In this network security video tutorial we will study and understand the working of Output Feedback (OFB) also known as OFB algorithm mode.
Output Feedback (OFB) -
1. In this mode data is encrypted in units that are smaller (e.g. they could be of size 8 bits) than a defined block size (which is usually 64 bits).
2. OFB mode works with j bits at a time (as we have seen, usually, but not always , j = 8)
3. OFB mode is extremely similar to the CFB
4. The only difference is that in the case of CFB, the cipher text is fed into the next stage of encryption process.
5. In case of OFB, the output of the IV encryption process is fed into the next stage of encryption process.
Following are the steps of OFB mode -
Step 1 - Encrypt the IV(initialization vector) using the KEY to get the Encrypted IV.
Step 2 - Perform XOR operation between first j bits of encrypted IV and j bits of Plain Text to get j bits of Cipher Text(Cipher text block 1)
Step 3 - left shift the IV by j bits & add theencrypted IV from the previous step to the right most side of the original IV.
Complete Network Security / Information Security Playlist - https://www.youtube.com/watch?v=IkfggBVUJxY&list=PLIY8eNdw5tW_7-QrsY_n9nC0Xfhs1tLEK
Download my FREE Network Security Android App - https://play.google.com/store/apps/details?id=com.intelisenze.networksecuritytutorials
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#OutputFeedbackMode #AlgorithmModes #NetworkSecurity #Cryptography #BlockCiphers

Views: 2127
Simple Snippets

1. Electronic Code Book Mode
2. Cipher Block Chaining Mode
3. Output Feedback Mode
4. Cipher Feedback Mode
5. Counter Mode

Views: 45786
Sundeep Saradhi Kanthety

This video is part of an online course, Applied Cryptography. Check out the course here: https://www.udacity.com/course/cs387.

Views: 36510
Udacity

This video is part of an online course, Applied Cryptography. Check out the course here: https://www.udacity.com/course/cs387.

Views: 2286
Udacity

This presentation video shows the working process of the Output feedback mode's Encryption and Decryption process.

Views: 1118
Bryan Loh

This video is explains about the process of output feedback mode.

Views: 58
Calven Wong

Views: 514
Ting Ye Han

This video is part of the Udacity course "Intro to Information Security". Watch the full course at https://www.udacity.com/course/ud459

Views: 285
Udacity

Simple animation demonstrating how OFB Encryption/Decryption works.

Views: 583
Abdul Mohd

Views: 249
Chyi Wei Wong

DES vs Simplifed DES; DES design; Avalanche effect. Course material via:
Stream vs block ciphers; ideal block cipher and Feistel structure; example of Simplified-DES. Course material via:
Modes of operation for block ciphers, introducing ECB, CBC and Counter mode. Course material via:
CSS441, Semester 2, 2015, Lectures at Sirindhorn International Institute of Technology, Thammasat University, Thailand by Steven Gordon. Course material via: .

Views: 56
Rick Dodele

This video is part of an online course, Applied Cryptography. Check out the course here: https://www.udacity.com/course/cs387.

Views: 912
Udacity

Video made by Askarbek Almazbek uulu and Tan Hsiang Weih. CSCI361- Cryptography and Secure Application.

Views: 218
Askar Almazbekuulu

A stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream (keystream). In a stream cipher each plaintext digit is encrypted one at a time with the corresponding digit of the keystream, to give a digit of the ciphertext stream. An alternative name is a state cipher, as the encryption of each digit is dependent on the current state. In practice, a digit is typically a bit and the combining operation an exclusive-or (xor).
The pseudorandom keystream is typically generated serially from a random seed value using digital shift registers. The seed value serves as the cryptographic key for decrypting the ciphertext stream.
This video is targeted to blind users.
Attribution:
Article text available under CC-BY-SA
Creative Commons image source in video

Views: 3477
Audiopedia

This video is part of the Udacity course "Intro to Information Security". Watch the full course at https://www.udacity.com/course/ud459

Views: 2124
Udacity

Views: 2476
Udacity

Full Video Details: http://www.securitytube.net/video/343

Views: 9871
TheSecurityTube

https://8gwifi.org/CipherFunctions.jsp
Reference book: http://leanpub.com/crypto
Cryptographic Algorithms generally fall into one of two different categories, or are a combination of both.
Symmetric
Fast
Only provide confidentiality
Examples: DES, AES, Blowfish, RC4, RC5
Asymmetric
Large mathematical operations make it slower than symmetric algorithms
No need for out of band key distribution (public keys are public!)
Scales better since only a single key pair needed per individual
Can provide authentication and nonrepudiation
Examples: RSA, El Gamal, ECC, Diffie-Hellman
problem with symmetric key cryptography
DES (Data Encryption Standard)
64 bit key that is effectively 56 bits in strength
Actual algorithm is called DEA (Data Encryption Algorithm)
DES Modes
Electronic Code Book
Cipher Block Chaining (most commonly used for general purpose encryption)
Cipher Feedback
Output Feedback
Counter Mode (used in IPSec)
3DES
112-bit effective key length
Uses either 2 or 3 different smaller keys in one of several modes
Modes
EEE2/3
EDE2/3
AES
NIST replaced DES in 1997 with this
Uses the Rijndael algorithm
Supports key/block sizes of 128, 192, and 256 bits
Uses 10/12/14 rounds as block size increases
IDEA (International Data Encryption Algorithm)
Operates on 64 bit blocks in 8 rounds with 128 bit key
Considered stronger than DES and is used in PGP
Blowfish
64 bit block cipher with up to 448 bit key and 16 rounds
Designed by Bruce Schneier
RC4
Stream cipher with variable key size created by Ron Rivest
RC5
Another Rivest cipher
Block cipher with 32/64/128 bit blocks and keys up to 2048 bits
RC6
Beefier version of RC5 submitted as AES candidate
CAST
64 bit block cipher with keys between 40-128 bits with 12-16 rounds depending on key length
CAST-256 used 128-bit blocks and keys from 128-256 bits using 48 rounds
SAFER (Secure and Fast Encryption Routine)
Set of patent-free algorithms in 64 and 128 bit block variants
Variation used in Bluetooth
Twofish
Adapted version of Blowfish with 128 bit blocks, 128-256 bit keys and 16 rounds
AES Finalist
Kryptografie mit symmetrischem Schlüssel
symmetric key cryptography
symmetric key cryptography tutorial
symmetric key cryptography example
symmetric key cryptography vs asymmetric key cryptography
symmetric and asymmetric key cryptography
symmetric key cryptography
Kryptografie mit symmetrischem Schlüssel
Kryptographie mit symmetrischem Schlüssel
Kryptographie mit symmetrischem Schlüssel
Kryptografie mit symmetrischem Schlüssel und asymmetrische Schlüsselkryptographie
symmetrische und asymmetrische Schlüsselkryptographie
Kryptografie mit symmetrischem Schlüssel

Views: 41496
Zariga Tongy

Views: 5099
Udacity

Views: 52
Min Yue Yong

Views: 1086
zzbornzz

In cryptography, a mode of operation is an algorithm that uses a block cipher to provide an information service such as confidentiality or authenticity. A block cipher by itself is only suitable for the secure cryptographic transformation (encryption or decryption) of one fixed-length group of bits called a block. A mode of operation describes how to repeatedly apply a cipher's single-block operation to securely transform amounts of data larger than a block.
Most modes require a unique binary sequence, often called an initialization vector (IV), for each encryption operation. The IV has to be non-repeating and, for some modes, random as well. The initialization vector is used to ensure distinct ciphertexts are produced even when the same plaintext is encrypted multiple times independently with the same key. Block ciphers have one or more block size(s), but during transformation the block size is always fixed. Block cipher modes operate on whole blocks and require that the last part of the data be padded to a full block if it is smaller than the current block size. There are, however, modes that do not require padding because they effectively use a block cipher as a stream cipher.
This video is targeted to blind users.
Attribution:
Article text available under CC-BY-SA
Creative Commons image source in video

Views: 3552
Audiopedia

Views: 1533
Udacity

📚📚📚📚📚📚📚📚
GOOD NEWS FOR COMPUTER ENGINEERS
INTRODUCING
5 MINUTES ENGINEERING
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SUBJECT :-
Discrete Mathematics (DM)
Theory Of Computation (TOC)
Artificial Intelligence(AI)
Database Management System(DBMS)
Software Modeling and Designing(SMD)
Software Engineering and Project Planning(SEPM)
Data mining and Warehouse(DMW)
Data analytics(DA)
Mobile Communication(MC)
Computer networks(CN)
High performance Computing(HPC)
Operating system
System programming (SPOS)
Web technology(WT)
Internet of things(IOT)
Design and analysis of algorithm(DAA)
💡💡💡💡💡💡💡💡
EACH AND EVERY TOPIC OF EACH AND EVERY SUBJECT (MENTIONED ABOVE) IN COMPUTER ENGINEERING LIFE IS EXPLAINED IN JUST 5 MINUTES.
💡💡💡💡💡💡💡💡
THE EASIEST EXPLANATION EVER ON EVERY ENGINEERING SUBJECT IN JUST 5 MINUTES.
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YOU JUST NEED TO DO
3 MAGICAL THINGS
LIKE
SHARE
&
SUBSCRIBE
TO MY YOUTUBE CHANNEL
5 MINUTES ENGINEERING
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Views: 3049
5 Minutes Engineering

In this video we discuss about the Cipher Block Chaining (CBC) mode of operation, the process of encryption and decryption.
Video prepared by : Chin Yi Kang & Tan Xin Huan
Facebook : https://www.facebook.com/alfiechin0
Instagram : https://www.instagram.com/imkang919/

Views: 1343
Alfie Chin

Views: 28
施凱文

Speaker: Tor E. Bjørstad
Turning data into line noise and back
Even with "nothing to hide", we want to protect the privacy of our bits and bytes. Encryption is an important tool for this, and stream ciphers are a major class of symmetric-key encryption schemes. Algorithms such as RC4 (used in WEP/WPA, bittorrent, SSL), A5/1 (GSM telephony), E0 (bluetooth), as well as AES in counter (CTR) mode, are important examples of stream ciphers used in everyday applications.
Whereas a block cipher such as AES works by encrypting fixed-length data blocks (and chaining these together in a suitable mode of operation), stream ciphers output an unique and arbitrary-length keystream of pseudorandom bits or bytes, which is simply XORed with the plaintext stream to produce the ciphertext. Advantages of stream ciphers often include smaller hardware footprint and higher encryption speeds than comparable block ciphers such as AES. However, cryptanalysis has led to attacks on many of the existing algorithms.
The ECRYPT Stream Cipher Project (eSTREAM) has been a 4-year project funded by the EU to evaluate new and promising stream ciphers. The project ended in April 2008, with a final portfolio which currently consists of 7 ciphers: 3 suitable for hardware implementation, and 4 aimed at software environments. The portfolio ciphers are considered to provide an advantage over plain AES in at least one significant aspect, but the designs are very different and often suited for different applications.
Since the eSTREAM ciphers are quite new, many of them are not well known outside the academic community. The goal of this talk is to give a very quick presentation of each of the 7 portfolio ciphers: Grain v1, MICKEY v2, Trivium, HC-128, Rabbit, Salsa20/12 and SOSEMANUK.
More information about the 25th Chaos Communication Congress can be found via the Chaos Communication Congress website: http://bit.ly/25c3_program
Source: http://bit.ly/25c3_videos

Views: 2622
Christiaan008

Blok şifreleme modları olan Elektronik Kod Defteri Şekli (Electronic Codebook Mode, ECB)
Şifre Blok Zincirlemesi Şekli (Cipher Block Chaining Mode, CBC)
Yayılımlı Şifre Blok Zincirlemesi ( Propagating Cipher Block Chaining, PCBC)
Şifre Geri Beslemeli (Cipher FeedBack , CFB)
Çıktı Geri Beslemeli (Output FeedBack Mode, OFB)
Sayıcı Şekli Şifreleme (Counter Mode Encryption, CTR, CM, ICM, SIC)
Modları anlatılmıştır.

Views: 5335
BilgisayarKavramlari

video lectures from iit professors.... not available in NPTEL.....
video Lectures on "Active Filter Design" by Dr.Shanthi Pavan , IIT Madras
for more videos .... www.satishkashyap.com
for free ebooks.....www.ebook29.blogspot.com
Lecture 1 - Course overview and introduction.
Lecture 2 - The Butterworth approximation
Lecture 3 - The Chebyshev approximation
Lecture 4 - The Chebyshev approximation (contd)
Lecture 5 - The Chebyshev approximation (contd), the Inverse Chebyshev approximation
Lecture 6 - The Inverse Chebyshev approximation (contd).
Lecture 7 - Synthesis of doubly terminated all-pole LC ladders filters
Lecture 8 - Synthesis of doubly terminated LC ladders (contd).
Lecture 9 - Synthesis of doubly terminated LC ladders with finite zeros of transmission.
Lecture 10 - Network sensitivity - low sensitivity of doubly terminated ladders
Lecture 11 - Introduction to frequency transformations.
Lecture 12 - Frequency (reactance) transformations (contd) - properties of the driving
impedance of lossless LC networks- Tellegen's theorem and positive real functions.
Lecture 13 - Driving point impedance of LC networks (contd), Low Pass-to-Low Pass, Low
Pass-to-Band Pass, Low Pass-to-High Pass and Low Pass-to-Band Stop transformations
Lecture 14 - The Richard's Transformation, RC-CR transformation
Lecture 15 - Emulation of an inductor with a capacitor and controlled sources, the
gyrator, a second order transconductor capacitor filter.
Lecture 16 - Cascade of biquads realization of high order low pass filters, equivalence
of the parallel RLC and series RLC circuits with their Gm-C counterparts.
Lecture 17 - The idea of Dynamic Range in active filters - impedance scaling and its
effect on dynamic range
Lecture 18 - Introduction to noise in electrical networks.
Lecture 19 - Introduction to noise in electrical networks (contd), the idea of node
scaling.
Lecture 20 - Dynamic range scaling in active filters.
Lecture 21 - Biquad Ordering.
Lecture 22 - Active Ladder Emulation / Leapfrog Filters, Effect of Transconductor
nonidelaities (parasitic capacitance/output resistance).
Lecture 23 - Effect of Transconductor Nonidealities (contd) - parasitic poles.
Lecture 24 - Viewing the Gm-C biquad as a Double Integrator Loop, Revisiting the Effect
of Finite Gain of the Transconductors.
Lecture 25 - Single-ended Versus Differential Filters, Introducing the Differential-pair
Based Fully Differential Transconductor, the Need for Common-mode Feedback
Lecture 26 - Common-mode Feedback (continued).
Lecture 27 - Common-mode Feedback (continued), examples of Common-mode Detectors.
Lecture 28 - Stability of the Common-mode Feedback Loop
Lecture 29 - Common-mode Positive Feedback in Gyrators.
Lecture 30 - Common-mode Positive Feedback in Gyrators (contd), Noise in the
Differential Pair.
Lecture 31 - Noise in the Differential Pair (contd), Linearity of the Differential Pair,
Cascoding to Improve Output Impedance
Lecture 32 - Noise in Cascodes, Layout Considerations and Multi-finger Transistors.
Lecture 33 - Linearizing the Differential Pair, Resistive Degeneration.
Lecture 34 - Noise in Degenerated Transconductors, The Folded Cascode and Noise Analysis
Lecture 35 - Stabilizing filter bandwidth over process and temperature - the resistor
servo loop, master-slave loops.
Lecture 36 - Turning the filter into a VCO to estimate center frequency, example of a
practical precision fixed-gm bias circuit.
Lecture 37 - Introduction to accurate measurement and characterization techniques for
active filters.
Lecture 38 - Introduction to Active-RC filters.
Lecture 39 - Active-RC filters (contd), the use of an OTA instead of an opamp, swing and
noise considerations, single stage OTAs
Lecture 40 - Multistage OTAs for use in CMOS Active-RC filters.
Lecture 41 - The Miller compensated opamp in active-RC filters, noise considerations,
noise in active-RC filters .
Lecture 42 - Distortion and Intermodulation in filters, miscellaneous discussion on fixed gm-bias circuits

Views: 1861
Satish Kashyap

Netsim cryptographic XOR Encryption and Decryption

Views: 148
krishna v

Views: 1417
Udacity

video lectures from iit professors.... not available in NPTEL.....
video Lectures on "Active Filter Design" by Dr.Shanthi Pavan , IIT Madras
for more videos .... www.satishkashyap.com
for free ebooks.....www.ebook29.blogspot.com
Lecture 1 - Course overview and introduction.
Lecture 2 - The Butterworth approximation
Lecture 3 - The Chebyshev approximation
Lecture 4 - The Chebyshev approximation (contd)
Lecture 5 - The Chebyshev approximation (contd), the Inverse Chebyshev approximation
Lecture 6 - The Inverse Chebyshev approximation (contd).
Lecture 7 - Synthesis of doubly terminated all-pole LC ladders filters
Lecture 8 - Synthesis of doubly terminated LC ladders (contd).
Lecture 9 - Synthesis of doubly terminated LC ladders with finite zeros of transmission.
Lecture 10 - Network sensitivity - low sensitivity of doubly terminated ladders
Lecture 11 - Introduction to frequency transformations.
Lecture 12 - Frequency (reactance) transformations (contd) - properties of the driving
impedance of lossless LC networks- Tellegen's theorem and positive real functions.
Lecture 13 - Driving point impedance of LC networks (contd), Low Pass-to-Low Pass, Low
Pass-to-Band Pass, Low Pass-to-High Pass and Low Pass-to-Band Stop transformations
Lecture 14 - The Richard's Transformation, RC-CR transformation
Lecture 15 - Emulation of an inductor with a capacitor and controlled sources, the
gyrator, a second order transconductor capacitor filter.
Lecture 16 - Cascade of biquads realization of high order low pass filters, equivalence
of the parallel RLC and series RLC circuits with their Gm-C counterparts.
Lecture 17 - The idea of Dynamic Range in active filters - impedance scaling and its
effect on dynamic range
Lecture 18 - Introduction to noise in electrical networks.
Lecture 19 - Introduction to noise in electrical networks (contd), the idea of node
scaling.
Lecture 20 - Dynamic range scaling in active filters.
Lecture 21 - Biquad Ordering.
Lecture 22 - Active Ladder Emulation / Leapfrog Filters, Effect of Transconductor
nonidelaities (parasitic capacitance/output resistance).
Lecture 23 - Effect of Transconductor Nonidealities (contd) - parasitic poles.
Lecture 24 - Viewing the Gm-C biquad as a Double Integrator Loop, Revisiting the Effect
of Finite Gain of the Transconductors.
Lecture 25 - Single-ended Versus Differential Filters, Introducing the Differential-pair
Based Fully Differential Transconductor, the Need for Common-mode Feedback
Lecture 26 - Common-mode Feedback (continued).
Lecture 27 - Common-mode Feedback (continued), examples of Common-mode Detectors.
Lecture 28 - Stability of the Common-mode Feedback Loop
Lecture 29 - Common-mode Positive Feedback in Gyrators.
Lecture 30 - Common-mode Positive Feedback in Gyrators (contd), Noise in the
Differential Pair.
Lecture 31 - Noise in the Differential Pair (contd), Linearity of the Differential Pair,
Cascoding to Improve Output Impedance
Lecture 32 - Noise in Cascodes, Layout Considerations and Multi-finger Transistors.
Lecture 33 - Linearizing the Differential Pair, Resistive Degeneration.
Lecture 34 - Noise in Degenerated Transconductors, The Folded Cascode and Noise Analysis
Lecture 35 - Stabilizing filter bandwidth over process and temperature - the resistor
servo loop, master-slave loops.
Lecture 36 - Turning the filter into a VCO to estimate center frequency, example of a
practical precision fixed-gm bias circuit.
Lecture 37 - Introduction to accurate measurement and characterization techniques for
active filters.
Lecture 38 - Introduction to Active-RC filters.
Lecture 39 - Active-RC filters (contd), the use of an OTA instead of an opamp, swing and
noise considerations, single stage OTAs
Lecture 40 - Multistage OTAs for use in CMOS Active-RC filters.
Lecture 41 - The Miller compensated opamp in active-RC filters, noise considerations,
noise in active-RC filters .
Lecture 42 - Distortion and Intermodulation in filters, miscellaneous discussion on fixed gm-bias circuits

Views: 919
Satish Kashyap

Views: 1539
Udacity

Program Used : Bandicam [ PAID ]
KineMaster [ PAID ]
Visual Studio 2012 Ultimate
Can We Get 5 Likes For This Video? Subscribe for more videos! Have a nice day!
@ CoderEin
Special Thanks to Microsoft Guides Tech!
Music used : Costollo - Dancing Lorea

Views: 63
CodeRein VS

Views: 9076
Udacity

Implementation of Hummingbird Cryptography Algorithm on DE2 115 Cyclone IV FPGA Board. Leave your comments regarding the code. You can approach me if you have any queries related to Hummingbird Cryptography Algorithm.

Views: 149
Hinpreet kaur Basra

51% attacks have been on the rise in the cryptocurrency world in 2018 and 2019. Particularly, they have attacked altcoin blockchain networks which are vulnerable because they don't have too much hash power securing the network. Coins like Verge, Ethereum Classic, Bitcoin Gold, etc. have all suffered attacks. A big reason this is now possible is because mining power is increasingly available for rent via services like NiceHash. Furthermore, in the bear market, more miners are leaving, making it easier to obtain 51% or more of the networks total hash power. To take advantage of this, malicious miners, send coins to exchanges, trade them, and then broadcast a longer blockchain with that transaction left out. That way they get their original coins back AND whatever coin they received for the trade. This is becoming a big problem and the market will have to find a solution for it that balances out the various factors.
The content from this video is from Anthony Xie of HodlBot.
- You can read the original article here: https://blog.hodlbot.io/51-attacks-for-rent
- And visit their site: https://www.hodlbot.io/
#Cryptocurrency #51attack #DoubleSpend

Views: 1984
Bitcoin for Beginners

MIT 6.046J Design and Analysis of Algorithms, Spring 2015
View the complete course: http://ocw.mit.edu/6-046JS15
Instructor: Srinivas Devadas
In this lecture, Professor Devadas covers the basics of cryptography, including desirable properties of cryptographic functions, and their applications to security.
License: Creative Commons BY-NC-SA
More information at http://ocw.mit.edu/terms
More courses at http://ocw.mit.edu

Views: 72818
MIT OpenCourseWare

Additional videos for this title: http://j.mp/1KBt1Ht
India 101: India Explored by Matt Vanacoro
Video 3 of 24 for India 101: India Explored
Creating a realistic-sounding Indian track requires a sample instrument with a lot of depth, articulations and playability options. Thats exactly what Native Instrument has created. Every instrument in this Discovery Series library, whether percussive or melodic in nature, has a very specific and deep set of samples to create the illusion of being the real Indian thing.
Watch as expert trainer Matt Vanacoro explores the ensemble mode where you can select your band, customize the mix, edit patterns, adjust the grooves and much more. Then, join Matt as he carefully and precisely explains each instrument and shows you how to perform them to create realistic ensembles or crazy ethnic mashups.
India has come to Kontakt! So watch, listen, learn and begin integrating this amazing instrument into your scores, electronic dance tracks and more.
More info on this title: http://j.mp/1KBt1Ht

Views: 2279
macProVideoDotCom

If you like this video and want to support me, go this page for my donation crypto addresses:
https://www.youtube.com/c/mobilefish/about
This is part 22 of the IOTA tutorial.
In this video series different topics will be explained which will help you to understand IOTA.
It is recommended to watch each video sequentially as I may refer to certain IOTA topics explained earlier.
The main objective of this video is to demonstrate a Masked Authenticated Messaging use case.
MUNICIPALITY OF HAARLEM IOTA POC
In 2017, Xurux Solutions in collaboration with ICTU, were commissioned by the municipality of Haarlem (the Netherlands) to create a Proof-of-Concept in which the citizens of Haarlem logs into a website using an existing Identity Management System (called DigID) to retrieve a publicly verifiable claim.
This verifiable claim is in fact a QR code.
The QR code contains information such as the hash value of the citizens personal data, root and other relevant data.
This hash value, called the attest hash, is stored on the IOTA Tangle (MAM) using the previous mentioned root.
Third parties, like housing corporations, can easily prove these verifiable claims.
The QR code is scanned, to get the root and hash value.
The attest hash value can now be retrieved from the Tangle and compared with the one stored in the QR code.
See: https://github.com/Haarlem/digitale-waardepapieren
VERIFIABLE CLAIMS DEMO
Based on the municipality of Haarlem IOTA Proof-of-Concept I have created the "IOTA MAM Demo: Verifiable Claims":
https://www.mobilefish.com/services/cryptocurrency/mam_verifiable_claims.html
This demonstration is created for educational purpose and is NOT the same as the Haarlem's PoC.
VERIFIABLE CLAIMS DEMO EXPLAINED
Bruce requires an attestation from Gotham City stating that he is a resident of this city and he is eligible for social housing.
Gotham City issues a verifiable claim to Bruce, attesting that he is a resident of Gotham City and he meets all the conditions for social housing.
The claim is hashed (also known as attesthash) and stored on the Tangle using the Masked Authenticated Messaging in restricted mode.
Bruce shares this claim with the social housing cooperative because he wants to be eligible for a social rental home.
The social housing cooperative needs to verify that Bruce's claim is signed by Gotham City.
The social housing cooperative does this by first hashing Bruce's claim.
Let call this the "calculated attesthash".
Next the social housing cooperative extracts the "stored attesthash" from the Tangle.
All relevant information, such as root and uuid are stored in Bruce's claim.
If the "calculated attesthash" is the same as the "stored attesthash" than this is the proof that Gotham City has signed Bruce's claim.
To make this all work Gotham City must provide the social housing cooperative with the side key because of the use of the Masked Authenticated Messaging restricted mode.
The social housing cooperative does not need to have any connection to or interaction with Gotham City.
Each time Bruce requests for a verifiable claim an Universally Unique IDentifier (UUID) is generated compliant with RFC-4122 Version 4.
One of the main reasons for using UUIDs is that no centralised authority is required to administer them.
The chance of generating the same UUID is quite small especially if the UUIDs are generated using sufficient entropy.
More information see:
https://en.wikipedia.org/wiki/Universally_unique_identifier
WHAT IS HMACSHA384
HMACSHA384 is a type of keyed hash algorithm that is constructed from the SHA-384 hash function and used as a Hash-based Message Authentication Code (HMAC).
The output hash is 384 bits in length.
An HMAC can be used to determine whether a message sent over an insecure channel has been tampered with, provided that the sender and receiver share a secret key.
The sender computes the hash value for the original data and sends both the original data and hash value as a single message.
The receiver recalculates the hash value on the received message and checks that the computed HMAC matches the transmitted HMAC.
Any change to the data or the hash value will result in a mismatch, because knowledge of the secret key is required to change the message and reproduce the correct hash value.
Therefore, if the original and computed hash values match, the message is authenticated.
Please note: In our demo the key for the HMACSHA384, which is the uuid, is not secret because MAM restricted mode is being used.
Check out all my other IOTA tutorial videos:
https://www.youtube.com/playlist?list=PLmL13yqb6OxdIf6CQMHf7hUcDZBbxHyza
Subscribe to my YouTube channel:
https://www.youtube.com/channel/UCG5_CT_KjexxjbgNE4lVGkg?sub_confirmation=1
The presentation used in this video tutorial can be found at:
https://www.mobilefish.com/developer/iota/iota_quickguide_tutorial.html
#mobilefish #howto #iota

Views: 1379
Mobilefish.com

CTF CYPHER "16
Dir|@StevenQSpeilberg
| EBAN FILMS
[email protected]
443-430-1764
for more videos: https://www.youtube.com/SSBERG1

Views: 1444
EBAN FILMS