Categorygithub.com/virgilsecurity/virgil-purekit-go

modulepackage

2.0.0+incompatible

Repository: https://github.com/virgilsecurity/virgil-purekit-go.git

Documentation: pkg.go.dev

# README

Virgil PureKit Go SDK

Introduction

Virgil Security introduces an implementation of the Password-Hardened Encryption (PHE) protocol – a new mechanism that secures users' sensitive data and lessens the security risks associated with weak passwords.

Virgil PureKit allows developers to protect user passwords and sensitive data from offline/online attacks and makes stolen passwords useless if your database has been compromised. Neither Virgil nor attackers know anything about users' passwords.

Authors of the PHE protocol: Russell W. F. Lai, Christoph Egger, Manuel Reinert, Sherman S. M. Chow, Matteo Maffei and Dominique Schroder.

Features

Zero knowledge of user password
Protection from online attacks
Protection from offline attacks
Instant invalidation of stolen database
User data encryption with a personal key

Register Your Account

Before starting practicing with the SDK and usage examples make sure that:

you have a registered Virgil Account at Virgil Dashboard
you created PURE Application
and you got your PURE Application's credentials, such as: App Secret Key, Service Public Key, App Token

Install and Configure SDK

The PureKit Go SDK is provided as a package named purekit. The package is distributed via GitHub. The package is available for Go 1.10 or newer.

Install SDK Package

Install PureKit SDK library with the following code:

go get -u github.com/VirgilSecurity/virgil-purekit-go

PureKit uses Dep to do manage its dependencies: Please install dep and run the following commands:

cd $(go env GOPATH)/src/github.com/VirgilSecurity/virgil-purekit-go
dep ensure

Configure SDK

Here is an example of how to specify your credentials SDK class instance:

// here set your purekit credentials
import (
    "github.com/VirgilSecurity/virgil-purekit-go"
)

func InitPureKit() (*purekit.Protocol, error){
    appToken := "AT.OSoPhirdopvijQlFPKdlSydN9BUrn5oEuDwf3Hqps"
    appSecretKey := "SK.1.xacDjofLr2JOu2Vf1+MbEzpdtEP1kUefA0PUJw2UyI0="
    servicePublicKey := "PK.1.BEn/hnuyKV0inZL+kaRUZNvwQ/jkhDQdALrw6VdfvhZhPQQHWyYO+fRlJYZweUz1FGH3WxcZBjA0tL4wn7kE0ls="

    context, err := purekit.CreateContext(appToken, servicePublicKey, appSecretKey, "")
    if err != nil{
        return nil, err
    }

    return purekit.NewProtocol(context)
}

Prepare Your Database

PureKit SDK allows you to easily perform all the necessary operations to create, verify and rotate user's record.

PureKit record - a user's password that is protected with our PureKit technology. PureKit record contains a version, client & server random salts and two values obtained during execution of the PHE protocol.

In order to create and work with user's record you have to set up your database with an additional column.

The column must have the following parameters:

Parameters	Type	Size (bytes)	Description
purekit_record	bytearray	210	A unique record, namely a user's protected purekit.

Usage Examples

Enroll User Record

Use this flow to create a new PureKit record in your DB for a user.

Remember, if you already have a database with user passwords, you don't have to wait until a user logs in into your system to implement PureKit technology. You can go through your database and enroll (create) a user's record at any time.

So, in order to create a record for a new database or available one, go through the following operations:

Take a user's password (or its hash or whatever you use) and pass it into the EnrollAccount function of SDK on your Server side.
PureKit SDK will send a request to PHE Service to get enrollment.
Then, PureKit SDK will create a user's record. You need to store this unique user's record in your database in associated column.

package main

import (
    "encoding/base64"
    "fmt"
    "github.com/VirgilSecurity/virgil-purekit-go"
    "github.com/VirgilSecurity/virgil-phe-go"
)

// create a new encrypted password record using user password or its hash
func EnrollAccount(password string, prot *purekit.Protocol) error{
    
    record, key, err := prot.EnrollAccount(password)
    if err != nil {
        return err
    }

    //save record to database
    fmt.Printf("Database record:\n%s\n", base64.StdEncoding.EncodeToString(record))
    //use encryptionKey for protecting user data
    encrypted, err := phe.Encrypt(data, key)
    ...

}

When you've created a PureKit record for all users in your DB, you can delete the unnecessary column where user passwords were previously stored.

Verify User Record

Use this flow when a user already has his or her own PureKit record in your database. This function allows you to verify user's password with the record from your DB every time when the user signs in. You have to pass his or her record from your DB into the VerifyPassword function:

package main

import (
    "fmt"
    "github.com/VirgilSecurity/virgil-purekit-go"
    "github.com/VirgilSecurity/virgil-phe-go"
)


func VerifyPassword(password string, record []byte, prot *purekit.Protocol) error{
    key, err := prot.VerifyPassword(password, record)
    if err != nil {

        if err == purekit.ErrInvalidPassword{
            //invalid password
        }
        return err //some other error
    }

    //use encryptionKey for decrypting user data
    decrypted, err := phe.Decrypt(encrypted, key)
    ...

}

Encrypt user data in your database

Not only user's password is a sensitive data. In this flow we will help you to protect any Personally identifiable information (PII) in your database.

PII is a data that could potentially identify a specific individual, and PII can be sensitive. Sensitive PII is information which, when disclosed, could result in harm to the individual whose privacy has been breached. Sensitive PII should therefore be encrypted in transit and when data is at rest. Such information includes biometric information, medical information, personally identifiable financial information (PIFI) and unique identifiers such as passport or Social Security numbers.

PureKit service allows you to protect user's PII (personal data) with a user's encryptionKey that is obtained from EnrollAccount or VerifyPassword functions. The encryptionKey will be the same for both functions.

In addition, this key is unique to a particular user and won't be changed even after rotating (updating) the user's record. The encryptionKey will be updated after user changes own password.

Here is an example of data encryption/decryption with an encryptionKey:

package main

import (
    "fmt"
    "github.com/VirgilSecurity/virgil-phe-go"
)

func main() {

    //key is obtained from proto.EnrollAccount() or proto.VerifyPassword() calls

    data := []byte("Personal data")

    ciphertext, err := phe.Encrypt(data, encryptionKey)
    if err != nil {
        panic(err)
    }
    decrypted, err := phe.Decrypt(ciphertext, encryptionKey)
    if err != nil {
        panic(err)
    }

    //use decrypted data
}

Encryption is performed using AES256-GCM with key & nonce derived from the user's encryptionKey using HKDF and random 256-bit salt.

Virgil Security has Zero knowledge about a user's encryptionKey, because the key is calculated every time when you execute EnrollAccount or VerifyPassword functions at your server side.

Rotate app keys and user record

There can never be enough security, so you should rotate your sensitive data regularly (about once a week). Use this flow to get an UPDATE_TOKEN for updating user's PureKit RECORD in your database and to get a new APP_SECRET_KEY and SERVICE_PUBLIC_KEY of a specific application.

Also, use this flow in case your database has been COMPROMISED!

This action doesn't require to create an additional table or to do any modification with available one. When a user needs to change his or her own password, use the EnrollAccount function to replace user's oldRecord value in your DB with a newRecord.

There is how it works:

Step 1. Get your UPDATE_TOKEN using PureKit CLI

Move to your Application panel and press “Show update token” button to get the update_token.

./purekit login [email protected] purekit login [email protected] ./purekit application rotate <app_token> purekit application rotate <app_token> Step 2. Initialize PureKit SDK with the UPDATE_TOKEN. Move to PureKit SDK configuration file and specify your UPDATE_TOKEN:

// here set your purekit credentials
import (
    "github.com/VirgilSecurity/virgil-purekit-go"
)

func InitPassw0rd() (*purekit.Protocol, error){
    appToken := "AT.0000000irdopvijQlFPKdlSydN9BUrn5oEuDwf3Hqps"
    appSecretKey := "SK.1.000jofLr2JOu2Vf1+MbEzpdtEP1kUefA0PUJw2UyI0="
    servicePublicKey := "PK.1.BEn/hnuyKV0inZL+kaRUZNvwQ/jkhDQdALrw6Vdf00000QQHWyYO+fRlJYZweUz1FGH3WxcZBjA0tL4wn7kE0ls="
    updateToken := "UT.2.00000000+0000000000000000000008UfxXDUU2FGkMvKhIgqjxA+hsAtf17K5j11Cnf07jB6uVEvxMJT0lMGv00000="

    context, err := purekit.CreateContext(appToken, servicePublicKey, appSecretKey, updateToken)
    if err != nil{
        return nil, err
    }

    return purekit.NewProtocol(context)
}

Step 3. Start migration. Use the NewRecordUpdater("UPDATE_TOKEN") SDK function to create an instance of class that will update your old records to new ones (you don't need to ask your users to create a new password). The UpdateRecord() function requires user's oldRecord from your DB:

package main

import (
    "crypto/subtle"
    "github.com/VirgilSecurity/virgil-purekit-go"
)

func main(){
	
	updater, err := purekit.NewRecordUpdater("UPDATE_TOKEN")
	if err != nil{
            //something went wrong
    }
	
    //for each record
    //get old record from the database
    oldRecord := ...

    //update old record
    newRecord, err := updater.UpdateRecord(oldRecord)
    if err != nil{
        //something went wrong
    }

    // newRecord is nil ONLY if oldRecord is already the latest version
    if newRecord != nil{
        //save new record to the database
        saveNewRecord(newRecord)
    }

}

So, run the UpdateRecord() function and save user's newRecord into your database.

Since the SDK is able to work simultaneously with two versions of user's records (newRecord and oldRecord), this will not affect the backend or users. This means, if a user logs into your system when you do the migration, the PureKit SDK will verify his password without any problems because PHE Service can work with both user's records (newRecord and oldRecord).

Step 4. Get a new APP_SECRET_KEY and SERVICE_PUBLIC_KEY of a specific application

Use Virgil CLI update-keys command and your UPDATE_TOKEN to update the APP_SECRET_KEY and SERVICE_PUBLIC_KEY:

// FreeBSD / Linux / Mac OS
./purekit application update-keys <service_public_key> <app_secret_key> <update_token>

// Windows OS
purekit application update-keys <service_public_key> <app_secret_key> <update_token>

Step 5. Move to PureKit SDK configuration and replace your previous APP_SECRET_KEY, SERVICE_PUBLIC_KEY with a new one (APP_TOKEN will be the same). Delete previous APP_SECRET_KEY, SERVICE_PUBLIC_KEY and UPDATE_TOKEN.

// here set your purekit credentials
import (
    "github.com/VirgilSecurity/virgil-purekit-go"
)

func InitPassw0rd() (*purekit.Protocol, error){
    appToken := "APP_TOKEN_HERE"
    appSecretKey := "NEW_APP_SECRET_KEY_HERE"
    servicePublicKey := "NEW_SERVICE_PUBLIC_KEY_HERE"


    context, err := purekit.CreateContext(appToken, servicePublicKey, appSecretKey, "")
    if err != nil{
        return nil, err
    }

    return purekit.NewProtocol(context)
}