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Bruce Schneier has changed his PGP key to 4096 bits

news.ycombinator.com

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Re: Bruce Schneier has changed his PGP key to 4096 bits

#21

Post by reconbot »

IgorPartola wrote: post #3

So I have a GPG key. I used it a couple of times. Currently, it's most useful to me to sign my own Debian package repository. However, I can't seem to figure out how to get into the whole Web of Trust thing. Nobody I know has their own GPG/PGP key that they use and have signed by others and tools like BigLumber and other places where I looked for key signing parties have not turned up any results. I not spending all…

http://biglumber.com/ is any oldy but a goodie. There's room for improvement in this area.

Re: Bruce Schneier has changed his PGP key to 4096 bits

#22

Post by vabmit »

mrjj wrote: post #13

Is he really afraid of 2^n/2 brute power of quantum computers or this is just overkilling of overkill?

There's no need for a quantum computer. Everyone should be using at least 4096bit RSA.

1024bit RSA keys can be factored with conventional non-specialized hardware (read: CPU's, not even GPU's) with GNFS.

IMHO, 2048bit RSA keys can be factored by custom hardware that the NSA has developed. I posted my reasoning for this hypothesis in other hackernews threads. A very quick/terse run down of the main key points - 1) NSA is known to use customer hardware (they have their own chip fabs. You can extrapolate performance gain from things like GPUs, FGPAs, and Deepcrack 2. Al Qaeda uses 2048bit RSA for internal communications 3. Most corps, diplomats, criminals, and normal people use 2048bit RSA either directly (SSH keys, Website Certs, VPNs) or indirectly (CA's still use 2048bit RSA certs valid until 2020)

Re: Bruce Schneier has changed his PGP key to 4096 bits

#23

Post by riquito »

mrjj wrote: post #13

Is he really afraid of 2^n/2 brute power of quantum computers or this is just overkilling of overkill?

The complexity is 2^n/2, but we don't know (afaik) if the quantum computer is also way faster for a single computation than standard computers. In that case, the more the better

Re: Bruce Schneier has changed his PGP key to 4096 bits

#24

Post by gcv »

Karunamon wrote: post #4
autodidakto wrote: post #2

Anyone know of a good tutorial for revoking and recreating your key as painlessly as possibly?

I'd imagine the process works something like this: * Generate the new key * Sign the new key with the old key * Generate the revocation cert for the old key * Push the revocation publicly with a reason of "Superseded by (fingerprint of new key)" or similar * Push the new key * Try to get your new key signed by everyone that signed your old key for authenticity's sake I'm not too sure how the community of GPG users ou…

If you do this, will you still be able to decrypt data encrypted with the old key?

Re: Bruce Schneier has changed his PGP key to 4096 bits

#25

Post by michiel3 »

In the post he also describes that he now uses a new process which involves a computer that has never been connected to the internet and its sole purpose is encrypting and decrypting files. Why not use it to encrypt and decrypt emails as well? That'd also potentially involve generating a new key pair.

> 3) Assume that while your computer can be compromised, it would take work and risk on the part of the NSA – so it probably isn't. If you have something really important, use an air gap. Since I started working with the Snowden documents, I bought a new computer that has never been connected to the internet. If I want to transfer a file, I encrypt the file on the secure computer and walk it over to my internet computer, using a USB stick. To decrypt something, I reverse the process. This might not be bulletproof, but it's pretty good.

Re: Bruce Schneier has changed his PGP key to 4096 bits

#27

Post by hannibal5 »

There is nothing suspicious with that.

He has worked previously in mostly corporate and private context, so 2048 is just fine. Now he works with people and data NSA wants their hands on and he wants the data to be secure also in the future. It's just reasonable to move to 4096 key sizes.

http://www.pgp.net/pgpnet/pgp-faq/pgp-faq-keys.html#key-size

>Dr Lenstra and Dr Verheul offer their recommendations for keylengths. In their calculation, a 2048 bit key should keep your secrets safe at least until 2020 against very highly funded and knowledgeable adversaries (i.e. you have the NSA working against you). Against lesser adversaries such as mere multinationals your secret should be safe against bruteforce cryptoanalysis much longer, even with 1024 bit keys.

See also: http://www.keylength.com

Re: Bruce Schneier has changed his PGP key to 4096 bits

#28

Post by malandrew »

michiel3 wrote: post #25

In the post he also describes that he now uses a new process which involves a computer that has never been connected to the internet and its sole purpose is encrypting and decrypting files. Why not use it to encrypt and decrypt emails as well? That'd also potentially involve generating a new key pair. > 3) Assume that while your computer can be compromised, it would take work and risk on the part of the NSA – so it p…

With linux, is there any way to compromise the USB stick used for the air gap? AFAIK the Stuxnet virus was originally spread via USB stick, however I reckon that it involved Windows machines that are known to execute files on USB sticks.

Re: Bruce Schneier has changed his PGP key to 4096 bits

#29

Post by taproot »

gcv wrote: post #24
Karunamon wrote: post #4

Earlier quoted context omitted.

I'd imagine the process works something like this: * Generate the new key * Sign the new key with the old key * Generate the revocation cert for the old key * Push the revocation publicly with a reason of "Superseded by (fingerprint of new key)" or similar * Push the new key * Try to get your new key signed by everyone that signed your old key for authenticity's sake I'm not too sure how the community of GPG users ou…

If you do this, will you still be able to decrypt data encrypted with the old key?

Only with the old private key.

Re: Bruce Schneier has changed his PGP key to 4096 bits

#30

Post by betterunix »

knowtheory wrote: post #10
tptacek wrote: post #9

Or: - he really doesn't use his PGP key all that often, had the same one for 16 years on god knows how many computers, and decided that if he's going to generate a new one, he might as well send a message with it.

Normally i'd let it go, but i actually would like some clarity on your intent here. Are you implying that Schneier doesn't use encrypted communications on a regular basis, that PGP is impractical, or both? (and to be clear, my intent is not to bait, i'm actually curious)

Considering the fact that most people at CRYPTO, Usenix Security, IEEE Security and Privacy, and other prominent cryptography and security conferences do not have PGP or S/MIME keys...it would not be surprising if Schneier was not using PGP on a regular basis.
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