Older blog entries for mau (starting at number 7)

17 Nov 2004 (updated 11 Aug 2012 at 17:22 UTC) »
error27 Please make your hash trees be compatible with the THEX spec. And you should modify your code to use different hash functions for leaves and internal nodes. Just prepend 0x00 and 0x01 respectively before hashing.
Bayesian spam filters solved the spam problem for me. But I don't like the use of a big (X MB) and slow database for word counts. (And I want that deleted emails leave no traces on disc.) So I modified some bloom filter code I had around to classify my emails. While this code is still untuned and uses a stupid shell script as tokenizer, the first results look promising. Two 64 KB bit-arrays are more than enough information to detect spam emails.
nuncanada Gödels incompleteness theorem does not show that certain traditional theories are not able to handle arithmetics. It states that all formal systems which can handle arithmetics are incomplete. Formulated differently: All systems which are complete are boring because they can't even handle arithmetics. So incompletness is a feature and not a bug.
16 May 2003 (updated 16 May 2003 at 17:00 UTC) »

Started working on a pseudonymous, secure and decentralized messaging system. Features:

Everybody is identified by the hash of his public key. Exchanging this identifier over a secure channel (in real life) or via trusted third parties ("If you need help with this, contact my good friend Bob (rsa-sha1:38484848)") is all that is needed to have secure communication. The local client will map those identifiers to (local) human readable nick names.

No peers communicate directly without prior negotiation via other peers. This has a lot of advantages: It is easy to implement downstream bandwith throttling; Peers can hide their participation in this network to the world (most other p2p networks will widely distribute your IP adress.) and even stay completely anonymous by the use of mix chains; and it makes it possible to implement DoS/Spam-defences which are impossible to implement in a network where everybody can send to everbody else without prior negotiation.

Message routing uses xor metric. This scales (a limited search horizon is acceptable in a file sharing network but not in a messaging system) and eleminates the use of central servers.

Who needs Citrix Metaframe? Finally there is a good X windows protocoll compressor. I didn't test the final product yet, but a prototype was already usable over modem. And the core components are GPL!
25 Dec 2002 (updated 26 Dec 2002 at 11:50 UTC) »
wireless VoIP

There are already portable VoIP phones which use 801.11b. And I read that there are chips in development which can do both 802.11b and GSM. (And Nokia already sells a PCMCIA card which can do both.)

I predict that telcos will soon be fighting free wireless networks like the RIAA is fighting file sharing networks today.

global namespaces

All global namespaces should really be built upon cryptographically secure hashes. Static content should be indentified by content hashes. (Even MSG-IDs of emails and usenet posts should be content hashes.) Every hash of a public key should be the root of a namespace which is owned by the owner of the public key. This would solve a lot of problems of the existing internet. A lot of 404s would never occur. All the problems of the domain name system would be solved too. And last but not least: All communication could be encrypted automatically and transparently to the user.

Notify Lists

Bram: I don't think that using email addresses as identifier for instant messaging is a good idea. Email addresses change sometimes, leak information about your identity and depend on the evil DNS.

It is much better to use the hash of your public key as identifier. This has a lot of advantages: The protocol can be made secure very easily: somebody who wants to communicate with you can just look up your host key and check the hash. With email addresses he has to fetch the key and must somehow make sure that he has the correct key which isn't really easy. Another advantage is that you can have as many addresses (pseudonyms) as you like.

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