Any projects which want to use Hush code from now on will need to be licensed as
GPLv3 or we will send the lawyers: https://www.softwarefreedom.org/
Notably, Komodo (KMD) is licensed as GPLv2 and is no longer compatible to receive
code changes, without causing legal issues. MIT projects, such as Zcash, also cannot pull
in changes from the Hush Full Node without permission from The Hush Developers,
which may in some circumstances grant an MIT license on a case-by-case basis.
libsecp256k1's API changed, so update key.cpp to use it.
Libsecp256k1 now has explicit context objects, which makes it completely thread-safe.
In turn, keep an explicit context object in key.cpp, which is explicitly initialized
destroyed. This is not really pretty now, but it's more efficient than the static
initialized object in key.cpp (which made for example bitcoin-tx slow, as for most of
its calls, libsecp256k1 wasn't actually needed).
This also brings in the new blinding support in libsecp256k1. By passing in a random
seed, temporary variables during the elliptic curve computations are altered, in such
a way that if an attacker does not know the blind, observing the internal operations
leaks less information about the keys used. This was implemented by Greg Maxwell.
This was added a while ago for testing purposes, but was never intended to be
used. Remove it until upstream libsecp256k1 decides that verification is
stable/ready.
Add a sanity check to prevent cosmic rays from flipping a bit in the
generated public key, or bugs in the elliptic curve code. This is
simply done by signing a (randomized) message, and verifying the
result.
- add a small wrapper in util around RAND_bytes() and replace with
GetRandBytes() in the code to log errors from calling RAND_bytes()
- remove OpenSSL header rand.h where no longer needed
Duke Leto
jl777