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vnmakarov / mum-hash

Hashing functions and PRNGs based on them
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is mum-hash suitable for authenticating network traffic just like SipHash-2-4 does in linux kernel? #9

Closed zrlw closed 4 years ago

zrlw commented 6 years ago

linux kernel now use siphash_4u32 in net/ipv4/syncookies.c & net/ipv6/syncookies.c: ( https://github.com/torvalds/linux/tree/master ) static u32 cookie_hash(be32 saddr, be32 daddr, be16 sport, be16 dport, u32 count, int c) { net_get_random_once(syncookie_secret, sizeof(syncookie_secret)); return siphash_4u32((force u32)saddr, (force u32)daddr, (force u32)sport << 16 | (force u32)dport, count, &syncookie_secret[c]); }

siphash maybe too heavy or slow to generate tcp syncookie, just a message authentication code can do it, syncookie not need second pre-image resistance or collision resistance, pre-image resistance may be enough, how to prove mum-hash can do it?

vnmakarov commented 6 years ago

I thought about possible ways to break it and did not figured out anything but brute force attack. I believe brute force preimage attack requires 2^64. But in constrast to siphash, nobody made a differential crypto-analysis of mum-hash. I am not going to do this. It is a big job. But anybody is welcomed to do this. Also mum-hash is fast for 64-bit machines. For 32-bit machines, it is much slower.