The principle of choosing a random number generator. Random number generator

All phenomena that happen to us are of two types - random and natural. For example, you didn’t have enough bills to buy a tape recorder, and you decided to buy a player - i.e. the action is logical and expected. But, walking to the store, you discover the required amount, which randomly changed plans. Generator operation random numbers completely depends on the mechanism specified in the operator, so that all numbers that are issued are pseudo-random in the current event. Operators that return random numbers, refer to time, namely system time. Those. Both in the world and in programming, nothing is completely absolute.

rand function

In C programming, built-in operators were invented to obtain random values, which give us the required results. And so, to create a random number, use rand function, which rand operator used to obtain random numbers that return a range from 0 to a certain constant. Moreover, this constant is declared in the system directive “stdlib.h”, where this rand function is based. The syntax of this function is simple: int m= rand(); those. an integer is returned. After testing the operator in practice, you will see that the numbers that appear when the application starts are identical. The oversight is that the rand operator works with the same system time, which was preserved during compilation. This generator random numbers is tied to an algorithm for changing program time, then everything works incorrectly.

Now about srand and random

For this problem, a function that would reset the built-in time to zero every time the rand operator was called was indispensable, and the software developers did srand function. The action allows the rand function to access each time not the installed, but the current built-in timer, which opens up the possibility for the generator to work correctly - to issue random values. Recently, in C++ programming, the mechanism for issuing random numbers has been improved due to the appearance of microseconds. In addition, the range of values ​​​​has expanded, and all current innovations have been transformed into the random function.

Etc., and is used by account owners to attract new audiences to the community.

The result of such drawings often depends on the user's luck, since the recipient of the prize is determined randomly.

To make this determination, lottery organizers almost always use an online or pre-installed random number generator that is distributed free of charge.

Choice

Quite often, choosing such a generator can be difficult, since their functionality is quite different - for some it is significantly limited, for others it is quite wide.

Enough is being implemented a large number of such services, but the difficulty is that they differ in scope.

Many, for example, are tied in their functionality to a certain social network(for example, many generator applications only work with links from this one).

Most simple generators they simply randomly determine a number within a given range.

This is convenient because it does not associate the result with a specific post, which means it can be used for sweepstakes outside the social network and in various other situations.

They essentially have no other use.

Advice! When choosing the most suitable generator, it is important to consider what it will be used for.

Specifications

For the fastest process of choosing the optimal online service for generating random numbers, the table below shows the main technical characteristics and functionality of such applications.

All applications discussed in the table are described in more detail below.

RandStuff

You can use this application online by following the link to its official website http://randstuff.ru/number/.

This is a simple random number generator, characterized by fast and stable operation.

It is successfully implemented both in the format of a separate stand-alone application on the official website, and as an application in .

The peculiarity of this service is that it can select a random number both from a specified range and from a specific list of numbers that can be specified on the site.

• Stable and fast work;
• Lack of direct connection to a social network;
• You can select one or several numbers;
• You can only choose among the specified numbers.

User reviews about this application are as follows: “We determine winners in VKontakte groups through this service. Thank you,” “You are the best,” “I only use this service.”

Cast Lots

This application is a simple function generator, implemented on the official website in the form of a VKontakte application.

There is also a generator widget for inserting into your website.

The main difference from the previous described application is that this allows you to disable the repetition of the result.

Every day, everything more people interested in online casinos. For some, these games are simply entertainment, while others consider them a means of earning money. Probably each of the players will be interested in how the random number generator works, which produces lucky combinations.

Slot machine device

Modern slot machines http://igrat-avtomati-wulcan.com have a rather complex algorithm that produces winning combinations. It can be divided into parts: Sensors in the form of generators, a counter that accepts payment and gives out winnings, a storage system for big prizes in the form of a jackpot, an algorithm in the form of a kernel for issuing winning funds. These Algorithms are formed into a mechanical structure in the form of slots or roulette.

Sensor of random combinations and numbers. (RNG)

Now we can describe the operation of the RNG itself. Such sensors were developed with the intention of making the game as unpredictable as possible. This scheme works due to an equally probable factor, for example, it stops the ball in different holes on the roulette wheel. With slots, the system works exactly the same, only it stops the symbols.

In a modern gaming slot, the developer can install more than one RNG. If we take the game three sevens as an example, there may be several sensors for individual combinations, as well as separate species sensor to stop the numbers of a digital wheel or drum.

In Games like Polka Miracles, sensors are installed to stop the numbers in the game, as well as sensors that calculate the time interval of each game and record the transition to other playing fields. The use of more than one sensor is intended to reduce the number of random wins. Also, for large prizes in the form of jackpots, separate sensors are usually installed that give winning combination by chance that cannot be calculated.

If we consider a random number generator from a mathematical point of view, it is impossible to calculate its operation using various formulas. However, if you take into account an already winning situation, and carry out calculations from the beginning of one game to the end, then you can still write the formula. It is sad that after the jackpot is issued, the generation of numbers will continue according to a new formula, which will be known only by the outcome of the game.

There is also an opinion that the owner of the machine can configure the sensor settings in such a way that each winning slot will appear, conditionally, every 300 or 500 games, however, the owner himself cannot know exactly how many derived algorithms will result in an exact win. But the fact that the sensors are adjustable is a fact. In order to avoid a conflict of interest, they install not one sensor, but several, otherwise the owner of the gambling house would always remain in the black, and otherwise the sensor could be figured out by any skilled person and clear the casino cash register in an almost legal way.

The principle of operation of the random number generator is known for its unpredictability, however, it is at least somewhat amenable to analysis, but coupled with a couple more sensors, everything becomes much more confusing, which makes the casino a gambling success, which is why it is extremely popular all over the world.

Random numbers are a simple element of cryptography that is the least talked about, but is just as important as the rest. Almost all computer security systems that use cryptography require random numbers - for keys, unique numbers in protocols, etc. - and the security of such systems often depends on the randomness of its random numbers. If the random number generator is unreliable, the entire system breaks down.

Depending on who you talk to, generating random numbers looks either trivial or impossible. Theoretically this is impossible. John von Neumann, the father of computing, said: “Anyone who believes that there are arithmetic methods for obtaining random numbers"is certainly sinning." He meant that it is impossible to get anything random in the full sense of the word out of such a deterministic beast as a computer. This is true, but fortunately there are some things we can do. What we need from a random number generator is not that the numbers are truly random, but that they cannot be predicted and reproduced. If we have these two conditions met, we can achieve security.

On the other hand, if we violate these two conditions, there is no security. In 1994, a computer random number generator for lotteries was installed in a Montreal casino. One observant player who spent a lot of time in the casino noticed that winning numbers were the same every day. He successfully hit three Jackpots in a row and received $600,000. (After wringing their hands, gnashing their teeth and investigating everything, the casino paid the winnings.)

There are several broad classes of random number generators. Some of them are based on physical processes that can be considered quite random. The National Security Agency likes to use electrical noise from diodes in its equipment to create random numbers. Other possibilities are Geiger counters or radio interference receivers. One system on the Internet uses digital camera, aimed at several strobes. Other systems use air turbulence in the drives or the timing of network packets.

Some random number generators track the user's random movements. The program may ask the user to type a large string of arbitrary characters on the keyboard; it can use a sequence of characters or even the time between keystrokes to generate random numbers. Another program can easily require the user to move the mouse back and forth or grunt into the microphone.

Some random number generators apply this entered information without modification. In others, it serves as a seed (initial number) for mathematical random number generators. This technique works best if the system requires more random numbers than the input provides.

Whatever the origin of the randomness, the generator will create a series of random bits. They can then be used as cryptographic keys and for everything else the system needs.