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Why is elliptic curve cryptography not widely used, compared to RSA?

crypto.stackexchange.com

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Re: Why is elliptic curve cryptography not widely used, compared to RSA?

#11

Post by mseebach »

VLM wrote: post #9

I thought the most interesting thing in the stack overflow was the complete lack of systems analysis. 99% of people who need encryption already have it, and they probably use RSA or at least a non-EC system. So almost by definition you're talking about converting an entire system, not just linking in a new library or CSS file... The question is really, "Why aren't people replacing their entire SSL cert system and all…

You don't need to replace your entire anything, and it's not "just for fun".

No, the question is really "EC has these benefits (lower CPU and memory usage) - why aren't these benefits attractive enough for someone to start experimenting with it?" - with those someones probably being companies like Google, Facebook, Dropbox etc that have very substantial amounts of SSL traffic and could surely benefit from saving on memory and CPU.

Re: Why is elliptic curve cryptography not widely used, compared to RSA?

#12

Post by VLM »

mseebach wrote: post #11
VLM wrote: post #9

I thought the most interesting thing in the stack overflow was the complete lack of systems analysis. 99% of people who need encryption already have it, and they probably use RSA or at least a non-EC system. So almost by definition you're talking about converting an entire system, not just linking in a new library or CSS file... The question is really, "Why aren't people replacing their entire SSL cert system and all…

You don't need to replace your entire anything, and it's not "just for fun". No, the question is really "EC has these benefits (lower CPU and memory usage) - why aren't these benefits attractive enough for someone to start experimenting with it?" - with those someones probably being companies like Google, Facebook, Dropbox etc that have very substantial amounts of SSL traffic and could surely benefit from saving on m…

"could surely benefit from saving on memory and CPU."

... at a certain labor cost. And memory and CPU prices are forever decreasing and labor cost is sorta increasing. So if it doesn't make sense as a system to do it today it probably never will, for an established organization anyway.

Also its not "why aren't they experimenting" but "why aren't they publicly experimenting". And it would nearly be a first in the security field to discuss algo changes this long in advance of rollout, if its ever discussed in public at all...

Finally its highly unclear why anyone uses SSL for these apps. That solely protects the relatively highly secure comm channel between two wide open insecure endpoints, so there's no point other than security theater/marketing. For email auth, yeah maybe. For finance its theater but necessary theater. But for G+, FB, DB as listed its just a waste of time. The MS windows enduser is probably owned 100x over with worms and keyloggers, and the server side will roll over and play dead to anyone remotely in .gov.

Re: Why is elliptic curve cryptography not widely used, compared to RSA?

#13

Post by cantos »

I've often heard the claim that elliptic curve cryptography is not used much in practice compared to RSA. I don't doubt its true but I would like to have some evidence for it so I can also say it without being a parrot.

I don't know anything about real world implementations of cryptography. How can I go about getting data that RSA is more widely used?

Re: Why is elliptic curve cryptography not widely used, compared to RSA?

#14

Post by mistercow »

The top answer tries to brush off the difference in hardness assumptions as "semi-valid", and I think that's rather odd. Assumptions about hardness are pretty damned important in cryptography, and 25 years is not really all that long for mathematicians to have been thinking about a problem.

Re: Why is elliptic curve cryptography not widely used, compared to RSA?

#15

Post by surespot »

check out www.surespot.me for a great example of elliptic curve cryptography. surespot is a free and open source mobile messenger encrypting all messages end-to-end with 256 bit AES symmetric-key encryption using keys created with 521 bit ECDH shared secret derivation. surespot was built from the ground up to provide this exceptional security in an unobtrusive way, this is not a layer over something existing. surespot is like whatsapp but actually encrypted! group chat on the way.

Re: Why is elliptic curve cryptography not widely used, compared to RSA?

#17

Post by ReidZB »

Not relevant to ECC, but if anyone here has spare time and any interest at all in crypto, please contribute to the linked site (http://crypto.stackexchange.com)! In case anyone doesn't know, StackExchange is a network of Q&A websites, of which StackOverflow was the first. Sites go through a proposal process and, if enough people commit, a private and then public beta. The Cryptography StackExchange site is currently in public beta. If it reaches a critical mass, then it will graduate and become fully-fledged member of the SE network.

As it is, the site is doing relatively well but daily activity is low (too few questions, too few visitors). But there are lots of knowledgeable people on it, and crypto is one of those areas everyone seems interested in, so the only real thing holding it back is a critical mass of good, active users. For many professions here on HN, it's useful to have a bit of crypto knowledge, so this post is a shameless plug. :)

You don't have to be an expert to contribute. In fact, one of the problem areas is a lack of good, well-researched, quality questions. Of course, any new expert is welcome too.

Re: Why is elliptic curve cryptography not widely used, compared to RSA?

#18

Post by btilly »

mistercow wrote: post #14

The top answer tries to brush off the difference in hardness assumptions as "semi-valid", and I think that's rather odd. Assumptions about hardness are pretty damned important in cryptography, and 25 years is not really all that long for mathematicians to have been thinking about a problem.

As another answer points out, the mathematics of the discrete logarithm on elliptic curves is closely related to factoring, and most factoring algorithms have close analogs for the discrete logarithm, so the difference is actually not that great.

However it does have a subtle consequence. We've developed some very good sieve based algorithms for factoring in recent decades that do not have obvious analogs for elliptic curves. A large part of the performance advantage that elliptic curves have is that you can get away with shorter keys. However if we developed an analog to our best factoring algorithms, then that size (and therefore performance) benefit becomes much less.

If you choose key size to "be good enough that people won't be able to break this for X years" you really should assume that such analogs exist, and will be discovered within X years.

Re: Why is elliptic curve cryptography not widely used, compared to RSA?

#19

Post by [deleted] »

ReidZB wrote: post #17

Not relevant to ECC, but if anyone here has spare time and any interest at all in crypto, please contribute to the linked site ( http://crypto.stackexchange.com )! In case anyone doesn't know, StackExchange is a network of Q&A websites, of which StackOverflow was the first. Sites go through a proposal process and, if enough people commit, a private and then public beta. The Cryptography StackExchange site is currentl…

[deleted]

Re: Why is elliptic curve cryptography not widely used, compared to RSA?

#20

Post by __david__ »

cantos wrote: post #13

I've often heard the claim that elliptic curve cryptography is not used much in practice compared to RSA. I don't doubt its true but I would like to have some evidence for it so I can also say it without being a parrot. I don't know anything about real world implementations of cryptography. How can I go about getting data that RSA is more widely used?

Well, probably the most widely used cryptography is SSL, specifically the kind used in HTTPS. The whole HTTPS ecosystem revolves around certificates authorities that sign your RSA key. So on that fact alone, I would say there's more RSA out there than ECC.

SSH is also very widely used and it has traditionally used RSA keys, though it supports DSA keys, too and, more recently, ECDSA (the "EC" being elliptic curve). Sadly, Mac OS X's built in openssh is an older version that doesn't support ECDSA and apparently Redhat turns off ECDSA support for some sort of legal/patent reasons. So that's another case where RSA is more popular.

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