6 ms·
Related: if you don't have enough entropy when creating keys, your public keys might not be identical, but they can share primes. Sharing primes allows this co
by chubot 12y ago
Related: if you don't have enough entropy when creating keys, your public keys might not be identical, but they can share primes. Sharing primes allows this cool factoring attack by DJB and others.
https://scholar.google.com/scholar?cluster=9203750458482965051&hl=en&as_sdt=0,5&sciodt=0,5 https://scholar.google.com/scholar?cluster=92037504584829650...
This paper explains how an attacker can efficiently factor 184 distinct RSA keys out of more than two million 1024-bit RSA keys downloaded from Taiwan's national "Citizen Digital Certificate" database.
These keys were generated by government-issued smart cards that have built-in hardware random-number generators and that are advertised as having passed FIPS 140-2 Level 2 certification. These 184 keys include 103 keys that share primes and that are efficiently factored by a batch-GCD computation. This is the same type of computation that was used last year by two independent teams (USENIX Security 2012: Heninger, Durumeric, Wustrow, Halderman; Crypto 2012:
Lenstra, Hughes, Augier, Bos, Kleinjung, Wachter) to factor tens of thousands of cryptographic keys on the Internet.
- abrodersen 12y agoThis is why we can't have nice things. And by nice things, I mean identification of people via cryptography rather than rectangular pieces of plastic.
- kordless 12y ago> rather than rectangular pieces of plastic Finally, the U.S. gets a mention.
- lifeisstillgood 12y agoTaiwan has a citizen digital certificate process - cool ! I mean that's a seriously big advance over anything I imagined a govt capable of. Estonia was the only other place I heard even close. And is 183 out of 2 million so bad? Just sign the next round of certificates with this lot and move on.
- pedrocr 12y agoPortugal also has a national ID card that's a smart card and includes a key. The last time I tried to use it in the justice ministry website it required accepting a self-signed HTTPS certificate. When I reported the issue I got a "oh, just accept it and it will be fine" response from a supposedly technical person. So yeah, these things are getting deployed in some places but I'm not too hopeful it will end up being much more than a gimmick. At least I hope not because the next step on the minds of some of these "technical" people is electronic voting and that won't end well...
- this_user 12y ago> Portugal also has a national ID card that's a smart card and includes a key. German ones do something similar since late 2010. The card can be used for online authentication and eletronic signatures (requires certificate that is separately available). http://en.wikipedia.org/wiki/German_identity_card#Chip http://en.wikipedia.org/wiki/German_identity_card#Chip
- sampo 12y ago> Portugal also has a national ID card that's a smart card and includes a key. So does Finland (since 2004). But under 10% of the population has such a card (most people use drivers licence and/or passport as ID), and thus almost no private web services accept it for identification.
- Sami_Lehtinen 12y agoFinnish passport also got RFID features: http://en.wikipedia.org/wiki/Finnish_passport http://en.wikipedia.org/wiki/Finnish_passport About ID card: : https://en.wikipedia.org/wiki/Finnish_identity_card https://en.wikipedia.org/wiki/Finnish_identity_card
- madeofpalk 12y agoDon't most countries have ePassports?
- kerkeslager 12y agoI almost didn't read the paper because I thought it was only about the batch-GCD method: that's fairly easy to understand. But I'm glad I read the paper because it goes on to explain how using the shared factors allowed them to understand the failure of the PRNG and use that understanding to break keys that didn't share factors, using a more sophisticated attack. It's definitely worth reading that paper.