[guardian-dev] GilgaMesh (was Re: FireChat moved off iOS proprietary mesh to their own xp mesh protocol?)

Michael Rogers michael at briarproject.org
Fri Oct 3 06:07:11 EDT 2014


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On 03/10/14 07:22, Nathan of Guardian wrote:
> I have implemented support for Wifi Direct, using the same device 
> renaming hack I used with Bluetooth:

This is so cool! What's the max length of a device name?

For aDTN we'd need to cram a signed message and its public key into
each packet, with an outer layer of symmetric encryption and
authentication.

Using libsodium the overhead would be 32 bytes for the public key and
64 bytes for the signature (crypto_sign), plus 24 bytes for the IV and
16 bytes for the MAC (crypto_secretbox) That's 136 bytes in total.

248 bytes of Bluetooth device name = 186 bytes of base64-encoded data
= 136 bytes of overhead + 50 bytes of payload. A bit on the small
side. Does Wi-Fi Direct provide more space?

Cheers,
Michael
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