Ciphers

If you have to send a quick secret message to one of your friends, but you don't have time to make up a clever code, check out some of the ciphers that are already on the Net. While they aren't exactly a secret, some of them certainly are clever. Maybe you will get lucky and pick one that nobody has read about.


Web:

http://home.ecn.ab.ca/~jsavard/crypto/ppen01.htm
http://www.codebreaker.dids.com/


Crypto Bibliography

There is a ton of cryptography information on the Internet. However, if for some reason you can't find everything you need to know from the Net, check out this bibliography of books about cryptology and cryptography. It is bound to get you going in the right direction.


Web:

http://liinwww.ira.uka.de/bibliography/Theory/crypto.se...
http://www.counterpane.com/biblio.html


Cryptographic Research

To be a cool cryptomaniac, you don't have to sit around in isolation planning new codes and trying to break old ones. No, you too can belong to a club of people just like you. (But remember what Groucho Marx once said, "I don't care to belong to any club that will have me as a member.")


Web:

http://www.iacr.org/~iacr/


Cryptography Archive

Here is a well-organized, compact collection of cryptography resources from around the Net. If you are at all serious about cryptography, you will want to put this site on your bookmark list. If you are not serious about cryptography, put this site on your list anyway. It's bound to impress your friends.


Web:

http://www.austinlinks.com/Crypto/


Cryptography Basics

Cryptography, the science of creating and breaking codes, is an ancient art. Modern cryptography is fascinating, but it can be very complex. To help you get started, here are some resources that will explain the basics. Start today with the ideas of plaintext, ciphertext and keys, and it won't be long before you are waxing eloquently on basic cryptographic algorithms, digital signatures, hash functions, random number generators, DES and advanced cryptanalysis. Eventually, no one will understand what you are talking about, but at least you will understand why.


Web:

http://www.ciphersbyritter.com/LEARNING.HTM
http://www.home.earthlink.net/~mylnir/crypt.intro.html
http://www.ssh.com/tech/crypto/intro.cfm


Cryptography FAQs

Cryptography is a fascinating pastime, and it's not difficult to spend many hours immersed in learning about codes. Before you spend too much time, however, take a few minutes and look at these FAQs (frequently asked question lists). Chances are most of your initial questions will be answered. Personally, I found reading these FAQs interesting and I bet you will too (especially if you know some math).


Web:

http://www.faqs.org/faqs/cryptography-faq/
http://www.rsasecurity.com/rsalabs/faq/


Cryptography Policy Issues

Cryptography is more than deciphering secret writing. There are also the political and administrative aspects. Here are some sites that consider cryptography from a political and legislative angle. Read about policies, legislative efforts, cryptography across international boundaries, and much more.


Web:

http://www.cdt.org/crypto/
http://www.eff.org/pub/Privacy/Crypto/Crypto_export/

Usenet:

Google Newsreader talk.politics.crypto


Cryptography Resources

One of the nice things about cryptography is that it will allow you to store copies of all your love notes on your computer at work and you don't have to worry about your colleagues reading anything that might embarrass you or perhaps cause you to lose a presidential election. Find out about other great uses for cryptography at these Web sites.


Web:

http://world.std.com/~franl/crypto/
http://www.cryptography.com/resources/
http://www.cryptome.org/
http://www.philzimmermann.com/bibliography.shtml


Cryptography Software

If you need some cryptography software, here are a few programs you can download and try for free: PGP, RPK, Crypto Kong and TEA. All of these programs are very secure, but each one has its own design and features. Try them all and see which one you like best.


Web:

http://disastry.dhs.org/xtea/
http://web.mit.edu/network/pgp.html
http://www.di-mgt.com.au/crypto.html
http://www.echeque.com/kong/kong.htm


Cryptography Talk and General Discussion

Here is a general discussion group for all aspects of data encryption and decryption. If you are a cryptography aficionado, this is the place to communicate with your peers on the Net. (Note: The following is a message in code. There is a prize if you can break it. --Harley)
F_eB7 n!K4r F^Pb2 M:Quf ^{9&L 0y}w# I/hH@ K`|eI 6N%-R G-(4u UA,,] .Gs2~ o&?_^ :|IJA V*e}@ ;a2#3 ZZuJB tOpx9 \@z)t {eNSr ;LSZx Kht9. 'oRFa J`/KH oF:q' Hn[\P vwqo1 4^:pI ~&8jb ]q4(2 1D)OE v.bvZ 6[M\$ l)n;b L$?q{ d,$}F Q4PBM c[<&U )2>j) Sh\yF !\u@j }:)ZW cOPKt 2_~P/ x|s]! ;<6.Q ";<;t UB,-{ 3@wzB HD4PH tb$Xr !2Rpm &7}BU 8sg)= {


Usenet:

Google Newsreader sci.crypt


Digital Signatures and Certificates

More and more, we have the need to send information over the Net in complete secret. For example, if you order merchandise online by typing your credit card number, you should be sure that no one else can tap into the line, capture the information and use it for their own purposes. Or you may want to send a message to a friend or colleague that no one but the recipient can read. The systems that send and receive secure information over the Net use what are called "digital signatures" and "digital certificates". Such facilities are going to be in common use, so it is a good idea to find out how they work.


Web:

http://digitalid.verisign.com/client/help/id_intro.htm
http://www.abanet.org/scitech/ec/isc/dsg-tutorial.html
http://www.howstuffworks.com/question571.htm


Hidden Messages

Here is the situation. You have an idea for a wonderful new book, one that, without a doubt, will revolutionize Western Civilization. You need to email a secret message to your editor to show him the outline of the book. However, other publishers (not to mention the government) have spies everywhere and will go to extreme lengths to steal your ideas. You could use a well-known encryption method, like PGP, but anyone who sees the message would know that it was encrypted, which would bring the harsh eye of suspicion down upon your efforts. Instead, why not hide the secret message in something that looks completely innocent? You could, for example, use "stegnography" to hide a message in a picture or sound file. You could then email the picture to the editor. Since he is the only one with the password, only he can decode the secret message. You could even put the picture on your Web site, secure in the knowledge that no one else would even suspect it of holding a message. Want to be even more sneaky? Hide your secret in a fake email message disguised as spam. (Really.)


Web:

http://www.cl.cam.ac.uk/~fapp2/steganography/
http://www.hacktivismo.com/projects/camerashy/
http://www.jjtc.com/Steganography/
http://www.spammimic.com/
http://www.stego.com/


Navajo Code Talkers

During World War II, there were a number of U.S. military personnel who were Navajo (a nation of native Americans), primarily Marines in the Pacific theater. At the time, the military authorities were having trouble because the Japanese were breaking many of the Allied codes. In order to create a secure code, a group of Navajo took the English alphabet and assigned each letter to specific Navajo words. For example, the letter "A" was assigned to the words wol-la-chee (which means "ant"), be-la-sana ("apple") and tse-nill ("axe"); "B" was assigned to na-hash-chid ("badger"), shush ("bear") and toish-jeh ("barrel"); and so on. In the basic system, an encoded message would use one Navajo word for each letter. In addition, some very important words were assigned to a single Navajo word. For example, the word "America" was encoded as ne-he-mah (which means "our mother"). The Navajo Code was extremely successful, and the people who used it came to be known as Navajo Code Talkers. The husband of one of my researchers (Kelly's husband, Charlie) is half Navajo and has clan relatives who were code talkers during the war (and to this day, Kelly still has trouble understanding everything that Charlie says.)


Web:

http://www.execpc.com/~shepler/codetalkers.html
http://www.history.navy.mil/faqs/faq12-1.htm
http://www.history.navy.mil/faqs/faq61-2.htm
http://www.history.navy.mil/faqs/faq61-4.htm
http://www.lapahie.com/navajocodetalker.cfm


PGP

The PGP (Pretty Good Privacy) system is widely used to encrypt and decrypt data. Download the software for free, and use it to send secret messages to your friends. Better yet, encrypt your diary with PGP and even your mother won't be able to read it.


Web:

http://web.bham.ac.uk/n.m.queen/pgp/pgp.html
http://www.pgp.com/products/freeware/default.asp
http://www.pgpi.org/

Usenet:

Google Newsreader alt.security.keydist
Google Newsreader alt.security.pgp
Google Newsreader comp.security.pgp.discuss

Listproc Mailing List:

List Name: pgp-users
Subscribe To: listproc@listproc.umbc.edu


RSA

RSA is a cryptography system, invented in 1977, that is used for both encryption and authentication. (The name comes from RSA's inventors, Ron Rivest, Adi Shamir and Leonard Adleman.) With RSA, each person has a public key and a private key. You can give your public key to everyone; it is not a secret. However, you do not give out your private key. When another person wants to send you a secret message, he uses your public key to encrypt a message. The nature of RSA is such that, once someone uses your public key to encrypt a message, the message can only be decrypted by using your private key. Thus, you are the only person in the world who can decrypt messages that have been encrypted with your public key (because no one else has your private key). RSA is secure because it is extremely difficult to use someone's public key to figure out his private key. Thus, you can give out your public key with no worries. Of course, the whole system depends on being able to create suitable pairs of private and public keys. To create such a pair, you start with large prime numbers -- call them p and q. Find their product n=pq. Choose a number e, less than n, such that e and (p-1)(q-1) have no common factors except 1. (In other words, e and (p-1)(q-1) are relatively prime.) Now find another number d, such that (ed-1) is divisible by (p-1)(q-1). The public key is the pair (n,e), and the private key is (n,d). Once the keys are generated, the factors p and q can be thrown away. Here is the Web site of a company called RSA Data Security, which was formed by the inventors of RSA in order to develop and explore the technology. You will find a lot of interesting information about RSA and about people's attempts to break the code.


Web:

http://www.rsasecurity.com/