A method for cracking modern cryptography. The attacker obtains the cipher texts corresponding to a set of plain texts of own choosing. Allows the attacker to attempt to derive the key. Difficult but not impossible.
Answer(s): A
Chosen Plaintext Attack https://en.wikipedia.org/wiki/Chosen-plaintext_attackA chosen-plaintext attack (CPA) is an attack model for cryptanalysis which presumes that the attacker can obtain the ciphertexts for arbitrary plaintexts. The goal of the attack is to gain information that reduces the security of the encryption scheme.Incorrect answers:Rainbow Tables - precomputed table for caching the output of cryptographic hash functions, usually for cracking password hashes.Transposition - swapping blocks of text.Steganography - the practice of concealing a file, message, image, or video within another file, message, image, or video.
A digital document that contains a public key and some information to allow your system to verify where that key came from. Used for web servers, Cisco Secure phones, E-Commerce.
Answer(s): D
Digital Certificate https://en.wikipedia.org/wiki/Public_key_certificateA public key certificate, also known as a digital certificate or identity certificate, is an electronic document used to prove the ownership of a public key. The certificate includes information about the key, information about the identity of its owner (called the subject), and the digital signature of an entity that has verified the certificate's contents (called the issuer).Incorrect answers:OCSP - Provides certificate validation in real time and will let you know if it is valid or has been revoked.Registration Authority (RA) - omponent of PKI that validates the identity of an entity requesting a digital certificate.Payload - In computing and telecommunications, the payload is the part of transmitted data that is the actual intended message. Headers and metadata are sent only to enable payload delivery. In the steganography - information to be concealed and sent secretly, or the data covertly communicated;
Which one of the following are characteristics of a hash function? (Choose two)
Answer(s): B,C
Correct answers: One-way, Fixed length output https://en.wikipedia.org/wiki/Cryptographic_hash_function A cryptographic hash function is a mathematical algorithm that maps data of arbitrary size (often called the "message") to a bit array of a fixed size (the "hash value", "hash", or "message digest"). It is a one-way function, that is, a function which is practically infeasible to invert.Incorrect answers:Symmetric. Cryptographic algorithms can be categorized into three classes: Hash functions, Symmetric and Asymmetric algorithms. Differences: purpose and main fields of application. Requires a key. Well, technically, this is the correct answer. But in the hash-function, "key" is input data.Fast. Fast or slow is a subjective characteristic, there are many different algorithms, and here it is impossible to say this unambiguously like "Symmetric encryption is generally faster than asymmetric encryption."
Collision resistance is an important property for any hashing algorithm. Joan wants to find a cryptographic hash that has strong collision resistance. Which one of the following is the most collisionresistant?
SHA2https://en.wikipedia.org/wiki/Collision_resistanceCollision resistance is a property of cryptographic hash functions: a hash function H is collision- resistant if it is hard to find two inputs that hash to the same output; that is, two inputs a and b where a b but H(a) = H(b). The pigeonhole principle means that any hash function with more inputs than outputs will necessarily have such collisions; the harder they are to find, the more cryptographically secure the hash function is.Due to the Birthday Problem, for a hash function that produces an output of length n bits, the probability of getting a collision is 1/2^n/2.So, just looking for a hash function with larger "n".The SHA-2 family consists of six hash functions with digests (hash values) that are 224, 256, 384 or 512 bits: SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, SHA-512/256.
How did the ATBASH cipher work?
By substituting each letter for the letter from the opposite end of the alphabet (i.e. A becomes Z, B becomes Y, etc.)https://en.wikipedia.org/wiki/AtbashThe Atbash cipher is a particular type of monoalphabetic cipher formed by taking the alphabet (or abjad, syllabary, etc.) and mapping it to its reverse, so that the first letter becomes the last letter, the second letter becomes the second to last letter, and so on.
Post your Comments and Discuss EC-Council 212-81 exam prep with other Community members:
Our website is free, but we have to fight against AI bots and content theft. We're sorry for the inconvenience caused by these security measures. You can access the rest of the 212-81 content, but please register or login to continue.