Additional Resources
1. Advanced Encryption Standard
http://en.wikipedia.org/wiki/Advanced_Encryption_Standard
2. Symmetric cryptography
http://www.ibm.com/developerworks/library/s-crypt02.html
3. Asymmetric cryptography
http://www.ibm.com/developerworks/library/s-crypt03.html
4. PGP Corporation
http://www.pgp.com/
5. Trusted Platform Module
http://en.wikipedia.org/wiki/Trusted_Platform_Module
Key Terms
 Advanced Encryption Standard (AES) A symmetric cipher that has been approved as
a replacement for DES.
 algorithm Procedures based on a mathematical formula; used to encrypt the data.
 asymmetric cryptographic algorithm Encryption that uses two mathematically related
keys.
 BitLocker A Microsoft Windows Vista hardware-enabled data encryption feature.
 block cipher A cipher that manipulates an entire block of plaintext at one time.
 Blowfish A block cipher that operates on 64-bit blocks and can have a key length from
32 to 448 bits.
 ciphertext Data that has been encrypted.
 cleartext Unencrypted data.
 collision In cryptography, two different sets of data that produce the same hash.
 cryptography The science of transforming information into an unintelligible form
while it is being transmitted or stored so that unauthorized users cannot access it.
 Data Encryption Standard (DES) A symmetric block cipher that encrypts data in 64bit blocks.
 decryption The process of changing ciphertext into plaintext.
 Diffie-Hellman A cryptographic algorithm that allows two users to share a secret key
securely over a public network.
 digest The unique signature created by a hashing algorithm.
 digital signature An electronic verification of the sender.
 elliptic curve cryptography An algorithm that uses elliptic curves instead of prime
numbers to compute keys.
 Encrypting File System (EFS) An encryption scheme for Windows operating systems.
 encryption The process of changing plaintext into ciphertext.
 file system A method used by operating systems to store, retrieve, and organize files.
 GNU Privacy Guard (GPG) Free, open-source software that is commonly used to
encrypt and decrypt e-mail messages.
 hash The unique signature created by a hashing algorithm.
 hashing The process for creating a unique signature for a set of data.
 homoalphabetic substitution cipher A cipher that maps a single plaintext character to
multiple ciphertext characters.
 International Data Encryption Algorithm (IDEA) A symmetric algorithm that dates
back to the early 1990s and is used mainly in Europe.
 key A mathematical value entered into the algorithm to produce the ciphertext.
 Message Digest (MD) A common hash algorithm of several different versions.
 Message Digest 2 (MD2) A hash algorithm that takes plaintext of any length and
creates a hash that is 128 bits in length after the message is divided into 128 bit sections.
 Message Digest 4 (MD4) A hash that was developed in 1990 for computers that
processed 32 bits at a time.
 Message Digest 5 (MD5) A revision of MD4 that is designed to address its weaknesses.
 metadata Data that is used to describe the content or structure of the actual data.
 monoalphabetic substitution cipher A cipher that simply substitutes one letter or
character for another.
 non-repudiation The process of proving that a user performed an action.
 one-time pad (OTP) Combining a truly random key with plaintext.
 one-way hash The process for creating a unique signature for a set of data.
 pad In cryptography, a truly random key.
 padding Additional data that is added to a hash to make it the correct number of bytes.
 plaintext Data input into an encryption algorithm.
 Pretty Good Privacy (PGP) A commercial product that is commonly used to encrypt
e-mail messages.
 private key An asymmetric encryption key that does have to be protected.
 private key cryptography Cryptographic algorithms that use a single key to encrypt
and decrypt a message.
 public key An asymmetric encryption key that does not have to be protected.
 public key cryptography Encryption that uses two mathematically related keys.
 RC2 A block cipher that processes blocks of 64 bits.
 RC4 A stream cipher that will accept keys up to 128 bits in length.
 RC5 A block cipher that can accept different length keys and blocks.
 RC6 A cipher that has three key sizes (128, 192, and 256 bit) and performs 20 rounds
on each block.
 Rivest Cipher (RC) A family of cipher algorithms designed by Ron Rivest.
 RSA An asymmetric algorithm published in 1977 and patented by MIT in 1983.
 Secure Hash Algorithm (SHA) A secure hash algorithm that creates hash values of
longer lengths.
 SHA-1 The first versions of Secure Hash Algorithm.
 SHA-2 A family of Secure Hash Algorithms that has four variations, known as SHA224, SHA-256, SHA-384, and SHA-512.
 steganography Hiding the existence of data within a text, audio, image, or video file.
 stream cipher An algorithm that takes one character and replaces it with one character.
 substitution cipher A cipher that simply substitutes one letter or character for another.
 symmetric cryptographic algorithm Encryption that uses a single key to encrypt and
decrypt a message.
 transposition cipher A cipher that rearranges letters without changing them.
 Triple Data Encryption Standard (3DES) A symmetric cipher that was designed to
replace DES.
 Trusted Platform Module (TPM) A chip on the motherboard of the computer that
provides cryptographic services.
 Twofish A later derivation of the Blowfish algorithm that is considered to be strong.
 Whirlpool A new cryptographic hash function that has received international
recognition and adoption by standards organizations.
 whole disk encryption Cryptography that can be applied to entire disks.