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Encryption algorithm solved.

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SHA1 is a hashing and not an encryption algorithm.

The impact of this collision attack is mainly forging file signatures, and it cannot be applied as a network attack to modify or inject traffic into VPN sessions.

HMAC-SHA1 is not vulnerable to this as well.

Occasional moderator, sometimes BOFH. Opinions are my own, except when my wife disagrees.

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As Zhang said, There is no problem. For those who do not already know, HMAC is a hash applied to the SHA1 hash. And it is done for each and every packet. Your system, even on a slow dial up modem uses a packet for every 1500 bytes or so. So in order to defeat HMAC-SHA1 you would have to not only break it in milliseconds, but also defy the laws of physics to get your fake packet there before the real one.


And let us see how long it takes a whole array of supercomputers to break SHA1 alone?


Here is the important part to note.

  • Nine quintillion (9,223,372,036,854,775,808) SHA1 computations in total
  • 6,500 years of CPU computation to complete the attack first phase
  • 110 years of GPU computation to complete the second phase

That is to do JUST ONE SINGLE hash. Not to break every hash SHA1 can do. That is one. And this absolutely cannot be done before the relevant packet is done and gone forever.


You are safe. Relax.

Debugging is at least twice as hard as writing the program in the first place.

So if you write your code as clever as you can possibly make it, then by definition you are not smart enough to debug it.

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To be fair, more security would not hurt anyone (I think?) 


Reading up on it, this was Google's push to get websites away from SHA1


We probably have no reason for concern but...


*tin foil hat on*

What Google can do, the NSA might be able to do better

*tin foil hat off* 

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the following paper is extremely important, because provides mathematical proof that HMAC is a PRF under the sole assumption that the compression function is a PRF. As long as the assumption holds true, as it is until now, after 10 years the paper was written, there is really no reasonable argumentation to grade "security" of HMAC SHA2 over HMAC SHA1. Or even HMAC MD5!


Kind regards

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Papers are long. Reddit does it shorter.

Four simple things:
There's a guide to AirVPN. Before you ask questions, take 30 minutes of your time to go through it.

Amazon IPs are not dangerous here. It's the fallback DNS.
Running TOR exits is discouraged. They're subject to restrictions on the internet and harm all AirVPN users.

Furthermore, I propose that your paranoia is to be destroyed. If you overdo privacy, you'll be unique among the mass again.


XMPP: gigan3rd@xmpp.airvpn.org or join our lounge@conference.xmpp.airvpn.org

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