Unable to decrypt aes-192-gcm - aes-gcm

Question

I'm using nodejs to encrypt and decrypt aes-192-gcm
here's my code:
const encrypted = decrypt.encryptText('aes-192-gcm', 'FnpkKuIoqZL5B3tnE0Htmg==', '1z3FtB6OitmFOIsP', 'helloWorld', 'base64');
const de = decrypt.decryptText('aes-192-gcm', 'FnpkKuIoqZL5B3tnE0Htmg==', '1z3FtB6OitmFOIsP', encrypted, 'utf-8');
console.log(encrypted);
console.log(de);
Functions used:
function encryptText(cipher_alg, key, iv, text, encoding) {
var cipher = crypto.createCipheriv(cipher_alg, key, iv);
encoding = encoding || "binary";
var result = cipher.update(text, "utf8", encoding);
result += cipher.final(encoding);
return result;
}
function decryptText(cipher_alg, key, iv, text, encoding) {
const decipher = crypto.createDecipheriv(cipher_alg, key, iv);
encoding = encoding || "binary";
let result = decipher.update(text, encoding);
result += decipher.final();
return result;
}
The error I'm getting:
Unsupported state or unable to authenticate data

Answer 1

The crypto module of NodeJS uses OpenSSL. This API has special parameters for GCM / AEAD ciphers. Methods to use them have been added to the API, such as getAuthTag and setAuthTag. Without the latter, the method always throws an exception for GCM mode decryption. The tag is (fortunately) not considered part of the ciphertext in NodeJS / OpenSSL. Other languages runtimes - such as Java - do consider it part of the ciphertext.

Answer 2

Couple of problems
you are passing a wrong encoding format for the decryptText()
AuthTag is required when using GCM, CCM and OCB.
I have attached a sample code based on the snippet you have shared.
var cipherTag;
const encrypted = encryptText('aes-192-gcm', 'FnpkKuIoqZL5B3tnE0Htmg==', '1z3FtB6OitmFOIsP', 'helloWorld', 'base64');
const de = decryptText('aes-192-gcm', 'FnpkKuIoqZL5B3tnE0Htmg==', '1z3FtB6OitmFOIsP', encrypted, 'base64');
console.log(encrypted);
console.log(de);
function encryptText(cipher_alg, key, iv, text, encoding) {
var cipher = crypto.createCipheriv(cipher_alg, key, iv);
encoding = encoding || "binary";
var result = cipher.update(text, "utf8", encoding);
result += cipher.final(encoding);
cipherTag = cipher.getAuthTag();
return result;
}
function decryptText(cipher_alg, key, iv, text, encoding) {
const decipher = crypto.createDecipheriv(cipher_alg, key, iv);
encoding = encoding || "binary";
decipher.setAuthTag(cipherTag);
let result = decipher.update(text, encoding, 'utf8');
result+= decipher.final('utf8');
return result.toString();
}
// Will output
b2SMQRBt/EgNgQ==
helloWorld