How to avoid the duplication of random factors in PHP language development?

In PHP language development, we often need to use random numbers. Random numbers refer to numbers that are generated irregularly within a range. In development, random numbers are often used to generate verification codes, random passwords, salted hashes, and other operations. However, if random numbers appear repeatedly, it is very likely to lead to information leakage, system errors, or vulnerability exposure. Therefore, how to avoid the duplication of random factors in PHP language development is very important.

1. Avoid using the rand() function

In PHP, the rand() function is one of the most commonly used functions to generate random numbers, but it is not reliable. The random numbers generated by the rand() function are based on timestamps, which means that if executed multiple times at the same time, the same result will be obtained.

In addition, the rand() function has periodicity when generating pseudo-random numbers, that is, the random numbers appear cyclically. Therefore, if the generated random numbers are used for key operations such as encryption or authentication, they can be easily cracked or attacked.

2. Use the mt_rand() function

In order to solve the unreliability and periodicity problems of the rand() function, PHP introduces the safer and more efficient random number generation function mt_rand() . The difference between mt_rand() and rand() is that the algorithms for generating random numbers are different.

The mt_rand() function uses the Mersenne Twister algorithm, which is a non-linear random number generation algorithm that is more random and average than the pseudo-random numbers generated by rand(). Therefore, when generating a large number of random numbers, using mt_rand() is faster than rand().

In order to ensure the randomness of random numbers, when using the mt_rand() function, you need to specify the range of random numbers, that is, the minimum and maximum values. For example:

$num = mt_rand(1, 100);

In this code, the random number generated is between 1 and 100.

3. Use the random_int() function

Although the mt_rand() function has solved the problem of the rand() function, in PHP7, a more secure and trustworthy random function has been introduced. Number generation function—random_int() function.

Therandom_int() function uses the Cryptographically Secure Pseudo-Random Number Generator (CSPRNG) algorithm to generate random numbers, which is a new feature in PHP7. CSPRNG is a random number generation algorithm with a higher encryption security level. The random numbers it generates are more random and unpredictable, thus meeting more secure application scenarios.

Similar to the mt_rand() function, the random_int() function requires a specified range. For example:

$num = random_int(1, 100);

4. Use other third-party libraries

In addition to the random number generation function provided by PHP itself, there are Many third-party libraries are available. For example:

1. OpenSSL: PHP comes with the OpenSSL extension, which provides many random number generation functions, such as openssl_random_pseudo_bytes(), openssl_random_pseudo_bytes(), etc.
2. Mcrypt: Mcrypt is a powerful encryption library that has a built-in function mcrypt_create_iv() that generates secure random numbers.
3. SecureRandom: SecureRandom is the standard way to generate random numbers in Ruby, but PHP can also use it through libraries such as phpseclib.

5. Summary

The duplication of random factors is a problem that cannot be ignored in PHP language development. In order to avoid this problem, developers should use more reliable, A more secure way to generate random numbers. (such as mt_rand() and random_int() functions, third-party libraries, etc.), and when using random numbers, you also need to pay attention to operations such as specifying the range and salting the key to ensure the security and stability of the system.

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