node.js crypto module cannot encrypt 16+ characters

Question

I am still rather new to all the terminology around cryptology, so please excuse my ignorance on the subject. I am having something strange happening when using node.js' crypto module. It will encrypt exactly 16 characters only. Any more and it fails with this error message:

TypeError: error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt
at Decipher.Cipher.final (crypto.js:292:27)
at decrypt (C:\node_apps\crypto_test\app.js:39:21)
at C:\node_apps\crypto_test\app.js:16:21
at Interface._onLine (readline.js:200:5)
at Interface._line (readline.js:531:8)
at Interface._ttyWrite (readline.js:760:14)
at ReadStream.onkeypress (readline.js:99:10)
at ReadStream.emit (events.js:98:17)
at emitKey (readline.js:1095:12)
at ReadStream.onData (readline.js:840:14)

The code I am using looks like this:

var rl = require('readline');
var crypto =require('crypto');

var interface = rl.createInterface({
input: process.stdin,
output:process.stdout
});

interface.question('Enter text to encrypt: ',function(texto){
var encrypted = encrypt(texto);
console.log('Encrypted text:',encrypted);

console.log('Decrypting text...');
var decrypted = decrypt(encrypted);
console.log('Decrypted text:',decrypted);
process.exit();
});

function encrypt(text)
{
var cipher =crypto.createCipher('aes192','password');
text = text.toString('utf8');
cipher.update(text);
return cipher.final('binary');

}

function decrypt(text)
{
var decipher = crypto.createDecipher('aes192','password');
decipher.update(text,'binary','utf8');
return decipher.final('utf8');
}

Why does this not encrypt more than 16 characters? Is it because of the algorithm I am using? How can I encrypt something without caring how long it is?

Answer 1

The problem is that you're discarding part of your encrypted and decrypted data. update() can return data just like final() can. So change your encrypt() and decrypt() like:

function encrypt(text)
{
var cipher =crypto.createCipher('aes192', 'password');
text = text.toString('utf8');
return cipher.update(text, 'utf8', 'binary') + cipher.final('binary');
}

function decrypt(text)
{
var decipher = crypto.createDecipher('aes192', 'password');
return decipher.update(text, 'binary', 'utf8') + decipher.final('utf8');
}