decipher.update() method in Node.js-JS Tutorial-php.cn

decipher.update() method in Node.js

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Release： 2023-08-25 08:13:16

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Node.js 中的 decipher.update() 方法

decipher.update() is used to update the decryption with the received data according to the given encoding format. It is one of the built-in methods provided by the Decipher class in the crypto module. If the input encoding is specified, the data parameter is a string, otherwise the data parameter is a buffer

Syntax

decipher.update(data, [inputEncoding], [outputEncoding])

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Parameters

The above parameters are described as follows-

data – It requires data as input passed to update the decrypted content.
inputEncoding - It takes the input encoding as a parameter. Possible input values are hexadecimal, base64, etc.
outputEncoding – It takes the output encoding as a parameter. The input type of this parameter is string. Possible input values are hexadecimal, base64, etc.

Example

Create a file named decipherUpdate.js and copy the following code snippet. After creating the file, run this code using the following command as shown in the example below -

node decipherUpdate.js

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decipherUpdate.js

// Example to demonstrate the use of decipher.final() method

// Importing the crypto module
const crypto = require(&#39;crypto&#39;);

// Initialising the AES algorithm
const algorithm = &#39;aes-192-cbc&#39;;
// Initialising the password used for generating key
const password = &#39;12345678123456789&#39;;

// Retrieving key for the decipher object
const key = crypto.scryptSync(password, &#39;old data&#39;, 24);

// Initializing the static iv
const iv = Buffer.alloc(16, 0);

const decipher = crypto.createDecipheriv(algorithm, key, iv);

// Initializing the decipher object to get decipher
const encrypted = &#39;083bfe1b2f91677e5d00add115be2f1b2e362e190406f5c6b60e86969bf03bff&#39;;
// const encrypted2 = &#39;8d11772fce59f08e7558db5bf17b3112&#39;;

let decryptedValue = decipher.update(encrypted, &#39;hex&#39;, &#39;utf8&#39;);
// let decryptedValue1 = decipher.update(encrypted1, &#39;hex&#39;, &#39;utf8&#39;);

decryptedValue += decipher.final(&#39;utf8&#39;);

// Printing the result...
console.log("Decrypted value -- " + decryptedValue);
// console.log("Base64 String:- " + base64Value)

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Output

C:\homeode>> node decipherUpdate.js
Decrypted value -- Some new text data

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Example

Let’s look at another example.

// Example to demonstrate the use of decipher.final() method

// Importing the crypto module
const crypto = require(&#39;crypto&#39;);

// Initialising the AES algorithm
const algorithm = &#39;aes-192-cbc&#39;;
// Initialising the password used for generating key
const password = &#39;12345678123456789&#39;;

// Retrieving key for the decipher object
crypto.scrypt(password, &#39;salt&#39;, 24,
   { N: 512 }, (err, key) => {
      if (err) throw err;

   // Initializing the static iv
   const iv = Buffer.alloc(16, 0);

   // Initializing the decipher with algo, key and iv
   const decipher = crypto.createDecipheriv(algorithm, key, iv);
   const encrypted = &#39;91d6d37e70fbae537715f0a921d15152194435b96ce3973d92fbbc4a82071074&#39;;

   //Getting the decrypted string value
   const decrypted = decipher.update(encrypted, &#39;hex&#39;, &#39;utf8&#39;);

   // Printing the result...
   console.log("Decrypted value:- " + decrypted);
});

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Output

C:\homeode>> node decipherUpdate.js
Decrypted value:- Some new text data

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