This document provides an overview of blockchain technology, including its advantages over conventional storage systems, such as enhanced security, immutability, and transparency. It discusses issues with traditional data storage, like trust and traceability, and explains how blockchain addresses these problems through mechanisms such as change logs, hashing, and peer consensus. The document also outlines the blockchain application ecosystem and its components.

1. Blockchain Technology
Basics
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Anjum Naveed, PhD (UNSW Australia)
Copyright © 2018 by ITROOS (Pvt.) Ltd
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2. Topics Covered
Conventional Storage
Issues with conventional storage
Introduction to Blockchain
Blockchain: Addressing the issues
Usecases of Blockchain
Blockchain Application Eco system
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3. Conventional Storage
Databases
SQL
noSQL
Files
Structured
Unstructured
Variations
In memory
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4. Issues with Conventional Storage
Data Modifications
Who changed what and when?
In general, record of modifications does
not exist
Trust
Since I last accessed my system, has the
data changed or it is same?
No change guarantee does not exist
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5. Issues with Conventional Storage
Transparency
Linked to “who changed what?”
Can I trace back all modifications to a
specific record?
How can we achieve such guarantees?
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6. Blockchain: Rising from Conventional Data Storage
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Database/File
Record 1
Record 2
Record 3
.
.
.
.
.
.
.
.
.
Record n
Change Log/Transaction Log on Data Store
Record 1, Name field changed to ABC by Z
Record 4, Make field changed to PDC by Q
.
.
.
.
Record 7, User field changed to XYZ by N
.
.
.
.
.
.
.
.
.
.
Block 1
Block 5
Block 97
Block 997
Technology 1: Maintain Change Log
On the data (Who did What)
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7. Blockchain: Blocks and Chain
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Change
Log }
Hash
Change log
}Hash
Change
Log
Database/File
Record 1
Record 2
Record 3
.
.
.
.
.
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.
.
.
Record n
Blocks
Chaining of blocks through hash
Technology 2: Use hashes to ensure the log entries
are not changed (Securing change log)
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8. Blockchain: Computation Power
Single Hash computation time?
(100) microseconds
8 hashes computation time?
8 * (100) microseconds
2^22 hash computation time?
2^22 (100) microseconds ~ 7 minutes
This is average time required to compute the
hash with specific form
0000 0000 0000 0000 0000 00XXXXXXXXXXXXX
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9. Blockchain: Computation Power
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Change log
Nonce
}
Hash
Correct
form? YesNo
New
Nonce
HashTechnology 3: Computation power to
enhance security of change log (Immutability)
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10. Blockchain: Peer Consensus
Save entire chain and
data at every
participating node
Verify before saving,
verify before extending
If one node acts malicious
or is attacked, others will
still have valid copies
If ‘x’ nodes produce
corrupt new blocks, stop
the operation and fix
before resuming
operation
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11. Blockchain: Issues addressed
Immutability
Once a block is created out of change
log entries, distributed among peers
and goes a few blocks deep, it is
virtually impossible to change the
entries in block
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12. Blockchain: Issues addressed
Immutability
Once a block is created out of change
log entries, distributed among peers
and goes a few blocks deep, it is
virtually impossible to change the
entries in block
Who changed what and when?
??????
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13. Blockchain: Issues addressed
Immutability
Once a block is created out of change
log entries, distributed among peers
and goes a few blocks deep, it is
virtually impossible to change the
entries in block
Trust? Can we trust our data? (not the
change log)
??????
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14. Blockchain: Issues addressed
Immutability
Once a block is created out of change
log entries, distributed among peers
and goes a few blocks deep, it is
virtually impossible to change the
entries in block
How to achieve transparency?
??????
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15. Blockchain:Additional Issues addressed
Verifiability of data
Distributed Computation
Third party elimination
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16. Blockchain Application Eco system
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GUI
Backend
Server
Blockchain
API
Blockchain
Business
Logic
Blockchain
Network
Blockchain
Blockchain
Cryptographic
Support
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17. Next
Blockchain Security
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