Hashing and Regrex

Question 1

What is hashing

Answer 1

Hashing is a cryptographic process that can be used to validate the authenticity and integrity of various types of input.

Hashing is a way of transforming your a file into a unique identifier that are hard to invert and essentially reverse.

Question 2

What is Hashing algroithm

Answer 2

A hashing algorithm is a cryptographic hash function. It is a mathematical algorithm that maps data of arbitrary size to a hash of a fixed size.

It is designed to be a one way function

Question 3

Types of hashing algo

Answer 3

MD5, SHA, CRC

Question 4

Describe MD

Answer 4

(MD stands for Message Digest): An MD5 hash function encodes a string of information and encodes it into a 128-bit fingerprint. It is one of the most commonly used yet amongst the most unsecure algorithms. Suffers extensive hash collision vunlerabilites

Question 5

Describe SHA

Answer 5

Secure Hash Algorithm (SHA-0, SHA-1, SHA-2 family of algorithms) SHA-2 developed by the National Security Agency (NSA). The SHA-2 family consists of six hash functions with digests (hash values) that are 224, 256, 384 or 512 bits

Question 6

Describe CRC

Answer 6

CRC (cyclic redundancy code):A cyclic redundancy check (CRC) is an error-detecting code often used for detection of accidental changes to data

Encoding the same data string using CRC32 will always result in the same hash output, thus CRC32 is sometimes used as a hash algorithm for file integrity checks.

Question 7

Give an example of using the hash password techniques

Answer 7

MessageDigest msgDigest = MessageDigest.getInstance(“SHA-256”);
msgDigest.update((new String(msg)). getByte(“UT8”));
String hash = new String(msgDigest.digest());

Question 8

Describe salt

Answer 8

Another best practice for secure password storage is to combine each password with a randomly generated string of characters called a “salt” and then to hash the result

Salting also prevents attackers from discovering duplicate passwords in a database. 16 characters long

Question 9

Describe Pepper

Answer 9

To add another layer of security, in addition to salts, developers can also combine all passwords with a randomly generated string of at least 32 characters called a pepper.

Unlike a salt, which is unique for every password, the pepper is the same for all passwords but should not be stored inside the database.