Blockchain HyperLedger Fabric Internals - Clavent

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BlockChain
ARAF KARSH HAMID
Co-Founder / CTO
MetaMagic Global Inc., NJ, USA
@arafkarsh
arafkarsh World Summit 2.0
February 1st, 2019,
Vivanta By Taj, Bengaluru, India
https://www.clavent.com/event-list/blockchain2-0-bangalore-2018/

Agenda
01-02-2019 2
1. Why do we need Blockchain?
o Problem Statement
o How Blockchain solves this problem
o Business Requirement
o Distributed Ledger
o HyperLedger Fabric
1 4. Fabric Getting Started
o Fabric Internals
o Blockchain Network
o Transaction Flow
o Private Data Usage
o Setting up Fabric Network
o Fabric Example (Node.JS)
3
6. Conclusion
o Ethereum Vs. Fabric Vs. Corda
o Blockchain Benefits
o Industry Scenarios – Media
o References
4U HyperLedger Fabric Architecture
o Fabric Key Components
o Microservices Architecture
o 3 Components of Fabric
o Fabric Models (Assets, Chaincode..)
o Fabric Channels
o Gossip Protocol
2

Problem Statement
01-02-2019 3
1
Customer A
Records
Insurer
Records
Bank
Records
Regulators
Records
Auditors
Records
Merchant A
Records
Expensive, Vulnerable & Inefficient
Source:BuildingBlockchainAppsforNode.JSdevelopers
withHyperLedgerComposer–SimonStoneIBM

How Blockchain Solves this Problem…
01-02-2019 4
1
Customer A
Records
Insurer
Records
Bank
Records
Regulators
Records
Auditors
Records
Merchant A
Records
Blockchain Ledger
A shared, replicated, permissioned ledger
 Consensus
 Immutability
 Provenance
 Finality
Source: Building Blockchain Apps for Node.JS developers with HyperLedger Composer – Simon Stone IBM

Business Requirements
01-02-2019 5
Shared Ledger
Append only
immutable
database
shared across
the business
network.
Business logic
is embedded
within the
database and
executed to
validate and
store the
transactions.
Smart Contract
Transactions are
secure,
authenticated
and access
controls are
enabled for
granular access.Privacy Trust
All the
transactions
are verified
and endorsed
by the trusted
relevant
parties
1

Properties of a Distributed Ledger
01-02-2019 6
o Decentralized, replicated across many
participants, each of whom collaborate in
its maintenance.
o Information recorded is append-only.
Immutable.
o Immutability makes it simple to
determine the provenance of the
information.
o These properties makes it called as
“Systems of Proof”
1 - - - - - - - - - - - n
1

How it differs from Bitcoin
01-02-2019 7
1
HyperLedger Fabric Bitcoin
Provides Identity Anonymity
Selective Endorsement Proof of Work
Assets Cryptocurrency
Bitcoin is a specific implementation of Blockchain technology

HyperLedger Fabric Key Features
01-02-2019 8
1
Source: http://hyperledger-fabric.readthedocs.io/en/latest/functionalities.html
o It is private and permission based
o Members of HyperLedger Fabric enrolls
thru MSP - Membership Service
Provider
o Different MSPs are supported
o Ledger data can be stored in multiple
formats.
o Consensus mechanisms can be
switched in and out
o Ability to create channels - Allowing a
group of participants to create a
separate ledger of transactions.
o Provides Membership Identity
Service that manages User IDs
and authenticates all participants
on the network.
o Access control lists can be used
to Provide additional layers of
permission.
o A Specific user ID could be
permitted to invoke a Chaincode
application but blocked from
deploying a Chaincode.
Identity Management

HyperLedger Fabric Key Features
01-02-2019 9
1
Source: http://hyperledger-fabric.readthedocs.io/en/latest/functionalities.html
o Transaction execution is
separated from
transaction ordering and
commitment.
o Division of labor un
burdens ordering nodes
from the demands of
transaction execution and
ledger maintenance,
o while peer nodes are
freed from ordering
(consensus) workloads.
Efficient Processing
o Chaincode Applications
encode logic that is
invoked by specific
types of transactions on
the channel.
o System Chaincode is
distinguish as
Chaincode that defines
operating params for
the entire channel.
Chaincode Functionality
o Private channels are
restricted messaging paths
that can be used to provide
transaction privacy and
confidentiality for specific
subset of network members.
o All data including transaction,
member and channel
information, on a channel are
invisible and inaccessible to
any network members not
explicitly access to that
channel.
Privacy & Confidentiality

Summary – Why do we need Blockchain?
01-02-2019 10
1
Reconciliation Issues in a
Multi Party environment.
o Expensive
o Vulnerable
o Inefficient
Problem Statement
o Consensus among the Parties
before a transaction is committed.
o Provenance – Origin of the asset
can be easily Tracked.
o Immutable – Transactions are
tamper proof
o Finality – Single Source of Truth
Solution

Fabric Architecture
01-02-2019 11

HyperLedger Fabric Architecture
12
2
Orderer
• Consensus
verification
• Creates Blocks
CA
• Registration
of identities
• Manage
Certificates
Peer
• Endorses Tx
• Simulates Tx
• Commits Tx
All these components can be clustered for scalability and to avoid Single Point of Failure
3 Components of Fabric
Ledger
Blockchain & World State
Smart Contract
• createCar
• queryAllCars
• queryCarProperties
• changeCarColor
• changeCarOwner
Other Concepts
• Assets : Anything that’s
valuable for the Organization
• Transactions (State changes
of Assets)
• Endorsement Policies
• Gossip Protocol : The glue
that keeps the peers in
healthy state.
Channels
• Private subnet for
a set of parties
based on Smart
contract
• Ledger / Channel
• Peers can have
multiple Channels
• Private Data
1
2
01-02-2019

01-02-2019 13
Fabric
Deployment
Model in every
Enterprise Customer A Merchant B Bank Insurer
RESTful Services
Two Roles = Endorser & Committer
Smart Contracts (Chaincode) – Programmable Ledger
Persistence Layer - Ledger
GetPut
Blockchain
Events
Block
Peer
2
Gossip Protocol for P2P Communication
Orderer
• Consensus
Verification
• Creates Blocks
CA
• Registration
of identities.
• Certificate
Management
Multiple Channels

01-02-2019 1414
Monolithic / Micro Services Architecture
Traditional Monolithic App using
Single Technology Stack
Micro Services with Multiple Technology Stack
Event Stream
API Gateway (Zuul Edge Server)
Load Balancer (Ribbon)
Circuit Breaker (Hysterix)
Service Discovery (Eureka)
UI Layer
Web Services
Business Logic
Database Layer
Database
UI Layer
Web Services
Business Logic
Database Layer
Micro
Service
1
EE 7
Container
UI Layer
Web Services
Business Logic
Database Layer
Micro
Service
2
Container
SE 8
UI Layer
Web Services
Business Logic
Database Layer
Micro
Service
4
Container
UI Layer
Web Services
Business Logic
Database Layer
Micro
Service
3
Container
2

HyperLedger Fabric – Ledger
01-02-2019 15
2
Source: http://hyperledger-fabric.readthedocs.io/en/release-1.0/fabric_model.html
There is one ledger
per channel.
Couch DB
As well as a state database to
maintain current fabric state.
This is auto derived by the Peers.
Each transaction results in a set of asset key-
value pairs that are committed to the ledger
as creates, updates, or deletes.
o The ledger is the
sequenced, tamper-
resistant record of all state
transitions in the fabric.
o State transitions are a result
of Chaincode invocations
(‘transactions’) submitted
by participating parties.
Blockchain
Tx Tx Tx Tx
Blocks
Tx
Ledger

HyperLedger Fabric : 3 Components
16
2
o Registration of identities, or
connects to LDAP as the
user registry
o Issuance of Enrollment
Certificates (ECerts)
o Certificate renewal and
revocation
o Every Single operation
MUST be signed with a
Certificate.
o Certificates are per user.
Certificate Authority
o Before anything is committed to
the Ledger it must pass thru
Orderer Service.
o Provides Order of
Transactions.
o It creates the Blocks for the
Blockchain.
o Block size can be based on no.
of transactions and / or timeout
value.
o Orderer in two modes - Solo for
the Dev environment and Kafka
for the Production environment.
Orderer
o Can update or Query the
ledger.
o One Peer can be part of
multiple channels.
o Peer Endorse the
transaction.
o All the Peers find each other
and synchronizes
automatically.
o Peer manages the Ledger
which consists of the
Transaction Log (Blockchain)
and World State.
o Peer has two roles
Endorser and Committer.
Peer
Source: http://hyperledger-fabric-
ca.readthedocs.io/en/latest/users-guide.html
01-02-2019

HyperLedger Fabric – CA
17
http://www.haproxy.org/
2
Source: http://hyperledger-fabric-ca.readthedocs.io/en/latest/users-guide.html#table-of-contents
CA
HA
Proxy
Peer Network
Cluster
REST API
CA Cluster with HA Proxy Load balancer
Fabric CA Server can
be connected using
1. Fabric CA Client
2. Fabric CA SDK
(REST API Calls)
Fabric CA servers in a cluster share the same database for
keeping track of identities and certificates. If LDAP is configured,
the identity information is kept in LDAP rather than the
database.
This ensures that there is NO Single Point of Failure for CA.No Single Point of
Failure for Peers.
01-02-2019

HyperLedger Fabric – Peer
18
2Source:http://hyperledger-fabric.readthedocs.io/en/release-1.0/fabric_model.html
Blockchain
Tx Tx Tx Tx
Block
Peer
Query ledger
history for a key,
enabling data
provenance
scenarios.
Peer
CouchDB
Read-only queries
using a rich query
language (if using
CouchDB as state
database)
Transactions contain
signatures of every
endorsing peer and
are submitted to
ordering service.
Peer
Tx
Peer
Peers validate transactions
against endorsement policies and
enforce the policies.
Endorsement
Policies
Peer
Peers can have multiple Channels
Peer
Prior to appending a block, a
versioning check is performed to
ensure that states for assets that
were read have not changed
since Chaincode execution time.
Tx
$ docker run -it hyperledger/fabric-peer bash
# peer chaincode --help01-02-2019

HyperLedger Fabric – Peer CLI
01-02-2019 19
$ docker run -it hyperledger/fabric-peer bash
# peer chaincode –help
Usage:
peer chaincode [command]
Available Commands:
install Package the specified chaincode into a deployment spec
and save it on the peer's path.
instantiate Deploy the specified chaincode to the network.
invoke Invoke the specified chaincode.
package Package the specified chaincode into a deployment spec.
query Query using the specified chaincode.
signpackage Sign the specified chaincode package
upgrade Upgrade chaincode.
2
Source : http://hyperledger-fabric.readthedocs.io/en/release-1.0/chaincode4noah.html

HyperLedgerFabric–PeerCLI
20
Flags:
--cafile string Path to file containing PEM-encoded trusted certificate(s) for the ordering endpoint
-C, --chainID string The chain on which this command should be executed (default "testchainid")
-c, --ctor string Constructor message for the chaincode in JSON format (default "{}")
-E, --escc string The name of the endorsement system chaincode to be used for this chaincode
-l, --lang string Language the chaincode is written in (default "golang")
-n, --name string Name of the chaincode
-o, --orderer string Ordering service endpoint
-p, --path string Path to chaincode
-P, --policy string The endorsement policy associated to this chaincode
-t, --tid string Name of a custom ID generation algorithm (hashing and decoding)
e.g. sha256base64
--tls Use TLS when communicating with the orderer endpoint
-u, --username string Username for chaincode operations when security is enabled
-v, --version string Version of the chaincode specified in install/instantiate/upgrade commands
-V, --vscc string The name of the verification system chaincode to be used for this chaincode
Global Flags:
--logging-level string Default logging level and overrides, see core.yaml for full syntax
--test.coverprofile string Done (default "coverage.cov")
Use "peer chaincode [command] --help" for more information about a command.
2
Source : http://hyperledger-fabric.readthedocs.io/en/release-1.0/chaincode4noah.html01-02-2019

HyperLedger Fabric - Orderer
01-02-2019 21
2
Source: http://hyperledger-fabric.readthedocs.io/en/release-1.0/kafka.html
Node 2
Orderer
Zookeeper
Node 1
Node 2
Node 3
Broker 1
Broker 2
Broker n
Broker ..
Kafka Zookeeper
Node 1
Orderer
Node 3
Orderer
Node 4
Orderer
Ordering
Service Client
Defining Consensus is
3 Phase Process
1. Endorsement
2. Ordering
3. Validation
ZooKeeper nodes 3,5,7
Service Type
1. Solo (Dev)
2. Kafka (Prod)
3. PBFT (Prod)* No Single Point of Failure for Orderer.

HyperLedger Fabric Model – Assets / Chaincode
01-02-2019 22
2
o The exchange of almost anything with monetary value over the network, from whole foods
to antique cars to currency futures.
o Represented as a collection of key-value pairs, with state changes recorded as transactions
on a Channel ledger.
o Assets can be represented in binary and/or JSON form.
Assets
Source: http://hyperledger-fabric.readthedocs.io/en/release-1.0/fabric_model.html
o It defines an asset or assets, and the transaction instructions for modifying the asset(s). Its the
business logic.
o It enforces the rules for reading or altering key value pairs or other state database information.
o It execute against the ledger’s current state database & are initiated through a transaction proposal.
o It’s execution results in a set of key value writes (write set) that can be submitted to the network
and applied to the ledger on all peers.
Chaincode / Smart Contract

Fabric - Endorsement Policy
23
2
• Peer uses Endorsement policies to decide if the
transaction is properly Endorsed.
• Peer invokes VSCC (Validation System Chaincode)
associated with transaction’s Chaincode
• VSCC is tasked to do the following
• All Endorsements are valid (Valid signatures from
Valid Certificates)
• There is an appropriate number of Endorsements.
• Endorsement came from expected Source(s)
Source: http://hyperledger-fabric.readthedocs.io/en/release-1.0/endorsement-policies.html
Examples
• Org1.admin
• Org2.member
• Org3.peer
Roles (of the
Signer) are
supported
1. Member
2. Admin
3. Client
4. Peer
4
01-02-2019

Fabric – Endorsement Policy Design
24Source: http://hyperledger-fabric.readthedocs.io/en/release-1.0/endorsement-policies.html
Endorsement Policy has two Components
P
A Principal (P) identifies the entity
whose signature is expected
T
A Threshold Gate <T> takes two inputs:
• <t> an integer : threshold
• [n] a list of : principals or gates
2
This Gate
essentially
captures the
expectation that:
• out of those
[n] principals
or gates,
• <t> are
requested to
be satisfied
T(2, ‘A’, ‘B’, ‘C’)
Requests a signature from any
2 Principals out of A,B,C
T(1, ‘A’, T(1, ‘B’, ‘C’))
Requests 1 signature from A or
1 from Principal B and C each.
01-02-2019

Fabric - Endorsement Policy using CLI
25
2
Source: http://hyperledger-fabric.readthedocs.io/en/release-1.0/endorsement-policies.html
Principals are described as MSP.ROLE
Examples
• Org1.admin
• Org2.member
• Org3.peer
EXPR(E[, E...])
where EXPR is either AND or OR, representing the two Boolean expressions and E is
either a principal (with the syntax described above) or another nested call to EXPR.
For example:
• AND ('Org1.member', 'Org2.member', 'Org3.member') requests 1 signature from
each of the three principals
• OR ('Org1.member', 'Org2.member') requests 1 signature from either one of the
two principals
• OR ('Org1.member', AND('Org2.member', 'Org3.member')) requests either one
signature from a member of the Org1 MSP or 1 signature from a member of
the Org2 MSP and 1 signature from a member of the Org3 MSP.
Roles (of the
Signer) are
supported
1. Member
2. Admin
3. Client
4. Peer
4
The policy can be specified at instantiate time using the -P switch, followed
by the policy. For example:
$ peer chaincode instantiate -C <channelid> -n mycc -P "AND('Org1.member', 'Org2.member')"
01-02-2019

HyperLedger Fabric Channels
01-02-2019 26
2
o A Hyperledger Fabric channel is a private “subnet” of communication between two or
more specific network members, for the purpose of conducting private and confidential
transactions.
o Channel is a completely separate instance of HyperLedger Fabric. Every Channel is
completely isolated and will never talk to each other.
o To create a new channel, the client SDK calls configuration system Chaincode and
references properties such as anchor peer**s, and members (organizations). This
request creates a **genesis block for the channel ledger, which stores configuration
information about the channel policies, members and anchor peers.
o The consensus service orders transactions and delivers them, in a block, to each
leading peer, which then distributes the block to its member peers, and across the
channel, using the gossip protocol.
Why Channel is unique to Fabric?
Source: http://hyperledger-fabric.readthedocs.io/en/release-1.0/channels.html

Gossip Protocol
01-02-2019 27
2
o Manages peer discovery and channel membership, by continually
identifying available member peers, and eventually detecting peers
that have gone offline.
o Disseminates ledger data across all peers on a channel. Any peer
with data that is out of sync with the rest of the channel identifies
the missing blocks and syncs itself by copying the correct data. A
state reconciliation process synchronizes world state across peers
on each channel. Each peer continually pulls blocks from other
peers on the channel, in order to repair its own state if
discrepancies are identified
o Bring newly connected peers up to speed by allowing peer-to-peer
state transfer update of ledger data.
Source: http://hyperledger-fabric.readthedocs.io/en/release-1.0/gossip.html

Summary – HyperLedger Fabric Architecture
28
2
Orderer
• Consensus
verification
• Creates Blocks
CA
• Registration
of identities
• Manage
Certificates
Peer
• Endorses Tx
• Simulates Tx
• Commits Tx
All these components can be clustered for scalability and to avoid Single Point of Failure
3 Components of Fabric
Ledger
Smart Contract
• createCar
• queryAllCars
• changeCarColor
• changeCarOwner
Other Concepts
• Endorsement Policies
• Assets : Anything that’s
valuable for the Organization
• Transactions (State changes
of Assets)
• Gossip Protocol : The glue
that keeps the peers in
healthy state.
Channels
• Private subnet for
a set of parties
based on Smart
contract
• Ledger / Channel
• Peers can have
multiple Channels
• Private Data
1
2
01-02-2019

Fabric : Internals
01-02-2019 29

Ledger
01-02-2019 30Source: https://hyperledger-fabric.readthedocs.io/en/release-1.3/ledger/ledger.html
• Ledger L comprises blockchain B and World State W.
• Blockchain B determines World State W.
• Also expressed as: World state W is derived from blockchain B.
3

Blockchain Structure
In the above diagram, we can see that block B2 has a block data D2 which contains all its transactions: T5, T6, T7.
Most importantly, B2 has a block header H2, which contains a cryptographic hash of all the transactions in D2 as
well as with the equivalent hash from the previous block B1. In this way, blocks are inextricably and immutably linked
to each other, which the term blockchain so neatly captures!
3

Blockchain Blocks
01-02-2019 32
Block Header
This section comprises three fields, written when a block is created.
• Block number: An integer starting at 0 (the genesis block), and increased by 1 for every new
block appended to the blockchain.
• Current Block Hash: The hash of all the transactions contained in the current block.
• Previous Block Hash: A copy of the hash from the previous block in the blockchain.
Source: https://hyperledger-fabric.readthedocs.io/en/release-1.3/ledger/ledger.html
3

Transactions
3

Peers
01-02-2019 34
3
Source: https://hyperledger-fabric.readthedocs.io/en/release-1.3/peers/peers.html

Peers and Channels
01-02-2019 35
3

Peers and Organizations
01-02-2019 36
3

Blockchain Network
01-02-2019 37

Blockchain Network
01-02-2019 38
3
Source: https://hyperledger-fabric.readthedocs.io/en/release-1.3/network/network.html

Blockchain Network
01-02-2019 39
3
Four organizations, R1, R2, R3 and
R4 have jointly decided, and written
into an agreement, that they will set
up and exploit a Hyperledger Fabric
network. R4 has been assigned to be
the network initiator – it has been
given the power to set up the initial
version of the network. R4 has no
intention to perform business
transactions on the network.
• R1 and R2 have a need for a private communications within the overall network, as do R2 and R3.
• Organization R1 has a client application that can perform business transactions within channel C1.
• Organization R2 has a client application that can do similar work both in channel C1 and C2.
• Organization R3 has a client application that can do this on channel C2.
• Peer node P1 maintains a copy of the ledger L1 associated with C1.
• Peer node P2 maintains a copy of the ledger L1 associated with C1 and a copy of ledger L2
associated with C2.
• Peer node P3 maintains a copy of the ledger L2 associated with C2.

Blockchain Network
01-02-2019 40
3
• The channel C1 is under the control of organizations R1 and R2.
• Channel C2 is governed according to the policy rules specified in channel configuration CC2;
• the channel is under the control of organizations R2 and R3.
• There is an ordering service O4 that services as a network administration point for N, and uses the
system channel.
• The ordering service also supports application channels C1 and C2, for the purposes of transaction
ordering into blocks for distribution.
• Each of the four organizations has a preferred Certificate Authority.
• The network is governed
according to policy rules
specified in network
configuration NC4,
• the network is under the
control of organizations R1
and R4.
• Channel C1 is governed
according to the policy rules
specified in channel
configuration CC1;

Fabric : Transaction Flow
01-02-2019 41

Fabric: Transaction Flow
42
3 Source:
http://hyperledger-fabric.readthedocs.io/en/release-1.0/txflow.html
1
2
Customer wants to order Red Roses
from Merchant for a new price.
Scenario
Customer Merchant
Customer
PeerBPeerA
Tx Proposal
• Endorsement Policy in the Chaincode states
proposal must be accepted by all parties.
• Proposal includes the function of the Chaincode
that needs to be triggered and other params.
• The SDK packages the transaction proposal into
the properly architected format (protocol buffer
over gRPC) and takes the user’s cryptographic
credentials to produce a unique signature for this
transaction proposal. Endorsing Peers
2.1 The Endorsing Peers : Verification
1. The transaction Proposal is well formed
2. It has not been submitted already in the past (replay attack protection)
3. The signature is valid using (MSP) and the
4. Submitter (Customer) is properly authorized to perform the proposed operation on the Channel.
01-02-2019

Fabric: Transaction Flow
43
3 Source:
http://hyperledger-fabric.readthedocs.io/en/release-1.0/txflow.html
2
2.2 The Endorsing Peers : Execute
1. The endorsing peers take the transaction proposal
inputs as arguments to the invoked chaincode’s
function It has not been submitted already in the
past (replay attack protection)
2. The chaincode is then executed against the current
state database to produce transaction results
including a response value, read set, and write set.
• No updates are made to the ledger at this point. Signed Proposal
3
Proposal Responses are inspected
1. App verifies the endorsing peer signatures.
2. Checks if the Endorsement policy is fulfilled (ie.
Customer and the Merchant Peer both endorse the
proposal).
01-02-2019

01-02-2019 44
Fabric: Transaction Flow3
Convert Endorsement to transaction
1. The App “broadcasts” the transaction proposal and
response within a “transaction message” to the
Ordering Service
2. The transaction will contain the read/write sets. The
endorsement signatures and Channel ID.
3. The ordering service doesn't need to inspect the
content of the transaction.
4. It receives transactions from all the channels from
the network and orders them chronologically by the
Channel and
5. Creates blocks of transactions per channel.
4 Ordering
Service
Channels

01-02-2019 45
Transaction Validated and Committed
1. The blocks of transactions are delivered to all Peers
in the network based on the Channel ID.
2. Validate the transaction based on Endorsement
policy.
3. Ensure that no change in the Ledger state based on
the Read-set variables since the read-set was
generated by the transaction execution.
4. Transactions in the block are tagged as being Valid
or Invalid.
5
Ordering
Service
Peers

01-02-2019 46
6
Ledger Updated
1. Each Peer appends the Block to the
Channels chain.
2. For Each VALID transactions the write-set is
committed to the World State Database.
3. An Event is emitted to Notify the Client
Application.
4. Transactions in the block are tagged as being
Valid or Invalid.
Block
appended
to Tx Chain
Sends Notification

01-02-2019 47
Fabric: Transaction Flow Summary3

Fabric : Private Data
01-02-2019 48
HyperLedger Fabric v1.2 onwards

Private Data
01-02-2019 49
3
Private Data
06/12/18 43
3
Source: https://hyperledger-fabric.readthedocs.io/en/release-1.3/private-data/private-data.html

Private Data – Use Case
01-02-2019 50
3
• A Farmer selling his goods
abroad
• A Distributor moving goods
abroad
• A Shipper moving goods
between parties
• A Wholesaler purchasing
goods from distributors
• A Retailer purchasing
goods from shippers and
wholesalers

Private Data – Transaction Flow
01-02-2019 51
3
1. The client application submits a proposal request to invoke a chaincode.
2. The endorsing peers simulate the transaction and store the private data in a transient data store (a
temporary storage local to the peer). They distribute the private data, based on the collection policy,
to authorized peers via gossip protocol.
3. The endorsing peer sends the proposal response back to the client with public data, including a hash
of the private data key and value. No private data is sent back to the client.
4. The client application submits the transaction to the ordering service (with hashes of the private
data) which gets distributed into blocks as normal. The block with the hashed values is distributed to
all the peers.
5. At block-committal time, authorized peers use the collection policy to determine if they are
authorized to have access to the private data. If they do, they will first check their
local transient data store to determine if they have already received the private data at chaincode
endorsement time. If not, they will attempt to pull the private data from another peer. Then they will
validate the private data against the hashes in the public block and commit the transaction and the
block. Upon validation/commit, the private data is moved to their copy of the private state database
and private writeset storage.

Fabric : Getting Started
01-02-2019 52

Fabric Example : Pre requisites – Fabric Network
01-02-2019 53
3
$ git clone -b master https://github.com/hyperledger/fabric-samples.git
$ cd fabric-samples
$ git checkout {TAG}
Source: http://hyperledger-fabric.readthedocs.io/en/latest/samples.html
To ensure the samples are compatible with the version of Fabric binaries you download below,
checkout the samples {TAG} that matches your Fabric version, for example, v1.1.0. To see a list
of all fabric-samples tags, use command “git tag”.
$ curl -sSL https://goo.gl/6wtTN5 | bash -s 1.1.0
Please execute the following command from within the directory into which you will extract the
platform-specific binaries:
If you get an error running the above curl command, you may have too old a version of curl that
does not handle redirects or an unsupported environment.
$ export PATH=<path to download location>/bin:$PATH
The script lists out the Docker images installed upon conclusion.

Fabric Example : Writing your First App
01-02-2019 54Source: http://hyperledger-fabric.readthedocs.io/en/latest/write_first_app.html
We will show the process for interacting with a Certificate
Authority and generating enrollment certificates, after which
we will leverage these generated identities (user objects) to
query and update a ledger.
1. Set up the Development Environment
2. Learn the parameters of Smart
Contract
3. Develop Apps that can Query and
Update the Ledger
3
Smart
Contract
Blockchain Network
CAOrderer
QueryExecute Smart Contracts
Get Ledger Updates
Ledger

Fabric Example : Install the Fabcar Example
55
3
$ cd fabric-samples/fabcar && ls *.js
enrollAdmin. js Invoke.js query.js registerUser.js
You will see for Node JS Programs as follows
Do a cleanup before u start installing the Sample App in the Ledger
$ docker rm -f $(docker ps -aq)
$ docker network prune
$ docker rmi dev-peer0.org1.example.com-fabcar-1.0-5c906e402ed29f20260ae42283216aa75549c571e2e380f3615826365d8269ba
$ npm install
$ ./startFabric.sh
Source: http://hyperledger-fabric.readthedocs.io/en/latest/write_first_app.html01-02-2019

Fabric Example : Enroll User
01-02-2019 56
3
Source: http://hyperledger-fabric.readthedocs.io/en/latest/write_first_app.html
$ node enrollAdmin.js
An admin user - admin - was registered with our Certificate Authority. Now we need to send an
enroll call to the CA server and retrieve the enrollment certificate (eCert) for this user.
This program will invoke a certificate signing request (CSR) and ultimately output an eCert and
key material into a newly created folder - hfc-key-store - at the root of this project.
$ node registerUser.js
Newly generated admin eCert, we will now communicate with the CA server once more to
register and enroll a new user. This user - user1 - will be the identity we use when querying and
updating the ledger.
Similar to the admin enrollment, this program invokes a CSR and outputs the keys and eCert
into the hfc-key-store subdirectory. So now we have identity material for two separate users -
admin & user1

Fabric Example : Smart Contract Functions
01-02-2019 57
Smart Contract
Chaincode (GoLang / NodeJS)
Blockchain Network
CAOrderer
Ledger
• createCar
• queryAllCars
• changeCarColor
• changeCarOwner
3

01-02-2019 58
3
Chaincode Constructor
Invoke(stub) method is called as result
of an application request to the
Chaincode
Ledger Persistence Calls – Commands
createCar(stub, args)
changeCarOwner(stub, args)

01-02-2019 59
3
queryCar(stub, args)
Ledger Persistence Calls – Queries
queryAllCars(stub, args)

Fabric Example : Query The Ledger
01-02-2019 60
3
$ node query.js
Similar to the admin enrollment, this program invokes a CSR and outputs the keys and eCert
into the hfc-key-store subdirectory. So now we have identity material for two separate users -
admin & user1
Source: http://hyperledger-fabric.readthedocs.io/en/latest/write_first_app.html
Smart
Contract
Blockchain Network
CAOrderer
QueryRun the query
Return Query Results
Queries are how you read data from the ledger. This data is stored as a
series of key-value pairs, and you can query for the value of a single
key, multiple keys, or – if the ledger is written in a rich data storage
format like JSON – perform complex searches against it (looking for all
assets that contain certain keywords, for example)
fabric_client.getUserContext('user1', true);
Ledger

HyperLedger Fabric – Node.JS Client API
61Source: http://hyperledger-fabric.readthedocs.io/en/release-1.0/write_first_app.html
1. Initialize the Client API
2. Create a Channel
3. Create a Peer
4. Add Peer to the Channel
3
Query ChainCode: fabcar
Query Function: queryAllCars
$ node query.js
GetHistoryForKey()
GetHistoryForKey()
01-02-2019

HyperLedger Fabric – Node.JS Client API
01-02-2019 62
3
1. Get a Transaction ID based on the
user assigned to the client.
2. Send Transaction Proposal for
3. createCar() function in the
Chaincode creates a new transaction
4. changeCarOwner() function in the
Chaincode updates the owner.
Update function doesn't update the Blockchain instead it will have a new record with the latest status of the Asset.
$ node invoke.js

Ethereum Vs. HyperLedger Fabric Vs. R3 Corda
64
4
Characteristics Ethereum HyperLedger Fabric R3 Corda
Description of
the Platform
Generic Blockchain Platform Modular Blockchain Platform
Specialized distributed ledger
platform for Financial Industry
Release History July 2015
v0.6 Sept 2016, v1.0 July 2017,
v1.3 2018
v-m0.0 May 2016, v1.0 Oct 2017,
v3.0 Mar 2018
Crypto Currency
Ether / Tokens (Usage, Work) via
Smart Contract
None
Currency and Tokens via Chaincode
None
Governance
Ethereum Developers
Enterprise Ethereum Alliance
Linux Foundation
IBM
R3
Consensus
Mining based on Proof of Work
(POW) – All participants need to
agree.
Ledger Level
Selective Endorsement. Consensus
can be even within a channel with
select parties instead of everyone.
Transaction Level
Specific understanding of
Consensus. (Validity, Uniqueness)
Transaction Level
Network Permissionless, Public or Private Permissioned, Private Permissioned, Private
State Account Data
Key-value Database
Transaction Log, World State
Vault contains States
Historic & Current State
Smart Contracts Solidity Chaincode (GoLang, Node.JS, Java) Smart Contract (Kotlin, Java)
Development
Languages
GoLang, C++, Python Java, Node.JS, Python (Post 1.0) Java, Kotlin
01-02-2019

Summary – Benefits of Blockchain Technologies
01-02-2019 65
4
Saves Time
Immutable
transaction across
parties done at the
same time.
Remove Cost
Overheads on
maintaining and
synchronizing silos.
Increases Trust
Through shared process
and unified Systems of
Record. For end
consumers it’s a System
of Proof.
Reduces Risk
Tampering of data,
fraud and cyber crime
is avoided.

Disrupting the Media Value Chain
01-02-2019 66
Introduction of
Blockchain will
result in
deprecation of
critical
roles/operations
played by some
of the Business
Entities.
4

Content Bypassing the Aggregators
67
Source: Deloitte : Blockchain @ Media
Content Producer
/ Artist Aggregator Consumer
Current Scenario
Content Producer
/ Artist
Distributed
Ledger Consumer
After Introduction of Blockchain
Benefits
• Direct Customer Artist
relationship.
• Easy to measure marketing and
performance.
Challenges
• Content Aggregators and
Advertising networks to loose
their dominant position.
• Blockchain has the potential to
make DRMsystems obsolete or at
least to reduce it’s complexity
4
01-02-2019

Distribution of Royalty Payments
68
Artist Aggregator User
Current Scenario
Music
Publisher Distributor
Artist User
After Introduction of Blockchain
Distributed Ledger Distributor
Source: Deloitte : Blockchain @ Media
Benefits
• Near Real-time distribution of
Royalty payments based on Smart
Contracts
• Every usage and consumption is
tracked in Blockchain
Challenges
• Handling large amount of Data
• All the parties agreeing to
common Blockchain Platform.
4
01-02-2019

01-02-2019 69
References
Blockchain Video Tutorials
• Blockchain Use Cases: https://wiki.hyperledger.org/groups/requirements/use-case-inventory
• Hyperledger Fabric Explainer: https://www.youtube.com/watch?v=js3Zjxbo8TM
• Blockchain Technology : https://www.youtube.com/watch?v=qOVAbKKSH10
• Smart Contracts : https://www.youtube.com/watch?v=ZE2HxTmxfrI
• Hyperledger Fabric v1.1 Node.JS Chaincode : https://www.youtube.com/watch?v=dzwR0dwzXNs
• Hyperledger Fabric v1.0 : https://www.youtube.com/watch?v=6nGIptzBZis
• Hyperledger Fabric for Beginners : https://www.youtube.com/watch?v=Y177TCUc4g0
• Fabric Composer : https://www.youtube.com/watch?v=fdFUsrsv5iw
• Hyperledger Composer : https://www.youtube.com/watch?v=iRlm4uY_9pA
• How does it works: Blockchain : https://www.youtube.com/watch?v=lD9KAnkZUjU
• How does Blockchain work: https://www.youtube.com/watch?v=LZEHOlZY2To
• 19 Industries The Blockchain will disrupt : https://www.youtube.com/watch?v=G3psxs3gyf8
• What is the difference between Bitcoin & Blockchain? : https://www.youtube.com/watch?v=MKwa-BqnJDg
• Bitcoin: What Bill Gates, Buffet, Elon Mush & Richard Branson has to say about Bitcoin?
4

70
1. HyperLedger Architecture Volume 1
2. Creating Tokens in Hyperledger Fabric : https://github.com/Kunstmaan/hyperleder-fabric-kuma-token-example/
3. Karame, Androulaki, & Capkun. (2012). Double spending fast payments in bitcoin. ACM Conference on Computer and
communications security, (pp. 906-917).
4. King, N. (2012). PPCoin: Peer to peer cryptocurrency with proof of stake.
5. Kwon. (2014). Tendermint: Consensus without Mining. Cornell Edu.
6. Mazieres, D. (2015). The Stellar Consensus Protocol: Federated Model for Internet level consensus. Stellar Development
Foundation.
7. Narayanan, B. F. (2016). Bitcoin and cryptocurrency technologies. Princeton: Princeton University Press.
8. O'Dwyer, & Malone. (2014). Bitcoin mining and its energy footprint. Irish Signals and Systems Conference, pp. 280-285
9. Byzantine Fault Tolerance : https://en.wikipedia.org/wiki/Byzantine_fault_tolerance
10. Building Blockchain Apps for Node.JS developers with HyperLedger Composer – Simon Stone IBM
References
My Slide share Presentations
1. Enterprise Software Architecture – http://www.slideshare.net/arafkarsh/software-architecture-styles-64537120
2. Functional Reactive Programming – https://www.slideshare.net/arafkarsh/functional-reactive-programming-64780160
3. Microservices – Part 1: https://www.slideshare.net/arafkarsh/micro-services-architecture-80571009
4. Event Storming and Saga Design Pattern – Part 2 : https://www.slideshare.net/arafkarsh/event-storming-and-saga
5. Docker and Linux Containers : https://www.slideshare.net/arafkarsh/docker-container-linux-container
6. Function Point Analysis : http://www.slideshare.net/arafkarsh/functional-reactive-programming-64780160
4
01-02-2019

71
Araf Karsh Hamid : Co-Founder / CTO
araf.karsh@metamagic.in
USA: +1 (973) 969-2921
India: +91.999.545.8627
Skype / LinkedIn / Twitter / Slideshare : arafkarsh
http://www.slideshare.net/arafkarsh
https://www.linkedin.com/in/arafkarsh/
http://www.arafkarsh.com/
DREAM | AUTOMATE | EMPOWER
01-02-2019

Transaction Proposal to Commit
01-02-2019 72
3

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