Node.js decipher.final() Method

The decipher.final() method is an inbuilt application programming interface of class Decipher within crypto module which is used to return the buffer containing the value of decipher object.

Syntax:

const decipher.final([outputEncoding])

Parameters: This method takes the output encoding as a parameter.

Return Value: This method return the object of buffer containing the deciphered value.

Example 1: In this example, we will use decipher.final() method

Filename: index.js

Javascript

// Node.js program to demonstrate the
// decipher.final() method

// Importing crypto module
const crypto = require('crypto');

// Creating and initializing algorithm and password
const algorithm = 'aes-192-cbc';
const password = 'Password used to generate key';

// Getting key for the decipher object
const key = crypto.scryptSync(password, 'salt', 24);

// Creating and initializing the static iv
const iv = Buffer.alloc(16, 0);

// Creating and initializing the decipher object
const decipher = crypto.createDecipheriv(algorithm, key, iv);

// Encrypted using same algorithm, key and iv.
const encrypted =
    'e5f79c5915c02171eec6b212d5520d44480993d7d622a7c4c2da32f6efda0ffa';

// Updating the data to the decipher
let decrypted = decipher.update(encrypted, 'hex', 'utf8');

// Deciphering data by using
// final() method
decrypted += decipher.final('utf8');

// Display the result
console.log(decrypted);

Output:

some clear text data

Example 2: In this example, we will use decipher.final() method

Filename: index.js

JavaScript

// Node.js program to demonstrate the
// decipher.final() method

// Importing crypto module
const crypto = require('crypto');

// Creating and initializing algorithm and password
const algorithm = 'aes-192-cbc';
const password = 'Password used to generate key';

// Getting key for the decipher object
const key = crypto.scryptSync(password, 'salt', 24);

// creating and initializing the static iv
const iv = Buffer.alloc(16, 0);

// creating and initializing the decipher object
const decipher = crypto.createDecipheriv(algorithm, key, iv);

// Encrypted using same algorithm, key and iv.
const encrypted =
    'e5f79c5915c02171eec6b212d5520d44480993d7d622a7c4c2da32f6efda0ffa';

// Creating and initializing empty buffer
let buf = [];

// Updating the data to the decipher
let decrypted = decipher.update(encrypted, 'hex', 'utf8');

// Pushing the updated data into buffer
buf.push(decrypted);

// Pushing decrypted data into buffer
buf.push(decipher.final('utf8'));

// Display the result
console.log(buf.join(' '));

Output:

some clear text  data

Run the index.js file using the following command:

node index.js

Reference: https://nodejs.org/dist/latest-v12.x/docs/api/crypto.html#crypto_decipher_final_outputencoding