Have Entropy_Accumulator dump everything into a BufferedComputation.

Since both Randpool and HMAC_RNG fed the input into a MAC anyway, this
works nicely. (It would be nicer to use tr1::function but, argh, don't
want to fully depend on TR1 quite yet. C++0x cannot come soon enough).
This avoids requiring to do run length encoding, it just dumps everything
as-is into the MAC. This ensures the buffer is not a potential narrow pipe
for the entropy (for instance, one might imagine an entropy source which
outputs one random byte every 16 bytes, and the rest some repeating pattern -
using a 16 byte buffer, you would only get 8 bits of entropy total, no matter
how many times you sampled).

1 files changed, 1 insertions, 3 deletions

diff --git a/src/rng/hmac_rng/hmac_rng.cpp b/src/rng/hmac_rng/hmac_rng.cpp
index f495dda4d..ffdfdc60d 100644
--- a/src/rng/hmac_rng/hmac_rng.cpp
+++ b/src/rng/hmac_rng/hmac_rng.cpp
@@ -69,7 +69,7 @@ void HMAC_RNG::reseed_with_input(u32bit poll_bits,
    feedback of the current PRK value, into the extractor function.
    */
 
-   Entropy_Accumulator accum(poll_bits);
+   Entropy_Accumulator accum(*extractor, poll_bits);
 
    for(u32bit i = 0; i < entropy_sources.size(); ++i)
       {
@@ -83,8 +83,6 @@ void HMAC_RNG::reseed_with_input(u32bit poll_bits,
    if(input_length)
       accum.add(input, input_length, 1);
 
-   extractor->update(accum.get_entropy_buffer());
-
    /*
    It is necessary to feed forward poll data. Otherwise, a good poll
    (collecting a large amount of conditional entropy) followed by a