adversary - Commonly used
to refer to the opponent, the enemy, or any other
mischievous person that desires to compromise
one’s security.
AES - The Advanced Encryption
Standard that will replace DES (The Data Encryption
Standard) around the turn of the century.
algorithm - A series of steps used to
complete a task.
ANSI - American National Standards
Institute.
API - Application Programming
Interface.
attack - Either a successful or
unsuccessful attempt at breaking part or all of a
cryptosystem.
authentication - The action of
verifying information such as identity, ownership
or authorization.
certificate - In cryptography, an
electronic document binding some pieces of
information together, such as a user's identity
and public key. Certifying Authorities
(CA's) provide certificates.
certificate revocation list - A list of
certificates that have been revoked before their
expiration date.
Certifying Authority (CA) - A person or
organization that creates certificates.
cipher - An encryption - decryption
algorithm.
ciphertext - Encrypted data.
collision - Two values x and y
form a collision of a (supposedly) one-way
function F if x y but F(x)
= F(y).
collision free - A hash function is collision
free if collisions are hard to find. The
function is weakly collision free
if it is computationally hard to find a collision
for a given message x. That is, it
is computationally infeasible to find a message y
x such that H(x) = H(y).
A hash function is strongly collision
free if it is computationally infeasible
to find any messages x, y
such that x y and H(x)
= H(y).
collision search - The search for a
collision of a one-way function.
time - Referring to the temporal
constraints involved in a certain computation.
cryptanalysis - The art and science of
breaking encryption or any form of
cryptography. See attack.
cryptography - The art and science of
using mathematics to secure information and
create a high degree of trust in the electronic
realm. See also public-key, secret-key,
symmetric-key, and threshold cryptography.
cryptology - The branch of mathematics
concerned with cryptography and cryptanalysis.
cryptosystem - An encryption
decryption algorithm (cipher), together with all
possible plaintexts, ciphertexts and keys.
decryption - The inverse (reverse) of
encryption.
DES - Data Encryption Standard, a block
cipher developed by IBM and the U.S. government
in the 1970’s as an official standard.
See also block cipher.
Diffie-Hellman key exchange - A key
exchange protocol allowing the participants to
agree on a key over an insecure channel.
digest - Commonly used to refer to the
output of a hash function, e.g. message digest
refers to the hash of a message.
digital envelope - A key exchange
protocol that uses a public-key cryptosystem to
encrypt a secret key for a secret-key
cryptosystem.
digital fingerprint - See digital
signature.
digital signature - The encryption of a
message digest with a private key.
digital timestamp - A record
mathematically linking a document to a time and
date.
discrete logarithm - Given two elements
d, g, in a group such that there is an
integer r satisfying gr
= d, r is called the discrete
logarithm.
distributed key - A key that is
split up into many parts and shared (distributed)
among different participants. See also
secret sharing.
DMS - Defense Messaging Service.
DOD - Department of Defense.
DSA - Digital Signature
Algorithm. DSA is a public-key method based
on the discrete log problem.
DSS - Digital Signature Standard.
DSA is the Digital Signature Standard.
ECC - Elliptic Curve Cryptosystem; A
public-key cryptosystem based on the properties
of elliptic curves.
EDI - Electronic (business) Data
Interchange.
electronic commerce (e-commerce) -
Business transactions conducted over the
Internet.
electronic mail (e-mail) - Messages
sent electronically from one person to another
via the Internet.
electronic money - Electronic
mathematical representation of money.
elliptic curve - The set of points (x,
y) satisfying an equation of the form y2
= x3 + ax + b,
for variables x, y and constants a,
b.
encryption - The transformation of
plaintext into an apparently less readable form
(called ciphertext) through a mathematical
process. The ciphertext may be read by
anyone who has the key that decrypts (undoes the
encryption) the ciphertext.
exclusive or - See XOR.
exhaustive search - Checking every
possibility individually till the right value is
found. See also attack.
expiration date - Certificates and keys
may have a limited lifetime; expiration dates are
used to monitor this.
exponential function A function
where the variable is in the exponent of some
base, for example, bN where N
is the variable, and b is some constant.
exponential running time - If the
running time, given as a function of the length
of the input, is an exponential function, the
algorithm is said to have exponential running
time.
export encryption - Encryption, in any
form, which leaves its country of origin.
For example, encrypted information or a computer
disk holding encryption algorithms that is sent
out of the country.
hacker - A person
who tries and/or succeeds at defeating computer
security measures.
handshake - A
protocol two computers use to initiate a
communication session.
hash-based MAC - MAC that uses a hash
function to reduce the size of the data it
processes.
hash function - A function that takes a
variable sized input and has a fixed size
output.
iKP - Internet Keyed Payments Protocol.
ISO - International Standards
Organization, creates international standards,
including cryptography standards.
identification - A process through
which one ascertains the identity of another
person or entity.
impersonation - Occurs when an entity
pretends to be someone or something it is not.
import encryption - Encryption, in any
form, coming into a country.
Internet - The connection of computer
networks from all over the world forming a
worldwide network.
ITEF - Internet
Engineering Task Force.
ITU-T - International
Telecommunications Union - Telecommunications
standardization sector.
Kerberos - An authentication service
developed by the Project Athena team at MIT.
key - A string of bits used widely in
cryptography, allowing people to encrypt and
decrypt data; a key can be used to perform other
mathematical operations as well. Given a
cipher, a key determines the mapping of the
plaintext to the ciphertext. See also
distributed key, private key, public key, secret
key, session key, shared key, sub key, symmetric
key, weak key.
key agreement - A process used by two
or more parties to agree upon a secret symmetric
key.
key escrow - The process of having a
third party hold onto encryption keys.
key exchange - A process used by two
more parties to exchange keys in cryptosystems.
key expansion - A process that creates
a larger key from the original key.
key generation - The act of creating a
key.
key management - The various processes
that deal with the creation, distribution,
authentication, and storage of keys.
key pair - The full key information in
a public-key cryptosystem, consisting of the
public key and private key.
key recovery - A special feature of a
key management scheme that allows messages to be
decrypted even if the original key is lost.
key schedule An algorithm that
generates the subkeys in a block cipher.
keyspace - The collection of all
possible keys for a given cryptosystem. See
also flat keyspace, linear key space, nonlinear
key space, and reduced key space.
life cycle - The length of time a key
can be kept in use and still provide an
appropriate level of security.
linear keyspace - A key space where
each key is equally strong.
Message Authentication Code(MAC) - A MAC is a
function that takes a variable length input and a
key to produce a fixed-length output. See
also hash-based MAC, stream-cipher based MAC, and
block-cipher based MAC.
MIME - Multipurpose Internet Mail
Extensions.
MIPS - Millions of Instructions Per
Second, a measurement of computing speed.
modulus - The integer used to divide
out by in modular arithmetic.
NSA - National Security Agency. A
security-conscious U. S. government agency whose
mission is to decipher and monitor foreign
communications.
patent - The sole right, granted by the
government, to sell, use, and manufacture an
invention or creation.
PKI - Public-key Infrastructure.
PKIs are designed to solve the key management
problem. See also key management.
padding - Extra bits concatenated with
a key, password, or plaintext.
password - A character string used as a
key to control access to files or encrypt them.
PKCS - Public-Key Cryptography
Standards. A series of cryptographic standards
dealing with public-key issues, published by RSA
Laboratories.
plaintext - The data to be encrypted.
privacy - The state or quality of being
secluded from the view and or presence of others.
private exponent - The private key in
the RSA public-key cryptosystem.
private key - In public-key
cryptography, this key is the secret key.
It is primarily used for decryption but is also
used for encryption with digital signatures.
protocol - A series of steps that two
or more parties agree upon to complete a task.
public exponent - The public key in the
RSA public-key cryptosystem.
public key - In public-key cryptography
this key is made public to all, it is primarily
used for encryption but can be used for verifying
signatures.
public-key cryptography - Cryptography
based on methods involving a public key and a
private key.
quantum computer - A theoretical
computer based on ideas from quantum theory;
theoretically it is capable of operating
nondeterministically.
RSA algorithm - A public-key
cryptosystem based on the factoring
problem. RSA stands for Rivest, Shamir and
Adleman, the developers of the RSA public-key
cryptosystem and the founders of RSA Data
Security, Inc.
running time - A measurement of the
time required for a particular algorithm to run
as a function of the input size. See also
exponential running time, nondeterministic polynomial
running time, polynomial running time, and
sub-exponential running time.
S-HTTP - Secure HyperText Transfer
Protocol, a secure way of transferring
information over the World Wide Web.
S/MIME - Secure Multipurpose Internet
Mail Extensions.
SSL - Secure Socket Layer. A
protocol used for secure Internet communications.
secret key - In secret-key
cryptography, this is the key used both for
encryption and decryption.
secret sharing - Splitting a secret
(e.g. a private key) into many pieces such that
any specified subset of N pieces may be
combined to form the secret.
secure channel - A communication
medium safe from the threat of eavesdroppers.
session key - A key for symmetric-key
cryptosystems which is used for the duration of
one message or communication session
shared key - The
secret key two (or more) users share in a
symmetric-key cryptosystem.
SMTP - Simple Mail Transfer Protocol.
smartcard - A card, not much bigger
than a credit card, that contains a computer chip
and is used to store or process information.
standards - Conditions and protocols
set forth to allow uniformity within
communications and virtually all computer
activity.
stream cipher - A secret-key encryption
algorithm that operates on a bit at a time.
stream cipher based MAC - MAC that uses linear
feedback shift registers (LFSR's) to reduce the size of the data
it processes.
sub key - A value generated during the
key scheduling of
the key used during a round in a block cipher.
S/WAN - Secure Wide Area Network.
symmetric cipher - An encryption
algorithm that uses the same key is used for
encryption as decryption.
symmetric key - See secret key.
synchronous - A property of a
stream cipher, stating that the keystream is
generated independently of the plaintext and
ciphertext.
timestamp - see digital timestamp
verification - The act of recognizing
that a person or entity is who or what it claims
to be.
weak key - A key giving a poor level in
security, or causing regularities in encryption
which can be used by cryptanalysts to break
codes.
WWW - World Wide Web.
XOR - A binary bitwise operator
yielding the result one if the two values are
different and zero otherwise.
