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Comment by nommm-nommm | Hacker News Reader

>It is not like security flaws grow spontaneously like rust a car.

They absolutely can. Its well know that cryptography algorithms "decay" over time as computer power increases. There was a time where encrypting with DES was secure, DES is no longer secure due to increase in computing power. In 50 years I doubt we'll be using many of today's algorithms. Its exactly like a car slowly rusting over time.

That's even assuming support is possible. I may have a stroke so I no longer have the ability to support my product.

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"for certain categories".

If a device was made in 99, I wouldn't blame it for having DES. If a web appliance was built in 2005, I wouldn't blame the maker for unsalted MD5 passwords.

If a device or critical app were made in 2017 and stored its passwords with 777 permissions in the clear, I would blame the maker.

I think the correct tradeoff is to judge the malfeasance of the product based on what security precautions were reasonable at the time the product was created.

Granting that "reasonability" is a very fuzzy standard, it seems obvious that a product with 30 year old crypto should not be subject to lawsuits because someone got solved integer factorization on real hardware.

Modern crypto algorithms are decay-free. They may still get weaker because of improved math, or quantum computers, but never because of increased computing power. That was an artifact of too slow computers at the beginning of computers history.

Modern algorithms are replaced mostly because the alternatives are easier to use, faster, or more flexible in some ways. With some huge emphasis on "easier to use" because that means "more secure" on practice.

> They may still get weaker because of improved math

But aren't we (and the NSA) discovering new attacks all the time? So hence, their de facto security decays.

Yes, that's improved math.

All the time is a bit of an exaggeration. Some algorithms are broken very fast, others slowly accumulate partial attacks until people don't trust them anymore. Those last ones don't normally get completely broken¹. I think the only exceptions were the shorter key lengths of RSA².

1 - But you will find many examples of algorithms with less than the modern strength parameters that were broken by the mix of faster computers and partial attacks.

2 - But by the time those were abandoned people were mostly using even shorter keys that wouldn't suffice by today's standards even without any known attack.

>They absolutely can. Its well know that cryptography algorithms "decay" over time as computer power increases

This is bullshit.

No reasonably modern crypto algorithms has ever been broken. If you use any crypto algorithm in your less-than-10-year-old product that gets broken it's because you shipped a product with sub-standard crypto.

There was a time when people thought DES is secure, but that time was in the 80s and early 90s. Nobody will blame you for bad crypto if you released software in that time.

And a new car today also probably won't be rusted in less than 10 years time, what exactly is your point?

>Nobody will blame you for bad crypto if you released software in [the 80s and early 90s].

So you are 100% agreeing with me.

Security expert Bruce Schneier expanded upon what I said back in 1998:

>Cryptographic algorithms have a way of degrading over time. It's a situation that most techies aren't used to: Compression algorithms don't compress less as the years go by, and sorting algorithms don't sort slower. But encryption algorithms get easier to break; something that sufficed three years ago might not today.

>Several things are going on. First, there's Moore's law. Computers are getting faster, better networked, and more plentiful... Cryptographic algorithms are all vulnerable to brute force--trying every possible encryption key, systematically searching for hash-function collisions, factoring the large composite number, and so forth--and brute force gets easier with time. A 56-bit key was long enough in the mid-1970s; today that can be pitifully small. In 1977, Martin Gardner wrote that 129-digit numbers would never be factored; in 1994, one was.

>Aside from brute force, cryptographic algorithms can be attacked with more subtle (and more powerful) techniques. In the early 1990s, the academic community discovered differential and linear cryptanalysis, and many symmetric encryption algorithms were broken. Similarly, the factoring community discovered the number-field sieve, which affected the security of public-key cryptosystems.

https://www.schneier.com/essays/archives/1998/05/the_crypto_...

The ironic thing is this article also said "I recommend SHA-1"... SHA-1 was broken 7 years later.

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