dblp: Nicolas Courtois

NYC Bitcoin Center - Monday July 21st: Satoshi Square Bitcoin Trading and Special Guests Richard Amores (BIP32 Multi-Sig Business Wallet) and Dr. Nicolas Courtois (Cryptography professor speaking about speed of txns on the blockchain) - Free Open Bar & Pizza!

NYC Bitcoin Center - Monday July 21st: Satoshi Square Bitcoin Trading and Special Guests Richard Amores (BIP32 Multi-Sig Business Wallet) and Dr. Nicolas Courtois (Cryptography professor speaking about speed of txns on the blockchain) - Free Open Bar & Pizza! submitted by ben_btc to Bitcoin [link] [comments]

Back from Bitcoin Expo 2015

Another interim update while I'm having lunch; back from Bitcoin Expo 2015, which was great, just wish I could have stayed longer (had to fly down and back within the weekend, made it home around 11pm on Sunday)! Quick highlights:
Overall, good experience, was great to be there, and I'd like to thank Cryptoevents for inviting myself and the other Dogecoiners along. They have an event in Amsterdam coming up in March, which I can't attend myself unfortunately (moving house), but it would be great if others can make it along to: http://signup.webtcexpo.com/
Edit: Oh, and I've finally beaten the Toshi patch to support Dogecoin until it got through the Travis checks. Not sure why the changes caused problems, but somehow address balances ended up as floating point values instead of integer, which... yeah, anyway, it's done now, hopefully Coinbase will merge that in as I'd like to start building tools on top of Toshi.
Edit 2: Clarify that /dogethereum is a parody.
submitted by rnicoll to dogecoindev [link] [comments]

July 2015 Flood Attack: Brain Wallet List

It is known that brain wallets were using during July 2015 Flood Attack : https://en.bitcoin.it/wiki/July_2015_flood_attack
Here we found and list 41 brain wallet addresses (uncompressed version) used in this attack.
An example : password = "power" bitcoin address = "1HDmTVYGdpZhsZgZ2aDjKUWvMb1WTRucb6"
https://blockchain.info/address/1HDmTVYGdpZhsZgZ2aDjKUWvMb1WTRucb6
The passwords used are the following: power tom the peter god car password1 password sex bob dog cat wallet Bitcoin Password1 frog free Money cookie sarah tree Rob freemoney cool1 Money2 Hamster Sean travel password2 master cow cows best donkey poker blockchain Bitcoins nitro food bestest coffee
Nicolas Courtois & Guangyan Song from UCL
submitted by gsonghashrate to Bitcoin [link] [comments]

July Flood Attack & Brain Wallets

It is known that brain wallets were used during July 2015 Flood Attack : https://en.bitcoin.it/wiki/July_2015_flood_attack
The idea was based on filling the blocks with lots of small transactions. This is because of limit of block size (1 mb).
Gavin Andersen posted a series of blogs aimed at increasing block size to a larger number (20 mb) in May 2015. http://gavinandresen.ninja/time-to-roll-out-bigger-blocks
Later in June, CoinWallet.eu, an UK based bitcoin exchange announced several stress tests. (22-23 June & 29-30 June) https://bitcointalk.org/index.php?topic=1094865.0 https://bitcointalk.org/index.php?topic=1098263.0 and they planned another one later in Sep, but cancelled https://bitcointalk.org/index.php?topic=1175321.0
Bitcoin wiki listed a few suspects for July Flood Attack (started from late night 30 June). We noticed CoinWallet.eu will normally announce their tests and give detailed updates. They never used brain wallets in their announced tests. It's more likely to be someone else did the attack in July.
Someone found out bitcointalk.org user "amaclin" was using his "1aa" addresses to create small spam attack in July 2015.
https://bitcointalk.org/index.php?topic=1175321.500
("amaclin" also posted another similar type of attack in https://bitcointalk.org/index.php?topic=1166928, which is also very interesting)
Here we found and list 41 brain wallet addresses (uncompressed version) used in this attack. More 1.5 million txs in total. Later we will give a more detailed version in pdf and put a link here.
An example : password = "power" bitcoin address = "1HDmTVYGdpZhsZgZ2aDjKUWvMb1WTRucb6"
https://blockchain.info/address/1HDmTVYGdpZhsZgZ2aDjKUWvMb1WTRucb6
The passwords used are the following: power tom the peter god car password1 password sex bob dog cat wallet Bitcoin Password1 frog free Money cookie sarah tree Rob freemoney cool1 Money2 Hamster Sean travel password2 master cow cows best donkey poker blockchain Bitcoins nitro food bestest coffee
Nicolas Courtois & Guangyan Song from UCL
submitted by gsonghashrate to btc [link] [comments]

Blockchain vision #3 - Nicolas Courtois Nicolas Courtois: How To Steal Bitcoins Part 3/4 Nicolas Courtois: How To Steal Bitcoins Part 1/6 What Bitcoin Private keys say to each other (Nicolas T. Courtois, October 2015) EB50 – BTC2B Conference: Nicolas Courtois & potential security vulnerabilities in Bitcoin ECDSA

5 ©Nicolas Courtois 2003-2014 Bitcoin Mining • Minting: creation of new currency. • Confirmation+re-confirmation of older transactions Ownership: – “policed by majority of miners”: – only the owner can transfer [a part of] 25 BTC produced. HASH must start with 64+ zeros data from previous transactions RNG miner’s public key. Wallets and Key Management 6 ©Nicolas Courtois 2003 ... 5 Nicolas T. Courtois 2009-2014 – a major innovation is that financial transactions CAN be executed and policed without trusted authorities. Bitcoin is a sort of financial cooperative or a distributed business. • based on self-interest: – a group of some 100 K people called bitcoin miners own the bitcoin “infrastructure” Security of Bitcoin 2 Dr. Nicolas T. Courtois 1. cryptologist and codebreaker 2. payment and smart cards (e.g. bank cards, Oyster cards etc…) Crypto Currencies Nicolas T. Courtois 2009-2014 3 My Blog and UCL Bitcoin Seminar blog.bettercrypto.com / SEMINAR or Google "UCL bitcoinseminar" 4 Bitcoin »Electronic money, secured with cryptography »Decentralised system based on p2p network ... In a research paper entitled “ Speed Optimizations in Bitcoin Key Recovery Attacks ” Nicolas Courtois, Guangyan Song, and Ryan Castellucci demonstrated that they could recover 18,000 Bitcoin wallet passwords using their technique. Hackers obviously exploited the vulnerability of brainwallets, draining 884 brain wallet accounts of 1,806 Bitcoins. Overview of Blockchain Security - Nicolas Courtois Blockchain Security as a Service - Komodo A Marriage of IoT with Blockchain for Improved Security ... NewsBTC is a news service that covers bitcoin news, technical analysis & forecasts for bitcoin and other altcoins. Here at NewsBTC, we are dedicated to enlightening people all around the world about bitcoin and other cryptocurrencies. We cover ...

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Blockchain vision #3 - Nicolas Courtois

http://bitcoinference.com/2015/How-To-Steal-Bitcoins.html http://bitcoinference.com/2015/How-To-Steal-Bitcoins.html Nicolas Courtois On Hash Rate 51 and Protection Against Double Spending In Bitcoin and Other Crypto This video is unavailable. Watch Queue Queue. Watch Queue Queue Bitcoin and Cryptocurrency Technologies Online Course 263,963 views 58:42 What Bitcoin Private keys say to each other (Nicolas T. Courtois, October 2015) - Duration: 1:18:29.

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