Top products from r/cryptography

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u/RSAnal · 2 pointsr/cryptography

Most modern ciphers don't really use math in the same way as the day of old (at least when you're talking about private key encryption) and the math of public key encryption (at least for starters) is pretty basic. Some elementary number theory concepts which you've likely learned in discrete math should be enough to understand a treatment of RSA that doesn't spend too much time talking about abstract algebra.

In terms of a way forward a lot of this depends on what stuff you really want to do. Designing new crypto is extremely tough and is heavily scrutinized and implementing it is no different. If you want to honestly try and design something usable you definitely need a background in theoretical crypto and I highly recommend the book Introduction to Modern Cryptography. https://www.amazon.com/Introduction-Modern-Cryptography-Principles-Protocols/dp/1584885513 There's a newer edition but I can't speak to the differences. This book is an excellent read for anyone interested in the art of Cryptographic proof.

If you are interested in the more implementation/security route of things taking a course on Computer Security is helpful although I'm not sure if this is what you're really interested in. I personaly was much more into pure Crypto until I started studying actual Security concepts and now I love both. There's something super satisfying about understanding buffer overflows and pretty much everything else in security enough to actually execute an attack. DISCLAIMER Don't attack a system you don't have permission to attack. It's illegal, you will get caught, and it won't be worth it. If you want to practice actual hacking in a legal way look into OWASP.

u/dionyziz · 5 pointsr/cryptography

The 'puzzle solving' enjoyment will come mostly from the theoretical cryptography stuff, in my experience. Even though it is a hard book to understand, I recommend that you take a look at Introduction to modern cryptography, perhaps the first couple of chapters. It is fascinating and deals with the fundamental, hard challenges of designing cryptographic systems to be provably secure. Every time you understand a difficult concept, it is very rewarding. Good luck! :)

u/wadcann · 3 pointsr/cryptography

This does not make sense to me.

> The Public keys will be base 36 numbers ranging from 00000 (0) to ZZZZZ (60,466,176).

As nsa_at_home points out, the key representation normally has nothing to do with the actual key. Cryptographers will represent things in binary as a convenient standard; you'd say "I want a key with at least 23.5 bits of entropy", say. It's very, very easy to represent a key with N bits of entropy in any form you want, which sounds to be your goal; in this case, you'd take a number in base 2 and just convert it to a number in base 36.

For most purposes, your keyspace is not large enough. Say encryption has a cost of N. That means that brute-forcing your entire keyspace only costs about 60 million times that much. If you want a signing operation to be reasonable on a computer, you probably can't blow more than, oh, say, let's say a second on it for most applications that I can think of. If I'm willing to brute force for a day, I've already covered 1/700th of the keyspace. If I get 700 computers, I've broken your encryption.

Your key has ~25.8 bits of entropy. ln(36\^5)/ln(2). A typical RSA pubkey in practical use today might have a key length of 2048 bits, to give you an idea of what you might want to shoot for.

> The Private Keys need to be originally derived from the public keys mathematically (or Vice Versa)

This makes no sense. The point of public/private key encryption is that the person who has the public key cannot derive the private key; this property means that you can give out the public key without needing to worry about anyone using the public key being able to decode messages others have encoded and sent to use using the public key.

If you don't care about this property, you would be using symmetric encryption, not pub/privkey encryption.

> The Private Keys need to be completely different yet within the same number range (0 - 60466176) without being guessable (ex: very complicated and possibly irreversible).

Now I'm really lost. A key isn't "reversible"; a process is. You can't run a key backwards; it's just a number.

The only other pieces of information out there that it might be deducible from would be the pubkey (and you've already specified that you want the privkey to be derivable from the pubkey, which doesn't make sense either, so that's already reversible) and a known-plaintext attack on the ciphertext (and as I point out above, for most practical uses, your mandated key length is so short that it probably is derivable from the ciphertext for most practical applications).

  • If you want a practical solution here, you don't want to invent a new pubkey system. That is incredibly difficult; it's taken years and many many people hammering on various crypto systems (and breaking some of them) to get us to where we are now. You want to build something with existing pubkey systems. You might want to explain what your practical goals are, because the requirements of the thing specified just don't make sense for any real-world system.

  • If you want to learn about crypto, and want to do a pubkey system as a form of practice, you are probably going to be better off reading your way through existing material than trying to learn by doing things from scratch. Honestly. I'd recommend reading and comfortably understanding Applied Cryptography to at least have a reasonable understanding of the issues that you're going to deal with. I have not read it, but I know enough people who do know what they're talking about who recommend it that it'd be my go-to recommendation. I think that you may be dramatically underestimating the scope of work that goes into developing basic crypto tools like pubkey systems.
u/an-anarchist · 5 pointsr/cryptography

Yes and no. If you're asking these questions you'll probably be very interested in Claude Shannon's work. Take a read of his seminal information theory paper: http://cm.bell-labs.com/cm/ms/what/shannonday/shannon1948.pdf

For an easy read and a fun intro take a look at "The Information: A History, A Theory, A Flood":
https://www.amazon.com/Information-History-Theory-Flood/dp/1400096235/

u/perror · 1 pointr/cryptography

I really love 'Cryptography: Theory and Practice (3rd)' by Douglas Stinson. For me, this is one of the best introduction to the mathematical part of the cryptography.

u/NicknameAvailable · 1 pointr/cryptography

I highly recomment Practical Cryptography - I heard there's a newer version out from the author but I haven't read that one personally, it's probably worth checking into. It's a great book for beginners, it goes over mostly methodologies and implementation, a bit of the math too.

u/Disinterpreter · 1 pointr/cryptography

Ok, it's good a question. I loved cryptography learned bitcoin. But i recommended this book!
And if you suck at math i recommended write a code with existing crypto-libs (on python,go,cpp etc....)

u/IkePAnderson · 1 pointr/cryptography

I haven't read it before, but from the Amazon and Goodreads reviews, it looks like more of a history book with some intro to cod breaking math.

Textbooks and/or technical papers/tutorials would probably be a more useful intro to code breaking.

u/T_911 · 2 pointsr/cryptography

I'm currently undertaking cryptography as a unit and I'm using this book:
http://www.amazon.com/Introduction-Cryptography-Coding-Theory-2nd/dp/0131862391
It starts at the start of encrypting with caesar ciphers and goes through DES and AES in a considerable amount of depth.
By all means it isn't for the faint hearted, but you're interested enough the book will help a lot.

u/alreadywinstonsmith · 1 pointr/cryptography

Anyone here interested in trying to solve this riddle? It's from a comic called Wild Embers about a team of hackers who do parkour and are solving an internet puzzle. Check it out.

The comic is here: https://www.amazon.com/dp/B07VVTBZXD?ref_=pe_3052080_276849420

The challenge is on Instagram @emusheret6

u/ddnomad · 1 pointr/cryptography

Thanks for your advice! As for know I'm going to look at Princeton textbook.

I came across this book. It claims to go deep into how the Blockchain works. What do you think about it? Is it any good?

u/ddp · 3 pointsr/cryptography

Applied Cryptography is considered one of the best introductions.

u/tufty_thesinger · 1 pointr/cryptography

Read: Applied Cryptography by Bruce Schneier. Goes through implementation and attack details on several older algorithms, as well as all sorts of cool applications. It's an older book, but the older algorithms are easier to understand and start with.

u/user908aa · 1 pointr/cryptography

Suggest to combine such protocols like it is described here

https://twitter.com/GoldBugIM/status/1196333988186603521

The Crypto Protocols are SSH Protocol (SFTP), Echo Protocol and using NETCAT and Cat.

This would be much original work as they haven not been analyzed in regard of #interoperability.

There is also an authenticaed key exchange based on Cryptographic Calling or based on EPKS:

Read here: https://www.amazon.com/Nomenclatura-Encyclopedia-Cryptography-Internet-Security/dp/3746066689

Kerberos is sooo oldfashioned.

u/MyEncryptedAccount · 5 pointsr/cryptography

An accessible undergraduate textbook that I have used and enjoy is Introduction to Cryptography with Coding Theory. That being said, I have not looked at many others.

A much more technical (but formally correct) textbook is Introduction to Modern Cryptography by Katz and Lindell.

On a side note, cryptography is a very mathematical field. So take as many math courses as you can. Number theory and algebra in particular.

u/pxdnr · 2 pointsr/cryptography

There are quite a few different types of cryptographic algorithms, some requiring more mathematics to get started than others. But it seems like you might be interested in block ciphers or stream ciphers.

/u/remyroy recommended rotation ciphers, which are probably the simplest and easiest to break.

The NSA has recently produced simple, but important, ciphers: Simon and Speck; release document and Bruce Schneier's comment. It will be difficult to break these ciphers, but at least this might lead you on a path to try to understand what it means to break a cipher.

If you want more information on block ciphers and how to break them, there's The Block Cipher Companion and I found this tutorial on differential and linear cryptanalysis which might provide a gentle introduction, but I haven't read it.

Anyway, have fun.

u/[deleted] · 2 pointsr/cryptography

http://www.amazon.com/Introduction-Modern-Cryptography-Principles-Protocols/dp/1584885513 is what I used in class. It goes deep. It may not be super easy to understand if you just jump around, as it has a lot of proofs and the book builds upon existing information as you go. But if you hammer concepts into your head and don't move on until you understand why things are the way the way they are explained, then you will be very, very competent at the subject.

u/agrajag9 · 5 pointsr/cryptography

"The Code Book" by Simon Singh was what got me into crypto at an early age and now I'm work in a field where I'm hands on with crypto algorithms and equipment on a nearly daily basis.