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Comment Re:What should happen and what will happen (Score 1) 112

The problem with that is on the other practical end: if you massively increase the resources needed will also increase the server side resources; it won't be as bad as it will be on the cracking end, but server resources are expensive.

It won't be as bad as on the cracking end, that's the whole point. The reason for doing password hashing is to exploit the asymmetric level of effort between hashing and brute force search. To make that work, though, you do need to invest as much as you can afford in the server, to move the bar for the attacker as high as possible -- hopefully out of reach of all but the most serious. If you can't afford very much, fine, but realize that you're also not setting the bar very high.

But this is exactly why good password hashing algorithms are moving to RAM consumption as the primary barrier. It's pretty trivial for a server with many GiB of RAM to allocate 256 MiB to hashing a password, for a few milliseconds, but it gets very costly, very fast, for the attacker. And if you can't afford 256 MiB, how about 64?

What you definitely do not want is a solution that takes microseconds and uses a few dozen bytes. That creates a trivial situation for the attacker given modern hardware, and your server absolutely can afford more than that.

This is similar to why we don't use much longer keys for public key encryption and use really large primes for DH key exchange.

Nope. The leverage factor in the password hashing case is linear, since the entropy of passwords is constant (on average). The leverage factor for cryptographic keys is exponential. The reason we don't use much longer keys for public key encryption, etc., is because there's no point in doing so, not because we can't afford it. The key sizes we use are already invulnerable to any practical attack in the near future. For data that must be secret for a long time, we do use larger key sizes, as a hedge against the unknown.

Comment Re:Are two hashes better than one? (Score 1) 112

... however it's worth noting that there are currently no ways of finding a collision for both MD5 and SHA-1 hashes simultaneously

Any crypto geeks want to weigh in on the truth of this statement? I've often wondered about this. Wouldn't using two hash algorithms be easier and more effective over the long term than getting the whole world to upgrade to the Latest And Greatest Hash every ~10 years?

MD5 + SHA1 is a "new hash algorithm". Think about what you have to do to shift to a new algorithm... all of the message formats that have to be updated, all of the stored values that have to be recomputed, all of the cross-system compatibility dances you have to do to ensure that you can upgrade both sides (or all sides; there are often more than two) in order to update without having to make some error-prone attempt to cut over simultaneously.

The challenge of changing hash algorithms has nothing to do with getting correctly-implemented source code for a new algorithm. That's super easy. The challenges are all about how to handle the changeover, which is exactly the same whether you're switching to an actual new algorithm that incorporates the latest ideas and is (currently) completely invulnerable to all known attacks, or to a combination of old, broken algorithms that may or may not be better than either one alone.

The right solution is to build systems with algorithm agility and algorithm negotiation, then to add new algorithms as soon as they're standardized and remove algorithms completely once all parties have updated.

Comment Re:First amendment ? WTH ? (Score 1) 95

The problem with their logic is, of course, that the police aren't forcing anyone to buy an Alexa device.

o.0 That's not a problem with their logic - that's something utterly irrelevant that you've pulled out of thin air.
 

If I choose to purchase a device that, by design, records everything I say, then I've voluntarily sacrificed my right to privacy in exchange for the benefits afforded by the device.

That's an assertion on your part, not a fact.
 

It's not the police's fault that I've done so, and they're entirely within their rights to seek a warrant for the information that I've served up on a platter.

Yes... and no. The police certainly are within their rights to seek a warrant to obtain information so long as is it relative to the case. They may not however use warrants to conduct fishing expeditions on the off-chance that information might be found that might be relevant to the case. Though they phrase it in First Amendment terms, that's the heart of Amazon's argument - they police have not established that the recordings are material to the case, and thus have no legal right to make a blanket request for private information.

Comment Re:For variable values of "practical" and "relevan (Score 2) 112

Not a lot you can do?

Anything that requires signatures is vulnerable to forgery if the signer's certificate specifies SHA1.

An attacker could forge:

1. Software signatures - to slip malware into a software vendor's distribution channels.

That requires a second pre-image attack, not just a collision attack. (What gweihir called "two-sided" rather than "one-sided"... though that is not standard terminology).

2. SSL certificates - to MITM web connections to phish, steal data, or distribute malware.

Also requires a second pre-image attack.

3. Personal digital signatures - to fabricate documents, including emails, transaction, orders, etc that are normally trusted implicitly due to the signature

This one can be done with a collision attack. You generate two different documents which hash to the same value, but have different contents. The PDF format, unfortunately, make it pretty easy to generate documents which look sensible and have this property. It's not possible with more transparent formats (not without a second pre-image attack).

4. Subordinate CA certificates - to create trusted certificates which permit all of the above

The problem lies with #4.

This can only be done with a collision attack if the CA is really, really stupid. Proper CAs should include chain-length restrictions in their certificates. That way even if you can create two certificates which hash to the same value, one of which has the keyCertSign bit set to true (which the CA would refuse to sign) and one of which does not (which presumably you can get the CA to sign), it wouldn't matter because if you used the former to generate other certs, no one would accept them due to the fact that your chain is too long.

The only solution is to discontinue the use of SHA1 internally and to revoke trust for all CAs that still use SHA1.

I certainly agree that any CA still issuing certificates with SHA1 should not be trusted. Any existing certs based on SHA1 should be scrutinized, but most of them are still secure.

Better crypto has existed for a long time---the standard for SHA2 was finalized in 2001, well over a decade ago.

Absolutely. Of course, I say that as the maintainer (ish) of an open source crypto library that still uses SHA1. In systems that weren't originally designed for digest agility, it's often hard to retrofit. Today's news is a nice kick in the pants, though.

Comment Re:What should happen and what will happen (Score 2) 112

The second to last Yahoo security breach was so bad in part because the passwords were hashed with a completely unsalted MD5 https://nakedsecurity.sophos.com/2016/12/15/yahoo-breach-ive-closed-my-account-because-it-uses-md5-to-hash-my-password/. The lack of salting would have been by itself a problem even when MD5 was still considered secure.

Actually, even with salting, no standard cryptographic hash function is appropriate for password databases. You can squeak by if you iterate the hash function enough times, but even that is pretty weak, since it means that an attacker with lots of GPUs -- or, even worse, special-purpose hardware -- can perform hashes so much faster than you can that the key stretching you obtain is minimal.

The state of the art in password hashing is algorithms like Argon2, with parameters that are tuned to require significant amounts of not just CPU time, but RAM and threads. Argon2, tuned to require, say, 10ms of time on four cores and 256 MiB of RAM, is going to significantly strengthen passwords. The RAM requirement means a GPU with 4 GiB of RAM can only test 16 passwords in parallel, making GPU-based cracking essentially useless, since what GPUs provide is huge parallelism. Custom ASICs would do better, but would still run into bottlenecks on the speed of the RAM. Making really fast cracking hardware would require either huge amounts of RAM, or large amounts of extremely fast RAM. Either way, big $$$.

Even better, if at all possible you should use a hash that is keyed as well as salted. Doing that requires having some place to store the key that won't be compromised by the same sorts of attacks that compromise your password database. In most cases that's hard to do. Argon2 will accept a key so you can get both sorts of protection, though if you can be really, really certain that no attacker can ever get the key, then you can use a standard cryptographic hash function in a keyed mode, e.g. HMAC-SHA256, though I'd still recommend using a purpose-designed password hash (e.g. Argon2) in case your key is compromised.

Comment Costing to the RIAA vrs Ignoring? (Score 3, Insightful) 72

When I RTFA, it seems like there are 100s of millions of DCMA requests going out each year - 35 million in the "latter half of September 2016"?

Even if "detection" (I don't know how good their detection process is if 99%+ of the claims are not found by Google) filing costs came out to a dollar per then I would think the cost to the industry would be $250+ million.

Looking at Warner Music revenues (the first company I could think of: https://www.statista.com/stati...), I would think that the cost of filing all these claims amounts to around 5% or so of total revenue.

Two things came to mind thinking about this:
1. The music company accountants should be going apeshit over the cost of this program and the damage to the company's bottom line.
2. There's a whole bunch of money to be made creating an application for generating DCMA demands that reduces the number of DCMA requests (and the total cost of the requests) by 10x or more.

Comment Re:Always wait for the S version (Score 1) 100

We switched away from buying our phones through Verizon, to the Apple Upgrade Program. It's a zero-interest loan over 24 months, but you can upgrade every 12 months by extending the loan so that you have another 24 months remaining.

On this plan, the most logical behaviors are to 1) pay off your phone and hold onto it as long as possible, or 2) upgrade the moment you can so that you're not continuing to make payments on last year's model. The worst option is to upgrade every two years, because your monthly payment is exactly the same as if you upgrade every year but you have an old phone half the time.

Comment Re: Umm (Score 1) 388

The amount of voter fraud in the United States is exceedingly low so the whole voter ID laws are a solution in search of a problem.

Voter ID laws solve a very clear problem, just not the one their proponents claim.

There is also widespread evidence that such laws are designed to target democratic voters and that they tend to target the poor and minorities.

Yep, that's the problem: blacks, latinos and white trash voting too much. Voter ID isn't a complete solution, but it's a useful step. I'm sure Bannon has some ideas about the final solution.

Hmm... maybe that is what Trump meant when he claimed three million "illegals" voted for Hillary. He meant "people who shouldn't be allowed to vote", rather than "people who aren't citizens", the way the silly media interpreted the words.

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