Ever wondered what keeps our e-mails as safe sealed envelopes rather than postcards that anybody can read ?(asssuming of course that TRANSLTR- the ultimate codebreaker from Dan Brown’s Digital Fortress doesn’t exist)

Here’s a little something about encryption and decryption algorithms…

The encryption of original data(plaintext) into its coded version(cipher text) through key based mechanism takes place using an algorithm and a key.

The algorithm is a set of rules that defines the encryption method from plaintext to ciphertext.A key is exactly what a key is – the specific combination of characters that helps to decrypt the message.There are mainly two types of algorithms:

• Symmetric – The same key is used for encryption as well as decryption.
• Asymmetric – A public key is used to encrypt the data and a private key is used to to decrypt it.This is the key used for encryption of our e-mails.

For example, if Mr. X wants to send a message to Mr.Y, then he simply looks at Mr.Y’s public key and uses it to code the message into plaintext and sends it to him.Mr.Y uses his private key to decrypt the message.Thias ensures that the message is not understood by a third party even if it is intercepted through some means.

The process also works the other way round.ie.Mr.Y can use his private key to encrypt a message and send it to Mr.X which he can be decoded using Mr.Y’s public key.Although this is less safe as compared to the earlier method it proves to Mr.X that Mr.Y is the real sender of the data.The most popular asymmetric algorithm used today is RSA(Rivest,Shamir and Adleman – its designers)

P.S Hope this gave all of you some food for thought…all these days I’ve been spellbound by Dan Brown’s genius once again having been busy reading Digital Fortress, which has left some questions unanswered…here’s one for all you ace programmers out there…Does a rotation cleartext algorithm really exist, and if it does how exactly does it work?