Network of trusted certificate authority servers. Use asymmetric key pairs and combines software, encryption and services to provide a means of protecting security of business communication and transactions.
Correct Answer: A
PKI https://en.wikipedia.org/wiki/Public_key_infrastructure A public key infrastructure (PKI) is a set of roles, policies, hardware, software and procedures needed to create, manage, distribute, use, store and revoke digital certificates and manage public-key encryption. The purpose of a PKI is to facilitate the secure electronic transfer of information for a range of network activities such as e-commerce, internet banking and confidential email. It is required for activities where simple passwords are an inadequate authentication method and more rigorous proof is required to confirm the identity of the parties involved in the communication and to validate the information being transferred. Incorrect answers: PIKE - stream cipher was invented by Ross Anderson to be a "leaner and meaner" version of FISH after he broke FISH in 1994. Its name is supposed to be a humorous allusion to the pike fish. GOST - hash function, defined in the standards GOST R 34.11-94 and GOST 34.311-95 is a 256-bit cryptographic hash function. It was initially defined in the Russian national standard GOST R 34.11-94 Information Technology - Cryptographic Information Security - Hash Function. The equivalent standard used by other member-states of the CIS is GOST 34.311-95. CA - certificate authority or certification authority (CA) is an entity that issues digital certificates. A digital certificate certifies the ownership of a public key by the named subject of the certificate. This allows others (relying parties) to rely upon signatures or on assertions made about the private key that corresponds to the certified public key. A CA acts as a trusted third party-trusted both by the subject (owner) of the certificate and by the party relying upon the certificate. The format of these certificates is specified by the X.509 or EMV standard.
Question 62
Which of the following is a type of encryption that has two different keys. One key can encrypt the message and the other key can only decrypt it?
Correct Answer: B
Asymmetric Public-key cryptography, or asymmetric cryptography, is a cryptographic system that uses pairs of keys: public keys, which may be disseminated widely, and private keys, which are known only to the owner. The generation of such keys depends on cryptographic algorithms based on mathematical problems to produce one-way functions. Effective security only requires keeping the private key private; the public key can be openly distributed without compromising security. Incorrect answers: Symmetric - Symmetric-key algorithms are algorithms for cryptography that use the same cryptographic keys for both encryption of plaintext and decryption of ciphertext. Block cipher - A block cipher is a deterministic algorithm operating on fixed-length groups of bits, called blocks. It uses an unvarying transformation, that is, it uses a symmetric key. Stream cipher - A stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream (keystream). In a stream cipher, each plaintext digit is encrypted one at a time with the corresponding digit of the keystream, to give a digit of the ciphertext stream.
Question 63
What is the solution to the equation 8 mod 3?
Correct Answer: D
2 https://en.wikipedia.org/wiki/Modulo_operation The modulo operation returns the remainder or signed remainder of a division, after one number is divided by another (called the modulus of the operation). Given two positive numbers a and n, a modulo n (abbreviated as a mod n) is the remainder of the Euclidean division of a by n, where a is the dividend and n is the divisor. The modulo operation is to be distinguished from the symbol mod, which refers to the modulus (or divisor) one is operating from. For example, the expression "5 mod 2" would evaluate to 1, because 5 divided by 2 has a quotient of 2 and a remainder of 1, while "9 mod 3" would evaluate to 0, because the division of 9 by 3 has a quotient of 3 and a remainder of 0; there is nothing to subtract from 9 after multiplying 3 times 3.
Question 64
A protocol for key aggreement based on Diffie-Hellman. Created in 1995. Incorporated into the public key standard IEEE P1363.
Correct Answer: C
Menezes-Qu-Vanstone https://en.wikipedia.org/wiki/MQV MQV (Menezes-Qu-Vanstone) is an authenticated protocol for key agreement based on the Diffie-Hellman scheme. Like other authenticated Diffie-Hellman schemes, MQV provides protection against an active attacker. The protocol can be modified to work in an arbitrary finite group, and, in particular, elliptic curve groups, where it is known as elliptic curve MQV (ECMQV). MQV was initially proposed by Alfred Menezes, Minghua Qu and Scott Vanstone in 1995. It was modified with Law and Solinas in 1998. Incorrect answers: Elliptic Curve - an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. ECC allows smaller keys compared to non-EC cryptography (based on plain Galois fields) to provide equivalent security. Euler's totient - function counts the positive integers up to a given integer n that are relatively prime to n. Blum Blum Shub - a pseudorandom number generator proposed in 1986 by Lenore Blum, Manuel Blum and Michael Shub that is derived from Michael O. Rabin's one-way function.
Question 65
Which of the following was a multi alphabet cipher widely used from the 16th century to the early 20th century?
Correct Answer: D
Vigenere https://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher The Vigenere cipher is a method of encrypting alphabetic text by using a series of interwoven Caesar ciphers, based on the letters of a keyword. It employs a form of polyalphabetic substitution. First described by Giovan Battista Bellaso in 1553, the cipher is easy to understand and implement, but it resisted all attempts to break it until 1863, three centuries later. This earned it the description le chiffre indechiffrable (French for 'the indecipherable cipher'). Many people have tried to implement encryption schemes that are essentially Vigenere ciphers. In 1863, Friedrich Kasiski was the first to publish a general method of deciphering Vigenere ciphers. Incorrect answers: Caesar - Monoalphabetic cipher where letters are shifted one or more letters in either direction. The method is named after Julius Caesar, who used it in his private correspondence. Atbash - Single substitution monoalphabetic cipher that substitutes each letter with its reverse (a and z, b and y, etc). Scytale - Transposition cipher. A staff with papyrus or letter wrapped around it so edges would line up. There would be a stream of characters which would show you your message. When unwound it would be a random string of characters. Would need an identical size staff on other end for other individuals to decode message.
