[LEDE-DEV] Planning v17.01.2
vincenzo.romano at notorand.it
Thu Jun 15 11:00:01 EDT 2017
2017-06-15 16:41 GMT+02:00 Jo-Philipp Wich <jo at mein.io>:
>> ... and, if I may throw my EUR 0.02 in, why not recompile dropbear
>> with "elliptic curve" support?
> whats the size impact?
> ~ Jo
>From the options.h file I read:
/* ECDSA is significantly faster than RSA or DSS. Compiling in ECC
* code (either ECDSA or ECDH) increases binary size - around 30kB
* on x86-64 */
/* Generate hostkeys as-needed when the first connection using that
key type occurs.
This avoids the need to otherwise run "dropbearkey" and avoids some problems
with badly seeded /dev/urandom when systems first boot.
This also requires a runtime flag "-R". This adds ~4kB to binary
size (or hardly
anything if dropbearkey is linked in a "dropbearmulti" binary) */
/* Enable Curve25519 for key exchange. This is another elliptic
* curve method with good security properties. Increases binary size
* by ~8kB on x86-64 */
/* Enable elliptic curve Diffie Hellman key exchange, see note about
* ECDSA above */
Then I have tried a compilation on my x86-64 macchine with defaults
(ECC enabled) and with those 4 options disabled.
In the first case I've got:
While in the second one:
More or less confirming what's in the options.h.
By rough comparison, my Archer C7 says its dropbear single binary is
176517 bytes long.
Unfortunately I haven't a cross compilation environment at hand right
now to provide RISC binary code sizes.
Maybe one could think about an alternative dropbear-full package.
Vincenzo Romano - NotOrAnd.IT
NON QVIETIS MARIBVS NAVTA PERITVS
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