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JWT using RSA Public/Private Key Pairs
 
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A little NodeJS demo of making and verifing JavaScript Web Tokens (JWT) using RSA Public/Private Key Pairs Table of Contents: 00:00 - Introduction 00:44 - 1. Get a RSA public/private PEM pair 01:41 - NPM Package for JWT 02:05 - Why this demo? 02:21 - Node - Read Keys off Disk 02:51 - Node - Specify the right algorithm 04:34 - Node - suggested option elements 04:41 - Issuer 04:48 - Subject 04:54 - Audiance 05:04 - Expires 05:40 - Signing Options 05:54 - Sign your payload with options 06:11 - Verify Options 06:37 - Node - Verify Token 06:53 - Node - Decode 07:02 - Demo 08:04 - Marker 22
Views: 5873 Stuart Williams
Nadim Kobeissi HOPE 9  Why Browser Cryptography Is Bad & How We Can Make It Great
 
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Nadim Kobeissi Web apps are becoming almost exponentially responsible for handling user data. This incredible increase summons an urgent requirement for client-side web browser crypto standards. However, web browsers lack client-side crypto standards for building blocks such as secure block ciphers, public key schemes, and hashing algorithms. Developers currently rely on JavaScript crypto libraries in order to implement these functions, which can, admittedly, provide strong crypto in some situations, but still falter when faced with certain attacks. This talk will look at Cryptocat, a security-centric web-chat client with client-side cryptography, and also focus on the problems, the solutions, and the limitations of JavaScript cryptography. There will be a discussion of potential solutions to these problems, which may very well require the implementation of an integrated universal web browser standard for client-side cryptography. crypto cat: https://crypto.cat
Views: 716 TheEthanwashere
Chrome vs. Firefox - Stanford Javascript Crypto Library
 
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http://bitwiseshiftleft.github.com/sjcl/
Views: 782 brinchjdk
IOTA tutorial 21: CryptoJS
 
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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 21 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 provide you with some basic knowledge about CryptoJS. CryptoJS is a collection of standard and secure cryptographic algorithms implemented in JavaScript using best practices and patterns. They are fast and they have a consistent and simple interface. Jeff Mott is the original author of the crypto-js library which was one of the many code projects hosted by the Google Code Project Hosting Service. The Google Code Project Hosting Service was turned down in early 2016. The many code projects can still be found at the Google Code Archive. https://code.google.com/archive/ Jeff Mott’s CryptoJS library can be found at: https://code.google.com/archive/p/crypto-js/ The CryptoJS last version is v3.1.2 and last updated in Jan 15, 2013. See: https://code.google.com/archive/p/crypto-js/downloads How to use the CryptoJS functions, see: https://code.google.com/archive/p/crypto-js https://code.google.com/archive/p/crypto-js/wikis/QuickStartGuide_v3beta.wiki It seems that this library is not maintained by Jeff Mott anymore. Jeff Mott’s CryptoJS library has been forked by several developers and can be found at Github: https://github.com/brix/crypto-js https://github.com/sytelus/CryptoJS https://github.com/gwjjeff/cryptojs The fork created by Evan Vosberg (brix/crypto-js) is still maintained. The (Brix) CryptoJS library can be found at: https://github.com/brix/crypto-js An npm module has been created for the (Brix) CryptoJS library which can be found at: https://www.npmjs.com/package/crypto-js To include all CryptoJS libraries in JavaScript: var CryptoJS = require(“crypto-js”); The (Brix) CryptoJS library is also available in the free and open source web front-end resource Content Delivery Network (CDN): https://cdnjs.com/libraries/crypto-js The (Brix) CryptoJS library are used by several Distributed Ledger projects, such as: - IOTA (in the iota.lib.js library) https://github.com/iotaledger/iota.lib.js/blob/master/package.json - Ethereum (in the web3js library) https://github.com/ethereum/web3.js/blob/develop/package.json Understanding how the CryptoJS library works would be beneficial to you if you are an IOTA or Ethereum front-end developer. The CryptoJS library has no asymmetric key algorithms, such as RSA. More information how to use CryptoJS, see: https://code.google.com/archive/p/crypto-js/wikis/QuickStartGuide_v3beta.wiki https://github.com/brix/crypto-js https://www.davidebarranca.com/2012/10/crypto-js-tutorial-cryptography-for-dummies/ 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: 1093 Mobilefish.com
ShmooCon 2015 - NaCl Crypto Library
 
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CyberPunk http://n0where.net
Views: 947 Ra Darth
10 Weird Applications of Public Key Cryptography - Tim Caswell
 
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Have you ever wondered about RSA keypairs, web certificates, JSON Web Tokens? How about those new-fangled Ed25519 keys ? This talk will visually explain the core concepts behind all this tech and then gives 10 concrete use cases for using it in JavaScript servers and applications. www.utahjs.com 2017 UtahJS Conference Monday, September 18, 2017 Jordan Commons Event Center
Views: 140 UtahJS
Developer's Guide to JavaScript and Web Cryptography
 
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The increasing capabilities and performance of the web platform allow for more feature-rich user experiences. How can JavaScript based applications utilize information security and cryptography principles? This session will explore the current state of JavaScript and Web Cryptography. We will review some basic concepts and definitions, discuss the role of TLS/SSL, show some working examples that apply cryptography to real-world use cases and take a peek at the upcoming W3C WebCryptoAPI. Code samples will use CryptoJS in the browser and the Node.js Crypto module on the server. An extended example will secure the popular TodoMVC project using PBKDF2 for key generation, HMAC for data integrity and AES for encryption. Slides available on Google Docs: https://docs.google.com/presentation/d/1Sx5ODjh_4lgfYgPNY3RqFzL4snvBbcGZ6byOn78K2ME/edit?usp=sharing
Views: 2942 Kevin Hakanson
Enrico Zimuel - The Sodium crypto library of PHP 7.2 - phpday 2018
 
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The Sodium crypto library (libsodium) is a modern, easy-to-use software library for encryption, decryption, signatures, password hashing and more. Sodium has been added to PHP 7.2 as core extension. In this talk we will show how to use Sodium in PHP projects to solve common problems, like how to store the users’ password, how to encrypt/decrypt sensitive information, how to authenticate user’s data, etc. We’ll also present some of the advanced features of libsodium like authenticated encryption, anonymous public-key encryption, and elliptic curve cryptography.
Views: 100 GrUSP
Blockchain tutorial 28: Bitcoin Improvement Proposal 39 (BIP-39) mnemonic words
 
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This is part 28 of the Blockchain tutorial. In this video series different topics will be explained which will help you to understand blockchain. It is recommended to watch each video sequentially as I may refer to certain Blockchain topics explained earlier. WHAT IS A WALLET -------------------------------- A wallet stores private keys. The word wallet is misleading, it just stores private keys and not the coins. The public addresses are automatically derived from the private keys. If you open your Bitcoin wallet and one of your Bitcoin addresses shows that is has a balance of 5 BTC, than these bitcoins are not actually stored in your wallet. It means that these 5 bitcoins were transferred to your Bitcoin address during a transaction. This transaction (TX) information is stored on the blockchain. Your wallet queries the blockchain and searches for Unspent TX Outputs (UTXO) for all your Bitcoin addresses to display their balances. The bitcoins on these UTXO can be unlocked and transferred to another Bitcoin address using the private keys stored in the wallet. NON-DETERMINISTIC WALLET ------------------------------------------------- Wallets stores private keys but they also create these private keys. The private keys are randomly generated numbers which are not related to each other. You can not derive these private keys with an algorithm. Hence the words "non-deterministic". If you use a non-deterministic wallet you must make regular backups of these private keys. If you have problems with your wallet, you can restore your wallet by importing the backupped private keys. Explaining a non-deterministic wallet (for educational purpose only), see: https://www.mobilefish.com/services/cryptocurrency/cryptocurrency.html DETERMINISTIC WALLET ----------------------------------------- A deterministic wallet uses 12 - 24 words to create a 512 bit seed. These words are called mnemonic words, because they are more easily to remember than this long hexadecimal string. The 512 bit seed is used to create a master private key. This master private key in turn is used to create private keys and corresponding public addresses. Generally speaking using these 12 - 24 words will complete restore your wallet with exactly the same private keys and corresponding public addresses. Hence the word "deterministic". It is imperative that you safely store these 12 - 24 words, without it you have no access to your private keys. To see how an Ethereum deterministic wallet works, see YouTube movie: https://youtu.be/cqz8-hOz_nk BIP-39 ----------- The acronym BIP means Bitcoin Improvement Proposal. BIPs are design documents for introducing features or information to Bitcoin. An overview can be found at: https://github.com/bitcoin/bips BIP-39 describes the implementation of mnemonic words for the generation of deterministic wallets, see: https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki BIP-39 is becoming an industry standard which is not only used for Bitcoin wallets but it is also used in Ethereum, Dash and other Altcoin wallets. The wordlist can be found at: https://github.com/bitcoin/bips/blob/master/bip-0039/bip-0039-wordlists.md For additional security you can allow users to enter a passphrase. Use the Password-Based Key Derivation Function 2 (PBKDF2) together with the mnemonic phrase and salt to produce a 512 bits seed. If an attacker gets its hands on your mnemonic words the passphrase (it you have set it) will prevent the attacker to access the private keys. PBKDF2 is purposefully made slow to make brute force dictionary attack very difficult. The 512 bit seed is used to generate deterministic wallets. How to generate deterministic wallets is explained in BIP-32 and BIP-44. It is important to know that each time you enter a different passphrase it will generate a valid 512 bit seed and thus a valid wallet with valid public and private key pairs. This feature can help you limit your loss after a 5$ wrench attack. You can setup a second deterministic wallet with some coins to satisfy the attacker. If you do not know what a 5$ wrench attack is watch this comic: https://xkcd.com/538/ Storing your passphrase at the same location as your mnemonic words is not recommended and beats the purpose. But if you lose your passphrase, you have lost access to your coins. A JavaScript implementation of BIP-39 can be found at: https://github.com/bitcoinjs/bip39 How this JavaScript library is used see: https://www.mobilefish.com/download/ethereum/bip39.html A Mnemonic Code Converter web application can be found at: https://iancoleman.github.io/bip39 Check out all my other Blockchain tutorial videos https://goo.gl/aMTFHU Subscribe to my YouTube channel https://goo.gl/61NFzK The presentation used in this video tutorial can be found at: https://www.mobilefish.com/developer/blockchain/blockchain_quickguide_tutorial.html #mobilefish #blockchain #bitcoin #cryptocurrency #ethereum
Views: 6611 Mobilefish.com
Java prog#129. How to encrypt and decrypt data in Java Part 1
 
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------------------Online Courses to learn---------------------------- Java - https://bit.ly/2H6wqXk C++ - https://bit.ly/2q8VWl1 AngularJS - https://bit.ly/2qebsLu Python - https://bit.ly/2Eq0VSt C- https://bit.ly/2HfZ6L8 Android - https://bit.ly/2qaRSAS Linux - https://bit.ly/2IwOuqz AWS Certified Solutions Architect - https://bit.ly/2JrGoAF Modern React with Redux - https://bit.ly/2H6wDtA MySQL - https://bit.ly/2qcF63Z ----------------------Follow--------------------------------------------- My Website - http://www.codebind.com My Blog - https://goo.gl/Nd2pFn My Facebook Page - https://goo.gl/eLp2cQ Google+ - https://goo.gl/lvC5FX Twitter - https://twitter.com/ProgrammingKnow Pinterest - https://goo.gl/kCInUp Text Case Converter - https://goo.gl/pVpcwL -------------------------Stuff I use to make videos ------------------- Stuff I use to make videos Windows notebook – http://amzn.to/2zcXPyF Apple MacBook Pro – http://amzn.to/2BTJBZ7 Ubuntu notebook - https://amzn.to/2GE4giY Desktop - http://amzn.to/2zct252 Microphone – http://amzn.to/2zcYbW1 notebook mouse – http://amzn.to/2BVs4Q3 ------------------Facebook Links ---------------------------------------- http://fb.me/ProgrammingKnowledgeLearning/ http://fb.me/AndroidTutorialsForBeginners http://fb.me/Programmingknowledge http://fb.me/CppProgrammingLanguage http://fb.me/JavaTutorialsAndCode http://fb.me/SQLiteTutorial http://fb.me/UbuntuLinuxTutorials http://fb.me/EasyOnlineConverter Password Encryption.java JAVA ENCRYPTION/DECRYPTION PROGRAM HELP Encrypting and Decrypting Java Cryptography using Java in Netbeans IDE Cryptography using Java in Netbeans IDE Java Cryptography APIs Cryptography Encrypting and Decrypting a text file in java
Views: 92457 ProgrammingKnowledge
Blockchain tutorial 29: Hierarchical Deterministic wallet - BIP32 and BIP44
 
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This is part 29 of the Blockchain tutorial. In this video series different topics will be explained which will help you to understand blockchain. It is recommended to watch each video sequentially as I may refer to certain Blockchain topics explained earlier. DETERMINISTIC WALLET BIP-39 describes how the mnemonic words are created. These mnemonic words together with a password (optionally) are used to generate a 512 bit seed. The 512 bit seed is also called the "BIP-39 seed". This seed is used to create deterministic wallets. There are two types of deterministic wallets: - Sequential deterministic wallets. - Hierarchical deterministic wallets. SEQUENTIAL DETERMINISTIC WALLET Sequential deterministic wallets generates private keys for example by taking SHA256(seed + n) HIERARCHICAL DETERMINISTIC WALLET Nowadays most wallets are Hierarchical Deterministic (HD) wallets. More information: https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki Most HD wallet vendors have implemented BIP-32, BIP-39 and BIP-44. These 3 Bitcoin Improvement Proposals are becoming an industry standard. BIP-39 BIP-39 describes the implementation of mnemonic words to generate a 512 bit seed. More information: https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki BIP-32 BIP-32 describes how you can build a general hierarchical deterministic wallet. More information: https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki https://bitcoin.org/en/developer-guide#hierarchical-deterministic-key-creation If you want to see how BIP32 is implemented in the bitcoinjs library, see: https://raw.githubusercontent.com/bitcoinjs/bitcoinjs-lib/master/src/hdnode.js Online web application: https://www.mobilefish.com/download/ethereum/hd_wallet.html BIP-32 explains how master keys and master chain code are created from a BIP-39 seed. The chain code is used as entropy in the Child Key Derivation function. Using different index numbers will create different unlinkable child keys from the same parent keys. Repeating the procedure for the child keys using the child chain code will create unlinkable grandchild keys. By changing the chain code, a new node (aka wallet) is created. Extended private (xprv) keys can create a complete branch with child private keys and child public keys Extended public (xpub) keys can only generate public keys. BIP-44 BIP-44 defines a specific logical hierarchy for deterministic wallets based on an algorithm described in BIP-32. More information: https://github.com/bitcoin/bips/blob/master/bip-0044.mediawiki BIP-44 uses the following derivation path: m/purpose'/coin_type'/account'/change/address_index The letter m denotes the master node and all hierarchical levels are separated with slashes (/). m is level 0, purpose is level 1, coin_type is level 2 etc. The purpose scheme is described in BIP-43. Because we are using BIP44 scheme we should use 44'. The apostrophe (for example in purpose') indicates hardened derivation. More information: https://github.com/satoshilabs/slips/blob/master/slip-0044.md account level can be seen as bank account types, for example payment account, savings account etc. change level is also known as "external / internal level" where external (0) is used for addresses that are meant to be visible outside of the wallet (receiving payments) and internal (1) is used for addresses which are not meant to be visible outside of the wallet (signing transactions). address_index is a sequence of addresses starting at 0. BIP-44 XPRV AND XPUB DEMONSTRATION Suppose a webshop wants to receive payments in only in ETH. For each payment received a different Ethereum address must be used. The webshop should use a wallet containing only public keys. The webshop wallet uses a xpub key with derivation path: m/44'/60'/0'/0 This wallet creates the following addresses: m/44'/60'/0'/0/0 m/44'/60'/0'/0/.. The accounting department uses another wallet containing the same public keys AND accompanied private keys. The accounting department can transfer payments made on these public addresses and transfer it to a separate accounting address. This is possible because they have access to the private keys. The accounting department wallet uses a xprv key with the same derivation path: m/44'/60'/0'/0 BIP-32 RISK If a hacker gets it hands on any child private key and the account xpub key, the hacker can recompute the account xprv key and thus have access to every private and public key descending from the account level. More information: https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#implications Check out all my other Blockchain tutorial videos https://goo.gl/aMTFHU Subscribe to my YouTube channel https://goo.gl/61NFzK The presentation used in this video tutorial can be found at: https://www.mobilefish.com/developer/blockchain/blockchain_quickguide_tutorial.html #mobilefish #blockchain #bitcoin #cryptocurrency #ethereum
Views: 7775 Mobilefish.com
RSA Digital Signature: SIGN in Python pyCrypto & verify in JavaScript jsrsasign
 
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In most cases, we want to interact our python server (Flask/Django) with multiple clients over the web that uses JavaScript. This is a demonstration of how can you generate a signature in python and verity that signature in JavaScript and Vice Versa. jsrsasign library test console: https://kjur.github.io/jsrsasign/sample/sample-rsasign.html
Views: 2084 Anum Sheraz
AppSec EU 2017 On The (In-)Security Of JavaScript Object Signing And Encryption by Dennis Detering
 
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JavaScript Object Signing and Encryption (JOSE) has been standardized as a lightweight alternative to XML Signature and Encryption. It has early been integrated in authentication and authorization protocols like OpenID Connect and OAuth. In addition, it has been adopted in Web services. In our research, we provide the first study regarding the JSON security adapting and extending known attack techniques. We provide an evaluation of four different libraries revealing critical cryptographic attacks, ranging from attacks bypassing JSON Signature (Signature exclusion, Key Confusion, and Timing Attack on HMAC), to JSON Encryption (Bleichenbacher Million Message Attack). To facilitate the analysis we developed JOSEPH - the first open-source automated tool for evaluating JSON security. The extensible design of JOSEPH allows one to implement further cryptographic attacks, for example, padding oracle or invalid curve attacks. - Managed by the official OWASP Media Project https://www.owasp.org/index.php/OWASP_Media_Project
Views: 1466 OWASP
Managing encryption of data in the cloud (Google Cloud Next '17)
 
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Can management of encryption keys be easier in the cloud than on-premise? During this video, Maya Kaczorowski discusses the continuum of encryption options available, from encryption of data at rest by default, to Cloud Key Management System, to Customer Supplied Encryption Keys. You'll learn how our encryption tools allow management of your own keys, including generation, rotation and destruction of those keys. She also shares best practices for managing and securing secrets. Missed the conference? Watch all the talks here: https://goo.gl/c1Vs3h Watch more talks about Infrastructure & Operations here: https://goo.gl/k2LOYG
Views: 6488 Google Cloud Platform
Network Security - Use Crypto API to Encrypt and Decrypt
 
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Fundamentals of Computer Network Security This specialization in intended for IT professionals, computer programmers, managers, IT security professionals who like to move up ladder, who are seeking to develop network system security skills. Through four courses, we will cover the Design and Analyze Secure Networked Systems, Develop Secure Programs with Basic Cryptography and Crypto API, Hacking and Patching Web Applications, Perform Penetration Testing, and Secure Networked Systems with Firewall and IDS, which will prepare you to perform tasks as Cyber Security Engineer, IT Security Analyst, and Cyber Security Analyst. course 2 Basic Cryptography and Programming with Crypto API: About this course: In this MOOC, we will learn the basic concepts and principles of cryptography, apply basic cryptoanalysis to decrypt messages encrypted with mono-alphabetic substitution cipher, and discuss the strongest encryption technique of the one-time-pad and related quantum key distribution systems. We will also learn the efficient symmetric key cryptography algorithms for encrypting data, discuss the DES and AES standards, study the criteria for selecting AES standard, present the block cipher operating modes and discuss how they can prevent and detect the block swapping attacks, and examine how to defend against replay attacks. We will learn the Diffie-Hellman Symmetric Key Exchange Protocol to generate a symmetric key for two parties to communicate over insecure channel. We will learn the modular arithmetic and the Euler Totient Theorem to appreciate the RSA Asymmetric Crypto Algorithm, and use OpenSSL utility to realize the basic operations of RSA Crypto Algorithm. Armed with these knowledge, we learn how to use PHP Crypto API to write secure programs for encrypting and decrypting documents and for signing and verify documents. We then apply these techniques to enhance the registration process of a web site which ensures the account created is actually requested by the owner of the email account. Develop Secure Programs with Crypto API In this module, we learn how to use Crypto API to write secure programs for encrypting and decrypting documents, and for signing and verify documents. We then apply the techniques to enhance the registration process of a web site which ensures the account created is actually belonging to the owner of the email account the request profile. Learning Objectives • Develop secure programs with Crypto API for encryption, authentication, and integrity checking • Enhance the registration process of the web site by using the crypto api • Create and utilize the Crypto API to sign and verify documents Subscribe at: https://www.coursera.org
Views: 112 intrigano
IOTA tutorial 6: Why you should not reuse an address for outgoing transactions
 
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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 6 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. Digital signatures are used for authentication, integrity checking and non-repudiation.  Development of quantum computers threatens the security of currently used digital signature algorithms such as Rivest–Shamir–Adleman (RSA) and Elliptic Curve Digital Signature Algorithm (ECDSA). Cryptographers developed a variety of quantum-resistant alternatives of which hash based signatures are the most promising. Hash based signatures are based on so called One Time Signatures (OTS). The term implies that a single public/private key pair must only be used once. Otherwise, an attacker is able to reveal more parts of the private key and spoof signatures. In 1979 Leslie Lamport created a method to construct digital signatures using only cryptographically secure one way hash functions. This method is called the Lamport signature or Lamport One Time Signature (OTS) scheme. Other One Time Signature schemes are the Merkle OTS and Winternitz OTS. The Lamport One Time Signature scheme is very easy to understand and is VERY LOOSELY comparable to Winternitz OTS. For simplicity's sake I will be using the Lamport One Time Signature scheme explaining why you should never reuse an IOTA address for outgoing transactions. Alice uses a random number generator and produces two pairs of 256 random numbers, total 512 numbers. Each random number is 256 bits in size. These random numbers forms the private key. Each of the 512 random numbers are separately hashed, using for example SHA-256. These hashed random numbers forms the public key. Alice has a document (or transaction data) which is hashed using SHA-256. The document hash is of course 256 bits long: 101..011 Alice wants to create a digital signature for her document. She applies the following procedure: - Loop thru each bit (n) of the hash from 0-255. - If the bit is a 0, publish the nth number from pair 0. - If the bit is a 1, publish the nth number from pair 1. - When all bits are looped, destroy all unused numbers from pair 0 and 1. This produces a sequence of 256 random numbers. The digital signature is a sequence of 256 random numbers. After the digital signature is created, delete all unused numbers from the private key. The digital signature consist half of the private key, the other 256 random numbers are still unknown and thus nobody can create signatures that fit other message hashes. Alice sends her document, together with the corresponding digital signature and public key to Bob. Bob wants to verify Alice's document signature. He first hashes the document using SHA-256. The document hash is again: 101..011 Bob follows the same steps when Alice created the digital signature, but instead uses the public key. Bob produces a sequence of 256 hashes picked from Alice's public key. Bob now hashes each of the random number in the digital signature. If both sequence of hash numbers match then the signature is ok. The Lamport signature creates a digital signature which reveals part of the private key. The private key has 512 numbers and using it once will reveal 256 numbers. Using the private key twice weakens the security of the scheme again by half. The probability of an attacker being able to successfully forge a signature for a given message increases from 1/(2^256) to 1/(2^128). A third signature using the same key would increase the probability of a successful forgery to 1/(2^64) and a fourth signature to 1/(2^32), and so on. Please note IOTA's signature scheme is based on the Winternitz One Time Signature (WOTS) scheme and is NOT the same as the Lamport signature scheme. However by using the Lamport One Time Signature scheme I am trying to give you a very simplistic understanding why you should never reuse an IOTA address for outgoing transactions. Check out all my other IOTA tutorial videos: https://goo.gl/aNHf1y Subscribe to my YouTube channel: https://goo.gl/61NFzK 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: 5110 Mobilefish.com
Bitcoin, Blockchain and Node - Portia Burton, The Atlantic Magazine
 
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Bitcoin, Blockchain and Node - Portia Burton, The Atlantic Magazine
Views: 6552 node.js
Encrypt Decrypt Hashing - PHP & MYSQL - Protect your data in your database
 
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Databases are becoming vulnerable to hacking and other means of attack. $10 Free credit for hosting on DigitalOcean https://m.do.co/c/7e7436ae5d07 Please protect the sensitive data in your system. I will show you a couple simple methods to start protecting your database. Update: This method is now out of date, please search for newer solutions.
Views: 80039 Devvid
Python3 Advanced Tutorial 10 - PyCrypto
 
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This is a tutorial on PyCrypto, looking at encrypting and decrypting files using AES-256. All Links and Slides will be in the description. Subscribe for more cool stuff! Slides & files - https://www.mediafire.com/folder/blqyh7qotgu2r/Tutorial_10_-_PyCrypto Python - http://python.org/ Ubuntu - http://www.ubuntu.com/ Steam Group: http://steamcommunity.com/groups/DrapsTV Twitter: https://twitter.com/DrapsTV Ello: https://ello.co/drapstv If you like what you see be sure to subscribe and thumbs up!
Views: 23158 DrapsTV
HOPE Number Nine (2012): Why Browser Cryptography is Bad and How We Can Make It Great
 
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Saturday, July 14, 2012: 10:00 am (Nutt): Web apps are becoming almost exponentially responsible for handling user data. This incredible increase summons an urgent requirement for client-side web browser crypto standards. However, web browsers lack client-side crypto standards for building blocks such as secure block ciphers, public key schemes, and hashing algorithms. Developers currently rely on JavaScript crypto libraries in order to implement these functions, which can, admittedly, provide strong crypto in some situations, but still falter when faced with certain attacks. This talk will look at Cryptocat, a security-centric web-chat client with client-side cryptography, and also focus on the problems, the solutions, and the limitations of JavaScript cryptography. There will be a discussion of potential solutions to these problems, which may very well require the implementation of an integrated universal web browser standard for client-side cryptography. Hosted by Nadim Kobeissi
Views: 41 Channel2600
Invited Talk: Failures of secret key cryptography
 
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Invited talk by Daniel Bernstein at FSE 2013.
Views: 1945 TheIACR
Introduction to JWT (JSON Web Token) - Securing apps & services
 
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-What is JWT (JSON Web Token) -What is the structure of JWT -What are Header, Payload (claims) and Signature of JWT -How is JWT used in applications -How to create, tamper and verify JWT (understanding JWT, with no code)
Views: 159698 Tech CBT
Cryptography Best Practices - Bart Preneel
 
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Application architects need to make informed choices to use cryptography well: + Alternative key architectures have their merits and drawbacks. PKIs, in particular, should be contrasted with symmetric key architectures such as Kerberos. + Network protocol characteristics are pivotal in ensuring distributed applications meet security requirements. Key strength choices impact on security guarantees offered, as do cryptographic algorithm modes. + While strong keys and wise use of cryptographic algorithms may thwart cryptanalytic attack, applications are insecure without prudent key management. In this context, key generation and key storage require particular attention. + The selection of crypto-libraries requires awareness of inherent library qualities and failures. Application developers are advised not to implement their own. Learning objectives + decide if and when cryptography should be used. + make informed key architecture and management decisions. + use appropriate algorithms and parameters. + select an appropriate cryptographic library. + choose network protocols for distributed applications. This lecture was delivered by Bart Preneel at SecAppDev 2013 in Leuven, Belgium. Professor Bart Preneel of KU Leuven heads the COSIC (COmputer Security and Industrial Cryptography) research group. His main research area is information security with a focus on cryptographic algorithms and protocols as well as their applications to both computer and network security, and mobile communications. He teaches cryptology, network security and coding theory at the KU Leuven and was visiting professor at the Ruhr Universitaet Bochum (Germany), the T.U.Graz (Austria), the University of Bergen (Norway), and the Universiteit Gent (Belgium). In '93-'94 he was a research fellow at the University of California at Berkeley. He has taught intensive courses around the world. He undertakes industrial consulting (Mastercard International, S.W.I.F.T., Proton World International,...), and participates in the work of ISO/IEC JTC1/SC27/WG2. Professor Preneel is Vice President of the International Association for Cryptologic Research (IACR) and co-founder and chairman of LSEC vzw (Leuven Security Excellence Consortium).
Views: 2835 secappdev.org
Signature Validation Solution - Applied Cryptography
 
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This video is part of an online course, Applied Cryptography. Check out the course here: https://www.udacity.com/course/cs387.
Views: 465 Udacity
Memory Encryption Presentation
 
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Summary of "Memory Encryption: A Survey of Existing Techniques by Michael Henson and Stephen Taylor (Dartmouth College, 2014) for ECE289
Views: 103 Andrew Byrne
IOTA tutorial 9.1: Key, Digests and Address
 
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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 19.1 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 generation of a key, digests and address, all starts with a seed. How the key is calculated, see: https://github.com/iotaledger/iota.crypto.js/blob/v0.4.2/lib/crypto/signing/signing.js var key = function(seed, index, length) Every index number refers to an address, also known as public key, and each address has a corresponding unique key, also known as the private key. seed is a randomly generated 81 trytes (A-Z9), converted to trits (81x3=243 trits) index is an integer (0,1,2 .. 9007199254740991) and every address has a corresponding index number. length is the security level (1,2 or 3) Security level 1: key has 1x27 = 27 segments, each segment consists of 81 trytes. key has in total 27 x 81 = 2187 trytes Security level 2: key has 2x27 = 54 segments, each segment consists of 81 trytes. key has in total 2 x 27 x 81 = 2 x 2187 = 4374 trytes Security level 3: key has 3x27 = 81 segments, each segment consists of 81 trytes. key has in total 3 x 27 x 81 = 3 x 2187 = 6561 trytes Security level 1, key size = (2187 x 3 x ln(3) / ln(2)) / 8 = ~1300 bytes Security level 2, key size = (4374 x 3 x ln(3) / ln(2)) / 8 = ~2600 bytes Security level 3, key size = (6561 x 3 x ln(3) / ln(2)) / 8 = ~3900 bytes How the digests is calculated, see: https://github.com/iotaledger/iota.crypto.js/blob/v0.4.2/lib/crypto/signing/signing.js var digests = function(key) Security level 1, digests size = 1x243 = 243 trits = 243 / 3 = 1 x 81 trytes Security level 2, digests size = 2x243 = 486 trits = 486 / 3 = 2 x 81 trytes Security level 3, digests size = 3x243 = 729 trits = 729 / 3 = 3 x 81 trytes How the address is calculated, see: https://github.com/iotaledger/iota.crypto.js/blob/v0.4.2/lib/crypto/signing/signing.js var address = function(digests) Security level 1, address = hash(digests[0-242]) Security level 2, address = hash(digests[0-485]) Security level 3, address = hash(digests[0-728]) Address size is always 243 trits = 243 / 3 = 81 trytes Check out all my other IOTA tutorial videos: https://goo.gl/aNHf1y Subscribe to my YouTube channel: https://goo.gl/61NFzK 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: 1126 Mobilefish.com
Introduction to Bitcoin with Yours Bitcoin, Lecture 2: Private Keys and Public Keys
 
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A course on how bitcoin works and how to program bitcoin stuff with the javascript bitcoin library Yours Bitcoin. Taught by Ryan X. Charles, Cofounder & CEO of Yours, and former cryptocurrency engineer of reddit. The second lecture gives a first-pass introduction to private keys and public keys. Because a complete understanding of private keys and public keys requires understanding elliptic curves and hash functions, we will revisit them again later after covering elliptic curves and hash functions. https://github.com/yoursnetwork/yours-bitcoin-examples https://github.com/yoursnetwork/yours-bitcoin https://www.yours.network https://www.ryanxcharles.com/ https://twitter.com/ryanxcharles
Views: 897 Yours
Cryptography Lunch and Learn
 
01:24:30
Learn about cryptography basics and more advanced topics including symmetric encryption, hashing and hashing best practices, CSPRNGs, public key cryptography, asymmetric encryption, RSA, Diffie-Hellman key exchange, digital signatures, secure messaging, public key certificates, authenticated secure messaging, Certificate Authorities, SSL/TLS, and how to use cryptographic algorithms in .NET. Credits to this session from Chicago Coder Conference for much of the material: https://www.youtube.com/watch?v=cmTv4Y2zVeA Slides: https://onedrive.live.com/view.aspx?resid=2CB9673AE67C7748!26406&app=PowerPoint&authkey=!AO8G8Eh33v7S6PQ
Views: 367 feature[23]
Demo: Very early stages of coding an encrypted facebook chat.
 
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Playing with an AES encryption library for JavaScript from Movable Type Scripts: http://www.movable-type.co.uk/scripts/aes.html Using grease monkey, I was able to inject javascript and encrypt and decrypt messages in a chat session. This is a very early proof of concept though. There is a lot I need to change in the usability. I also need to learn how to handle the XMLHttpRequest (AJAX) events, and use RSA to distribute the AES key between facebook users.
Views: 167 n2fole00
29C3: Re-igniting the crypto-wars on the web (2012)
 
01:04:41
http://events.ccc.de/congress/2012/Fahrplan/events/5374.en.html RE-IGNITING THE CRYPTO WARS ON THE WEB This talk will give an overview of the ongoing work by the W3C on a controversial general purpose Javascript cryptography API in context of the larger desire to create trusted and encrypted cloud services with rich web applications. Today, cryptography is difficult to use and the Web is an insecure environment at best, but can this situation be improved and cryptography be put in the hands of ordinary developers and users? The W3C specification, currently under development, will be described, as well as its interaction with other parts of the emerging Web Security Model at the W3C and IETF such as Content Security Policy, HTTP Strict Transport Security, and Certificate Transparency. A number of use-cases, ranging from decentralized identity systems to secure cloud services for activists, will be detailed. As the specification will be under active development until autumn 2013, feedback from the hacker community is needed! Recently, the W3C has released as a First Public Working Draft the Web Cryptography API [1], which defines a number of cryptographic primitives to be deployed across browsers and native Javascript environments. This proposal is moving fast, and will likely be finalized by the end of 2013 and in all major browsers shortly thereafter, as browser vendors Google, Microsoft, Mozilla, and Opera are all on board. As has been discussed in a number of blog-posts [2], cryptography in Javascript on the Web is an unsafe bet at best today (Javascript Crypto O RLY?), although technically the Web Crypto API is a WebIDL that could be bound to programming languages beyond Javascript. Even with excellent implementations such as the Stanford Javascript Crypto Library [3], browsers still do not have basic cryptographic functionality not provided natively by Javascript, such as key storage. Yet is Javascript cryptography doomed on the Web? Much of the critique of Javascript cryptography boils down to a critique of current Web browsers, and as has been shown by the W3C and browser vendors - the Web Platform can evolve. Due to TLS, almost every web browser and operating system already contains well-verified and reviewed cryptographic algorithms. At its core, the Web Cryptography API will simply expose this functionality to WebApp developers, with a focus on essential features such as cryptographically strong random number generation, constant-time cryptographic primitives, and a secure keystore. Without these functions, Javascript web cryptography would be impossible. Yet we realize the Web Cryptography API is only a single component in building the emerging Web Security model that is necessary to make the Web part of a trusted environment. For example, one open issue is whether or not applications using the Web Cryptography API also should be required to use Content Security Policy (and attendant work such as HSTS) to prevent XSS attacks [4]. Indeed, should and can browser vendors and the W3C as a whole tackle the malleability of the browser Javascript run-time environment? Furthermore, can we use the Cryptography API to manipulate and check certificates, as is needed by proposals such as the new IETF Certificate Transparency proposal? Without a doubt these security considerations are of utmost importance, and getting them right to enable cryptography on the Web will require holistic thinking about attack surfaces and threat models. There are a number of use-cases, ranging from decentralized identity systems to secure cloud services for activists, will be detailed - including some One issue with the Web Cryptography API is that the Working Group decided to expose the low-level functionality first rather than aiming only for a high-level API aimed at the developer on the street who may not have a grasp of the finer details of cryptography. The Working Group did this on purpose after taking a survey of users [5], in order to allow experienced developers to build the functionality needed across the largest number of use-cases, but a "high-level" API similar to KeyCzar that makes using cryptography easy for Web developers will also be presented. A second issue is that the current Web Cryptography API exposes legacy cryptographic algorithms that can be used insecurely, which was done in the draft to allow Web Application developers to create applications with interoperability with widely used applications such as GPG, SSH, and the like. A number of thorny issues will be presented, and feedback from the audience will be encouraged. Speaker: Harry Halpin EventID: 5374 Event: 29th Chaos Communication Congress (29c3) by the Chaos Computer Club [CCC] Location: Congress Centrum Hamburg (CCH); Am Dammtor; Marseiller Straße; 20355 Hamburg; Germany Language: english Start: 27.12.2012 17:15:00 +01:00 License: CC-by-nc-sa
Views: 308 Aa
Python Bitcoin Tutorial for Beginners
 
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My Book: https://www.amazon.com/Building-Bitcoin-Websites-Beginners-Development/dp/153494544X A simple introduction tutorial to get started with the pybitcointools Python library. https://github.com/vbuterin/pybitcointools
Views: 53332 m1xolyd1an
Cryptography Project - Secure Message Send
 
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A secure message send application - Flask web application, using asymmetric/symmetric encryption and digital signatures for security and SQLite storage.
Views: 47 Catherine E
Coding Math: Episode 52 - Pseudo Random Number Generators, Part II
 
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This time we look at a couple of existing PRNG libraries available in JavaScript, and look at some examples of how PRNGs can be used in cryptography, games, and generative art. Support Coding Math: http://patreon.com/codingmath Source Code: Crypto: http://jsbin.com/kipequk/2/edit?js,console Landscape: http://jsbin.com/zizeje/1/edit?js,output Circles: http://jsbin.com/zizeje/2/edit?js,output
Views: 5109 Coding Math
Bill Automata - Require Cyrpto is a Human Right - CascadiaFest 2016
 
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An accessible tour of the Node.js Crypto API through the lens of history and politics. * Diffie-Hellman & RSA: key generation, encrypt, and decrypt. * RSA sign and verify. * AES and other symmetric ciphers. Almost everything in OpenSSL has a rich history. A lot of the code we link when compiling Node.js was once illegal to disseminate under treaties that regulate things like fighter jets and night vision. The effort to weaken these tools is still underway. You can't help fight that effort unless you are knowledgeable of more than just the basic implementation details. By the end of the talk you will have been exposed to the important concepts, applied and theoretical, necessary to use strong cryptography in any of your Node.js projects. I'll crack some weak keys of different types in realtime using the cluster API and some spare cloud resources if my company has any spare AWS reserved instances. I'll also leave you with a drive to protect access to strong cryptography all over the world.
Views: 131 Cascadia JS
Be Anonymous Online Part 5.1 (Email) PGP | GnuPG | Openpgp.js Encryption
 
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In this tutorial you will know how Free email providers or spy agency dig into your email, and how you can protect your mails using Encryption also demonstrate how you can use PGP in Browser (mailvelope ext using openpgp.js) & Mail Client (GnuPG and enigmail in Thunderbird).
Views: 1096 Anish Mandal
Block Chain Utilizing Polymorphic Encryption
 
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Existing BlockChains use standard hash functions and in most cases asymmetric encryption algorithms where the algorithm is public and also the implementation code is made public. This surely opens the door for known attacks especially side channel attacks. Using The Polymorphic Block Cipher is faster and more secure when compared to asymmetric cryptographic algorithms that is vulnerable to future quantum computer attacks. The key distribution issues of symmetric encryption can be resolved using different methods such as El-Gamal encryption or even Key Hiding techniques.
Views: 66 Magdy Saeb
C# encrypting and decrypting using AES CBC, safe storing the encrypted data
 
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In this tutorial i'm going to show you how to encrypt, decrypt data using AES(Advanced Encryption Standard), and storing the encrypted data in safe place. Source code: https://drive.google.com/file/d/0BxW01l6w6JYfd1pTZVBjaWxhWEU/view?usp=sharing
Views: 55641 Dawisko1
Introduction to Bitcoin with Yours Bitcoin, Lecture 3: Elliptic Curves
 
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A course on how bitcoin works and how to program bitcoin stuff with the javascript bitcoin library Yours Bitcoin. Taught by Ryan X. Charles, Cofounder & CEO of Yours, and former cryptocurrency engineer of reddit. The third lecture covers elliptic curves and in particular secp256k1, the curve used by bitcoin. This curve is used for public keys and ECDSA, the digital signature algorithm of bitcoin. https://github.com/yoursnetwork/yours-bitcoin https://github.com/yoursnetwork/yours-bitcoin-examples https://www.yours.network https://www.ryanxcharles.com/ https://twitter.com/ryanxcharles
Views: 741 Yours
2017 gpg4libre - OpenPGP signing & encryption in LibreOffice
 
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https://media.ccc.de/v/froscon2017-1996-gpg4libre_-_openpgp_signing_encryption_in_libreoffice Transparently and securely use your existing keys to sign and encrypt ODF documents, using public key cryptography Come to hear how we implemented transparent gpg/openpgp support for LibreOffice ODF document signing and encryption. Thorsten Behrens
فك تشفير اكواد الجافا سكربت بسهولة وكسر حمايات حقوق التصميم و غيرها Decrypt Java script بالتفصيل
 
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فك تشفير اكواد java بسهولة وكسر حمايات حقوق التصميم و غيرها Decrypt Java script بالتفصيل الممل كل الروابط و المتطلبات تجدونها هنا : http://www.wejdane.com/2016/05/how-to-decrypt-java-script.html صفحتنا على الفيسبوك : https://www.facebook.com/wejdane.blogger حسابنا على تويتر : https://goo.gl/Gq0FNv ملاحظة : لكل من لديه مشكل ف فك التشفير او يريد مساعدة في فك تشفير كود جافا يتصل بي و انشاء لن اتاخر في المساعدة ----------------------------------------------------------------------------------------------------------- كلمات دلالية : فك تشفير java فك تشفير اكواد الجافا في القوالب decrypt javascript code decrypt javascript decrypt javascript online decrypt java decrypt javascript code online decrypt java class file decrypt javascript file decrypt java code decrypt javascript eval decrypt java class file online decrypt java keystore password decrypt java class decrypt java password online decrypt java password decrypt java online decrypt java bytecode decrypt base64 java java decrypt blowfish java decrypt by public key java encryption blowfish example java decrypt byte array decrypt java code online decryption java code java decrypt caesar cipher java decrypt caesar decrypt ciphertext java encryption java code java decrypt des java decrypt desede encryption java database encryption java des java encryption data java encryption des example java encryption des3 encrypt decrypt des java encrypt decrypt data java decrypt des java example decrypt java example java decrypt encrypt java decrypt encrypt string java decrypt encrypt password encryption java example encryption java example aes encrypt decrypt java example md5 decrypt java example decrypt rsa java example java encryption example code decrypt java file encryption java file java encryption framework java encryption function java encryption file example encryption for java java encryption for password java encryption files encrypt decrypt java gui java encryption generate key java decrypt gpg file java decrypt given final block not properly padded java decrypt gpg java decrypt gnupg java encryption given final block not properly padded java encryption guide java gpg decrypt example decrypt java hash decrypt java hashcode java encryption hash java decrypt md5 hash string java decrypt hmac java decrypt hmac-sha1 java decrypt hmac sha256 java decrypt https java decrypt https request decrypt hmac sha1 java decrypt in java encryption in java encryption in java example encryption in java tutorial encryption in java code encryption in java using public key encryption in java using aes encryption in java pdf encryption in java program encryption in java using rsa java decrypt ltpa token java decrypt ldap password java decrypt large file java encryption library java encryption library open source java encryption library example java encryption library download decrypt java md5 java decrypt md5 example java decrypt md5 password decrypt method java java decrypt_sa java decrypt openssl decryption java program decrypt password java code java decrypt using rsa decrypt java.security.invalidkeyexception parameters missing decrypt sha1 java java decrypt string decrypt sha1 java code java decrypt sha1 password encryption java source code encryption java sample encrypt decrypt java string java encryption string decrypt text java encryption java tutorial java encryption types java encryption triple des example java encryption tutorial aes java encryption text java encryption triple des java encryption text file encrypt decrypt text java java decrypt triple des java decrypt using public key encryption using java java encryption using public key java encryption using aes encryption using java code encryption url java java encryption using rsa java encryption using triple des java decrypt vigenere java decrypt with private key java decrypt with public key java decrypt with rsa private key encryption with java java encryption with key java encryption with public key java encryption with aes java encryption with private key encryption with java example java encryption with password decrypt xor java java decrypt xml encryption xor java encryption xml java java decrypt x509 certificate java decrypt with x 509 java encryption xtea java xor decrypt file java decrypt xor encryption java decrypt zip java decrypt zip file java encryption zip java encryption zip file java decrypt aes 128 java encryption 1024 java encryption 1.7 java decrypt aes 128 cbc how to decrypt sha1 in java java encryption 256 bit java encryption 256 java decrypt aes 256 java decrypt aes 256 cbc java decrypt rijndael 256 java decrypt sha256 java decrypt mcrypt_rijndael_256 decrypt 3des java java encryption 3des java encryption 3des example java 3des decrypt example how to decrypt sha512 in java decrypt pkcs#7 java encryption java 8
Blockchain 101 - A Visual Demo
 
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This is a very basic visual introduction to the concepts behind a blockchain. We introduce the idea of an immutable ledger using an interactive web demo. Part 2 is here: https://youtu.be/xIDL_akeras If you are interested in playing with this on your own, it is available online at: http://anders.com/blockchain/ The code that runs this demo is also on GitHub: https://github.com/anders94/blockchain-demo I'm @anders94 on Twitter and @andersbrownworth on Steemit. Donations: BTC: 1K3NvcuZzVTueHW1qhkG2Cm3viRkh2EXJp ETH: 0x84a90e21d9d02e30ddcea56d618aa75ba90331ff ETC: 0xab75ad757c89fa33b92090193a797e6700769ef8
Views: 893505 Anders Brownworth
Simple Custom Encryption / Decryption  of Files using Python
 
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This video explains how to Encrypt / Decrypt Files with a key using Python. A very simple process to encrypt the files. Very basic implementation . In video a Image is encrypted but it can be applied for any file format. The key value can range from 0 to 255 Resources XOR operator https://en.wikipedia.org/wiki/XOR_gate Enumerate Python https://docs.python.org/2/library/functions.html#enumerate
Views: 1633 akbweb
Encrypting and decrypting files with openssl
 
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Type "openssl -h" or "openssl --help" to look all.
Views: 1294 True False
RustConf 2017 - Fast, Safe, Pure-Rust Elliptic Curve Cryptography
 
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Fast, Safe, Pure-Rust Elliptic Curve Cryptography by Isis Lovecruft & Henry De Valence This talk discusses the design and implementation of curve25519-dalek, a pure-Rust implementation of operations on the elliptic curve known as Curve25519. We will discuss the goals of the library and give a brief overview of the implementation strategy. We will also discuss features of the Rust language that allow us to achieve competitive performance without sacrificing safety or readability, and future features that could allow us to achieve more safety and more performance. Finally, we will discuss how -dalek makes it easy to implement complex cryptographic primitives, such as zero-knowledge proofs.
Views: 532 Confreaks
How To Create An Ethereum Account
 
05:34
How To Create An Ethereum Account http://www.Blockgeeks.com Today, we'll be learning about Ethereum accounts and the math behind creating one. To interact with Ethereum in any meaningful way, you need to have a user account. The simplest way to create an account on Ethereum is by using the Mist e-theorem wallet, which is an application that allows you to manage and interact with multiple Ethereum accounts. Launching the application will sync to the black chain, meaning it download the entire block chain data to your computer, which can take upwards of 100 gigabytes, so be warned. when you first launch the application, it will walk you through creating an account and setting a password for it. It's very important that you never forget this password to maintain access to the account, there is no forgot your password option. Your new account then shows up in the wallet section of the app and it has a balance of zero. Clicking on the account will give us more details about it and provide some options for putting some real ether into it. The main thing to note is the public address, which you will share with other people. Another way to create an account is via the command line. If you download the Go Ethereum Client of GETH, can simply invoke GETH account new to create an account. This will prompt you to enter a password which again you should never forget and at the end it prints out the public address of your new account. You can create as many accounts as you like and you can view them all by typing GETH Account List. Note that this also shows the account we created in Ethereum Wallet. Another interesting thing to note is that we don't even have to be connected to the block chain or even the internet to create an account. It can happen entirely offline. How is this possible? We know what we need to generate a cryptographic key pair which consists of a public and private key. But don't we have to register this key pair somewhere? What if someone else is already using this key pair? Even though it's technically possible, it is highly, highly, improbable. Let's talk about why. There are three steps involved in generating an Ethereum public address. The first step is to generate a private key which is just a random number represented by 256 bits. The second step is to use elliptic curve cryptography to generate a 512 bit public key. Each private key maps to exactly one public key. The third and final step is to calculate the Keccak256 has of the public key and then keep the right most 160 bits of the Keccak256 hash to get the public address. This is essentially a mapping of 256 bit private keys to 160 bit public addresses. Meaning each account has more than one private key. Security is achieved in the randomness of selecting the private key. As long as you get something sufficiently random and not like one or two, it's highly unlikely that someone else would also generate the same private key. To give you a sense of how many possible private keys there are let's take a look at some numbers. There are 10,000 possible four digit iPhone passcodes. So if someone were to try to break into your phone by guessing each passcode, it would be pretty hard because they would have a one 1 in 10,000 chance of getting it right. But it would be fairly easy for a computer to try 10,000 passcodes pretty quickly. Apple also claims a 1 in 50,000 chance of a fingerprint ID matching a strangers and a 1 in a million chance of a face ID matching making your phone more secure. At a few orders of magnitude larger to we have seven and a half billion humans on the planet and we estimate that the big bang took place some 14 billion years ago. Larger still we estimate around 400 billion different stars just in our own galaxy. Many, many orders of magnitude larger still, we estimate that there are around seven times 10 to the power of 27 atoms in the average adult male weighing 150 pounds. Many orders larger still we estimate that are 1.3 times 10 to the power of 50 atoms in the earth. And even larger still, we come to the total number of possible private keys using 256 bits, one times 10 to the power of 77. This number is so big that if we took all the numbers we just talked about before and added them all up, they still wouldn't even be half of this number. It's unbelievably big. So the chances of someone randomly generating the same private key is sufficiently that it's practically impossible. Staging a brute force attack by trying each possible private key would also require an unachievable amount of computational power, like a planet sized computer working since the beginning of time. To learn more about Ethereum accounts and using wallets, check out our online guides and courses at Blockgeeks.com. Thank for watching and see you next time.
Views: 47563 Blockgeeks
How to do Encryption And Decryption in JQuery | www.jqueryexamplecode.blogspot.com
 
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http://jqueryexamplecode.blogspot.in/2014/04/how-to-do-encryption-and-decryption.html Most of the times, we have give encrypt and decrypt our security in the browser operation. In this JQuery example i am going to explain how to do encrypt and decrypt our security data and how to disable and enable button using JQuery. Here we using third party plug-in for doing encryption and decryption operations using JQuery.
Views: 3914 JQuery Example Code
14. SSL and HTTPS
 
01:18:18
MIT 6.858 Computer Systems Security, Fall 2014 View the complete course: http://ocw.mit.edu/6-858F14 Instructor: Nickolai Zeldovich In this lecture, Professor Zeldovich discusses how to cryptographically protect network communications, as well as how to integrate cryptographic protection of network traffic into the web security model. License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu
Views: 60044 MIT OpenCourseWare
Stanford Encryption Pioneer Who Risked Career Wins Medal
 
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Stanford Professor Martin Hellman helped make it possible for companies and ordinary people to encrypt their Internet communications, and he has a story to tell about it. Stanford University: http://www.stanford.edu/ Stanford News: http://news.stanford.edu/ Stanford University Channel on YouTube: http://www.youtube.com/stanford
Views: 1157 Stanford