The DMZ

Simon

14:00

Makes sense lads, makes sense.

SEJPM

@MarkBuffalo "Q: Is there a somewhat reliable method to forecast security breaches before they are announced so I can act and don't have to react? Bonus: What steps can I take to ensure security of my data in case there actually is an unannounced breach?"

Mark Buffalo

@SEJPM Sure

silverpenguin

@diagprov I grew up here :( and @RоryMcCune That would be useful my hopeful new employer is giving me a test though to generate a report! (just have to wait until the tests can be given to me)

M'vy

@MarkBuffalo technically, the RSA signature uses the same process as encryption

Mark Buffalo

2

A: How does an attack on a digital signature work?

A digital signature, like all cryptographic algorithm, does not solve problems, it just moves them around. Take care that signatures are NOT encryption. If someone tried to explain signatures as a kind of encryption, then go find them and hit them in the teeth with a wrench, repeatedly. Tell the...

Simon

14:01

@SEJPM Let's not start a trend of bonus questions, please.

Rоry McCune

@silverpenguin well I'm guessing you'll be starting as a relatively junior consultant if you're coming from outside the industry, so hopefully they'll give you some leeway :)

SEJPM

@Simon I always did them :(

then @MarkBuffalo stole the idea from me

Thomas Pornin

@M'vy Hold on, I am fetching my wrench...

Simon

@ThomasPornin Did you already cap on big bear?

diagprov

RSA is a trapdoor permutation, meaning encryption and signatures can use the same operation. Most signature functions and public key functions are trapdoor functions, and not permutations.

SEJPM

14:02

@MarkBuffalo security.stackexchange.com/q/116396/71460

Thomas Pornin

@Simon Yes.

Simon

@ThomasPornin Jerk.

SEJPM

@diagprov the core primitive is mathematically the same for both. THAT'S IT!

Thomas Pornin

@Simon About 5 hours ago, so at 09:00 AM UTC (04:00 AM here, I was sleeping)

SEJPM

they even have different names in PKCS#1

diagprov

14:04

@SEJPM Yes, that's what I'm saying. For every other signature scheme it is not true.

SEJPM

@ThomasPornin are you still DROWNing in rep?

silverpenguin

@RоryMcCune Yup! well i would hope so but my pay is still fairly high and relative to my current pay because this firm wants a developer with a security mind set to pen test as well as consult on making applications secure for the clients (which is a smart move IMO, not alot of pen testers have a commercial development back ground, correct me if im wrong)

Simon

@ThomasPornin Sigh.

Thomas Pornin

@diagprov In fact even trapdoor permutations cannot really be used for both encryption and signatures; if you want to do it safely, you need to add extra things, which will be different for encryption and for signatures.

Rоry McCune

@silverpenguin yep that's a sensible approach. As to tester backgrounds, these days more will have a dev. background compared to the olden days when most came from more IT/network admin, but definitely not all testers do dev'y things...

diagprov

14:05

@ThomasPornin Sure. Perhaps I should have said "textbook RSA", which of course you don't want to be using as a deployed system.

M'vy

@ThomasPornin Well, RSA sig is using the exponent on the hash value, am I wrong ?

Thomas Pornin

A trapdoor permutation is hard to invert on average. To have a completely reversible encryption/signature system, you would need a trapdoor permutation that is hard to invert in all cases.

SEJPM

@M'vy ON A PADDED HASH VALUE

AviD

@silverpenguin a better move would be to train you up in security, and have you work on whitebox, not pentests.

Simon

@AviD You're a white box.

Matthew

14:06

@RоryMcCune I do dev-type things... And IR type things... And testing type things... And all sorts...

AviD

e.g. code reviews, design, architecture, etc. Much rarer, and more lucrative.

Thomas Pornin

@M'vy RSA signature is using the exponent on a padding hash value. RSA encryption does not use the same padding and does not operate on the hash value because there is no hash value.

And the corresponding private keys should have distinct life cycles anyway.

SEJPM

@ThomasPornin well, there are hashes in OAEP...

M'vy

@ThomasPornin yeah ofc. The mathematical part stays the same.

Thomas Pornin

@M'vy I would dispute that. Only the exponentiation part is similar; the rest of the maths is quite different (and harder).

AviD

14:08

@ThomasPornin "This flawed explanation does not work, never worked, and spreads only confusion." Do you have a better one? To actually explain the logic, even informally and inaccurately, to non-crypto types? E.g. developers. And avoid the maths of it.

Thomas Pornin

@AviD Do you explain encryption as "it's a signature, but taken in reverse" ?

diagprov

@ThomasPornin Really? Even for the textbook case? I'm not disputing this for any kind of actually deployed system; my understanding is that the misunderstanding really arises because people learn about RSA using the textbook format, and they learn about signatures using the textbook algorithm.

M'vy

Yeah, this view is very too much simplified to be true.

silverpenguin

@AviD in all honesty I hope not, I mean i dont mind doing it for a short while of course until i am trained but I really want to black box eventually. Though i will mainly be on just web applications for my start because of my developer background (mostly PHP, java, android etc)

diagprov

Specifically, what normally happens is a maths professor decides to introduce encryption as a "practical use of number theory"

AviD

14:10

@ThomasPornin pffft

Simon

@AviD get rekt son

AviD

@ThomasPornin so you're saying, dont explain it, not really - just treat as a magic black box - now lets talk about some of its properties?

Mark Buffalo

1

Q: Is it possible to detect security breaches as a user before they're announced?

I'm always concerned about the security of services I use. I'm even more concerned since security breaches have been happening more and more lately, and they always generate a lot of noise in the media. Now I'm already trying to secure my accounts to the maximal amount possible, like using 2FA w...

account-security

@SEJPM

AviD

actually - that could actually work

SEJPM

@MarkBuffalo I saw your answer

Mark Buffalo

14:12

I'm going to update it with your bonus question

SEJPM

However somebody else was first on another question and I want to read it before upvoting or accepting

AviD

I have used that explanation (like encryption but in reverse but not really) to explain what signatures arent. or rather used it to explain what is missing.

Mark Buffalo

@SEJPM don't accept. leave it for a while

someone may have a better method than me

AviD

but I agree that it is far too pervasive.

Thomas Pornin

@AviD You do it for encryption; why not do the same for signatures ? It's less confusing than trying to explain one with the other.

Simon

14:13

^ I was about to say that.

SEJPM

@MarkBuffalo I usually try to wait for 24h inactivity on a question before accepting anythiong

Simon

Encryption, hashing.

It's all magic!

AviD

you're not wrong.

^ least surprising statement of the week.

Thomas Pornin

@diagprov The fault is really from Rivest, Shamir and Adleman themselves.

Stu W

@diagprov CRT is one crest exam (sorry for late reply)

Matthew

14:14

@SEJPM Good policy

SEJPM

@ThomasPornin just blame the authors for bad explanations?

Thomas Pornin

They originally explained signatures with the "reversed encryption" analogy.

This was at a time when people had not caught up with the importance of padding, key life cycle, and randomness.

E.g. you really need randomness injected in public key encryption, but you usually prefer not to have some in signatures.

AviD

what I sometimes struggle with is explaining public keys. I have found a useful metaphor (or s it a simile?) but for encryption, doesnt work for signatures.

Simon

@ThomasPornin I don't agree with this, most women have been aware of padding for a long time.

(I'm sorry guys)

AviD

@ThomasPornin oh! really? thats where that comes from?

kalina

14:16

@Simon no you're not, you just keep spewing your offensive nonsense

I mean... hi

SEJPM

@ThomasPornin RSA-PSS signatures?

Thomas Pornin

When the flaws in basic RSA were found, it has been colloquially called "textbook RSA" to avoid pointing out that the semi-gods of crypto had blundered.

Rоry McCune

@Matthew yay for variety \o/

AviD

@ThomasPornin I will freely admit that is how I originally learned about it, even knowing it was inaccurate and leaving a lot of mathematical detail on the side. Still took me a while to get a better understanding of how that is wrong.

Thomas Pornin

But calling flawed RSA "textbook" is akin to stating: "we lie to students and we are proud of it".

silverpenguin

14:17

whats the standard rate for a JR pentest in the uk if anyone here knows? the jobs are impossible to find so i cant compare my dev wage to a pen tester (I am interested)

AviD

@ThomasPornin shouldnt that be "demigods"?

kalina

well students do get lied to

that's how creationism still gets taught

Thomas Pornin

@AviD Ah yes. Although Rivest is quite short.

kalina

@silverpenguin 18,000

AviD

@kalina and abstinence

silverpenguin

14:18

@kalina ouch really?

diagprov

@ThomasPornin Did they actually blunder though, or were such things just not known at that stage? I'm not particularly familiar with that period.

kalina

@silverpenguin the role has junior in it

AviD

@silverpenguin cant tell you there (but ignore @kalina, she doesnt know either), but I do know there is a massive difference between "UK" and "London".

diagprov

I just call it "textbook RSA" as the kind of RSA your maths professor is likely to present to you as a first-year undergrad. I.e. minus 40 years of cryptographic research in how to deploy these things successfully.

Thomas Pornin

@SEJPM RSA-PSS is defined with randomness but you can make it deterministic with derandomization, and this is often desirable (e.g. it helps a lot with unit tests).

kalina

14:19

@AviD who says I don't know

how rude

Matthew

@silverpenguin Varies a lot. Even within companies, based on experience, useful backgroun knowledge...

Rоry McCune

@silverpenguin no not really, I don't think (although I could be wrong) that @kalina works in that industry

AviD

@kalina yeah I shouldnt have said to ignore you, I meant just about that statement

apologies

kalina

@silverpenguin more like upto 30k outside london and "whatever you can con them out of" inside london

SEJPM

@ThomasPornin or you can plug a different PRNG in for those tests...

diagprov

14:20

@RоryMcCune In fairness, I was offered that by a Manchester-based firm. Exactly that.

kalina

but 18k is starters for most IT jobs in the UK

disclaimer: I'm on the wrong side of the gender pay gap so your wages will probably be higher

Matthew

@diagprov Really? Fresh out of uni?

silverpenguin

hmm interesting, I know the experience can rack up 6 figures, my first pen tester job as far as I am aware will be about 30k which is a bit sad but I dont mind taking a step back for my dream job T_T

Rоry McCune

@diagprov ... interesting

Thomas Pornin

@diagprov Well, most of the details were not known at that time; the problem really is in how later researchers endeavoured to make pedagogy with explanations that they knew didn't work.

SEJPM

14:22

@MarkBuffalo +1

probably will do

Rоry McCune

@silverpenguin from my knowledge of the industry if you want 6 figs you'd better be in London and pretty senior in pen. testing (TBH not sure I've seen that kind of level for delivery pen. testing, although then again I've not looked that much)

diagprov

@Matthew Nope. I don't have a degree (yet, it is ongoing). At the time I was a developer.

Stu W

@silverpenguin a lot more likely to get that if you are in pentesting sales

Rоry McCune

yeah good sales people can make a lot

diagprov

@ThomasPornin Ahhh OK, that's what I suspected.

Matthew

14:24

@diagprov Hmm, probably makes some sense then. I'd expect a graduate to be a bit higher, or someone with more experience

Rоry McCune

although it's all OTE and that lot

SEJPM

@MarkBuffalo do you actually use aliases / home hosted mail / external mail providers / VPS for the mail adresses?

Mark Buffalo

@SEJPM aliases / google / yahoo / personally-hosted domains

silverpenguin

@RоryMcCune well yea would have to be senior! thats years and years away I just cant wait to get into this industry, i know very little on pentesting in all fairness but thats only because im so busy I dont have the time. @StuW pentesting sales??

Rоry McCune

@silverpenguin people who sell customers testing services. Usually they'll be on commission so the more they sell, the more they make.. in a hot market this can generate a lot of money ... but then you have to do sales and spend your days travelling to client meetings

Matthew

14:26

@silverpenguin If you work for a large organisation, there will be a sales team looking for people to sell pen testing services to. They will earn lots if they are selling lots

diagprov

@Matthew I might have remotely considered it if it weren't for the fact it was a significant pay cut from my dev pay.

Rоry McCune

@silverpenguin if you want more data on salaries, here's some data points jobserve.com/gb/en/JobSearch.aspx?shid=078C2A51812590774F

Matthew

@diagprov Yeah, I went into interview with a lower bound on what would accept, and a requirement for pay review. Not always an option for everyone though

diagprov

@RоryMcCune Not your firm, though. They just said "you don't have a degree, so go away", but a bit more politely.

silverpenguin

meeting people! yea im used to that, my position at current means I always have to go and meet clients. I am a jack of all trades, small companies means more roles to fill! :<

Mark Buffalo

14:27

@SEJPM I added a butchered quote from Kung Fu Hustle as a comment

diagprov

Another Manchester based firm :)

Matthew

@diagprov Interesting...

silverpenguin

@diagprov manchester? brutal, come down south the weather is nice down here

Rоry McCune

@diagprov it amuses/disappoints me how hung up on degrees some companies get, given that my accountancy degree likely hasn't been that relevant in any job I've had in the last 20 years

silverpenguin

@diagprov p.s. I hate manchester airport and now i blame you for it >_>

Stu W

14:29

@silverpenguin also live in manchester and agree

Simon

@RоryMcCune Oh, you're an accountant? It complains the relationship with the other roro, you bank donuts.

Stu W

about the weather - though airport is fine

Rоry McCune

@Simon I have a degree in accountancy, but I'd like to think I've recovered :op

silverpenguin

@StuW I work with aircraft, imagine getting through security with tools... manchester didnt like me very much lol!

diagprov

@Matthew Yeah. I might have accepted a bit of a cut as I understand I'm not experienced with web-based pentests. On the other hand, I'm most experienced with Win32 Kernel driver dev and I refuse to believe that my knowledge of C and the like won't come in useful at some point.

@silverpenguin I'm not there any more. I moved to Switzerland :)

Stu W

14:30

@silverpenguin ah ok lol - thought they would have different procedures for maintenance crews with airside passes

diagprov

@Matthew South West Manchester specifically.

Stu W

@silverpenguin - how much do you know about the computer systems on planes then?

diagprov

i.e. outside the city centre.

silverpenguin

@StuW nah still have to go security like made and manchester is different in B'ham and luton .... not so different gatwick... and I know more than the average person :P but only about specific things

diagprov

and they recently sponsored a conference the Rories ~~invaded~~ went to.

silverpenguin

14:32

mad* not made

Stu W

@diagprov - the VA scanning shop?

Rоry McCune

@diagprov I know who you mean...

Stu W

@diagprov or the one in the town at the end of the tram line

diagprov

@RоryMcCune The amusing thing is my (in progress) degree is in Mathematics. Pretty sure that my getting it will not help in a web penetration test.

Stu W

@silverpenguin looks like an interesting research area. Think people have owned flight director / nav systems in the past

Rоry McCune

14:34

@diagprov no but it'd help in areas like crypto research and that's something many pentest companies could do with more knowledge of

Stu W

@diagprov I have a maths degree - the crypto side / group theory / number theory helped a little

kalina

.oO( do you think you're better off alone... )

Matthew

@StuW Mine is Computer Science and Mathematics

silverpenguin

@StuW you would find somethings about aircraft scary! but I have to install wireless IFE systems.. which means Its more about the planes communications rather than nav systems :P

kalina

@StuW nuuuuuuuuuuuuuuuuuuurrrdd

Stu W

14:37

@silverpenguin is funny when you get bored and start typing random key combinations into them to find out what makes them reboot / try to accidentally stumble on a service menu

diagprov

@StuW I've found that useful to explain crypto to people, but I've only ever done that as a kind of tech talk at a dev shop.

Stu W

@silverpenguin especially when you get talking to the passenger next to you and it turns out they have an interview at for the airline at their hub as an accountant

diagprov

@RоryMcCune Maybe one day :)

silverpenguin

@StuW haha yes :P what airline was this ? ;) it wouldnt have been one of mine i dont think! must of mine are on private jets (which is fun to fly on btw smug face )

Stu W

@kalina am currently reading a crypto textbook before bed each night so probably qualify as a nurd

@kalina one of the major middle eastern ones

silverpenguin

14:40

@StuW reading is effort, i tip my hat to you for being able to do that. i prefer learning through examples

diagprov

@StuW I'm not sure what the VA scanning shop is, so probably not them. They're outside the M60 in any case, not sure if they're on a tramline, it might have changed since I was there anyway.

@silverpenguin I guess you are in London then?

Stu W

@silverpenguin usually read through once and then read again and do the exercises

diagprov

@StuW Is there any reason to like Manchester airport? :)

silverpenguin

@diagprov not far off! little bit north of london

Rоry McCune

I like Glasgow airport

queues are always small and staff seem friendly

Simon

14:42

@RоryMcCune I've typed "complains" instead of "explains" wot

diagprov

@StuW Which one?

Stu W

@diagprov a company that do Nessus scans with loads of custom plugins rather than actual pentesting

@diagprov manchester airport has always been better than CDG or heathrow T4 for me

though not sure what makes a good airport

diagprov

@StuW Sorry I meant crypto textbook. I'm not sure if the place I went do that, I don't think they do, as I did a test of a vulnerable app for the interview.

silverpenguin

@StuW dont even mention nessus... I cant get it working on my kali lol!! its so frustrating :< a good airport is where security does not take ages, you dont feel personally insulted and dont come out walking funny

Stu W

@diagprov amazon.co.uk/Introduction-Cryptography-Edition-Chapman-Security/… - was a textbook for one of my uni courses ( or the older version was)

diagprov

14:44

@StuW ah, good choice.

Stu W

@silverpenguin - try the appliance vm

diagprov

btw:

Simon

While we're getting evaded by the Brits in the chat, I'd like to remind everyone that the canonical timezone is EST.

diagprov

Yehuda Lindell, Israel

5.5k 5 21

encryption hash provable-security public-key multiparty-computation aes authenticated-encryption

The author of that textbook is on crypto.se :)

Mark Buffalo

I like that name

Yehuda. That's awesome

Xander

14:45

@Simon Why are they evading you? Besides the obvious, of course.

Stu W

@diagprov is a pretty decent book - though I think handbook of applied cryptography is free to download now too. Just stuck with that as I have already gone through some of it

silverpenguin

@StuW its the registration for the free version, i just can never do it, it asks me for two bits of information one bit that i do not have. I will have to try the VM you suggests...

#britsAreAwesome

Stu W

@silverpenguin VM is paid for by my employer so not sure if it is common

Simon

@Xander Because they want my donuts.

Thomas Pornin

@StuW Handbook of Applied Crypto is really good, but it is beginning to get a bit old. It is not up to date with the last 15 years or so.

diagprov

14:47

Exactly.

Mark Buffalo

@ThomasPornin Have you written a book on Cryptography? I would buy it.

Thomas Pornin

@MarkBuffalo No, not on cryptography.

Mark Buffalo

@ThomasPornin On what, then? 1000 ways to maul a man?

diagprov

but you can read about how to choose a programming language :)

silverpenguin

@StuW jedi mind trick ...cough...cough...

Thomas Pornin

14:48

@diagprov I am not sure it is still available though.

diagprov

@ThomasPornin amazon.fr/Comment-choisir-langage-programmation-Thomas/dp/…

Mark Buffalo

okay, searching for books written by @ThomasPornin on amazon was a mistake... NSFW

I don't know what I was expecting.

Stu W

@ThomasPornin true - though for basic beginner stuff if you don't want to buy or torrent a book it probably isn't a bad choice. (Like learning about block / stream ciphers and different modes and Kerckhoffs's principle)

Xander

@diagprov Except for the fact that he spelled all of the words wrong, so it's incomprehensible.

Mark Buffalo

@ThomasPornin You should write a book on crypto

Thomas Pornin

14:50

Mmh, writing a book...

diagprov

@Xander I haven't brought it (sorry @ThomasPornin) but I'd be able to read it :)

Thomas Pornin

@diagprov I don't even cash in the yearly check for royalties. It is too much effort from about 40 EUR.

silverpenguin

hey speaking about crypography... how possible do you think it would be to make a small bios system stored on flash nand which actually was just there to decrypt a bigger bios which would then function as normal with hardware decryption keys for an embedded SSD technology ?

diagprov

@ThomasPornin :(

Can you cash Euro cheques (Brit spelling, sorry) in Canada anyway, or would you lose it all in international fees?

Mark Buffalo

@ThomasPornin If you wrote a crypto book, I could steal your secrets... plus you might get a lot more in royalties... actually, just self-publish

Simon

14:54

@ThomasPornin Hey docteur en informatique, my PC is ill, can you cure it?

Thomas Pornin

@Simon I cure PC like I cure werewolves: I shoot them.

3

Simon

jeezus

diagprov

@Simon Lol. He only went to "normal school", how did he end up so clever :P

kalina

@StuW you read a crypto book to sleep?

M'vy

@Simon old joke is old

kalina

14:55

what, like JRR Tolkien?

Simon

@diagprov Normal superior though!

Thomas Pornin

@diagprov I think it is doable, but it would require taking the time to do so, and I value my time immensely.

Simon

@M'vy I've never heard it.

kalina

his work is very wordy and cryptic

M'vy

BTW if I order the book right now, I could read it tomorrow. Wow

@Simon Obviously you're no docteur en informatique then

diagprov

14:56

@ThomasPornin Yep. I can't cash sterling cheques here - in fact there are no cheques/checks in Switzerland at all. It's far too much effort to cash any form of cheque now.

kalina

RELEASE THE MOD SWARM

M'vy

That is like, THE overused joke for that. And I guess a lot of other Ph.D fields, when applicable.

Simon

@M'vy I did not want to spend 7 more years doing "superior" studies, yeah.

M'vy

@kalina Kalina Jones ?

Mark Buffalo

@Simon You're a superior study.

diagprov

14:57

@M'vy I know :) Still amusing though ;)

kalina

@M'vy non

Rоry McCune

@kalina something got flegged?

kalina

@RоryMcCune u

i fleg u

Rоry McCune

@kalina noooooooooooooooooooooooooooooo.

M'vy

@diagprov depends on which side of the joke you are I guess

Simon

14:59

@M'vy Oh you poor Dr. Yves.

diagprov

@M'vy ENS is one of the best universities in the world, so I guess if you went there or go there, the joke is not on you :)

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