This document discusses using the Exonum framework to build blockchain-driven web applications. Exonum is an extensible framework that allows building blockchain projects using a Byzantine Fault Tolerant algorithm, light clients, anchoring to hashes, and the Rust programming language. It describes how a traditional web application architecture relies on a centralized admin, whereas a blockchain-driven one using Exonum distributes trust across multiple nodes reaching consensus. Users would authenticate using public/private key pairs and directly control and sign transactions to modify their own data on the blockchain, improving security, transparency and fault tolerance compared to traditional architectures.

1. Blockchain for Web-Applications
DenisKolodin AlekseySidorov

2. Blockchain for Web-Applications 2
Exonum is
an extensible
framework for
blockchain projects
What is Exonum?
• BFT Algorithm
• Light Client
• Anchoring
• Rust

3. Blockchain for Web-Applications 3
Traditional Web-Application Architecture
Admin is a King:
• Can change any data
• Can lose sensitive data
• Absolute faith
a server or two
maybe...

4. Blockchain for Web-Applications 4
AWSAzureGCE
Office
Blockchain-driven Web-Application Architecture
Exonum Node 1 Exonum Node 2
Exonum Node 3
Exonum Node N
CONSENSUS

5. Blockchain for Web-Applications 5
Key pair
User Authentication
Public Key
Private Key
Exonum Node
Transaction
Only user modifies data.
Signed
User doesn’t need to pass
special registration process.
User creates
own key pair

6. Blockchain for Web-Applications 6
Offline signing of transactions
Create and sign transaction offline…
Exonum Node
and send it to Exonum Node
(by another device)
Only owners can
change their data
(depends on business logic)

7. Blockchain for Web-Applications 7
Exonum Node 1 Exonum Node 2 Exonum Node 3 Exonum Node N
Fault!
Exonum Node 3.1
CONSENSUS
Fault tolerance, hardware updates, scaling
Audit Node 1 Audit Node 2
Scaling up throughput

8. Blockchain for Web-Applications 8
Proofs are the core of integrity
Exonum contains
merkle-tree
indices to maintain
proofs
• Data “fingerprints”
• Shared confidence
• Digital law
enforcement

9. Blockchain for Web-Applications 9
Service Data Keys Transactions
Implement all
necessary
services
(contracts)
with Exonum
framework
Add light
client to
browser
application
and let users
derive
protected
keys.
Configure the
web-server to
pass
transaction to
Exonum Node
Migrate initial
data to
blockchain
with a genesis
block.
Launch!
Deploy
Exonum
Nodes and
enjoy the
blockchain in
your
application!
Integrate to existent Web-Application

10. Questions?