Can I add salt to my salt for password hash? [duplicate]

Question

Following this tutorial, I got a bunch of questions with this code :

const crypto = require("crypto")

async function hash(password) {
    return new Promise((resolve, reject) => {
        // generate random 16 bytes long salt
        const salt = crypto.randomBytes(16).toString("hex")

        crypto.scrypt(password, salt, 64, (err, derivedKey) => {
            if (err) reject(err);
            resolve(salt + ":" + derivedKey.toString('hex'))
        });
    })
}

Is it worth or relevant to:

• encrypt my salt before saving it to the database (with a key I have for example in a .env file to decrypt it when verifying password)
• concat a random key (another one that I keep in a .env also I guess) to the salt (but I don't add it in the db) and use it for verification also.

For example, the code above will become something like this:

const crypto = require("crypto")

async function hash(password) {
    return new Promise((resolve, reject) => {
        // generate random 16 bytes long salt
        const generatedSalt = crypto.randomBytes(16).toString("hex")
        const salt = `${generatedSalt}${process.env.BASE_SALT}`

        crypto.scrypt(password, salt, 64, (err, derivedKey) => {
            if (err) reject(err);
            const encryptedSalt = someEncryptionfunction(generatedSalt,process.env.SALT_ENCRYPT_KEY)
            resolve(encryptedSalt + ":" + derivedKey.toString('hex'))
        });
    })
}

And the verification function will be like:

async function verify(password, hash) {
    return new Promise((resolve, reject) => {
        const [encryptedSalt, key] = hash.split(":")
        const generatedSalt = someDecryptionfunction(encryptedSalt,process.env.SALT_ENCRYPT_KEY)
        const salt = `${generatedSalt}${process.env.BASE_SALT}`
        crypto.scrypt(password, salt, 64, (err, derivedKey) => {
            if (err) reject(err);
            resolve(key == derivedKey.toString('hex'))
        });
    })
}

Answer 1

There's absolutely no point in encrypting the salt. The salt isn't secret, it just has to be globally unique and unpredictable -- which is already the case when you use random bytes.

Storing the plaintext salt next to the hash is perfectly fine. In fact, algorithms like bcrypt and the newer Argon2 have a specific output format which includes all input parameters (salt, iterations etc.):

$argon2i$v=19$m=65536,t=2,p=4$c29tZXNhbHQ$RdescudvJCsgt3ub+b+dWRWJTmaaJObG

Here, c29tZXNhbHQ (base64-encoded string somesalt) is the salt, separated with a $ sign from the hash.

For scrypt, you could use the generic Password Hashing Competition string format.