The process of converting data into a coded form (ciphertext) to prevent it from being read and understood by an unauthorized party.
Encryption refers to algorithmic schemes that encode plain text into non-readable form or cyphertext, providing privacy. The receiver of the encrypted text uses a “key” to decrypt the message, returning it to its original plain text form. The key is the trigger mechanism to the alogrithm.
Web browsers will encrypt text automatically when connected to a secure server, evidenced by an address beginning with
https. The server decrypts the text upon its arrival, but as the information
travels between computers, interception of the
transmission will not be fruitful to anyone “listening in.” They would only see unreadable gibberish.
There are many types of encryption and not all of it is reliable. The same computer power that yeilds strong encryption can be used to break weak encryption schemes. Initially, 64-bit encryption was thought to be quite strong, but today 128-bit encryption is the standard, and this will undoubtedly change again in the future.
The original design of electronic mail did not make any allowances for security. As email has evolved into a mess medium, users have begun to use two solutions to existing serious problems with email security.
- Authentication:Email services rely on the person sending an email to provide his/her own identity — i.e., they only pass along the email address that a message claims to be “from.” It is extremely easy for anyone to change this address and send messages that claim to be “from” someone they are not. Most current users of email have experienced the frustration with large amounts of spam originating from forged return addresses — or even discovered that their own addresses have been forged as a source of spam. This same vulnerability has allowed virus authors to pass viruses through email for many years, by making an infected attachment appear to come from a trusted source.Modern encryption techniques allow an email to be digitally “signed” by a sender. The recipient of such a message can check a signature to determine that an email message actually came from the person claiming to be the sender .
- Secure Transmission: Email systems, by default, send messages in plain text. As a consequence, any person using a software package called a “packet sniffer” to “eavesdrop” on a network can easily read email messages being delivered over that network.To put it another way, when you send an email message, you should think of it as a postcard readable by anyone handling email — not as a letter inside an envelope. This clearly presents problems for anyone wishing to exchange sensitive information via email. Encrypting email messages offers a solution
Simple Encryption with XOR: Now depending on the encryption algorithm, we may also need a decryption key. Public-key encryption has two keys- this is assymetrical encryption. A simple xor though can use the same password for both encryption and decryption as the XOR
operator has
the property that when
C = A XOR B
then
B = A XOR C
and
A = B XOR C.
Any algorithm can be used that takes the original text and processes it using the encryption key so long as there is a corresponding decryption key. For the strongest encryption, one of the well-tested algorithms such as AES (Advanced Encryption Standard) should be used.
