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| author | Nick Mathewson <nickm@torproject.org> | 2019-02-05 12:49:04 -0500 |
|---|---|---|
| committer | Nick Mathewson <nickm@torproject.org> | 2019-02-14 09:26:40 -0500 |
| commit | f3cbd6426cbb27b9ab4e5492a50a785cce77f805 (patch) | |
| tree | fe986b31fcf87010db296fa38fed759ed4aeb66d /src/lib/crypt_ops/include.am | |
| parent | 3d3578ab41c9be602fad5c4172a880668994c8c3 (diff) | |
| download | tor-f3cbd6426cbb27b9ab4e5492a50a785cce77f805.tar.gz tor-f3cbd6426cbb27b9ab4e5492a50a785cce77f805.zip | |
Implement a fast aes-ctr prng
This module is currently implemented to use the same technique as
libottery (later used by the bsds' arc4random replacement), using
AES-CTR-256 as its underlying stream cipher. It's backtracking-
resistant immediately after each call, and prediction-resistant
after a while.
Here's how it works:
We generate psuedorandom bytes using AES-CTR-256. We generate BUFLEN bytes
at a time. When we do this, we keep the first SEED_LEN bytes as the key
and the IV for our next invocation of AES_CTR, and yield the remaining
BUFLEN - SEED_LEN bytes to the user as they invoke the PRNG. As we yield
bytes to the user, we clear them from the buffer.
Every RESEED_AFTER times we refill the buffer, we mix in an additional
SEED_LEN bytes from our strong PRNG into the seed.
If the user ever asks for a huge number of bytes at once, we pull SEED_LEN
bytes from the PRNG and use them with our stream cipher to fill the user's
request.
Diffstat (limited to 'src/lib/crypt_ops/include.am')
| -rw-r--r-- | src/lib/crypt_ops/include.am | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/src/lib/crypt_ops/include.am b/src/lib/crypt_ops/include.am index 19cfee1355..4730440143 100644 --- a/src/lib/crypt_ops/include.am +++ b/src/lib/crypt_ops/include.am @@ -17,6 +17,7 @@ src_lib_libtor_crypt_ops_a_SOURCES = \ src/lib/crypt_ops/crypto_ope.c \ src/lib/crypt_ops/crypto_pwbox.c \ src/lib/crypt_ops/crypto_rand.c \ + src/lib/crypt_ops/crypto_rand_fast.c \ src/lib/crypt_ops/crypto_rand_numeric.c \ src/lib/crypt_ops/crypto_rsa.c \ src/lib/crypt_ops/crypto_s2k.c \ |