?scope=all&state=all I wonder if it's used. The reason for asking is that I'm willing to integrate a ppc64le-specific implementation using SIMD registers for the SHA-2 algorithm so I would create an Issue to discuss it and then submitting the code as a Merge Request. But only if that's the way for upstreaming code on nettle. If not, please advise if this list can be used. Sorry for using the "nettle-bugs" mailing list, which is not a discussion mailing list. Cheers, Gustavo Serra Scalet

3 3

[PATCH] Make nettle compile with pre-UAL arm assembler.
by Marcus Hoffmann 09 Mar '17

09 Mar '17

See: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0204j/Cjagjj… The pre-UAL instruction is also accepted by modern assemblers. Signed-off-by: Marcus Hoffmann <m.hoffmann(a)cartelsol.com> --- arm/ecc-521-modp.asm | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arm/ecc-521-modp.asm b/arm/ecc-521-modp.asm index c311a89..3fba239 100644 --- a/arm/ecc-521-modp.asm +++ b/arm/ecc-521-modp.asm @@ -91,7 +91,7 @@ PROLOGUE(nettle_ecc_521_modp) adcs F0, F0, F3, lsr #9 C Copy low 9 bits to H, then shift right including carry and H, F0, T0 - rrx F0, F0 + mov F0, F0, rrx lsr F0, F0, #8 C Add in F1 = rp[33], with weight 2^1056 = 2^14 adds F0, F0, F1, lsl #14 -- 2.9.3

2 1

lock-free random generator
by Nikos Mavrogiannopoulos 28 Feb '17

28 Feb '17

Hi, One of the items that have been on my todo-list after discussing with application writers of multi-threaded applications (mainly servers), is addressing the issue of synchronization for the random generator. Currently gnutls provides a "central" random generator based on yarrow (for keys) and salsa20 (for nonces) primitives, and it is thread safe by utilizing mutexes over it. An application that has more than 100-200 threads is most likely to spend more time in synchronization rather than the random generator itself. A solution to that would be to provide a thread-local random generator which will work lock-free, at the cost of additional memory per-thread -around 600-700 bytes for the current generator-. I have an experimental patch set, implementing this idea at: https://gitlab.com/gnutls/gnutls/merge_requests/259 On the patch above, the additional cost per thread will only be for threads actually utilizing gnutls, and in particular the random generator, as the required memory will be allocated after the first call to gnutls_rnd() by the thread. Are there any objections on such an enhancement to gnutls, or suggestions on how such a lock-free random generator could be improved (in terms of memory utilization for example)? regards, Nikos

2 5

detecting sha1 collisions
by Nikos Mavrogiannopoulos 24 Feb '17

24 Feb '17

Hi, There is a sha1 collision detection library at: https://github.com/cr-marcstevens/sha1collisiondetection Given that algorithms like sha1 are notoriously hard to phase out, does it make sense for nettle to add support for collision detection, in effect giving applications the option to switch to a mode where a known to be insecure hash is enabled, but with such collision detection mitigations in place. Does something like the above library make sense to be added to nettle? regards, Nikos

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nettle-bugs February 2017