otp-without-db

OTP verification using Cryptography and without any Database

Background

This module is derived from my blog post on the technique. You can read the blog post here to understand the technique and motivation.

Dependencies:

This module depends on the Crypto built in module on nodeJS. This is the only dependency and should work in any system that has crypto support (Which is technocally majority of the systems at this moment)

This module also uses some modern JavaScript features like Template literals, Default arguments and modern object literal. This might be a problem if you are planning to use it with older versions of nodeJS

Installation

You can use npm to install the package with the following code

npm install --save otp-without-db

Usage

You need additional tool to crete OTP, and send SMS, This module only takes care of the verification part.

You can take a look at the otp-generator module to create OTP for your users.

Verification process

OTP verification is done in the following steps:

• A hash is created with the phone number/email address and the then sent to the user.

• The user also receives the OTP via SMS, email or any other method.

• The sends back the hash, otp and phone/email used in the first request.

• The server verifies the information and returns true if they match.

Generating OTP Hash

We will use the otp-generator tool mentioned previously to create OTP. You can use any other too or technique.

const otpGen  = require("otp-generator");
const otpTool = require("otp-without-db"); 
const key     = "secretKey"; // Use unique key and keep it secret

let phone = "88017009090";  
let otp   = otpGen.generate(6, { upperCase: false, specialChars: false,alphabets: false });  

let hash = otpTool.createNewOTP(phone,otp,key);

You can then send this hash to the user as response. The generate function takes these following arguments (In particular order),

createNewOTP(phoneOrEmail,otp,key="",expiresAfter=5,algorithm="sha256")

Argument	Required	default	Description
phoneOrEmail	true	N/A	Phone or email
otp	true	N/A	OTP
key	false	""	unique and secret key for HMAC see: createHmac
expiresAfter	false	5	Expirty in minutes
algorithm	false	sha256	Algorithm used for hashing the data. Any supported algorithm from OpenSSL

Verifying OTP hash

The user should get the hash from the HTTP request. and should get the real OTP via phone or email.

Then when the user sends back the information, they can be verified with the following code:

otpTool.verifyOTP(phone,otp,hash,key);

This function returns a Boolean. if the verification is successful it will return true.

This function also takes the following arguments in particular order:

verifyOTP(phone,otp,hash,key="",algorithm="sha256")

Argument	Required	default	Description
phoneOrEmail	true	N/A	Phone or email
otp	true	N/A	OTP
hash	true	N/A	The hash that was returned from the user
key	false	""	unique and secret key for HMAC see: createHmac
algorithm	false	sha256	Algorithm used for hashing the data. Any supported algorithm from OpenSSL

This product is created with 🖤 by Anam Ahmed, Any improvements and PR is welcome.