Crypto.randomBytes in Node.js

In this article, we will discuss Crypto.randomBites in Node.js with its syntax, parameters, and examples. The crypto module in Node.js offers many cryptographic functionalities to assist developers in building secure applications. One of the most important functions in this module is crypto.randomBytes. This function is important if we need to generate random data that is guaranteed to be unpredictable and can be used for different purposes such as encryption, token generation, etc.

Purpose of Crypto.randomBytes

The main function of crypto.randomBytes is used to create random data of Buffer type. This random data is obtained from the cryptographically secure pseudo-random number generator (CSPRNG). It means that the bytes produced by a CSPRNG can be used for security-critical operations in the system.

Syntax:

It has the following syntax:

Parameters:

It takes two parameters in the function

• Size: Size indicates the number of bytes to be returned as the output.
• Callback: It is a function that is made of two parameters err and buf. These bytes are generated synchronously. If a callback function is available in the stated code, the bytes are generated asynchronously.

Return Type:

If the callback function is given, it returns a Buffer.

Example 1:

Let us take an example to illustrate the crypto.randomBytes() function in Node.js.

Output:

 The random data generated is: 5f90b49342105bd7f08aa0dd259f4188d3a16d947320544aec573c608842c16822eea9981b3f455df96faca6b6c59fec8ca8d6f9d13ea6596fdab2f6f42a14b876c365f86d0d6e87b67e4afec7d934cf86c7a5acfa9c1544d3e21ad7a0ac30e77fb8b280d8705960789e3ebd7c9e359708cf991683427d54eadfeb3ad8a68c 

Explanation:

• The above node.js program shows how to use crypto.randomBytes() method for the generation of random data of the required size, which is cryptographically safe. First, the program uses the required libraries, such as the crypto module, which provides the usage of the cryptographic functions.
• After that, the randomBytes function is called with two parameters: the number of random bytes to generate where 127 has been used and a callback function to write the result. There is also error-checking in the callback function to check if there is any error when generating the filled-in PDF forms. The error message will be printed to the console, and the function will terminate.
• When no error occurs, the random bytes generated is stored in a buffer, and then converted to Hexa decimal string by the buffer.toString('hex'). This hexadecimal string is printed to the console so that you have an easily readable format of the random data.

Example 2:

Let us take another example to illustrate the crypto.randomBytes() function in Node.js.

Output:

 The random data generated is: 107b8b331a931014fbacfb8cc3c8ce692af6613c11a94e8347fb887b7f7b95697857ffa439c0a7396fd8fd495d1d45464a73ec2a821636b65ab4bb2b 

Explanation:

• This Node.js program shows the application of crypto. The randomBytes() method is used to generate random data of a specific size that is also considered secure for encryption. The randomBytes() method is called with the argument 60 in which 60 random bytes should be generated. This method is also synchronous, it blocks the event loop until the random bytes are generated completely and are stored in a Buffer object.
• From this buffer, the program proceeds to convert it into a hexadecimal string using the function, buffer.toString('hex') is one of the formats that is most commonly used to represent binary data in a readable format. Finally, the program prints this hexadecimal string to the console with a descriptive message: "The random data generated is: ". This approach is useful where there is a need to generate simple and secure, random data such as tokens or keys.

Conclusion:

In conclusion, the crypto.randomBytes method in Node.js is an effective way of generating strongly protected random data by using mathematical computing. It generates random numbers for secure applications where the use of random numbers is required, such as encryption, tokenization, and other security-related tasks.

The crypto module provides a method for generating random bytes, which can be synchronous or asynchronous based on the parameter of the last argument. The synchronous version is basic and blocks the event loop until the random bytes are generated, whereas the async version allows the application to do other things while waiting on the random data.