A simple substitution cipher where the last letter of the alphabet is replaced by the first, and vice versa. Here is a table explaining which letter becomes which:
ABCDEFGHIJKLMNOPQRSTUVWXYZ
becomes
ZYXWVUTSRQPONMLKJIHGFEDCBA
The device used by the allies in World War II to break German codes.
The same as cracking. Forcing the decryption of something without knowing
the key used to encrypt it.
A code, or system of encoding.
The encrypted version of a message.
American Indians used in the World Wars to speak out important communication
in their native language, so enemies would not know what is being said.
This word is deceiving -- an oxymoron. Coffee was created so that breaks were no longer necessary. Thus to take a break to drink coffee is an utterly absurd idea.
Obtaining the plaintext of an encrypted message without knowing the
key used to encode it.
The process of breaking or cracking a code.
A person who engages in encoding or encrypting documents.
The science of encoding something.
Often used interchangeably with Cryptography
Turning an encrypted message into something intelligible to a human
or machine.
Data Encryption Standard. A block-cipher system developed by the US
Government in 1977. It was endorsed for all non-classified communications.
Today, it is not strong.
A rotor-based encrypted system used by the Germans in World War II.
A mathematically-irreversible algorithm used often for checking the
validity of something without knowing what the something really is. For
example, a password might be "encrypt." The computer doing the authentication
would only store the hash of "encrypt," or #)GHLDB#893S. When someone tries
to log in, the computer takes the password supplied, "hashes" it, and sees
if the hash values match up. This is useful because even if an intruder
knows the hash value, it is impossible to generate the actual password
from that.
drawing-based writing used by ancient Egypt. In this form of writing,
symbols take the place of words and phrases.
The password used to encrypt something. The more random a key is, the
harder it is to guess.
Writing on a piece of white paper with lemon juice is a simple mechanism for hiding writing. If the paper is exposed to a heat source such as a warm lightbulb, the lemon juice will change color, exposing the message.
An encryption algorithm developed by IBM in the 1970s. Originally IBM
had wanted it to be based on 128 bits (or 2 ^ 128 possible combinations
of keys), but the NSA convinced them that 56 bit was adequate.
National Security Agency.
A system of encryption where the key is the same length as the message
to be encrypted, and never repeats. For example, COMPUTER could be encrypted
as AAAAAAAA or CUCUMBER, depending on the key used. This is the only totally
safe form of encryption proven mathematically.
See hash.
Packet Sniffing is generally a method used to intercept information. Information travels over networks in "packets" -- bundles of information. If the stream is unencrypted then the infromation can simply be observed as it travels from computer to computer through the network.
Pretty Good Privacy, a system of public key encryption developed by
Phil Zimmerman in the United States.
Pig latin is a way of speaking that changes normal english into another "language." The first part of the word until the first vowel is usually taken and appended to the end of the word along with an "ay." If the word starts with a vowel then an "ay" is simply added. Thus we get "Ouyay annotcay eadray isthay."
A system of encryption that uses two different keys. One is kept secret,
the other given away freely. A message encrypted with the private key can
only be decrypted with the public key. Thus, the origin of a message can
be guaranteed. On the other hand, a message encrypted with the public key
can only be decrypted with the private key. As a result, a message can
be preserved only for the eyes of the recipient.
The unencrypted form of a message, which can be viewed immediately.
The system of encryption used by Japan during World War II. It was broken
by William Friedman.
A public-key system of encryption where both parties have a public key
and a private key.
A device that substitutes one letter for another in an encryption machine.
"Rotating" the rotor can change which letter is substituted for which.
The substitution is accomplished with electrical contacts.
Encoding something so the fact that an encoded document exists is hidden.
An example of this is software that allows hiding text within computer
graphics.
A strong rotor machine used by the allies in late World War II.
The method of encryption involving replacing one letter with another.
For example, the word DOG could become EPH, by moving each letter forward
one position in the alphabet.
Changing the position of letters to encipher a message. A common use
of transposition ciphering is when people scramble their email address
to avoid being spammed. For example, president@whitehouse.gov
could become pxrxexsxixdxexnxt@whitehouse.gov.
Official encryption standard for encrypting plaintext three times.
A rotor encryption system similar to the ENIGMA used by the British
in World War I.
See page on Jefferson’s Wheel Cipher for explanation.