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scottp99

join:2010-12-11

1 edit

File Encryption AES-128 versus AES-256?

I have this file encryption wizard software which is certified by the US Air Force Research Laboratory. So my question is, is (AES-128/SHA-256 Hashing) good enough for storing financial records and credit card info in this encryption Data at Rest (DAR) software tool? According to the page link below, it says AES-128 with SHA-256 Hashing.

I know that AES-256 would be better, but is there a huge difference? Sorry, Im rusty in this encryption stuff...
»spi.dod.mil/ewizard.htm

I would go for the enterprise tools instead, but those have remote admin "backdoors"

Thanks.



nwrickert
sand groper
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What are you protecting?

If this is something like ordinary household records that probably won't leak anyway, then 128 bits is probably enough to deter anyone who stumbles upon the records.

If you are a known keeper of valuable records, and a potential attack target, then better play it safe and go with 256 bits.
--
AT&T Uverse; Zyxel NBG334W router (behind the 2wire gateway); openSuSE 12.3 RC1; firefox 18.0.1


scottp99

join:2010-12-11

Would it be safe to say that Truecrypt would be far much better?



Snowy
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said by scottp99:

Would it be safe to say that Truecrypt would be far much better?

If you don't mind paying for the additional strength, particularly if you fall within nwrickert See Profile's description of
"If you are a known keeper of valuable records, and a potential attack target, then better play it safe and go with 256 bits."
then yes, it would be safe to say Truecrypt would be far much better.
Otherwise the cost of the additional encryption strength isn't justified, IMO.


Ian
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join:2002-06-18
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reply to scottp99

While there are theoretical attacks on AES128, there have been none that are in any way currently practical. Assuming someone with the resources of the NSA wanted to look at your stuff, it will still take them Trillions of centuries to work on that (and little else).
--
“Any claim that the root of a problem is simple should be treated the same as a claim that the root of a problem is Bigfoot. Simplicity and Bigfoot are found in the real world with about the same frequency.” – David Wong


scottp99

join:2010-12-11

If AES-128 is so insecure than AES-256, then why is it approved by the US Air Force as decribed the link I posted?

Dont understand.



Ian
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said by scottp99:

If AES-128 is so insecure than AES-256, then why is it approved by the US Air Force as decribed the link I posted?

Dont understand.

I don't understand what you're saying. No. AES-128 is NOT considered insecure. Far from it.

The best published attacks take the relative security down by 2 bits, or say AES-126. Still not practical to attack, even with a global cluster of supercomputers.

As for standards? It's possible that a military would require far stronger encryption than what is currently strong. They might have an interest in keeping their secrets safe 20, 30, 50 years into the future.
--
“Any claim that the root of a problem is simple should be treated the same as a claim that the root of a problem is Bigfoot. Simplicity and Bigfoot are found in the real world with about the same frequency.” – David Wong


Ian
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reply to scottp99

Incidentally, if you are looking to encrypt your files, I do also recommend setting yourself up a Truecrypt container or drive, or this for file level »www.axantum.com/axcrypt/. Both free (and open source).


scottp99

join:2010-12-11

1 edit

Does TrueCrypt support AES-256 or only AES-128?

Well, I thought the lower the number of bits or whatever, (sorry, Idont know enough about crypto), than I though that it would be less secure. For example, I thought AES-128 is far less secure than using AES-256.

So basically, my understanding was that the lower the number like (128) than its less secure than a higher number like (256)?

Expand your moderator at work

scottp99

join:2010-12-11

Re: File Encryption AES-128 versus AES-256?

Well, I thought the lower the number of bits or whatever, (sorry, I dont know enough about crypto), than I thought that it would be less secure. For example, I thought AES-128 is far less secure than using AES-256.

So basically, my understanding was that the lower the number like (128) than its less secure than a higher number like (256)?

Trust me, I am doing more studying regarding crypto technology. But I am kind of "rusty" at it now.

Sorry, But I just thought this would be the right place to ask this here since I know there are many experts on here.

Thanks.



nwrickert
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said by scottp99:

So basically, my understanding was that the lower the number like (128) than its less secure than a higher number like (256)?

This is correct. However, the 128 bit encryption might still be adequate.

Where I have a choice, I choose AES-256. But if I am using software that only supports AES-128, I won't be sweating it.
--
AT&T Uverse; Zyxel NBG334W router (behind the 2wire gateway); openSuSE 12.3 RC1; firefox 18.0.1

scottp99

join:2010-12-11

Thanks so much to all.
Sorry, but I want to learn this stuff. But limping along.

And does TrueCrypt support AES-256?
Because Im using TrueCrypt now as we speak to encrypt a volume or file, and when its mounted, it just shows AES encryption type but I dont know if its 128 or 256?



Ian
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said by scottp99:

And does TrueCrypt support AES-256?

»www.truecrypt.org/docs/


Anav
Sarcastic Llama? Naw, Just Acerbic
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reply to scottp99

What version of truecrypt are you running.


SoLostNow

join:2013-02-07
Haltom City, TX
reply to scottp99

From Wikipedia:

"The key size used for an AES cipher specifies the number of repetitions of transformation rounds that convert the input, called the plaintext, into the final output, called the ciphertext. The number of cycles of repetition are as follows:

10 cycles of repetition for 128-bit keys.
12 cycles of repetition for 192-bit keys.
14 cycles of repetition for 256-bit keys."

A 128-bit key is considered computationally secure against a brute force attack from any technology currently in the public domain. On a practical note, no one will attack the cipher or the keys unless there is a known implementation weakness in an encryption program. If you use a mature, open source program like TrueCrypt, your data will be as safe as your password is strong.


scottp99

join:2010-12-11

SoLostNow - thanks for this brief explaination.
Im using the latest TrueCrypt version.

But would this be also fine for sensitive files like my projects, banking records if I use this one here?
»spi.dod.mil/ewizard.htm

If its approved by the DoD or the Air Force I guess its better than nothing. And I am refering to the Public version which anyone can get there for free.



Ian
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3 recommendations

said by scottp99:

But would this be also fine for sensitive files like my projects, banking records if I use this one here?
»spi.dod.mil/ewizard.htm

I don't think anybody here can properly evaluate your security needs remotely. If you're doing something banking-wise or project-wise that you think might attract the attention of a 3-letter US agency like the NSA, or perhaps a foreign power like Russia or China, perhaps budgeting a bit for a security professional would be a smart investment?


--
“Any claim that the root of a problem is simple should be treated the same as a claim that the root of a problem is Bigfoot. Simplicity and Bigfoot are found in the real world with about the same frequency.” – David Wong

HELLFIRE
Premium
join:2009-11-25
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reply to scottp99

A non Wiki link for why you want longer keys; no related to encryption, but still a good general read.

Last paragraph is probably most relevant to your question about 128 vs 256 bits.

quote:
Having longer symmetric keys will increase security at a performance cost (more or less depending on the algorithm selected). All depends on how paranoid we are and the options that the VPN service provider gives to us.
Ian's xkcd post is pretty relevant as well. The strongest encryption in the world doesn't beat torturing / wheedling / sneaking / etc.
the password out of a user.

Regards


dslcreature
Premium
join:2010-07-10
Seattle, WA
reply to scottp99

Broken algorithms such as MD5 are still perfectly useful in certain configurations while perfectly secure hash algorithms are useless when abused to protect low entropy information such as credit card numbers.

Almost never is crypto attacked. Instead misuse of crypto and or misplaced trust is leveraged to defeat the system.

Some questions I would think about instead...

What do you trust?
Where are keys stored?
How are they protected?
Are all systems handling decryption and decrypted data secure?


scottp99

join:2010-12-11

Lets put it this way, does not matter what encryption program is in use to encrypt a file or whatever crypto one is using, if someone has a keylogger installed, then your screwed anyways.

So its best to scan the system even before encrypting files.


scottp99

join:2010-12-11
reply to dslcreature

As a matter of fact, no one really knows who is the creator of TC really is. I heard its some teams from the Czech Republic or something. That makes me even more nervous about using TC in the first place


OZO
Premium
join:2003-01-17
kudos:2

Let me guess, Al Gore, may be? Oh, wait, ism't that some team from Czech Republic?

No, of course you can't trust them. Even if they say it's open source project and you can see that source code with your own eyes. Better use a proprietary closed solution without (as you mentioned in your first post) remote backdoor... Go for it. It's much better then TC.
--
Keep it simple, it'll become complex by itself...


scottp99

join:2010-12-11
reply to dslcreature

I also noticed something in the TrueCrypt Volume file container properties of a Block Size being 128-bits. And I see two encryption keys being of 256 as (Primary and Secondary) using AES.

So my question is, is my encryption file container using AES-128 or AES-256?

Im sorry, But I will have to read up more about encryption technologies. Sorry for the added questions here.

Thanks in advance.


Ian
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join:2002-06-18
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From the previously posted Trucrypt documentation link.

"TrueCrypt uses AES with 14 rounds and a 256-bit key (i.e., AES-256, published in 2001) operating in XTS mode (see the section Modes of Operation)."

Block size for AES is 128 bits, regardless of the key size. It's in the specification.
--
“Any claim that the root of a problem is simple should be treated the same as a claim that the root of a problem is Bigfoot. Simplicity and Bigfoot are found in the real world with about the same frequency.” – David Wong



Link Logger
Premium,MVM
join:2001-03-29
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reply to scottp99

Different levels of security for different things, for example NSA Suite B »en.wikipedia.org/wiki/NSA_Suite_···tography and then NSA Suite A »en.wikipedia.org/wiki/NSA_Suite_···tography, but of course you can render even the most secure of encryption useless with sloppy key handling or a chocolate bar

Blake
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Vendor: Author of Link Logger which is a traffic analysis and firewall logging tool