MEIA ENTRADA OTP

This is a simple library to implement features based on OTP (One-Time Password) algorithms, more specific TOTP algorithm. OTP algorithms are commonly used to implement two factor authentication (2FA).
There are two algorithms: HOTP(HMAC-based One-Time Password) and TOTP(Time-Based One-Time Password):
- HOTP
This algorithm generates a otp code based in a secret, current timestamp and a event counter, see RFC 4226.
- TOTP
This algorithm generates the otp code based in a secret and current timestamp. see RFC 6238

To install

To install and save this dependencie in package.json:
``

javascript
npm i meiaentrada-otp --save


To simple install:

javascript
npm i meiaentrada-otp


Knowledge

- secret:
	A unique key value per user to generate otp values;
	For example: "secret_of_client_01"
- holder:
	A value to represent a people or entity that is using otp value like a client.
	For example: "bank_01"
- issuer:
	A value to represent the website or enterprise that is generating otp values to clients.
	For example: "bank_client_01"
- otp value:
	A positive number with 6 characters.
	For example: "123456"
Methods

generateKey()


Generates a 32-character (160-bit) base32 key

generateOtpURI(secret, holder, issuer)Generate a URI base on OTPAUTH protocol - for more info. There is only a exception, the holder information is present on the URI params.

isValidTokenOTP(secret, otpValue)Validates a time-based token within a +/- 30 second (90 seconds) window. Return true or false in according with secret, current timestamp and otp value.

generateTokenOTP(secret)Generates a 6-digit (20-bit) decimal time-based token

`Usage`

javascript
const otp = require('meiaentrada-otp');
const secret = otp.generateKey();
console.log(secret); // "igxo jj5n gpuj gv4c lotw ve7d tmlu xftb"
const holder = 'user_01';
const issuer = 'enterprise_01';
const uri = otp.generateOtpURI(secret, holder, issuer);
console.log(uri); // otpauth://totp/enterprise_01:user_01?secret=7MEYUZ52337HOOKX25GE3RVIMQ6MJK4O&issuer=enterprise_01&algorithm=SHA1&digits=6&period=30&holder=user_01
const otpCode = otp.generateTokenOTP(secret);
console.log(otpCode); // 774729
let isValidToken = otp.isValidTokenOTP(secret, otpCode);
console.log(isValidToken); // true

isValidToken = otp.isValidTokenOTP('wrong-secret', otpCode); console.log(isValidToken); // false``