Blockchain vs.
Cryptocurrencies
Kaliya Young
BridgeSF May 23, 2018
What is a Blockchain?
The first blockchain was
the Bitcoin blockchain
How does it work?
we will get to that
Why is it Interesting?
Solves the
Double Spend Problem
BitCoin
Number
What is a BitCoin?
BitCoin
Address 1
BitCoin
Number
BitCoin
Address 1
BitCoin
Number
WALLET for
BITCOIN ADDRESS
PRIVATE Key
of BitCoin Address 1
BitCoin
Address 1 SENDS
WALLET for
BITCOIN ADDRESS
PRIVATE Key
of BitCoin Address 1
BitCoin
Number
BitCoin
Address 1
BitCoin
NumberSENDS
BitCoin
Address 2TO
BitCoin
Address 1
BitCoin
NumberSENDS
BitCoin
Address 2TO
THIS IS A TRANSACTION
The transactions are broadcast
to the network of computers.
BitCoin
Address 3 SENDS
WALLET for
BITCOIN ADDRESS
PRIVATE Key
of BitCoin Address 1
BitCoin
Number
BitCoin
Address 3
BitCoin
NumberSENDS
BitCoin
Address 3
BitCoin
NumberSENDS
BitCoin
Address 5TO
BitCoin
Address 3
BitCoin
NumberSENDS
BitCoin
Address 4TO
THIS IS A TRANSACTION
THIS IS A TRANSACTION
THIS IS A TRANSACTION
These transactions are broadcast
to the network of computers.
About Ten Minutes
??????
<—— What is the HASH (Special Number)
of the Bundle of Transactions
<——- The Special is Found by a Miner Node
and they are rewarded with a
totally New Bitcoin Number
This number becomes
the top of the next block.
??????
This number becomes
the top of the next block.
??????
This number becomes
the top of the next block.
??????
These transactions are broadcast
to the network of computers.
The ledger is updated
across the network.
???
….
This LEDGER of Transactions
One SHARED LEDGER of Transactions
this is CHAIN of BLOCKS of Transaction
This is all maintained by a network of
commuters a, DISTRIBUTED LEDGER
….
WHAT IS SPECIAL ABOUT THIS?
It is Immutable
You can’t erase
transactions.
Its Transparent
Anyone can
see the transactions
Its “Trustless”
The software of the network
runs it. NOT a central
institutional authority.
Do You Need a Blockchain?
* Do you need a shared, constant data store?
* Does more than one entity need to contribute
data? * (Do you need Auditing)
* Sensitive identifiers WILL NOT be written to
the data store?
* Data records, once written, are never
updated or deleted?
* Are the entities with write access having a
hard time who should be control of the data
store?
* Do you want a tamperproof log of all the writes
to the data store?
ONLY if the answers is YES to the above questions
You may have a useful Blockchain use case.
Lessons Learned from R&D Investments

Most Organizations Don’t Need A Blockchain
59
Do you need a shared,
consistent data store?
Does more than one
entity need to
contribute data?
Data records, once
written, are never
updated or deleted?
Sensitive identifiers
WILL NOT be written to
the data store?
Blockchains provide a historically
consistent data store. If you don’t need
that, you don’t need a Blockchain

CONSIDER: Email / Spreadsheets
Your data comes from a single entity.
Blockchains are typically used when data
comes from multiple entities.
CONSIDER: Database

CAVEAT: Auditing Use Cases
Blockchains do not allow modifications
of historical data; they are strongly
auditable
CONSIDER: Database
You should not write sensitive information
to a Blockchain that requires medium to
long term confidentiality, such as PII, even
if it is encrypted
CONSIDER: Encrypted Database
Are the entities with
write access having a
hard time deciding
who should be in
control of the data
store?
If there are no trust or control issues
over who runs the data store,
traditional database solutions should
suffice

CONSIDER: Managed Database
Do you want a
tamperproof log of all
writes to the data
store?
If you don’t need to audit what
happened and when it happened, you
don’t need a Blockchain 

CONSIDER: Database
You may have a
useful Blockchain
use case
YES
YES
YES
YES
YES
YES
AUDITING
NO
NO
NO
NO
NO
NO
What can you do with this
type of Data Store?
There is Lots of Experimentation Now
Show Proof A Particular
Action/Transaction
Happened at a Certain Time
Supply Chains
Tracing Provenance
Traceable Medicine to
prevent counterfeiting
1. Performance History, vehicle maintenance,
quality assurance
2. Dynamic Optimization - capacity monitoring
3. Payments and Pricing - fraud detection, theft
prevention
Blockchain Use Cases:
Have Immutable Records
for Data
Institutions can Issue
Verified (Digital) Credentials
to Organizations
Verifiable Organizations Network
British Columbia Government
is building it,
and its all up on GitHub
Verifiable Organizations Network
Verifiable Organizations Network
Verifiable Organizations Network
OrgBookProfile
a Business
Public Business Permits
Verifiable Organizations Network
OrgBookProfile
a Business
Business Owner
Can Claim These
Public Business Permits
Verifiable Organizations Network
OrgBookProfile
a Business
Business Owner
Can Claim These
In the Verifiable
Credentials Format
Public Business Permits
Verifiable Organizations Network
OrgBookProfile
a Business
Business Owner
Can Claim These
In the Verifiable
Credentials Format
In a Digital Wallet
Public Business Permits
Verifiable Organizations Network
HolderIssuer Verifier
Issues 

Claim
Decentralized Identifiers (DIDs)
Public Blockchain or other Decentralized Network
Signs
Claim
Countersigns
Claim
Wallet
Slide credit: Drummond Reed, Sovrin Foundation
BC GOVERNMENT BC BUSINESS
Verifiable Organizations Network
HolderIssuer Verifier
Issues 

Claim
Decentralized Identifiers (DIDs)
Public Blockchain or other Decentralized Network
Signs
Claim
Countersigns
Claim
Verifies
Signatures
Wallet
Slide credit: Drummond Reed, Sovrin Foundation
BC GOVERNMENT BC BUSINESS CANADIAN GOVERNMENT
Verifiable Organizations Network
HolderIssuer Verifier
Issues 

Claim
Presents

Claim
Decentralized Identifiers (DIDs)
Public Blockchain or other Decentralized Network
Signs
Claim
Countersigns
Claim
Verifies
Signatures
Wallet
Slide credit: Drummond Reed, Sovrin Foundation
BC GOVERNMENT BC BUSINESS CANADIAN GOVERNMENT
Create Addressable Identifiers
Created and Owned by People
Self Sovereign Identity
no facebook
no phone number
no email provider
Decentralized IDentifier - DID
did:sov:3k9dg356wdcj5gf2k9bw8kfg7a
Method
Scheme
Method-Specific Identifier
Slide credit: Drummond Reed, Sovrin Foundation
did:sov:3k9dg356wdcj5gf2k9bw8kfg7a
Slide credit: Drummond Reed, Sovrin Foundation
did:sov:3k9dg356wdcj5gf2k9bw8kfg7a
Public
Key
cc2cd0ffde594d278c2d9b432f4748506a7f9f2
5141e485eb84bc188382019b6
Slide credit: Drummond Reed, Sovrin Foundation
did:sov:3k9dg356wdcj5gf2k9bw8kfg7a
047d599d4521480d9e1919481b024f29d2693f2
72d19473dbef971d7d529f6e9
Private

Key
Public
Key
cc2cd0ffde594d278c2d9b432f4748506a7f9f2
5141e485eb84bc188382019b6
Slide credit: Drummond Reed, Sovrin Foundation
did:sov:3k9dg356wdcj5gf2k9bw8kfg7a
047d599d4521480d9e1919481b024f29d2693f2
72d19473dbef971d7d529f6e9
Private

Key
Public
Key
cc2cd0ffde594d278c2d9b432f4748506a7f9f2
5141e485eb84bc188382019b6
Slide credit: Drummond Reed, Sovrin Foundation
{ “Key”: “Value” }
DID
Decentralized
Identifier
DID Document
JSON-LD document
describing the
entity identified by
the DID
Slide credit: Drummond Reed, Sovrin Foundation
1. DID (for self-description)
2. Set of public keys (for verification)
3. Set of auth protocols (for authentication)
4. Set of service endpoints (for interaction)
5. Timestamp (for audit history)
6. Signature (for integrity)
89
The standard elements of a DID doc
Slide credit: Drummond Reed, Sovrin Foundation
1. DID (for self-description)
2. Set of public keys (for verification)
3. Set of auth protocols (for authentication)
4. Set of service endpoints (for interaction)
5. Timestamp (for audit history)
6. Signature (for integrity)
90
The standard elements of a DID doc
Slide credit: Drummond Reed, Sovrin Foundation
1. DID (for self-description)
2. Set of public keys (for verification)
3. Set of auth protocols (for authentication)
4. Set of service endpoints (for interaction)
5. Timestamp (for audit history)
6. Signature (for integrity)
91
The standard elements of a DID doc
Slide credit: Drummond Reed, Sovrin Foundation
1. DID (for self-description)
2. Set of public keys (for verification)
3. Set of auth protocols (for authentication)
4. Set of service endpoints (for interaction)
5. Timestamp (for audit history)
6. Signature (for integrity)
92
The standard elements of a DID doc
Slide credit: Drummond Reed, Sovrin Foundation
1. DID (for self-description)
2. Set of public keys (for verification)
3. Set of auth protocols (for authentication)
4. Set of service endpoints (for interaction)
5. Timestamp (for audit history)
6. Signature (for integrity)
93
The standard elements of a DID doc
Slide credit: Drummond Reed, Sovrin Foundation
NO PERSONALLY IDENTIFIABLE
INFORMATION
ENDS UP ON THE BLOCK CHAIN
Shared Ledgers
DID Layer
The decentralized identity “stack”
Cloud Layer
Cloud Wallet Cloud Wallet
Cloud Agent Cloud Agent
Identity Owners
Edge Layer
Edge Wallet Edge Wallet
Edge Agent Edge Agent
Slide credit: Drummond Reed, Sovrin Foundation
Identity Owners
My Credit Union ID
HolderIssuer Verifier
Issues 

Claim
Decentralized Identifiers (DIDs)
Public Blockchain or other Decentralized Network
Signs
Claim
Countersigns
Claim
Wallet
Slide credit: Drummond Reed, Sovrin Foundation
CREDIT UNION CU MEMBER
HolderIssuer Verifier
Issues 

Claim
Decentralized Identifiers (DIDs)
Public Blockchain or other Decentralized Network
Signs
Claim
Countersigns
Claim
Verifies
Signatures
Wallet
Slide credit: Drummond Reed, Sovrin Foundation
CREDIT UNION CU MEMBER 2nd CREDIT UNION
HolderIssuer Verifier
Issues 

Claim
Presents

Claim
Decentralized Identifiers (DIDs)
Public Blockchain or other Decentralized Network
Signs
Claim
Countersigns
Claim
Verifies
Signatures
Wallet
Slide credit: Drummond Reed, Sovrin Foundation
CREDIT UNION CU MEMBER 2nd CREDIT UNION
101
Coordinate Activity Across
Many Organizations
The Amply project, supported by UNICEF and
Innovation Edge, built a mobile app using the ixo
protocol to track attendance in pre-schools in
South Africa.
Combining mobile and blockchain technology to
increase impact and accountability of public
services and generate real-time data.
HIE OF ONE
HEALTH
INFORMATION
EXCHANGE
BlockChain and Land Rights?
Blockchain and Property in 2018: 

At the End of the Beginning
Intro: Why Blockchain
Makes Sense for Real Estate
• The technology is decentralized, fault-tolerant, and tamper-resistant; offering
security and resiliency.
• Blockchain is disruptive for land governance, it may promote property
rights formalization, registry modernization, and the collection/analysis of
data.
• Blockchain can generate increased efficiency and lower transaction
costs in the global real estate sector.
• The technology allows for improved liquidity of property, financial inclusion,
and increased foreign investment.
Paper Overview
1. FPR’s seven prerequisites for blockchain
introduction into a land registry.
2. Conceptual framework: Eight levels of integration
from the simple to more radical.
3. Five topics on the future interaction of blockchain
and land, from title insurance to regulation.
4. Six case studies of companies active in the space.
Different Blockchain Flavors
Bitcoin,

Ethereum, IOTA,

Veres One
Permissionless Permissioned
Public
Private
Validation
Access
Hyperledger Sawtooth*
Sovrin,
IPDB
Hyperledger (Fabric,
Sawtooth, Iroha),

R3 Corda,

CU Ledger* in permissionless mode
Slide credit: Drummond Reed, Sovrin Foundation
Should I use a Blockchain?
Does my use case involved a database?
Will there be numerous users updating my database?
Do these users need to trust each other?
Are there problems caused by the use of central/third
party entity?
Do transactions depend on/interact with each other?
I should be using a blockchain!
Kaliya Young
kaliya@IdentityWoman.net
Get the Self-Sovereign Identity Scoop
SSIScoop.com
HumanFirst.Tech
Blockchain v Cryptocurrency: Talk for BridgeSF

Blockchain v Cryptocurrency: Talk for BridgeSF