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This article will explain in detail the Linux system to generate random numbers, the quality of the article content is high, so Xiaobian share for everyone to make a reference, I hope you have a certain understanding of related knowledge after reading this article.

The Linux system generates random numbers by using the system environment variable [$RANDOM], such as [echo $RANDOM]. RANDOM has a limited range of random numbers, which can be solved by adding an encrypted string after the random number.

Method 1: Through the system environment variable ($RANDOM)

[root@test ~]# echo $RANDOM11595[root@test ~]# echo $RANDOM21625

RANDOM's random number range is 0~32767, so encryption is not very good. It can be solved by adding an encrypted string (that is, a string related to password generation) after the random number, and finally performing the md5sum operation together and intercepting the last n bits of the result, so that it is impossible to guess the specific result according to the random range 0~32767.

Examples:

[root@test ~]# echo "$RANDOM"|md5sum|cut -c 5-154eaf70019cc

Method 2: Generate random numbers through openssl

Examples:

[root@test ~]# openssl rand -base64 8yB0maNWRoQw=

Random numbers are safe by combining numbers with upper and lower case characters and special characters, which can reach very long digits.

Method 3: Obtain random number by date

Examples:

[root@test ~]# date +%s%N1523402619479946400[root@test ~]# date +%s%N1523402622015235600

Method 4: Generate random numbers by combining/dev/urrandom with chksum

[root@test ~]# head /dev/urandom|cksum2866845253 2890[root@test ~]# head /dev/urandom|cksum2131526544 2440

The/dev/random device stores real-time data about the current operating environment of the system.

It can be seen as the unique value of the system at a certain time and therefore can be used as random metadata. We can read the data inside by reading the file./ dev/urrandom This device has the same data as random. Only, it's a non-blocking random number generator, and reads don't block.

About the Linux system to generate random number method to share here, I hope the above content can be of some help to everyone, you can learn more knowledge. If you think the article is good, you can share it so that more people can see it.

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