Information
- Teaching Team
- Dr.Faisal Tariq (Course Coordinator) (faisal.tariq@glasgow.ac.uk)
- Dr.Yao Sun (Yao.Sun@glasgow.ac.uk)
- Course Arrangement –Blockchain
- Part 10 lectures (including 4 tutorials)
- 2 labs
- Moodle Page
- UESTC4036: Information Security
- All the relevant information can be found there
Introduction and outline
Lesson Plan
- Aim
- An introduction of Distributed Ledger Technology
- An introduction of database management
- Learning Objectives
- Understand the big picture of the second part
- Understand the basic idea of DLT and database management
- Assumed Previous Knowledge
- Wireless Communication System
- Intended Learning Outcomes
- Basic concepts of distributed ledger technologies
- Basics of Blockchain (consensus, smart contract …)
- Wireless blockchain
- Blockchain applications
Outline
- Course Introduction – Part II
- Distributed Ledger Technology
- Blockchain - Basics
Distributed Ledger Technology
Ledger
- Ledger: The records of maintenance for a property.
- Property: Money, Accommodation, Information
- Maintenance: Transactions / ownership updates of the property
e.g
- a ledger for payroll, a ledger for bills, any valuable information exchanges.
- All these ledgers can be linked together to form a bigger ledger.
发散
- Ledger
- Managed Manually
- Digital Ledger
- Managed using a ‘computer’
- Distributed Digital Ledger
- Records kept on multiple computers but managed by a central entity
- Decentralized Distributed Digital Ledger
- Records kept on multiple computers but managed in a decentralized way
Distributed Ledger Technology (DLT)
e.g., Blockchain
Generally, DLT is a database
Classification
- In terms of “Identity of nodes”
- Permissioned DLTs: the identity of nodes needs to be known.
- Permissionless DLTs: the identity does not need to be known.
- In terms of “Reading Data”
- Public DLTs: anyone can read the data
- Private DLTs: only approved nodes can read the data over the ledger.
Difference from traditional database management system (DBMS)
- DLT: Distributed/decentralized management (Or Peer-2-Peer)
- DBMS: Centralized management (Or Client-Server)
Blockchain - Basics
The data management and organization in DLT can be done through various ways.
Data Structure:
- Linear linked list of blocks
- Directed Acyclic Graph (DAG)
- Tree-like data structures
Blockchain：Linear linked list of blocks
Blockchain does not essentially be chain of blocks but it can be DAGs as well.
Definition
Blockchain
“Blockchain”: a data structure that is read only and data cannot be modified once it is entered into the blockchain and new data can only be appended at the end of blockchain, making blockchain highly immutable
Block
A “block” is termed as a basic component in which transactions are assembled.
Chain
Each of these blocks is linked together to form a blockchain.
- One simple way is to link these blocks in a linear order. However, there may be issues such as scalability, accessing these blocks quickly, and in terms of security.
- Other structures can be used such as the blocks can be organized into graphs or trees.
Transactions
Transactions in blockchain can store information such as
- tracking property ownership
- digital currency (cryptocurrency)
- loans
- records of anything such as death records, birth records, and land records
- tracking information of goods.
Key feature
It completely eliminates the role of trusted third party involvement in the maintainability of blockchain network.
Blockchain has some unique features that distinguish it from traditional database systems. Below these features are discussed in more detail.
Decentralization
- No central entity or intermediary to control and validate transactions.
- The data controlling capability is in the hands of users
Transparency
- Anyone can track the transaction history and track transactions, thus making the blockchain system highly transparent. (Especially public blockchain)
Immutability
- Once transactions have been added to the blockchain and validated by the participating nodes that transaction cannot be changed or tampered.
Availability
- Due to the distributed and decentralized nature of blockchain, the ledger itself is available to nodes, thus making the system highly available as compared to centralized systems (with single point of failure).
Pseudonymity
- Nodes in the blockchain system use pseudonymity, i.e., an identity that is partially revealed. Therefore, making blockchain systems privacy aware.
Security
Blockchain is secured by
- Strong public/private keys,
- hashing algorithms,
- digital signatures,
- encryption techniques.
Non-Repudiation
- Once a transaction has been added and validated in a blockchain, it cannot be disowned by the blockchain node.
Auditability
It enables the user to trace any transaction within the ledger.
- In public blockchain, one can audit the whole ledger itself.
- In private blockchain, only authorized entities can perform this audit.
Data Tampering
- Blockchain stores the hash of the previous block in the current block.
- Then a process is carried out for every block in the blockchain in which current block is considered and its hash is generated.
blockchain network
Multiple blocks (each having several transactions) linked together to form a blockchain
network
Block & Chain & Transactions
History
Example-Food Supply Chain
Blockchain for Food Supply Chain
- All the parties involved in food supply chain can trust on each other.
- The data recorded on the blockchain will be immutable and tampering cannot be possible.
- Ensure the provenance and traceability of the food products.
- Traceability and Provenance Within Food Supply Chain
- Identification and Removal of Contaminated Food
Traceability and Provenance Within Food Supply Chain
- Correct labelling
- Traceability
- Provenance of food
Track the food that has been declared risky for customers and recall the contaminated food.
Identification and Removal of Contaminated Food
- Monitoring the food condition at every stage of the food supply chain and record the state of the food
Determine that food got contaminated at which level