Convert XoRoShiRo128PlusPlus into a full RandomMixin-based RNG class,
providing all utility functionality that FastRandomContext has. In doing so,
it is renamed to InsecureRandomContext, highlighting its non-cryptographic
nature.
To do this, a fillrand fallback is added to RandomMixin (where it is used by
InsecureRandomContext), but FastRandomContext still uses its own fillrand.
This adds the FSChaCha20 stream cipher as specified in BIP324, a
wrapper around the ChaCha20 stream cipher (specified in RFC8439
section 2.4) which automatically rekeys every N messages, and
manages the nonces used for encryption.
Co-authored-by: dhruv <856960+dhruv@users.noreply.github.com>
There are two variants of ChaCha20 in use. The original one uses a 64-bit
nonce and a 64-bit block counter, while the one used in RFC8439 uses a
96-bit nonce and 32-bit block counter. This commit changes the interface
to use the 96/32 split (but automatically incrementing the first 32-bit
part of the nonce when the 32-bit block counter overflows, so to retain
compatibility with >256 GiB output).
Simultaneously, also merge the SetIV and Seek64 functions, as we almost
always call both anyway.
Co-authored-by: dhruv <856960+dhruv@users.noreply.github.com>
Blindly chose a cap of 10000 iterations for every loop, except for
the two in script_ops.cpp and scriptnum_ops.cpp which appeared to
(sometimes) be deserializing individual bytes; capped those to one
million to ensure that sometimes we try working with massive scripts.
There was also one fuzzer-controlled loop in timedata.cpp which was
already capped, so I left that alone.
git grep 'while (fuzz' should now run clean except for timedata.cpp
-BEGIN VERIFY SCRIPT-
# Rename
sed -i -e 's/MakeFuzzingContext/MakeNoLogFileContext/g' $(git grep -l MakeFuzzingContext)
# Bump the copyright of touched files in this scripted diff to avoid touching them again later
./contrib/devtools/copyright_header.py update ./src/test/fuzz/
-END VERIFY SCRIPT-
