Re: [hiprg] use of sha-1 in the DHT interface draft

["Ahrenholz, Jeffrey M" <[e-mail]>]

> However, my understanding is that the DHT server does not enforce the
> use of SHA-1; modified clients (that are HIP-aware) could use SHA-256
> truncated to 160 bits.

The DHT server does use SHA-1 internally to process removes. If the client uses another hash function, the secret given in the DHT remove will not match the SHA-1 hash used in the put.

The draft does not currently require a modified OpenDHT/Bamboo server. It states in sections 3 and 7 that the server MAY/SHOULD be modified for signature and host ID verification (it looks like the "MAY" in section 3 should be changed to "SHOULD".)  Use of another hash algorithm would require further server modifications (and specifying an interface that deviates from OpenDHT.)

> - keep the draft as is, citing that OpenDHT interface prescribes SHA-1,
> and that the other usage of SHA-1 is not trying to obtain any crypto
> properties.  However, the implication of this is we will need to add
> more text in the security section and elsewhere to defuse this "red
> flag"

I would prefer the above option. The security considerations section can include text about deviating from the OpenDHT interface in order to support other hash functions. The original intent of the draft was to re-use the freely-available OpenDHT interface in an interoperable fashion.

-Jeff