Node crypto sign & verify

crypto.js

const id         = '__JUNK__';
// Public key need to be in PKCS8 format
// ssh-keygen -e -m PKCS8 -f id_rsa.pub > id_rsa.pkcs8
const publicKey  = fs.readFileSync(path.join(__dirname, 'id_rsa.pkcs8'), { encoding : 'utf8' });
const privateKey = fs.readFileSync(path.join(__dirname, 'id_rsa'), { encoding : 'utf8' });

// Sign
const signer = crypto.createSign('RSA-SHA512');
signer.update(id);
const signature = signer.sign(privateKey, 'hex');

// ...

// Verify
const verifier = crypto.createVerify('RSA-SHA512');
verifier.update(ruid);
const publicKeyBuf = new Buffer(publicKey, 'utf-8');
const signatureBuf = new Buffer(signature, 'hex');
const result       = verifier.verify(publicKeyBuf, signatureBuf);

Where does the variable ruid get defined on line 16?

Where does the variable ruid get defined on line 16?

ruid should be id

This is great, thanks !. You'd have to change new Buffer(variable, 'utf-8'); to Buffer.from(variable, 'utf-8');

Otherwise, you would get below warning

DeprecationWarning: Buffer() is deprecated due to security and usability issues. Please use the Buffer.alloc(), Buffer.allocUnsafe(), or Buffer.from() methods instead.