How to decrypt data encoded with NaCl cryptographic algorithm using NodeJS?

NaCl, or Networking and Cryptography library, is a powerful cryptographic library that can be used to encrypt and decrypt data.

One of the great things about NaCl is that it is relatively easy to use, even for developers who are not experts in cryptography. In this blog post, we will go over the steps you need to take to decrypt data that has been encoded with the NaCl cryptographic algorithm using NodeJS.

The first step in decrypting data encoded with NaCl is to find a library that can help you with the process. One popular option is the 'ecma-nacl' library, which can be found on npm. This library provides a number of useful methods that can be used to encrypt and decrypt data, so it's well worth checking out.

To decrypt data encoded with NaCl, you will need a few pieces of information:

• The encryption key

• The nonce for the data

• The nonce for the decryption key

• The cipher data

• The cipher decryption key

Once you have all of this information, you can start the decryption process. The first thing you will need to do is convert the string of data into an array of Uint8 values. Usually, this can be done using the TextEncoder and TextDecoder classes in NodeJS. But in our case, we have string of hexadecimal values so we can use this method:

Convert hexadecimal string to an array of Uint8 values

Once you have your data in the correct format, you can begin the decryption process. There are two iterations of decryption that need to be done in this case.

The first iteration is to decrypt the decryption key based on the cipher decryption key, the nonce for the decryption key, and the encryption key. This can be done using the crypto_secretbox_open method from the 'ecma-nacl' library.

let resultKeyBytes = nacl.secret_box.open(decryptionKeyCipherUInt8Array, decryptionKeyNonceUInt8Array, encryptionKeyUInt8Array));
const decryptionKey = Buffer.from(result_bytes).toString("utf8");

The second iteration is to use the decrypted decryption key, the nonce for the data, and the cipher data to decrypt the data itself. This can be done using the crypto_secretbox_open method again.

let result = nacl.secret_box.open(dataCipherUInt8Array, dataNonceUInt8Array, decryptionKeyUInt8Array);

Once you have completed these steps, you should have successfully decrypted your data encoded with NaCl.