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C839v5/D334 Practice Revision Questions and
Answers.
The hash value in bits for MD5 is ____. A. 128 B. 160 C. 256 - Solution 128 Hashing involves taking a _____ length input and producing a _____ length output (message digest). A. fixed; fixed B. variable; fixed C. fixed; variable - Solution variable; fixed The hash value in bits for SHA-1 is ____. A. 128 B. 160 C. 256 - Solution 160 The hash value in bits for MD4 is ____. A. 128 B. 160 C. 256 - Solution 128 IPSec ______ mode involves "end-to-end" encryption; i.e. data remains encrypted from the time it leaves a sender's device to the time it arrives at the receiver's device. A. Tunnel B. Transport C. Trusted - Solution Transport IPSec ______ mode involves encryption from gateway to gateway, i.e. just through the public network space. A. Tunnel B. Transport C. Trusted - Solution Tunnel
A security analyst on a local network using monitoring tools is likely to only be able to read contents of traffic encrypted using IPSec ______ mode. A. Tunnel B. Transport C. Trusted - Solution Tunnel Remember, with tunnel mode, encryption does not happen until just before it leaves the local network. Traffic likely remains unencrypted between the end user device and the local network boundary. _____ is a lightweight cryptography method for signing messages (MAC). It boasts a relatively undemanding hardware implementation (only ~3, gates required at 1MHz clock rate) making it suitable for IoT implementation. - Solution Chaskey Chaskey has a key size of _____ bits. A. 256 B. 128 C. 80 - Solution 128 A weakness of one-way hashing is that the same piece of plaintext will result in the same ciphertext unless _____ is applied. A. Salt B. Ash C. Ether - Solution salt The minimum recommended key size to use with RC4 is _____ bits. A. 40 B. 20 C. 64 - Solution 40 RC4 is a symmetric stream cipher with a variable key size up to a max of _____ bits. A. 256 B. 2048 C. 1024 - Solution 2048 _____ has a block size of 64 bits, key size of 56 bits, and 16 rounds of substitution & transposition. A. DES
B. 128; 64
C. 80; 64 - Solution 128-bit key size; 64-bit IV Skipjack has a block size of _____bits. A. 64 B. 80 C. 128 - Solution 64 PHOTON, SPONGENT, Lesamnta-LW, and Quark are examples of light- weight _____. A. hashing algorithms B. public-key algorithms C. symmetric block ciphers - Solution Light-weight hashing algorithms _____ has a block size of 64 bits, key size of 128 bits, and >17 rounds of substitution & transposition. A. RSA B. DSA C. IDEA - Solution IDEA _______ is a partially homomorphic crypto system that leverages prime number characteristics, operates with a 1024-4096 bit variable key size, and 1 round. A. RSA B. Diffie-Hellman C. Chaskey - Solution RSA Blowfish and Twofish are both _____ ciphers with common key sizes of 128, 192, or 256 bits. A. symmetric block B. symmetric stream C. asymmetric - Solution Symmetric Block _____ is a symmetric block cipher that uses block sizes of 32, 64, or 128 bits and boasts a variable key size up to 2048 bits. A. RC B. RC C. RC5 - Solution RC Quark produces a hash value of _____bits.
A. 128
B. 64 or 112 C. 80 or 128 - Solution 64 or 112 The block size used with XTEA is _____ bits. A. 56 B. 64 C. 80 - Solution 64 The key size used with XTEA is _____ bits. A. 128 B. 256 C. 2048 - Solution 128 Camelia is a _____. A. Hash Algorithm B. Symmetric block cipher C. Symmetric key exchange algorithm - Solution Symmetric block cipher RC6 can best be described as a _____. A. Lightweight Hash Algorithm B. Symmetric Stream Cipher C. Symmetric Block Cipher - Solution Symmetric Block Cipher RC2 has a block size of 64 bits and variable key size up to 128 bits. What is the minimum recommended key size to use when employing RC2? A. 1 B. 40 C. 64 - Solution 40 The light-weight symmetric steam cipher Mickey v2 operates with a key size of ______ bits and an initialization vector (IV) variable up to _____ bits. A. 80; 80 B. 64; 128 C. 128; 64 - Solution 80; 80 RC4 is a(n) _____. A. Symmetric block cipher B. Symmetric stream cipher
A. 40
B. 128
C. 256 - Solution 128 Wi-Fi Protected Access 2 (WPA2) uses 128-bit _____. A. RC B. AES C. ECC - Solution AES _____ substitution is where a single mapping from our alphabet to a cipher alphabet is created. A. Mono-alphabetic B. Polyalphabetic C. Pseudo-random - Solution Mono-alphabetic What step will a certificate authority (CA) take after generating a digital certificate for a requester, but before issuing the certificate to that requester? A. Sign the certificate with the CA's own private key B. Sign the certificate with the CA's own public key C. Sign the certificate with the requester's private key - Solution Sign the certificate with the CA's own private key _______ refers to the mapping of our alphabet to a number of cipher alphabets. A. Mono-alphabetic B. Polyalphabetic C. Pseudo-random - Solution Polyalphabetic _____ is considered to be unbreakable since it only uses its cipher code once. - Solution One-time pad _____ encoding involves 8-bit values and supports up to 256 characters. - Solution ASCII A _____ occurs when two different input values produce the same hash signature. A. collision B. rainbow C. tunnel - Solution collision
_____ is an encoding method with 16-bit values and supports up to 65, characters. - Solution UTF- The light-weight symmetric stream cipher Trivium operates with a key size of ______ bits and an initialization vector (IV) of _____ bits. A. 80; 80 B. 64; 128 C. 128; 64 - Solution 80; 80 A _____ is a tamper-evident and intrusion-resistant physical device that safeguards and manages cryptographic keys and provides cryptographic processing. A. TPM B. HSM C. DES - Solution hardware security module (HSM) A _____ is a dedicated processor that handles hardware-level encryption; allows the use of full disk encryption on a hard drive in a manner that minimizes the impact on system performance. A. TPM B. HSM C. PRNG - Solution trusted platform module (TPM) _____ is a message authentication code (MAC) that can be used to verify the integrity and authentication of the message. It involves hashing the message with a secret key, and thus differs from standard hashing, which is purely a one-way function. A. HMAC B. Rainbow table C. Key escrow - Solution HMAC _____ ciphers make use of a single secret key for both encryption and decryption. - Solution Symmetric Solve by applying the binary XOR function. 1 1 0 1 1 1 0 0 0 0 A. 11011
_____ are used to manage how blocks of data are processed in symmetric encryption. A. Stream ciphers B. Block cipher modes C. Padding - Solution Block cipher modes Which symmetric block cipher modes enable the block cipher to operate like a stream cipher? A. ECB, DES, ECC B. CFB, OFB, CTR C. DSA, RSA, RC6 - Solution CFB, OFB, CTR Symmetric block ciphers make use of _____ to perform substitution as part the encryption process. A. p-boxes B. s-boxes C. IVs - Solution S-boxes PRESENT is a light-weight symmetric block cipher with a key size of 80 or 128 bits, 32 rounds, and ______ bit block size. A. 32 B. 64 C. 128 - Solution 64 ______ cryptography makes use of a key pair (one public, one private) to perform encryption and decryption. If a given key in a key pair is used for encryption, only the opposite key in that key pair can perform the reverse decryption. A. Symmetric B. Asymmetric C. Hash - Solution Asymmetric When encrypting data using symmetric cryptography, which key may need to be exchanged to facilitate decryption? A. Secret key B. Private key C. Public key - Solution Secret key RC5 is a conventional symmetric block cipher that is suitable for light- weight implementations. It has a variable key size with a max of _____bits.
A. 128
B. 256
C. 2048 - Solution 2048 What is the block and key size in bits used by the light-weight symmetric block cipher CLEFIA? A. 64 bit blocks; 64 bit keys B. 64 or 80 bit blocks; 128 bit keys C. 128 bit blocks; 128, 192, or 256 bit keys - Solution 128 bit blocks; 128, 192, or 256 bit keys If Shawn employs public key cryptography to send Sue a digitally signed message, which key will Sue use to decrypt the message? A. Sue's private key B. Shawn's private key C. Sue's public key - Solution Sue's private key _____ is a public key encryption method that is an extension of El Gamal but adds a one-way hashing method which protects against an adaptive chosen ciphertext attack. A. Cramer-Shoup B. Ephemeral C. Key Clustering - Solution Cramer-Shoup With _____ encryption, we can perform mathematical operations on ciphered values i.e., before decryption. A. Polyalphabetic B. Homomorphic C. Quantum - Solution Homomorphic _____ allows for a new unique passcode to be created for each instance, based on an initial seed and for a given time period. A. One Time Passwords (OTP) B. Hashed One Time Passwords (HOTP) C. Timed One Time Password (TOTP) - Solution TOTP Which encoding scheme for x.509 certificates supports Base64 and ASCII formats? A. DER B. PEM
B. light-weight C. conventional - Solution conventional NIST categorizes embedded systems, RFID, and sensor networks as devices within the device spectrum for _____cryptography. A. non-cryptographic B. light-weight C. conventional - Solution light-weight _____ allows a new unique passcode to be created each instance, based on a counter value and an initial seed. A. One Time Passwords (OTP) B. Hashed One Time Passwords (HOTP) C. Timed One Time Password (TOTP) - Solution HOTP _____ computers have fast multiplication circuits, and thus can be used to perform multiplications and search a range of prime numbers at a speed which would break most existing RSA implementations. A.RFID B. Quantum C. Light-weight - Solution Quantum _____ is a light-weight symmetric block cipher with variable block sizes, key sizes, and rounds, that is optimized for hardware implementations. A. SIMON B. SPECK C. PRESENT - Solution SIMON _____ is a light-weight symmetric block cipher with variable block sizes, key sizes, and rounds, that is optimized for software implementations. A. SIMON B. SPECK C. PRESENT - Solution SPECK PRESENT is a symmetric block cipher that was one of the first to be considered as a(n) _____ replacement for light-weight implementations. A. AES B. BIFID
C. CBC - Solution AES Rabbit operates with a key size of ______ bits and an initialization vector (IV) of _____ bits. A. 80; 80 B. 64; 128 C. 128; 64 - Solution 128 bit keys; 64 bit IV ______ is a secret key encryption algorithm, designed by the NSA, and was used with the Clipper chip. A. Blowfish B. Twofish C. Skipjack - Solution Skipjack The IV used with WEP is ____ bits. A. 24 B. 48 C 12 - Solution 24 The IV used with WPA is _____ bits. A. 24 B. 48 C 12 - Solution 48 Two variations of WPA are ____ and ____. A. MIC; MOC B. PSK; enterprise C. transport; tunnel - Solution PSK; enterprise A5/3 is for _____ , and is based on the MISTY1 cipher. A. key transport B. GSM C. 3GPP - Solution 3GPP A5/1 is designed to be used for the _____ network. A. key transport B. GSM C. 3GPP - Solution GSM
With SSL/TLS, the tunnel is created with a _____ key method, and then a signature is created with a defined hashing method. A. asymmetric B. symmetric C. transport - Solution symmetric With a _____ tunnel we aim to create a connection from a host machine to a trusted network, and which is tunneled through a public network A. Virtual Private Network (VPN) B. Telnet C. Virtual machine - Solution Virtual Private Network (VPN) _____ involves using subscriber computers to route data packets over the internet, instead of using publicly available routers. A. Onion routing B. Sandboxing C. Whitelisting - Solution Onion routing With the ____ network, the routing is done using computers of volunteers around the world to route the traffic around the Internet, and within each hop the chances to trace the original source significantly reduces. A. Ethereum B. Cisco C. Tor - Solution Tor Establishing a fingerprint or thumbprint in cryptography is achieved by _____ algorithms. A. symmetric B. asymmetric C. Hash - Solution Hash algorithms such as SHA1 and MD A blockchain mining process where a new block of transactions is added to the blockchain and transactions within the block are considered to be processed occurs every ______ minutes or so. A. 60 B. 30 C. 10 - Solution 10 _____ describes a ledger of transactions that allows the Bitcoin network to know the number of bitcoins that a given user has in their account.
A. BTC
B. Blockchain C. Ether - Solution Blockchain Bitcoin transactions will be captured by ______ who will compile a list of the latest transactions. A. miners B. bankers C. administrators - Solution miners Regarding blockchain, miners receive _____ for successful mining efforts. A. penalties B. rewards C. contracts - Solution rewards _____ are programs stored on a blockchain that run when predetermined conditions are met; they typically are used to automate the execution of an agreement so that all participants can be immediately certain of the outcome, without an intermediary's involvement or time loss. A. Pseudo codes B. Smart contracts C. Miners - Solution Smart contracts Within Ethereum applications we define the concept of _____. This is basically the unit that is used to measure the amount of work that is required to perform a single Keccak-256 hash. A. gas B. mining C. smart contracts - Solution gas A _____ backdoor describes an instance where it is where it is mathematically possible for government agents to crack the encryption, but no-one else can. A. true random B. key escrow C. NOBUS - Solution NOBUS ('nobody but us') Cipher cracking method where the intruder uses brute force to decrypt the ciphertext and tries every possible key. A. Exhaustive search.
An alterative to the CRL is to use_____, an online service used to check the validity of a certificate. A. OSCP B. OCSP C. OWASP - Solution Online Certificate Status Protocol (OCSP) What is the main difference between a certificate in revoked status and a certificate in hold status? - Solution Hold status can be reversed; revoked status cannot be reversed A certificate that has been compromised, updated, or superseded warrants being ______. A. escrowed B. signed C. revoked - Solution revoked A ____attack involves determining the amount of time that a user takes to decrypt the message; from this the key could be found. A. Time B. Time resetting C. Replay - Solution Time Attack A ___ attack is where an attacker mixes parts of two different encrypted messages and is able to create a new message. This message is likely to make no sense but may trick the receiver into doing something that helps the intruder. A. Replay B. Man-in-the-middle C. Cut-and-paste - Solution Cut-and-paste ____ describes an instance where an attacker takes a legitimate message and sends it into the network at some future time. A. Crypto Spoofing B. The replay system C Known plaintext attack - Solution The replay system A ___ attack occurs when an attacker is hidden between two parties and impersonates each of them to the other. A. Time resetting B. Man-in-the-middle
C. Brute force - Solution Man-in-the-middle Key escrow and NOBUS (nobody but us) are two methods that can facilitate a ____ condition in cryptography. A. backdoor B. lockout C. exhaustive - Solution backdoor Ethereum, and Hyperledger are considered common options for implementing _____. A. secure tunnels B. Message digests C blockchain - Solution blockchain ___ is an early cipher that makes use of a grid and which maps the letters into numeric values. A. Pigpen B. Caesar C. Bifid - Solution Bifid _____ is an early cipher that uses a 5 × 5 matrix containing the alphabet less the letter J. Cipher/decipher process consists of a set of rules outlining use of column and row combinations. A. Pigpen B. Playfair C. Enigma - Solution Playfair ______ is a mono-alphabetic substitution cipher that makes use of mapping plaintext characters to graphical characters rather than to alphabetic ones. A. Pigpen B. Playfair C. Enigma - Solution Pigpen ______ is polyalphabetic early cipher that involves using a different mapping, based on a keyword, for each character of the cipher. A. Rail Code B. Playfair C. Vigenere - Solution Vigenere
