Chpt8Cryptography

Describe how hash functions work and what they are used for.

ANS: Hash functions are mathematical algorithms that generate a message summary or digest to confirm the identity of a specific message and to confirm that there have not been any changes to the content. While they do not create a ciphertext, hash functions confirm message identity and integrity, both of which are critical functions in e-commerce. Hashing functions do not require the use of keys, but it is possible to attach a message authentication code (MAC)—a key-dependent, one-way hash function—that allows only specific recipients (symmetric key holders) to access the message digest.

Describe symmetric and asymmetric encryptions.

ANS: Symmetric Encryption. Encryption methodologies that require the same secret key to encipher and decipher the message are using what is called private key encryption or symmetric encryption. Symmetric encryption methods use mathematical operations that can be programmed into extremely fast computing algorithms so that the encryption and decryption processes are executed quickly by even small computers. The primary challenge of symmetric key encryption is getting the key to the receiver, a process that must be conducted out of band (meaning through a channel or band other than the one carrying the ciphertext) to avoid interception. Asymmetric Encryption. Another category of encryption techniques is asymmetric encryption. While symmetric encryption systems use a single key to both encrypt and decrypt a message, asymmetric encryption uses two different but related keys, and either key can be used to encrypt or decrypt the message. Asymmetric encryption can be used to provide elegant solutions to problems of secrecy and verification. This technique has its highest value when one key is used as a private key, which means that it is kept secret (much like the key of symmetric encryption), known only to the owner of the key pair, and the other key serves as a public key, which means that it is stored in a public location where anyone can use it.

The successor to 3DES is the ____________________ Encryption Standard.

Advanced

___ algorithm, key(s) or cryptovariable(s), and procedures used to perform encryption and decryption.

Cipher

____________________ is the process of making and using codes to secure the transmission of information.

Cryptography

Describe digital certificates.

Digital certificates are public-key container files that allow computer programs to validate the key and identify to whom it belongs. The certificate is often issued and certified by a third party, usually a certificate authority. A digital signature attached to the certificate's container file certifies the file's origin and integrity. A certificate authority (CA) issues, manages, authenticates, signs, and revokes users' digital certificates, which typically contain the user name, public key, and other identifying information.

One of the most widely known cryptographic algorithms is the Data ____________________ Standard, which was developed by IBM and is based on the company's Lucifer algorithm.

Encryption

T or F: As DES became known as being too weak for highly classified communications, Double DES was created to provide a level of security far beyond that of DES.

False, Double is Triple

T or F: Encryption is the process of converting the ciphertext message back into plaintext so that it can be readily understood.

False, Encryption is Decryption

T or F: Symmetric encryption uses two different but related keys, and either key can be used to encrypt or decrypt the message.

False, Symmetric is Asymmetric

The number of horizontal and vertical pixels captured and recorded is known as the image's depth.

False, depth is resolution

T or F: A(n) key is the programmatic steps used to convert an unencrypted message into an encrypted sequence of bits that represent the message.

False, key is algorithm

T or F: Encryption methodologies that require the same secret key to encipher and decipher the message are using what is called public key encryption.

False, public is private

T or F: A(n) registration authority issues, manages, authenticates, signs, and revokes users' digital certificates, which typically contain the user name, public key, and other identifying information.

False, registration is certificate

T or F: To translate means to decrypt, decode, or convert, ciphertext into the equivalent plaintext.

False, translate is decipher

The Secure ____________________ Standard is a standard issued by the National Institute of Standards and Technology.

Hash

Netscape developed the ____________________ Layer protocol to use public key encryption to secure a channel over the Internet, thus enabling secure communications.

Secure Socket Secure Sockets

T or F: A(n) distinguished name uniquely identifies a certificate entity, to a user's public key.

True

T or F: AES implements a block cipher called the Rijndael Block Cipher.

True

T or F: Diffie-Hellman key exchange uses asymmetric encryption to exchange session keys.

True

T or F: Hash algorithms are public functions that create a hash value by converting variable-length messages into a single fixed-length value.

True

T or F: Plaintext or cleartext is the original unencrypted message, or a message that has been successfully decrypted.

True

Also known as the one-time pad, the ____________________ cipher, which was developed at AT&T, uses a set of characters only one time for each encryption process.

Vernam

Hashing functions do not require the use of keys, but it is possible to attach a message ____________________ code.

authentication

A digital ____________________ is an electronic document or container file that contains a key value and identifying information about the entity that controls the key.

certificate

Digital ____________________ are public-key container files that allow computer programs to validate the key and identify to whom it belongs.

certificates

The science of encryption is known as ____________________.

cryptology

A message ____________________ is a fingerprint of the author's message that is compared with the recipient's locally calculated hash of the same message.

digest

To ____________________ means to encrypt, encode, or convert plaintext into the equivalent ciphertext.

encipher

The ____________________ OR operation is a function of Boolean algebra in which two bits are compared, and if the two bits are identical, the result is a binary 0.

exclusive

A(n) ____________________ substitution uses one alphabet.

monoalphabetic

The encapsulating security ____________________ protocol provides secrecy for the contents of network communications as well as system-to-system authentication and data integrity verification.

payload

The more common name for asymmetric encryption is ____________________-key encryption.

public

A(n) ____________________ authority operates under the trusted collaboration of the certificate authority and can be delegated day-to-day certification functions, such as verifying registration information about new registrants, generating end-user keys, revoking certificates, and validating that users possess a valid certificate.

registration

Digital ____________________ are encrypted messages that can be mathematically proven to be authentic.

signatures

The process of hiding messages within the digital encoding of a picture or graphic is called ____________________.

steganography

To use a(n) ____________________ cipher, you substitute one value for another.

substitution

In a(n) ____________________ attack, the attacker eavesdrops on the victim's session and uses statistical analysis of patterns and inter-keystroke timings to discern sensitive session information.

timing

In IPSEC ____________________ mode, only the IP data is encrypted, not the IP headers.

transport

The ____________________ cipher simply rearranges the values within a block to create the ciphertext.

transposition permutation

A mathematical ____________________ is a "secret mechanism that enables you to easily accomplish the reverse function in a one-way function."

trapdoor