Encryption

[pgrmdave]

How do encryption formulas work, and what is the difference between encrypting and encoding?

[TINNY]

my guess is that both are similar in that they change data with a sort of algorithm. the difference lies in the purpose. encoding is to simplify data as to be readable. encryption is to obfuscate data as to be unreadable.

[TINNY]

i have no idea of encryption. but my guess is that the way to encrypt data is to manipulate the ASCII code of each character with an algorithm.

for example, lets say the ASCII code of A is 97.

then we put it in a function like f(x) = x+2

so the encrypted info is "101"

is this right?

[TINNY]

here's some simple encryptions done on VB. just open the .bas files with notepad:

http://www.planetsourcecode.com/vb/scripts/BrowseCategoryOrSearchResults.asp?txtCriteria=encryp&blnWorldDropDownUsed=TRUE&txtMaxNumberOfEntriesPerPage=10&blnResetAllVariables=TRUE&lngWId=1&B1=Quick+Search&optSort=Alphabetical

[Tormod]

An excellent book on encryption in a popularised presentation is Simon Singh's "The Code Book" which came out a few years ago. Highly recommended.

[TINNY]

what is meant by 16-bit or 8-bit encryption?

when a data is encrypted, the file size is increased right? and when something is encoded, it's size decreases? so that's one of the differences between them?

[pgrmdave]

I tried to write my own encryption/encoding program (I'm not sure which it was) in which "random" numbers were added to each letter's ASCII code. The numbers were based on a formula that basically accepted some values from a user (the key) and then used them to manipulate a sin curve, then, starting at a point along the curve determined by the key, it added the seventh decimal place to the ASCII. The next number got the seventh decimal place that was one number further along on the sin curve. The numbers repeat every 2pi, but since you're adding one and not pi, it seems random.

[Aki]

Well there are one-way encryptions, like MD-5. That's the type of encryption Hotmail uses when you login. The password you typed in is encrypted with MD-5, and they use it to compare with the "real" password hash. If they're the same, then you have the access, otherwise it'll tell you to try again.

There's a really nice tutorial on encryption at HowstuffWorks

http://computer.howstuffworks.com/encryption.htm

 

And there are a few really fun encryption games out there. If anyone is interested, I'll post the links.

[Tormod]

MD5 is what is used at Hypography, too.

[alexander]

MD5 hashes arent bad. The main difference between encryption and encoding is:

A character encoding is a code that pairs a set of natural language characters (such as an alphabet or syllabary) with a set of something else, such as numbers or electrical pulses.

A text encoding is a method of representing a piece of text as a sequence of codes (from a character encoding) for the purpose of computer storage or electronic communication of that text.

 

In cryptography, encryption is the process of obscuring information to make it unreadable without special knowledge. This is usually done for secrecy, and typically for confidential communications. Encryption can also be used for authentication. Even when encrypted, messages can still be subject to traffic analysis although this cannot typically be used to reveal the actual contents of the message.

from wiki

I had fun with encryption, i developed an algorithm that uses ascii variables for encryption with a private and public keys to generate an output. then i was bored and wrote a different program that generates a random 10 digit key and switches every 10 digits according to it and writes the key to the end (encrypted offcourse) then the program checks for more than 100 letters and generates a new algorithm, then switches every 10 letters around around and writes the new algorithm to the end. and so forth to 10000 letters. so then i was bored again, and i combined the two programs in one, built a gui interface for it and dropped the project. It worked fine, and it was written in QBasic.

but anyways here's some info on encryption:

http://world.std.com/~franl/crypto.html