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[johnls7424]

Moderator can we close this thread

 

[ElroyJetson]

OKAY, one more time, for the benefit of those mathematically challenged of you who think it might in some way be practical to brute force AES-256 encryption by some means such as modified ASICs of the same general principle as Bitcoin miners:

This isn't mine. I'm just quoting it from Reddit.

I did a report on encryption a while ago, and I thought I'd post a bit of it here as it's quite mind-boggling.

AES-256 is the standardized encryption specification. It's used worldwide by everyone from corporations to the US government. It's largest key size is 256 bits. This means that the key, the thing that turns encrypted data into unencrypted data, is string of 256 1s or 0s.

With each character having two possibilities (1 or 0), there are 2256 possible combinations. Typically, only 50% of these need to be exhausted to yield the correct key, so only 2255 need to be guessed. How long would it take to flip through each of the possible keys?

When doing mundane, repetitive calculations (such as brute-forcing or bitcoin mining), the GPU is better suited than the CPU. A high-end GPU can typically do about 2 billion calculations per second (2 gigaflops). So, we'll use GPUs.

Say you had a billion of these, all hooked together in a massively parallel computer system. Together, they could perform at 2e18 flops, or

2 000 000 000 000 000 000 keys per second (2 quintillion)

1 billion gpus @ 2 gigaflops each (2 billion flops)

Since there are 31 556 952 seconds in a year, we can multiply by that to get the keys per year.

*31 556 952
=6.3113904e25 keys per year (~10 septillion, 10 yottaflops)

Now we divide 2255 combinations by 6.3113904e25 keys per year:

2^255 / 6.3113904e25

=9.1732631e50 years

The universe itself only existed for 14 billion (1.4e10) years. It would take ~6.7e40 times longer than the age of the universe to exhaust half of the keyspace of a AES-256 key.

On top of this, there is an energy limitation. The The Landauer limit is a theoretical limit of energy consumption of a computation. It holds that on a system that is logically irreversible (bits do not reset themselves back to 0 from 1), a change in the value of a bit requires an entropy increase according to kTln2, where k is the Boltzmann constant, T is the temperature of the circuit in kelvins and ln2 is the natural log(2).

Lets try our experiment while considering power.

most high-end GPUs take around 150 watts of energy to power themselves at full load. This doesn't include cooling systems.

150 000 000 000 watts (150 gigawatts)

1 billion gpus @ 150 watts

1.5e11 watts

This is enough power to power 50 million american households.

The largest nuclear power reactors (Kashiwazaki-Kariwa) generate about 1 gigawatt of energy.

1.5e11 watts / 1 gigawatt = 150

Therefore, 1 billion GPUs would require 150 nuclear power plant reactors to constantly power them, and it would still take longer than the age of the universe to exhaust half of a AES-256 keyspace.

1 billion GPUs is kind of unrealistic. How about a supercomputer?

The Tianhe-2 Supercomputer is the world's fastest supercomputer located at Sun Yat-sen University, Guangzhou, China. It clocks in at around 34 petaflops.

Tianhe-2 Supercomputer @ 33.86 petaflops (quadrillion flops)

=33 860 000 000 000 000 keys per second (33.86 quadrilion)

3.386e16 * 31556952 seconds in a year

2255 possible keys

2^255 / 1.0685184e24

=1.0685184e24 keys per year (~1 septillion, 1 yottaflop)

=5.4183479e52 years

That's just for 1 machine. Reducing the time by just one power would require 10 more basketball court-sized supercomputers. To reduce the time by x power, we would require 10x basketball court-sized supercomputers. It would take 1038 Tianhe-2 Supercomputers running for the entirety of the existence of everything to exhaust half of the keyspace of a AES-256 key.

Edit: corrections on my grade 12 math.

This article does not cover such things as potential backdoors and theoretical algorithm exploits or simply getting access to the key sequence you need.

Quantum computing may offer some substantial encryption breaking potential. But that is truly an infancy stage technology.

 

[K5MPH]

Here we go again,wait i got to go find my Hat........

 

[RayAir]

Your friend wouldn't happen to go by the name of cowthief, would he?
prcguy

Yeah, he said you just look at the sine wave (instead of pt xor ct) and then use a "musty dusty" 486 to run the computations for the kp attack.
He went on to say that is how people have been breaking ProVoice and P25 VS for years.

Noticed he was banned off that site for nonsense like this.

On another note, a known key function would be nice on a receiver. AOR already has this for NXDN 15-bit digital scrambling. RC4 could be implemented with about 10 lines of C code. But then again, a real radio IS already a "known key" receiver.

What I would really like DSD+ to do, is not to have any known key functions, but I would like it to display the AMBE data frames to show what is going on.


Merry Christmas.

 

[CapStar362]

I think he's only 14 or 15, so cut him some slack.

We all had to learn.

14 or not, granted he is asking questions, but his original presentations brings him about as a troll.


like the OP of this topic:

Hello. So I was informed by a friend (whom I don't want to mention) is working with a company to make a trunked radio, that decrypts the encrypted. Yeah, sounds a bit far fetched. From the encryption being 4 characters to 256.. Sounds pretty far fetched. But.. He is working on it. I don't have many details to share. Its first going to be for motorola trunked systems.. Thought I'd share.


he cant share the name of this person ( probably not a person anyways ) and then says he sells illegal radios for certain bands and usages to BSA without even checking or having an ADULT who is certified in the area of radio communications checking it for him first.

sorry, but 14 or not, there are better ways to present yourself as asking questions first and not a bragging rights kid.