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95 Cards in this Set

  • Front
  • Back
What is

Cryptography
The science of altering information so that is cannot be decoded without a key,

and the study of cryptographic algorithms.
What is

Cryptanalysis
The study of how to break cryptographic algorithms.
What is a

Cipher
A method used to encode characters to hide their value.
What is a

Substitution Cipher
A type of coding or ciphering system that changes one character or

symbol to another.
What is a

Transposition Cipher
Involves transposing or scrambling the letters in a certain manner.
What

is

ROT13
One of the oldest known encoding algorithms, it is a simple algorithm that rotates

every letter 13 places in the alphabet. Thus, an A becomes an N, a B becomes an O, and so

forth.
What is

Steganography
The process of hiding a message in a medium such as a digital image, audio

file, or other file.
What is the

Least Significant Bit (LSB) method of steganography
The most common method of

steganography where the very last bit (the least significant bit in each byte) is changed. Doing

so does not make a noticeable change to the file.
What is a

Symmetric Algorithms
Requires that both ends of an encrypted message have the same key

and processing algorithms. They generate a secret key that must be protected.
What is a

Block Cipher
An algorithm that works on chunks of data, encrypting one chunk at a time.
What

is a

Stream Cipher
An algorithm that encrypts data one bit, or byte, at a time.
What is the

Data Encryption Standard (DES)
A symmetric algorithm that is based on a 56–bit key and has

several modes that offer security and integrity. It is now considered insecure because of the

small key size and has been replaced by AES.
What is

Triple–DES (3DES)
A symmetrical algorithm that is a technological upgrade of DES. It is still

used even though AES is the preferred choice for government applications. It is considerably

harder to break than many other systems and uses a key length of 168 bits (using three 56–bit

DES keys).
What is

Advanced Encryption Standard (AES)
A symmetric algorithm that replaced DES as the current

standard. It is the current product used by U.S. government agencies and supports key sizes of

128, 192, and 256 bits, with 128 bits being the default.
What is

AES256
A symmetrical algorithm that uses a 256 bit key and qualifies for US classification as

Top Secret.
What is

CAST
A symmetrical algorithm that is used in some products offered by Microsoft and IBM. It

uses a 40 bit to 128 bit key and is very fast an efficient. A 128 and 265 bit version also

exist.
What is

Ron's Cipher (RC)
A symmetric encryption family that was produced by RSA laboratories.

The current levels are RC4, RC5, and RC6.
What is

RC5
A symmetric algorithm that uses a key size of up to 2048 bits and is considered to be a

strong system.
What is

RC4
Popular with wireless and WEP/WPA encryption, it is a symmetric streaming cipher that

works with key sizes between 40 and 2048 bits, and it is used in SSL and TLS.
What is

Blowfish
An encryption system that performs a 64–bit block cipher at very fast speeds. It is a

symmetric block cipher that can use variable–length keys (from 32 bits to 448 bits).
What is

Twofish
Similar to blowfish, it works on 128–bit blocks and has a complex key schedule.
What

is the

International Data Encryption Algorithm (IDEA)
A symmetric algorithm that uses a 128–bit key.

Similar in speed and capability to DES, but it's more secure. It is also used in PGP.
What are

One–Time Pads
The only truly completely secure cryptographic implementations. They are

so secure for two reasons. They use a key that is as long as a plain text message, and they are

only used once before being discarded.
What is

In–band Key Exchange
A method of key exchange where the key is exchanged within the

same communications channel that is going to be encrypted. IPSec uses in–band key

exchange.
What is

Out–of–Band Key Exchange
A method of key exchange where the key is exchanged using

some other channel, other than the one that is going to be secured.
What is

Forward Secrecy
A property of any key exchange system, which ensures that if one key is

compromised, subsequent keys will not also be compromised.
What is

Perfect Forward Secrecy
When the process of key exchange is unbreakable. A common

approach uses ephemeral keys.
What is an

Asymmetric Algorithm
Uses two keys to encrypt and decrypt data. The keys are referred to as

the public and private keys. The sender uses the public key to encrypt a message, and the

receiver uses the private key to decrypt the message. What one key does, the other

undoes.
What is

RSA
An early public–key (asymmetric) encryption system that uses large integers as the basis

for the process. It's widely implemented, and it has become a de facto standard. It works with

both encryption and digital signatures and is used in many environments, including SSL and it

can be used for key exchange.
What is

Diffie–Hellman
An asymmetric system, it is primarily used to send keys across public networks

and works by splitting the key into two parts. The process isn't used to encrypt or decrypt

messages, and is used merely for the creation of a symmetric key between two parties.
What is

Elliptic Curve Cryptography
Similar in functionality to RSA, but it uses smaller key sizes to

obtain the same level of security. This asymmetric encryption system is based on the idea of

using points on a curve combined with a point at infinity and the difficulty of solving discrete

logarithm problems.
What is

ElGamal
An asymmetric algorithm that has several variations, including Elliptic Curve. It uses

an ephemeral key.
What are the

Three Characteristics of a Cryptography Hash Function
It must be one way and not reversible.

Variable–Length input produces fixed–length output.

The Algorithm must have few or no collisions.
What is the

Secure Hash Algorithm
Designed to ensure the integrity of a message. It is a one–way hash

that provides a hash value that can be used with an encryption protocol. It produces a 160–bit

hash value.
What is

SHA2
A hashing algorithm that has several sizes: 224, 256, 334, and 512. It is the most

widely used and recommended hashing algorithm.
What is the

Message Digest Algorithm
A hash value that uses a one–way hash to help maintain integrity.

There are several, the most common are MD5, MD4, and MD2. MD4 was used by NTLM to

compute the NT hash.
What is

MD5
The newest version of the algorithm, it produces a 128–bit hash, but the algorithm is

more complex than its predecessors and offers greater security. Its biggest weakness is that is

does not have strong collision resistance, and is no longer recommended for use.
What is the

RACE Integrity Primitives Evaluation Message Digest (RIPEMD)
A hashing algorithm based

on MD4 there were questions regarding it's security and it has been replaced with a 160 bit

version. There are also version that use 256 and 320 bits.
What is

GOST
A symmetric cipher developed in the old Soviet Union that has been modified to work

as a hash function. It processes a variable–length message into a fixed–length output of 256

bits.
What is

LANMAN
A protocol used for authentication prior to the release of Windows NT. While

functioning only has an authentication protocol, it used LM Hash and two DES keys.
What is

NT LAN Manager (NTLM)
A protocol that replaced the LANMAN protocol and uses MD4/MD5

hashing algorithms.
What is a

Rainbow Table
A table in which all of the possible hashes are computed in advance.
What is

Salt
A countermeasure to Rainbow Tables, it works by adding bits at key locations, either

before or after the hash.
What is

Key stretching
The processes used to take a key that might be a bit weak and make it

stronger, usually by making it longer.
What is the

Password–Based Key Derivation Function 2 (PBKDF2)
A part of PKCS #5, it applies some

function (like a hash or HMAC) to a password along with Salt to produce a derived key.
What is

Bcrypt
Used with passwords, it uses a derivative of the Blowfish algorithm, converted to a

hashing algorithm, to hash a password and add Salt to it.
What is

Frequency Analysis
Looking at blocks of an encrypted message to determine if any common

patterns exist. Initially, the analyst doesn't try to break the code, but looks at the patterns in the

message.
What is

Chosen Plaintext
An attacker obtains the ciphertexts corresponding to a set of plaintexts of

their own choosing. This allows the attacker to attempt to derive the key used and thus decrypt

the other messages encrypted with that key.
What is a

Related Key attack
Similar to a chosen–plaintext attack, except the attacker can obtain

ciphertexts encrypted under two different keys. It is a very useful attack if you can obtain the

plaintext and matching ciphertext.
What is a

Brute–Force Attack
Accomplished by applying every possible combination of characters that

could be the key. Although it may take a long time to find the key, it can indeed be found.
What

are the

Three Most Important Concepts in Security
Confidentiality

Integrity

Availability
What is the

Work Factor
An estimate of the amount of time and effort that would be needed to break a

system.
What is a

Message Authentication Code (MAC)
A common method of verifying integrity. It is derived

from the message and a shared secret key.
What is a

Hash–Based Message Authentication Code (HMAC)
A MAC that uses a hashing algorithm

along with a symmetric key.
What is a

Digital Signature
Validates the integrity of the message and the sender. The message is

encrypted using the encryption system, and a second piece of information, the digital signature,

is added to the message. Most implementations also use a hash to verify that the message

has not been altered.
What is

Nonrepudiation
Prevents one party from denying actions they carried out.
What is

Key Escrow
Addresses the possibility that a third party may need to access keys used to

encrypt/decrypt data. The keys are held in an account and made available if the third party

requests them.
What is a

Key Recovery Agent
An entity that has the ability to recover a key, key components, or

plaintext messages as needed. Typically used to access information that is encrypted with

older keys.
What is

Key Registration
The process of providing certificates to users.
What is the

Certificate Revocation List (CRL)
The most widely used method to find out if a key is still valid.

It is literally a list of certificates that a specific CA states should no longer be used.
What is the

Online Certificate Status Protocol (OCSP)
A real–time protocol that is replacing CRLs.
What is

a

Request For Comment (RFC)
The mechanism used to propose a standard. It's a

document–creation process with a set of practices and can be categorized as standard, best

practice, informational, experimental, or historic.
What is the

Internet Engineering Task Force (IETF)
An international community of computer professionals

that is mainly interested in improving the Internet. It is also very interested in security.
What is

the

Internet Society (ISOC)
A professional group whose membership consists primarily of Internet

experts. It oversees a number of committees and groups, including the IETF.
What is the

World Wide Web Consortium (W3C)
An association concerned with the interoperability,

growth, and standardization of the World Wide Web.
What is the

International Telecommunications Union (ITU)
Responsible for virtually all aspects of

telecommunications and radio communication standards world wide.
What is the

Institute of Electrical and Electronics Engineers (IEEE)
An international organization focused

on technology and related standards. It is organized into several working groups and standards

committees, and is actively involved in the development of PKC, wireless, and networking

protocol standards.
What is

Public–Key Infrastructure X.509 (PKIX)
The working group formed by the IETF to develop

standards and models for the PKI environment.
What are the

Public–Key Cryptography Standards (PKCS)
A set of voluntary standards created by RSA and

security leaders. There are 15 published standards.
What is the

X.509 Standard
Defines the certificates formats and fields for public keys. It also defines the

procedures that should be used to distribute public keys and is the standard certificate format

supported by the ITU.
What is an

End–Entity Certificate
The most common certificate, which is issued by a CA to an end

entity.
What is a

CA certificate
Issued by one CA to another CA. The second CA can, in turn, then issue

certificates to an end entity.
What do

All X.509 Certificates contain
Signature

Version

Serial Number

Signature Algorithm ID

Issuer Name

Validity Period

Subject Name

Subject Public–Key Information

Issuer Unique Identifier

Subject Unique Identifier

Extensions
What is

Secure Sockets Layer (SSL)
used to establish a secure communications connection between

two TCP–based machines. The number of steps in the handshake is always between four and

nine, inclusive, based on who is doing the documentation. One of the early steps will always be

to select an appropriate cipher suite to use.
What is

Transport Layer Security (TLS)
A security protocol that expands upon SSL and may replace

SSL in the future.
What is the

Certificate Management Protocol (CMP)
A messaging protocol used between PKI entities, and

is used in some PKI environments.
What is the

XML Key Management Specification (XKMS)
Designed to allow XML–based programs access

PKI services, it is a standard that is build on CMP and uses it as a model.
What is the

Secure Multipurpose Internet Mail Extensions (S/MIME)
A standard used for encrypting email

and contains a signature. It uses the PKCS #7 standard and is the most widely supported

standard used to secure email communications.
What is

Secure Electronic Transaction (SET)
Provides encryption for credit card number that can be

transmitted over the Internet. It was developed by Visa and MasterCard.
What is

Pretty Good Privacy (PGP)
A freeware encryption system. It uses both symmetrical and

asymmetrical systems as a part of its process.
What is

Secure Hypertext Transport Protocol (S–HTTP)
HTTP with message security (added by using

RSA or a digital certificate). Creates a secure message not a secure channel. It can use

multiple protocols and mechanisms to protect the message. It also provides data integrity and

authentication.
What is

Federal Information Processing Standard (FIPS)
A set of guidelines for U.S. federal

government information systems. It is used when an existing commercial or government

system does not meet federal security requirements.
What is

Public–Key Infrastructure (PKI)
A security framework that should work across multiple

vendors, systems, and networks. It is a two–key, asymmetric system with four main

components: Certificate Authority (CA), Registration Authority (RA), RSA (the encryption

algorithm), and digital certificates. Messages are encrypted with a public key and decrypted

with a private key.
What is a

Certificate Authority (CA)
An organization that is responsible for issuing, revoking, and

distributing certificates.
What is a

Certificate
A mechanism that associates the public key with an individual.
What is a

Certificate–Signing Request (CSR)
A request formatted for the CA. It will have the public key you wish to use and your fully

distinguished name (often a domain name).
What is a

Registration Authority
Offloads some of the work from a CA and operates as a middle man. It

can distribute keys, accept registration for the CA, and validate identities. It can not issue

certificates.
What is a

Local Registration Authority (LRA)
Can be used to identify or establish the identity of an

individual for certificate issuance.
What are

Certificate Policies
Define what certificates do (i.e. this certificate can only be used for email,

or this certificate can only be used for e–commerce, etc)
What is a

Certificate Practice Statement (CPS)
A detailed statement the CA uses to issue certificates

and implement its policies. They should discuss how certificates are issued, what measures are

taken to protect certificates, and the rules that CA users must follow in order to maintain their

certificate eligibility.
What is

Certificate Revocation
The process of revoking a certificate before it expires possibly due to

the certificate being stolen, an employee leaving the company, or someone has had their

access revoked.
What is the

Hierarchical Trust Model
Also known as a tree, a root CA at the top provides all of the

information. The intermediate CAs are next and only trust information provided by the root CA.

The root CA also trusts the intermediate CAs that are in their level in the hierarchy and none

that aren't.
What is the

Bridge Trust Model
A peer–to–peer relationship exists among the root CAs. The root CAs can

communicate with one another, allowing cross certification. Each intermediate CA trusts only

the CAs above and below it, but the CA structure can be expanded without creating additional

layers of CAs.
What is the

Mesh Trust Model
Expands the concepts of the bridge model by supporting multiple paths and

multiple root CAs. Each of the root CAs can cross–certify with the other root CAs.
What is the

Hybrid Trust Model
Can use the capabilities of any or all of the trust models.