commit 10d1b0b33ed73d9696d1695196bf397ccaab31d9 Author: Nick Mathewson nickm@torproject.org Date: Wed Feb 12 12:20:29 2014 -0500

Changes file for feature4900 --- changes/feature4900 | 12 ++++++++++++ 1 file changed, 12 insertions(+)

diff --git a/changes/feature4900 b/changes/feature4900 new file mode 100644 index 0000000..378ce12 --- /dev/null +++ b/changes/feature4900 @@ -0,0 +1,12 @@ + o Minor features: + + - Avoid hash-flooding denial-of-service attacks by using the secure + SipHash-2-4 hash function for our hashtables. Without this + feature, an attacker could degrade performance of a targeted + client or server by flooding their data structures with a large + number of data entries all calculated to be stored at the same + hash table position, thereby degrading hash table + performance. With this feature, hash table positions are derived + from a randomized cryptographic key using SipHash-2-4, and an + attacker cannot predict which entries will collide. + Closes ticket 4900.