Cryptography Study Notes
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In 1953, Giovan Batista Belaso introduced the idea of the passphrase (password) as a key for encryption.

False

In 1917, Gilbert S. Vernam, an AT&T employee, invented a polyalphabetic cipher machine that used a non-repeating random key.

True

Sequence encryption is a series of encryptions and decryptions between a number of systems, wherein each system in a network decrypts the message sent to it and then reencrypts it using different keys and sends it to the next neighbor. This process continues until the message reaches the final destination.

False

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

<p>True</p> Signup and view all the answers

In addition to being credited with inventing a substitution cipher, Julius Caesar was associated with an early version of the transposition cipher.

<p>True</p> Signup and view all the answers

You cannot combine the XOR operation with a block cipher operation.

<p>False</p> Signup and view all the answers

To perform the Caesar cipher encryption operation, the pad values are added to numeric values that represent the plaintext that needs to be encrypted.

<p>False</p> Signup and view all the answers

One encryption method made popular by spy movies is the book cipher, which involves using the text in a book to encrypt and decrypt messages.

<p>True</p> Signup and view all the answers

Hashing functions require the use of keys.

<p>False</p> Signup and view all the answers

A cryptovariable is a value representing the application of a hash algorithm on a message.

<p>False</p> Signup and view all the answers

A brute force function is a mathematical algorithm that generates a message summary or digest (sometimes called a fingerprint) to confirm message identity and integrity.

<p>False</p> Signup and view all the answers

Popular cryptosystems use a hybrid combination of symmetric and asymmetric algorithms.

<p>True</p> Signup and view all the answers

The AES algorithm was the first public-key encryption algorithm to use a 256-bit key length.

<p>False</p> Signup and view all the answers

When an asymmetric cryptographic process uses the sender's private key to encrypt a message, the sender's public key must be used to decrypt the message.

<p>True</p> Signup and view all the answers

Asymmetric encryption systems use a single key to both encrypt and decrypt a message.

<p>False</p> Signup and view all the answers

Usually, as the length of a cryptovariable increases, the number of random guesses that have to be made in order to break the code is reduced.

<p>False</p> Signup and view all the answers

PKI systems are based on public-key cryptosystems and include digital certificates and certificate authorities.

<p>True</p> Signup and view all the answers

The registration authority (RA) is a third party that issues, manages, authenticates, signs, and revokes users' digital certificates.

<p>True</p> Signup and view all the answers

The most common hybrid system is based on the Diffie-Hellman key exchange, which is a method for exchanging private keys using public-key encryption.

<p>True</p> Signup and view all the answers

Steganography is a data hiding method that involves embedding information within other files, such as digital pictures or other images.

<p>True</p> Signup and view all the answers

Standard HTTP (S-HTTP) is an extended version of the Hypertext Transfer Protocol that provides for the encryption of individual messages transmitted via the Internet between a client and server using AES over HTTP.

<p>False</p> Signup and view all the answers

SSL builds on the encoding format of the digital encryption standard (DES) protocol and uses digital signatures based on public-key cryptosystems to secure e-mail.

<p>False</p> Signup and view all the answers

Bluetooth is a de facto industry standard for short-range wireless communications between devices.

<p>True</p> Signup and view all the answers

Secure Electronic Transactions was developed by MasterCard and Visa in 1997 to protect against electronic payment fraud.

<p>True</p> Signup and view all the answers

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

<p>True</p> Signup and view all the answers

Nonrepudiation means that customers or partners can be held accountable for transactions, such as online purchases, which they cannot later deny.

<p>True</p> Signup and view all the answers

Adopted by NIST in 1976 as a federal standard, DES uses a 64-bit block size and key.

<p>False</p> Signup and view all the answers

3DES was created to offer the same strength as the DES algorithm but ran three times as fast, thus saving time.

<p>False</p> Signup and view all the answers

Ciphertext or a cryptogram is an encoded message, or a message that has been successfully encrypted.

<p>True</p> Signup and view all the answers

In a book cipher, the key consists of a list of codes representing the page number, line number, and word number of the plaintext word.

<p>False</p> Signup and view all the answers

Hash algorithms are mathematical functions that create a message digest by converting variable-length messages into a single fixed-length value.

<p>True</p> Signup and view all the answers

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

<p>False</p> Signup and view all the answers

A multipart authentication code (MAC) is a key-dependent, one-way hash function that allows only specific recipients (symmetric key holders) to access the message digest.

<p>True</p> Signup and view all the answers

Encryption methodologies that require the same secret key to encipher and decipher the message are using public-key encryption.

<p>False</p> Signup and view all the answers

PKI is the a federal information processing standard that specifies a cryptographic algorithm developed to replace both DES and 3DES.

<p>False</p> Signup and view all the answers

AES implements a block cipher called the Rijndael Block Cipher with a variable block length and a key length of 128, 192 or 256 bits.

<p>True</p> Signup and view all the answers

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

<p>False</p> Signup and view all the answers

Within a PKI, 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.

<p>True</p> Signup and view all the answers

The Digital Signature Standard established by NIST is used for electronic document authentication by federal information systems. It is based on a variant of the ElGamal algorithm.

<p>True</p> Signup and view all the answers

A(n) distinguished name uniquely identifies a certificate entity to a user's public key.

<p>True</p> Signup and view all the answers

Diffie-Hellman key exchange uses asymmetric encryption to exchange session keys - limited use symmetric keys for temporary communications.

<p>True</p> Signup and view all the answers

HTTPS is an extended version of Hypertext Transfer Protocol that provides for the encryption of protected e-mail transmitted via the Internet between a client and server.

<p>False</p> Signup and view all the answers

Privacy Enhanced Mail was proposed by the Internet Engineering Task Force and is a standard that uses 3DES symmetric key encryption and RSA for key exchanges and digital signatures.

<p>True</p> Signup and view all the answers

Secure Multipurpose Internet Mail Extensions builds on the encoding format of the MIME protocol and uses digital signatures based on public-key cryptosystems to secure e-mail.

<p>True</p> Signup and view all the answers

In IPSec transport mode, only the IP data is encrypted, not the IP headers.

<p>True</p> Signup and view all the answers

Originally released as freeware, Pretty Good Privacy is a hybrid cryptosystem that combines some of the best available cryptographic algorithms as an open-source de facto standard for encryption and authentication of e-mail and file storage.

<p>True</p> Signup and view all the answers

The process of obtaining the plaintext message from a ciphertext message without knowing the keys used to perform the encryption is called cryptanalysis.

<p>True</p> Signup and view all the answers

The science of encryption is known as .

<p>False</p> Signup and view all the answers

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

<p>True</p> Signup and view all the answers

A(n) or cryptosystem is an encryption method or process encompassing the algorithm, key(s) or cryptovariable(s), and procedures used to perform encryption and decryption.

<p>True</p> Signup and view all the answers

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

<p>True</p> Signup and view all the answers

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

<p>True</p> Signup and view all the answers

In a(n) cipher, you replace one value with another.

<p>True</p> Signup and view all the answers

A(n) substitution uses one alphabet.

<p>True</p> Signup and view all the answers

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

<p>True</p> Signup and view all the answers

The 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.

<p>True</p> Signup and view all the answers

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.

<p>True</p> Signup and view all the answers

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

<p>True</p> Signup and view all the answers

Hashing functions do not require the use of keys, but it is possible to attach a message code to allow only specified recipients to access the message digest.

<p>True</p> Signup and view all the answers

The Secure Standard issued by the National Institute of Standards and Technology specifies secure algorithms, such as SHA-1, for computing a condensed representation of a message or data file.

<p>True</p> Signup and view all the answers

One of the most widely known cryptographic algorithms is the which was developed by IBM and is based on the company’s Lucifer algorithm.

<p>True</p> Signup and view all the answers

The successor to 3DES is the Encryption Standard.

<p>True</p> Signup and view all the answers

The more common name for asymmetric encryption is _key encryption.

<p>True</p> Signup and view all the answers

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

<p>True</p> Signup and view all the answers

In the context of a PKI, 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.

<p>True</p> Signup and view all the answers

Digital 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 certificate authority (CA) issues, manages, authenticates, signs, and revokes users’ digital certificates, which typically contain the user name, public key, and other identifying information.

<p>True</p> Signup and view all the answers

Are encrypted messages that can be mathematically proven to be authentic.

<p>True</p> Signup and view all the answers

Is an electronic document or container file that contains a key value and identifying information about the entity that controls the key.

<p>True</p> Signup and view all the answers

Study Notes

Cryptography Study Notes

  • Cryptography is the science of encryption
  • Cryptanalysis is the process of deciphering encrypted messages.
  • Ciphertext is an encoded message
  • Plaintext is the original message before encryption.
  • Key is a sequence of characters used in conjunction with an algorithm to encrypt and decrypt messages.
  • Algorithm is a set of instructions to change plaintext into ciphertext
  • Hash functions are mathematical algorithms used to create a message digest that confirms the identity of a message and confirms there are no changes to the content.
  • Digital certificates are public-key container files that allow computer programs to validate keys and identifying information.
  • P(ublic) K(ey) I(nfrastructure) (PKI) is a system that consists of software, encryption methodologies, protocols, legal agreements and third-party services to facilitate secure communications.
  • Steganography is a data hiding method using a cover file such as a picture or image to hide information within the cover file.
  • Symmetric encryption uses the same key to encrypt and decrypt a message
  • Asymmetric encryption uses two different but related keys. Either key can be used to encrypt or decrypt a message; one key is private, the other is public.
  • Cipher can use substitution or transposition
  • Password is a sequence of characters used by an authorized user to access a system
  • XOR operation is a bitwise operation comparing two different values to create a third value.
  • Block cipher an encryption algorithm with a block size often used for digital encryption.
  • One time pad is a method used to encrypt a message by using a unique key for each encryption process.
  • Digital Signature Standard (DSS) is a U.S. federal information processing standard for digital signatures.
  • Advanced Encryption Standard (AES) is a symmetric-key algorithm used in government to protect information.
  • Pretty Good Privacy (PGP) is a popular cryptographic algorithm that has become a standard for e-mail and file encryption.
  • RSA is a popular public-key encryption algorithm; keys are created, one published and one private.

Cryptography History

  • Significant events and discoveries in the history of cryptography are covered, including important figures and pivotal points in the development of cryptographic systems. This also includes early forms of cipher development.

Major Cryptographic Protocols

  • Covers significant details about major protocols used for secure communication including SSL, HTTPS, TLS etc.

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Mod 10 Cryptography Quiz PDF

Description

Explore the essential concepts of cryptography and cryptanalysis through this quiz. Understand key terms such as ciphertext, plaintext, algorithms, and hash functions. This quiz will test your knowledge of encryption methodologies and digital security.

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