Take, for example, scrambled eggs. First, break the shell, pour the contents into a bowl and vigorously whisk to the desired result – in general, scrambled eggs. This action by mixing egg molecules is encoding. Because the molecules are mixed together, we say that the egg has reached a higher state of entropy (a state of chance). Returning the scrambled eggs to its original form (including the removal of the shell) is a decipherment. That’s impossible?

However, if we replace the word “egg” with “number,” “molecules” to “numbers,” it’s REALLY. This is, my friend, an exciting world of cryptocurrency (for the shortness of cryptocurrency). This is a new field dominated by talented mathematicians using terms such as “non-linear polynomial relationships,” “override systems of multidimensional polynomial equations,” “Galois fields,” etc.

Everything stored on the computer consists of numbers. Your MP3 is a song. Your SMS is a number. Your address book is a longer number. Number 65 is the letter “A,” 97 is a small letter “a” and so on.

For humans, we recognize numbers with numbers from 0 to 9, otherwise the computer can only recognize 0 or 1. It is a binary system that uses bits instead of numbers. To convert bits into numbers, simply multiply the number of bits by 0.3 to get a good score. For example, if you have 256 bits of Indonesian rupee (one of the lowest currencies in the world), Bill Gates’ wealth compared to that would be microscopic.

The hexa system (base 16) uses ten digits from 0 to 9 plus six additional characters from A to F. This set consists of sixteen different “digits”, hence the name of the hex. This notation is useful for computer professionals to look at the “real content” stored in the computer. You can also view these different digital systems as currency, be it the euro, the Swiss franc, the British pound, etc.

Have you ever wondered why you need to study simple numbers at school? I’m sure most math teachers don’t know this answer. Answer: A branch called open-key cryptography, which uses simple numbers, particularly to encrypt email. There they talk about even larger numbers, such as 2048, 4096, 8192 bits.)

If we want to encrypt something, we have to use the number. The number is just an algorithm similar to a baking recipe. He has clear and unambiguous steps. You’ll need a key (some call it a password) to complete the encryption process. In cryptography, it is considered good practice that the key used in encryption has a high entropy to ensure efficiency.

The Data Encryption Standard (DES), introduced as a standard in the late 1970s, was the most commonly used encryption in the 1980s and early 1990s. It uses a 56-bit key. It was destroyed in the late 1990s with specialized computers costing about $250,000 in 56 hours. With today’s equipment (2005) you can crack in one day.

Triple-DES subsequently replaced DES as a logical way to maintain compatibility with previous investments by large companies (mostly banks). It uses two 56-bit keys in three stages:

- Encrypt with key 1.
- Deciphering with Key 2.
- Encrypt with key 1.

The effective key length used is only 112 bits (equivalent to 34 digits). The key is the random number from 0 to 5192296858534827628530496329220095. Some modify the last process with Key 3, making it more efficient with 168-bit keys.

Advanced Encryption Standard (AES) was adopted as a standard in 2001 by the U.S. National Institute of Standards and Technology (NIST). AES is based on the Rijndael cipher (pronounced “rhino doll”) developed by two Belgian cryptographers Victor Reimen and Joan Daymen. Usually AES uses 256 bits (equivalent to 78 digits) for keys. The key is the number from 0 to 159208923731619542357098500868788532699984665640394558400791312963935. This number coincides with the approximate number of atoms in the universe.

The National Security Agency (NSA) approved the AES in June 2003 to protect key secrets in U.S. government agencies (subject, of course, to their approval of implementation methods). They say that they can listen to all the phone conversations in the world. In addition, the organization is recognized as the largest employer of mathematicians in the world and possibly the largest consumer of computer equipment in the world. The NSA probably has cryptographic experience many years ahead of society and can undoubtedly hack many systems used in practice. For national security reasons, almost all information about the NSA – even its budget – is classified.

In fact, a brute force attack involves using all possible combinations to decrypt encrypted material.

A dictionary attack is usually associated with text passwords using commonly used passwords. The total number of passwords frequently used is surprisingly small from a computer point of view.

An adversary is someone, whether it’s an individual, a company, a business rival, an enemy, a traitor, or a government agency that is likely to benefit from “access to your encrypted secrets.” A decisive adversary is someone who has more brains and resources. The best form of security is not to have opponents (almost impossible to get to them), it is best not to have decisive opponents!

Keylogger is software or hardware for recording all keystrokes. This is by far the most effective mechanism for cracking the implementations of crypto systems based on passwords. Software keyloggers are more common because they are small, work in stealth mode and are easy to download from the Internet. Advanced keyloggers can work on a target computer silently and remotely deliver registered information to the user who initiated this covert surveillance session. Monitoring keystrokes, like anything else created by people, can be useful or harmful, depending on the monitor’s intentions.

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