This document provides an overview of blockchain fundamentals and related concepts through a presentation given by Bruno Lowagie at JavaOne 2018. The presentation covers topics such as bits and bytes, hashing, encryption, digital signatures, and distributed ledger technology. It defines these concepts, provides examples, and discusses their applications, particularly in relation to blockchain. The goal is to explain the underlying theory behind blockchain in an accessible manner.
14 Jan17- Nullmeets -Blockchain concept decoded by Ninad SarangNinad Sarang
Introduction to Blockchain and Bitcoin technologies
Things we will cover,
* What is TRANSACTION ?
* BlockChain !!!……Never heard what is that??
* The BTC Aka BitCoins
* Who discovered?
* How it works?
* Advantages & Disadvantages
* Applications
Blockchain: An Introduction, by Ruben Merre NGRAVERuben Merre
Blockchain - An Introduction is an extensive intro to blockchain technology and cryptocurrencies. Ruben Merre, CEO of blockchain hardware wallet tech company Ngrave, uses this slide deck for University lectures, introducing university level college students to the basics and the inner workings of blockchain technology.
14 Jan17- Nullmeets -Blockchain concept decoded by Ninad SarangNinad Sarang
Introduction to Blockchain and Bitcoin technologies
Things we will cover,
* What is TRANSACTION ?
* BlockChain !!!……Never heard what is that??
* The BTC Aka BitCoins
* Who discovered?
* How it works?
* Advantages & Disadvantages
* Applications
Blockchain: An Introduction, by Ruben Merre NGRAVERuben Merre
Blockchain - An Introduction is an extensive intro to blockchain technology and cryptocurrencies. Ruben Merre, CEO of blockchain hardware wallet tech company Ngrave, uses this slide deck for University lectures, introducing university level college students to the basics and the inner workings of blockchain technology.
Blockchain overview, use cases, implementations and challengesSébastien Tandel
Most know about Bitcoin, the well-known crypto-currency. Less know the details about the underlying and enabling technology, Blockchain.
Hopefully, this presentation provides enough insights to understand blockchain concepts and why it's perceived to potentially disrupt many market segments, from retail to governments, from finance to health care. At last, I hope to brush fairly the many challenges of this rather new technology.
A brief introduction to Blockchain and the underlying technology of distributed computing, challenges and future scope.
Copyrights belong to the respective owners, intention is purely for informational/educational purpose
I would like to thank various blogs, technical tutorials, books, videos to help me understand the basics and collate this presentaion
Understanding Bitcoin (Blockchain) and its Potential for Disruptive ApplicationsIndicThreads
Presented at the IndicThreads.com Software Development Conference 2016 held in Pune, India. More at http://www.IndicThreads.com and http://Pune16.IndicThreads.com
--
An introductory look at various Blockchain Technologies and examples. In this slide I explain about basics of Etherium and types of Blockchain technology currently present and some known public projects/examples which use Blockchain.
I spent quite some time to digest how Blockchain works and how it can influence our everyday life in the upcoming decades. My slides focus on that from a non-IT expert point view.
Blockchain , Deploying your first smart contract to azure ethereum blockchain.
Slides from my session in "Global Azure Bootcamp Chandigarh"
Presentation starts with basic terms like transactions , ledger and contracts. Talks about what is blockchain and ethereum and concludes with deployment of a smart contract to azure ethereum blockchain.
Virtual or digital currencies, with Bitcoin chief amongst them, have been gaining momentum and investment over the last couple of years. Offering an almost costless means of making payments around the globe, virtual currencies have the potential to bring significant disruption to the banking industry. This potential is not lost on either Bitcoin startups or banks themselves. But how does Bitcoin actually work? A peer-to-peer network maintains the “blockchain”, an innovative cryptographic protocol which securely mediates payments between parties without mutual trust. This session will step through the structure of the blockchain, showing how it solves the “double spend” problem and allows decentralised processing of financial transactions. Whether Bitcoin will become the currency of the internet or it’s a bubble that is doomed to burst sooner or later, the blockchain itself will change the face of transactional banking and perhaps other industries along the way.
Presentation to the Sydney Financial Mathematics Workshop (11 March 2015)
http://www.qgroup.org.au/content/bitcoin-banking-and-blockchain
Bitcoin and blockchain are not the same things, although they are related in that blockchain technology was first described and implemented in Bitcoin. Learn More about Blockchain:
Blockchain, cryptography and tokens — NYC Bar presentationPaperchain
Concise version of presentation delivered at the NYC Bar Association.
Overview of blockchains, how cryptography works on blockchains and the difference between cryptocurrencies and tokens.
Blockchain workshop PwC March 2018. Explanation of bitcoin and blockchain, Historical analogies, pros and cons, examlples. (Slides don't tell the full story, it included hands on activtiies)
What Video Games and BotCoin Did To The World Of Security... On AccidentBen Finke
Advances in graphics processing for both video games and crypto-currency mining have given us exceptional computing power to attack hashing algorithms, an underpinning foundational element of many of the security protections we use today. In this talk we'll explore how GPUs can be used in a security context, mostly by the bad guys.
A Deep Dive into the Interplay of Cryptographic Schemes and Algorithms powering the state of the art security models in Blockchain as manifested by the legendary Cryptocurrency Scheme Bitcoin. Presented in the IT Audit and Cybersecurity Conclave Organised by ISACA and Red Team Hacker Academy in Kochi, Kerala.
Blockchain overview, use cases, implementations and challengesSébastien Tandel
Most know about Bitcoin, the well-known crypto-currency. Less know the details about the underlying and enabling technology, Blockchain.
Hopefully, this presentation provides enough insights to understand blockchain concepts and why it's perceived to potentially disrupt many market segments, from retail to governments, from finance to health care. At last, I hope to brush fairly the many challenges of this rather new technology.
A brief introduction to Blockchain and the underlying technology of distributed computing, challenges and future scope.
Copyrights belong to the respective owners, intention is purely for informational/educational purpose
I would like to thank various blogs, technical tutorials, books, videos to help me understand the basics and collate this presentaion
Understanding Bitcoin (Blockchain) and its Potential for Disruptive ApplicationsIndicThreads
Presented at the IndicThreads.com Software Development Conference 2016 held in Pune, India. More at http://www.IndicThreads.com and http://Pune16.IndicThreads.com
--
An introductory look at various Blockchain Technologies and examples. In this slide I explain about basics of Etherium and types of Blockchain technology currently present and some known public projects/examples which use Blockchain.
I spent quite some time to digest how Blockchain works and how it can influence our everyday life in the upcoming decades. My slides focus on that from a non-IT expert point view.
Blockchain , Deploying your first smart contract to azure ethereum blockchain.
Slides from my session in "Global Azure Bootcamp Chandigarh"
Presentation starts with basic terms like transactions , ledger and contracts. Talks about what is blockchain and ethereum and concludes with deployment of a smart contract to azure ethereum blockchain.
Virtual or digital currencies, with Bitcoin chief amongst them, have been gaining momentum and investment over the last couple of years. Offering an almost costless means of making payments around the globe, virtual currencies have the potential to bring significant disruption to the banking industry. This potential is not lost on either Bitcoin startups or banks themselves. But how does Bitcoin actually work? A peer-to-peer network maintains the “blockchain”, an innovative cryptographic protocol which securely mediates payments between parties without mutual trust. This session will step through the structure of the blockchain, showing how it solves the “double spend” problem and allows decentralised processing of financial transactions. Whether Bitcoin will become the currency of the internet or it’s a bubble that is doomed to burst sooner or later, the blockchain itself will change the face of transactional banking and perhaps other industries along the way.
Presentation to the Sydney Financial Mathematics Workshop (11 March 2015)
http://www.qgroup.org.au/content/bitcoin-banking-and-blockchain
Bitcoin and blockchain are not the same things, although they are related in that blockchain technology was first described and implemented in Bitcoin. Learn More about Blockchain:
Blockchain, cryptography and tokens — NYC Bar presentationPaperchain
Concise version of presentation delivered at the NYC Bar Association.
Overview of blockchains, how cryptography works on blockchains and the difference between cryptocurrencies and tokens.
Blockchain workshop PwC March 2018. Explanation of bitcoin and blockchain, Historical analogies, pros and cons, examlples. (Slides don't tell the full story, it included hands on activtiies)
What Video Games and BotCoin Did To The World Of Security... On AccidentBen Finke
Advances in graphics processing for both video games and crypto-currency mining have given us exceptional computing power to attack hashing algorithms, an underpinning foundational element of many of the security protections we use today. In this talk we'll explore how GPUs can be used in a security context, mostly by the bad guys.
A Deep Dive into the Interplay of Cryptographic Schemes and Algorithms powering the state of the art security models in Blockchain as manifested by the legendary Cryptocurrency Scheme Bitcoin. Presented in the IT Audit and Cybersecurity Conclave Organised by ISACA and Red Team Hacker Academy in Kochi, Kerala.
A Quick Start To Blockchain by Seval CaprazSeval Çapraz
Blockchain is one of the most innovative discoveries of the past century.
The first cryptocurrency, Bitcoin, was proposed in 2008 by Satoshi Nakamoto with a white paper.
Blockchain concept and technology. How this is becoming the next trend after the Bitcoin, expanding to a myriad of solutions. Smart contracts might be using a public distributed, and encrypted platform to support data persistence.
Explains what the Blockchain is and how it works. Features slides about the Cryptography, P2P Networking, Blockchain Data Structure, Bitcoin Transactions, Proof of Work Algorithm (Mining) and Scripts.
CBGTBT - Part 1 - Workshop introduction & primerBlockstrap.com
A Complete Beginners Guide to Blockchain Technology Part 1 of 6. Slides from the #StartingBlock2015 tour by @blockstrap
Part 1: http://www.slideshare.net/Blockstrap/cbgtbt-part-1-workshop-introduction-primer
Part 2: http://www.slideshare.net/Blockstrap/02-blockchains-101
Part 3: http://www.slideshare.net/Blockstrap/03-transactions-101
Part 4: http://www.slideshare.net/Blockstrap/cbgtbt-part-4-mining
Part 5: http://www.slideshare.net/Blockstrap/05-blockchains-102
Part 6: http://www.slideshare.net/Blockstrap/06-transactions-102
BlockChain basics for the non-technical banker covering what's happening, what the opportunities are, and the problems we all face. Covers BitCoin and Ethereum with brief mentions made of Ripple and the HyperLedger project.
Short presentation about bitcoin in particular and crypto currencies in general.
Its mainly a description of whats money and what is bitcoin
why bitcoin will dominate
Welcome to the world of cryptocurrencies, the next step in the evolution of the means of value exchange. This is
the part where many authors would veer off into the fascinating history of money. Though that is or at least can
be interesting, it’s ultimately a side note — and one that, frankly, isn’t going to make you any richer.
Instead, this book will begin with and focus on what you need to know to participate in and potentially profit
from this white-hot frontier investment space. With that in mind, we’re not going to begin at the beginning and
regale you with tales of humankind’s early currencies or some such; instead, we’re going to take the leap off the
high board and start to teach you right away about the now and the newest computer-based currencies
In this presentation, I look at the valuation of start-ups from two different angles: from the point of view of the founder/owner and from the point of view of the investor/business angel.
Open Source Survival: A Story from the TrenchesBruno Lowagie
In this slide deck, I discuss eight different ways you can make money as an open source developer. It's part of a series of presentations to promote my book "Entreprenerd."
Slides for the book presentation of "Entreprenerd: Building a Multi-Million-Dollar Business with Open Source Software" in which Bruno Lowagie tells the story about how he developed the open source PDF library iText, how he created an international group of companies for the project, and how he grew the business from start-up to exit.
Open source: an introduction to IP and LegalBruno Lowagie
Open Source India (OSI) Days talk by Bruno Lowagie about intellectual property in the context of open source, about open source licenses, and about keeping track of the IP of your project.
Waarom iText de Leeuw van de Export 2016 moet winnenBruno Lowagie
10 redenen waarom iText volgende week de Leeuw van de Export niet mag verliezen. We zijn #1 exportkampioen, #2 groeikampioen, #3 werkgever, #4 innovator, #5 expert, #6 evangelist, #7 ambassadeur, #8 ondernemer, #9 reiziger, en #10 winnaar.
Belgium and the US: a mutual introductionBruno Lowagie
Slide deck for my guest lecture at the University College Leuven Limburg about doing business in Belgium and doing business in the US, based on my own experience at iText.
My slides for the Startup Weekend Ghent (December 5-7). It's also kind of a "Best of BizCamp" overview. Three really short, provocative, 10-minute talks about doing business.
Doing business in the US: Yes, You Can!Bruno Lowagie
Draft of the slide deck for my talk at VOKA on Friday, September 5, 2014: http://www.voka.be/oost-vlaanderen/opleidingen/2014/9/zakelijk-succes-in-de-vs/
Community Leadership Summit - Calistoga March 2013Bruno Lowagie
These are the slides of team 3 at the Community Leadership Summit in Calistoga (at the Open Source Think Tank). Our group discussed the topic "Developer Growth", answering questions such as: How will you attract new developers to participate? How will you retain developers so they become significant and sustained contributors? How will you attract new demographic of developers, outside of the current industry? How will you encourage existing partner organizations to contribute developers to the project? How will you deal with organizational requirements (e.g. NDAs, copyright assignment, re-licensing requirements, etc)? How will you keep developers motivated and feeling they have a sense of personal influence on the project? How will you avoid entitlement?
Bizcamp #8: The Founder's Dilemmas, Control vs. Wealth decisionsBruno Lowagie
In this talk, scheduled for May 28th, Bruno Lowagie, the CEO of the iText Software Group, will talk about the book "The Founder's Dilemmas" by Noam Wasserman, explain the different Control vs. Wealth decisions discussed in this book, and apply what is said in the book to his own business.
Ik heb een paar schetsen gemaakt van een kruispunt dat gevaarlijk is voor fietser. Ik heb twee scenario's getekend om dit kruispunt over te steken. De vragen die ik hierbij heb, zijn: "Heb ik de plicht om dit kruispunt op de gevaarlijke manier over te steken?" of "Heb ik het recht om dit kruispunt op de veilige manier over te steken?"
Slack (or Teams) Automation for Bonterra Impact Management (fka Social Soluti...Jeffrey Haguewood
Sidekick Solutions uses Bonterra Impact Management (fka Social Solutions Apricot) and automation solutions to integrate data for business workflows.
We believe integration and automation are essential to user experience and the promise of efficient work through technology. Automation is the critical ingredient to realizing that full vision. We develop integration products and services for Bonterra Case Management software to support the deployment of automations for a variety of use cases.
This video focuses on the notifications, alerts, and approval requests using Slack for Bonterra Impact Management. The solutions covered in this webinar can also be deployed for Microsoft Teams.
Interested in deploying notification automations for Bonterra Impact Management? Contact us at sales@sidekicksolutionsllc.com to discuss next steps.
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
Topics covered:
UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
GDG Cloud Southlake #33: Boule & Rebala: Effective AppSec in SDLC using Deplo...James Anderson
Effective Application Security in Software Delivery lifecycle using Deployment Firewall and DBOM
The modern software delivery process (or the CI/CD process) includes many tools, distributed teams, open-source code, and cloud platforms. Constant focus on speed to release software to market, along with the traditional slow and manual security checks has caused gaps in continuous security as an important piece in the software supply chain. Today organizations feel more susceptible to external and internal cyber threats due to the vast attack surface in their applications supply chain and the lack of end-to-end governance and risk management.
The software team must secure its software delivery process to avoid vulnerability and security breaches. This needs to be achieved with existing tool chains and without extensive rework of the delivery processes. This talk will present strategies and techniques for providing visibility into the true risk of the existing vulnerabilities, preventing the introduction of security issues in the software, resolving vulnerabilities in production environments quickly, and capturing the deployment bill of materials (DBOM).
Speakers:
Bob Boule
Robert Boule is a technology enthusiast with PASSION for technology and making things work along with a knack for helping others understand how things work. He comes with around 20 years of solution engineering experience in application security, software continuous delivery, and SaaS platforms. He is known for his dynamic presentations in CI/CD and application security integrated in software delivery lifecycle.
Gopinath Rebala
Gopinath Rebala is the CTO of OpsMx, where he has overall responsibility for the machine learning and data processing architectures for Secure Software Delivery. Gopi also has a strong connection with our customers, leading design and architecture for strategic implementations. Gopi is a frequent speaker and well-known leader in continuous delivery and integrating security into software delivery.
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
GraphRAG is All You need? LLM & Knowledge GraphGuy Korland
Guy Korland, CEO and Co-founder of FalkorDB, will review two articles on the integration of language models with knowledge graphs.
1. Unifying Large Language Models and Knowledge Graphs: A Roadmap.
https://arxiv.org/abs/2306.08302
2. Microsoft Research's GraphRAG paper and a review paper on various uses of knowledge graphs:
https://www.microsoft.com/en-us/research/blog/graphrag-unlocking-llm-discovery-on-narrative-private-data/
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
Learn about:
• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
• Test Automation: How AI-powered test case generation, optimization, and self-healing tests are making testing more efficient and effective.
• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
3. Table of
Contents Concepts
Bits & Bytes, Hashing, Encryption, Signatures, DLT,...
Blockchain use cases
Cryptocurrency Bitcoin, Smart Contracts Ethereum
Your own blockchain
When to use and when not to use, recipes for the future
5. Before we start, I want to say:
01000111 01101111 01101111 01100100 00100000
01100101 01110110 01100101 01101110 01101001
01101110 01100111 00100001
Bay Bridge, San Francisco Bay Area
7. In hexadecimals:
47 6F 6F 64 20 65 76 65 6E 69 6E 67 21
Or, in a more human version:
G o o d e v e n i n g !
San Francisco Bay
8. All information is transmitted,
received, and stored as a
sequence of zeros and ones
8 bits = 1 byte (today!)
Initially: 1 byte = 6 bits
ASCII: 7 bits needed
IBM System/360: 8 bits
Computers use
binary code
0 1 1 0 0 0 0 1
Bits:
Byte
(Octet)
9. Encoding
examples
ASCII:
American Standard
Code for Information
Interchange
UTF-16:
16-bit Unicode
Transformation Format
B
66
0100 0010
42
r
114
0111 0010
72
u
117
0111 0101
75
n
110
0110 1110
6E
o
111
0110 1111
6F
ASCII:
브
10111110 00001100
BE 0C
루
10111000 11101000
B8 E8
노
10110001 01111000
B1 78
UTF-16:
12. Compression
Reduce the size in
bytes without loss
of information
▪ Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do
eiusmod tempor incididunt ut labore et dolore magna aliqua.
Facilisi morbi tempus iaculis urna id volutpat. Cras tincidunt
lobortis feugiat vivamus at augue eget arcu dictum. Ac feugiat
sed lectus vestibulum mattis. Hac habitasse platea dictumst
quisque.
- 318 bytes
▪ eNo9kFtOxUAMQ7fiBaDuASEhPthEOhOKpXm0k6TrJ/eC+IsS
+1jO51zawdOio842F4wO6eovKHOYFlePBak8aYXjgDbm0bS
mAcqwPitc+5lmjsLKGsMRjiZ74qH+i1Z0OYZAGq+QDe9S2G
hEn2vnExEGSoncIlZKWXHPFn6Kb3hbYvBnxCOgzaR7Kr80D
orj5i09CTlKHJHBR0bLKoHK4tE3vJZ/9aNAy3ppuNWce7T8Q
RdP5IYPKfiWnS5mirOJq/xRzHEF7QrdfgBikHXp
- 276 bytes, using LZW compression
- Other compression algorithms: gzip, bzip2,…
14. Hashing
Creating a
“message digest”
A Cryptographic Hash function is a mathematical transformation algorithm
that takes an input of arbitrary length (“message”) and returns a fixed-size
byte sequence (the “message digest” or “hash”).
Example:
▪ Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
tempor incididunt ut labore et dolore magna aliqua. Facilisi morbi tempus
iaculis urna id volutpat. Cras tincidunt lobortis feugiat vivamus at augue
eget arcu dictum. Ac feugiat sed lectus vestibulum mattis. Hac habitasse
platea dictumst quisque.
- 318 bytes
▪ SHA-1, 160-bit (or 20 bytes):
cc1b6a165b20e5d31f6ccac8eaff0bf64b95bffb
▪ SHA-256, 256-bit (or 32 bytes):
a2ef46f63e8d8e093e1a263206692a973d332826a33e11270f37708c8c47faed
15. Use cases
not limited to
cryptographic
hash functions
▪ Digital signatures
▪ Integrity check
▪ Random ID
▪ Session Cookies
▪ Hash tables
▪ Caching
▪ Passwords
▪ InterPlanetary File System (IPFS)
▪ …
▪ Blockchain!
16. Integrity check
“fingerprint” of
digital content
▪ Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod
tempor incididunt ut labore et dolore magna aliqua. Facilisi morbi tempus
iaculis urna id volutpat. Cras tincidunt lobortis feugiat vivamus at augue
eget arcu dictum. Ac feugiat sed lectus vestibulum mattis. Hac habitasse
platea dictumst quisque.
▪ SHA-1, 160-bit (or 20 bytes):
cc1b6a165b20e5d31f6ccac8eaff0bf64b95bffb
▪ Lorem ipsum dolor sit amet. consectetur adipiscing elit. sed do eiusmod
tempor incididunt ut labore et dolore magna aliqua. Facilisi morbi tempus
iaculis urna id volutpat. Cras tincidunt lobortis feugiat vivamus at augue
eget arcu dictum. Ac feugiat sed lectus vestibulum mattis. Hac habitasse
platea dictumst quisque.
▪ SHA-1, 160-bit (or 20 bytes):
04085fd6c91aa3f4a83ac4ee7d4eaf211acc0266
17. Confidential
Document
(e.g. proof of funds)
Generate Hash
AF1B4C...D34E
Secure
Server or
Website
Retrieve Hash
AF1B4C...D34E
Compare!
Use case: integrity check
18. Requirements ▪ Deterministic: The same message always results in the same
digest
▪ Irreversible: The output doesn’t contain any info about the
input. E.g. Belgian National Number contains birth date and
last digit indicates the gender should be a hash!
▪ Collision resistant: It should be extremely difficult to find two
inputs resulting in the same digest. Although it’s
mathematically possible; e.g. with MD5 you “only” have
340,282,366,920,938,463,463,374,607,431,768,211,456
posible hash values (128 bit means 2128 combinations).
▪ Computationally efficient: It shouldn’t take a long time to
compute the hash.
▪ Random output: It should be unpredictable, as if someone
rolled dice. E.g. it should be very unlikely to get a hash like
0000000000000000000000000012345678abcdef
19. Types ▪ MD 5: Ron Rivest (broken)
▪ SHA: Secure Hashing Algorithm
- SHA-1: NSA (broken: see https://shattered.io )
- SHA-2: NSA / NIST
- SHA-3: Keccak (made in Belgium!)
▪ RIPEMD: KULeuven
▪ …
These algorithms “age”:
▪ Flaws are discovered, e.g. SHA-1 deprecated by NIST in 2011
▪ Computer power increases (brute force attacks)
24. ▪ Rot13: move 13 letters down the alphabet
▪ Good Evening!
▪ 7 8 26 15 1 17 9 9 21 5 19!
▪ Good Evening!
▪ Tbbq Riravat!
▪ Ghzo Aqiiues!
It’s easy if you
have the key!
1. A
2. B
3. C
4. D
5. E
6. F
7. G
8. H
9. I
10. J
11. K
12. L
13. M
14. N
15. O
16. P
17. Q
18. R
19. S
20. T
21. U
22. V
23. W
24. X
25. Y
26. Z
26. Asymmetric
Encryption
Keys come in pairs: one public key and one private key.
What one key encrypts, only the other key can decrypt!
Encryption:
Signing:
27. Encryption
Bob sends public key
to Alice
Alice encrypts
message with
public key Bob
Bob receives
encrypted
message
Bob decrypts
message with
private key
👦👩
🔑 🔑🔑
🔑 🔑
28. Some
“name dropping”
Some types are better
for encryptions, others
are better for signing.
▪ Public Key Cryptography Standards
- PKCS#1: RSA Cryptography Standard (Rivest, Shamir, Adleman)
- PKCS#7: Cryptographic Message Standard (CMS)
- PKCS#11: Cryptographic Token Interface
- PKCS#12: Personal Information Exchange Syntax Standard
- PKCS#13: Elliptic Curve Cryptography Standard (ECDSA)
▪ National Institute of Standards and Technology (NIST)
- AES: Advanced Encryption Standard (aka Rijndael)
- Vincent Rijmen – Joan Daemen (Belgium!)
▪ Federal Information Processing Standards (FIPS)
- DSA: Digital Signature Algorithm (DSA)
▪ European Telecommunications Standards Institute (ETSI)
- CMS Advanced Electronic Signatures (CAdES)
The size of the encrypted message depends on the size of the
original message, the type of encryption, and the key length.
32. How it’s
done in PDF
• There are no bytes in the
PDF that aren’t covered,
other than the PDF
signature itself.
• The digital signature isn’t
part of the ByteRange.
• The concept “to initial a
document” doesn’t exist;
you sign the complete
document at once, not on
a page per page basis.
37. “
Distributed Ledger Technology refers to a system to record
and share data across multiple data stores (ledgers), which
each have the exact same data records and are collectively
maintained and controlled by a distributed network of
computer servers, which are called nodes.
41. Distributed
Ledger
Technology
DLT is a type of distributed database technology with the
following characteristics:
▪ The records can be replicated over different nodes in a network
(decentralized environment),
▪ New records can be added by each node, upon consensus reached by
other nodes (ranging from one specific authoritative node to potentially
every node),
▪ Existing records can be validated for integrity, authenticity, and non-
repudiation,
▪ Existing records can’t be removed, nor can their order be changed,
▪ The different nodes can act as independent participants that don’t
necessarily need to trust each other.
Combined, these characteristics make DLT a great way to keep a
ledger of records in a trustless environment.
47. Blockchain
types
▪ Permissionless versus permissioned:
- Permissionless: no authorization or authentication needed
- Permissioned: nodes must have a member identity; authorization
and authentication is needed
▪ Public versus private:
- Public: any node can join to read blocks and records, append
records, and participate in the consensus mechanism
- Private: only nodes that have been granted authority have that
access
▪ Centralized, decentralized, distributed ledger control:
- Centralized: one central server decides on the validation of a new
block of records
- Decentralized: a central authority delegates the validation of new
blocks to a limited number of blocks
- Distributed: all the nodes work together using a consensus
mechanism
53. How to reach
consensus?
▪ Proof of Work (PoW):
- Example: Bitcoin
▪ Proof of Stake (PoS):
- Example: Ethereum’s Casper
the Friendly Finality Gadget
(FFG)
54. Things you read about in the news
papers
1. Bitcoin
• Proof of Work: mining
• Advantages
• Disadvantages
2. Ethereum
• Distributed Computing platform
• Smart contracts
• Proof of Stake
Part 2:
Blockchain use cases
56. Bitcoin
Cryptocurrency
👦👩 50 BTC
Carol 10 BTC Alice
David 30 BTC Alice
Erin 20 BTC Alice
🔑 B 50 BTC
🔑 A 9 BTC
Sign hash with🔑A
1 BTC for the Miner
who succeeds in solving the PoW puzzle
and ensures Alice doesn’t spend a BTC twice
Similar to lines in a ledger
A has 60 BTC to spend
🔑A🔑 🔑B🔑
wallet wallet
58. Bitcoin
Mining
Solving the puzzle
in 10 minutes
together!
T1 T2 T3 T4 T5 T6 T7 TM
hash hash hash hash
hash hash
hash
👤 miner Mike
“Merkle Tree” proof
00000a5f4c8687d78ef…68b
40 leading bits must be zero: difficult!
240 attempts needed on average (~1 trillion)
Testing proof is very easy
Miner gets reward:
• Sum of fees
• Newly created coin
60. Bitcoin
creation
▪ The system looks at the time to generate 2016 blocks:
- If > 2 weeks: proof of work is made easier
- If < 2 weeks: proof of work is made more difficult
- 6 (1 hour) x 24 (1 day) x 14 (2 weeks): 2016
▪ Miners get a reward if they succeed in solving the puzzle
- Reward decreases over time
- Cut in half every 210,000 blocks
- About every 4 year (208 weeks)
- Upper limit 21,000,000 BTC
https://www.investopedia.com/tech/how-does-bitcoin-mining-work/
- Fractional coins exist: 0,00000001 BTC = 1 Satoshi (named after
Satoshi Nakamoto)
61. On December 8, 2017, already16.7 million Bitcoins were created
About 30% of those may be lost forever (hard drive crashes, misplaced private keys,…)
https://coincentral.com/how-many-bitcoins-are-left/
62. Have you heard of… Owns… Expext to own…
Cryptocurrencyhttps://think.ing.com/uploads/reports/ING_International_Survey_Mobile_Banking_2018.pdf
Sample size: 14,828
15 countries
minimum 1000 respondents / country (except Luxemburg)
63. How risky is owning one of the following asses, compared to cryptocurreny?
https://think.ing.com/uploads/reports/ING_International_Survey_Mobile_Banking_2018.pdf
64. Advantages
(some of which
can also lead to
disadvantages)
▪ Not controlled by any central authority (e.g. a bank, country,…)
- Easy to make international payments,
- The protocol can’t be manipulated by any person,
organization, or government.
- Not dependent on the political situation of a country,…
(but other factors may influence the value of 1 BTC),
▪ The information is transparent
- Everyone can see and verify all the transactions anytime,
but only your public address is known, no personal info
is visible, unless…
▪ Lower fees because there’s no “man in the middle”
- In practice, there are BTC Exchange companies handling
bitcoin transactions, e.g. Mt. Gox (Tokyo): RIP 2014 after
announcing that 850,000 BTC ($450M) went missing.
67. https://digiconomist.net/bitcoin-energy-consumption
Bitcoin energy consumption
Bitcoin network versus VISA network average consumption
But aren’t we comparing
apples with oranges?
Bitcoin estimated to use 0.5% of the world’s
electric energy by the end of 2018…
and could someday consume 5% of the
world's electricity
The high cost of Proof of
Work created new and
original exploits, such as
malware that uses your
computer’s resources to
mine bitcoins for
hackers.
68. Disadvantages ▪ Exposure to fraud and scams
- BTC Exchanges can be hacked,
- Wallets can be lost (keys physically lost, keys stolen,…),
▪ No central authority is also a disadvantage
- Use in black markets damages reputation,
- No one can avoid “dump & pump”,
- There is no buyer protection (e.g. credit card),
▪ Technical limits
- Original bitcoin is slow
- Proof of Work requires a lot of energy
- May contain unexploited flaws
- If you have 51% of the resources, you can corrupt the system
- Could happen once miners stop mining if the reward drops
▪ High price volatility
- Result of “dump & pump”; scandals (e.g. Mt. Gox)
- many competing coins emerge; which one will “win”?
- Everyone goes ICO, but who will deliver?
70. “
Ethereum is an open-source, public, blockchain-based distributed computing
platform and operating system featuring smart contract (scripting) functionality.
Ether (ETH) is a cryptocurrency whose blockchain is generated by the Ethereum
platform. Ether can be transferred between accounts and used to compensate
participant mining nodes for computations performed.
71. Ethereum
Virtual
Machine
▪ The Ethereum Virtual Machine (EVM) is the runtime environment for
smart contracts in Ethereum. Every Ethereum node in the network runs
an EVM implementation and executes the same instructions.
- Distributed Computing Platform
- On February 1, 2018, there were 27,500 nodes in the main
Ethereum network.
▪ Smart contracts: computer code that is executed on a distributed ledger
- Smart contracts are high-level programming abstractions that are
compiled down to EVM bytecode and deployed to the Ethereum
blockchain for execution.
- Ethereum's smart contracts are based on different computer
languages, which developers use to program their own
functionalities.
72. Predefined
Contract
• All counterparties agree on the terms (e.g. terms & conditions for a sale)
• Known conditions for execution (e.g. 10% down-payment; full payment upon delivery)
• Expressed in source code stored in the blockchain
Events
• An event triggers contract execution
• An event can refer to:
• The initiation of a transaction (e.g. a down-payment)
• Information that is received (e.g. a parcel has been delivered)
Execute
• Terms of contract dictate movement of value based on conditions met
• E.g. a down-payment: a parcel is sent in the real world
• E.g. a parcel is received: the payment is processed
Settlement
• On-chain assets: e.g. cryptocurrency (for instance “paid with Bitcoin”)
• Off-chain assets: e.g. the parcel (for instance “a work of art”)
• The value bearing item resides outside (“off”) the blockchain; It has a digital counterpart in the blockchain (e.g. identified using an RFID tag)
• Lifecycle events of the item are mirrored in the blockchain: the blockchain contains the “rights” (e.g. owner’s claim to a work of art)
Smart contract: example
73. Coming soon:
Proof of Stake
Casper the Friendly
Finality Gadget (FFG)
(released on Github
for review)
▪ Proof of Work: all miners work on a difficult puzzle
▪ Proof of Stake: the creator of the next block is chosen based
on a criterium, e.g. the number of coin a miner owns.
- miners are limited to mining a percentage of
transactions that is reflective of their ownership stake.
- For instance: a miner who owns 3% of the coin available
can theoretically mine only 3% of the blocks.
- You’d need 51% of all coin to corrupt the system
- In the unlikely event you accumulate 51% of all coin, it’s
not in your interest to make the system fail.
▪ Ethereum plans to move from PoW to PoS
- Casper is a partial consensus mechanism combining
proof of stake algorithm research and Byzantine fault
tolerant consensus theory.
74. When, What to choose, Why
1. Do you need blockchain?
2. Which implementation?
• MultiChain
• Hyperledger project
3. Examples
• T-Mining
• iText
• …
Part 3:
Your own blockchain
75. Do you need
Blockchain?
10 questions to
decide whether
blockchain is the
technology you
need
1. Is it OK if the data is shared over all nodes? If not: NO BLOCKCHAIN
2. Is it OK if multiple identities can write? If not: NO BLOCKCHAIN
3. Is everyone known and trusted? If so: NO BLOCKCHAIN
4. Is having a central server necessary? If so: NO BLOCKCHAIN
5. Do you need to modify or erase data? If so: NO BLOCKCHAIN
6. Is performance critical? If so: MAYBE BLOCKCHAIN
7. Is data storage is going to be large? If so: MAYBE BLOCKCHAIN
8. Compliance with legal standards needed? If so: MAYBE BLOCKCHAIN
9. Are new participants free to enter?
If so, 10. Can all participants validate?
If so: PUBLIC PERMISSIONLESS BLOCKCHAIN
If not: PUBLIC PERMISSIONED BLOCKCHAIN
If not, 10. Can all participants validate?
Is so: PRIVATE PERMISSIONLESS BLOCKCHAIN
If not: PRIVATE PERMISSIONED BLOCKCHAIN
76. ▪ MultiChain by Coin Sciences Ltd.
- For private blockchains
▪ Hyperledger project started by the Linux Foundation
- Open source blockchains and tools: https://www.hyperledger.org/
- E.g. Hyperledger Fabric, contributed by IBM
80. How to make
this an
opportunity?
▪ Known flaws of data served to apps:
- Reliability: was the data presented correctly?
- Immutability: what if the data in the database changes?
- Security: who has access to the data?
▪ Known flaws of PDF
- Digital signatures are a pain
- Signatures need to be applied sequentially
- Certificate Authority (CA), Timestamp Authority (TSA) needed
- Not all viewers support signatures (Preview, mobile viewers)
- "Dark Data": it's difficult to unlock data from a PDF
- We can solve this with tools
- We're also working on "Next-Generation PDF"
▪ Enter blockchain: “A distributed database that serves
as an irreversible and incorruptible repository for
permanent records”
81. Storing the
signature in
the blockchain
Digital signatures in PDF Digital signatures in Blockchain
%PDF-1.5
…
/ID[<8AA01A08CDAAF3F46E6E121898C8FEE7
>
<EB4BDC9DA9206749952E4B89613D4658>
...
2 0 obj
<<… /Type/Sig /Contents<
> … >>
…
xref
0 81
0000000000 65535 f
…
trailer
<< … >>
startxref
15787
%EOF
DIGITAL SIGNATURE
PDFDocument
%PDF-1.5
…
/ID[
<8AA01A08CDAAF3F46E6E121898C8FEE7>
<EB4BDC9DA9206749952E4B89613D4658>
...
URI: my.blockchain.com
...
xref
0 81
0000000000 65535 f
…
trailer
<< … >>
startxref
15787
%EOF
Id:
<8AA01A08CDAAF3F46E6E121898C8FEE7>
<EB4BDC9DA9206749952E4B89613D4658>
Value: DIGITAL SIGNATURE
Metadata: URI, status
PDFDocumentBlockchain
82. Information
stored in the
blockchain
Document ID: [<ABCDEF>, <ABCDEF>]
Timestamp
Signed Document hash
Compressed property list with metadata:
- Status: e.g. “unpaid”, “paid”
- Location(s)
Certificate of signer
• Identity
• Public key
83. Advantages ▪ Criteria for signing are met:
- Integrity
- Authenticity
- Non-Repudiation
- Timestamp
- LTV => renew registration
▪ Parallel signing is possible
- Example: signing an NDA before a teleconference
▪ Make the existence of a document public, but not the content
- Example: first-to-invent
▪ Updating metadata is possible
- Example: avoid link-rot
▪ Due to the nature of IDs, related PDFs can be identified
- Example: always read the latest version
- Example: document processes can be automated
84.
85. Adapted
viewer
Upon opening an invoice, the viewer can inform you:
▪ This document was registered in blockchain XYZ
- Do you trust this blockchain?
- Do you want to check the document in this blockchain?
▪ A blockchain service can return the following info:
- The ID is not found:
- This is a ghost invoice!
- The ID is found, but the hash doesn’t correspond:
- This is a forged invoice!
- The ID is found and the hash corresponds:
- This is a genuine invoice
- It was originally signed by vendor ABC
- Bank Van Lanschot registered it as paid
87. Last Will &
Testament
▪ Suppose that I write my last will and testament today, and
I digitally sign it using today’s state-of-the-art technology,
would my digital signature survive me?
▪ I surely hope not:
- I hope I survive my signing certificate,
- I hope I survive the time-stamping certificate,
- I hope I survive the algorithms.
▪ A last will and testament is usually a document of which
the content may change over time, and of which the
content remains a secret until it needs to be executed.
▪ This is a good use case for blockchain.