technology:public key

  • Cryptographic essence of #bitcoin: Part 2 — How do public/private keys work?,

    Cryptographic essence of Bitcoin: Part 2 — How do public/private keys work?, Elliptical #cryptography & Proof of workLet’s find out how to create a Bitcoin AddressElliptic Curves CryptographyElliptic curve cryptography (ECC) is an approach to public-key cryptography (watch video) based on the algebraic structure of elliptic curves over finite fields.The elliptic curve below is an example of an elliptic curve, similar to that used by bitcoin.Example of an EllipticCurveThe elliptic curve technique is used to create the public key derived from the private key.How does it work:Starting with a private key in the form of a randomly generated number k, we multiply it by a predetermined point on the curve called the generator point G to produce another point somewhere else on the curve, which is the (...)

    #finance #cryptocurrency #blockchain

  • Public Key #cryptography Simply Explained

    Photo by Liam Macleod on UnsplashPublic key cryptography seems magical to everyone, even those who understand it. In this post, I’m going to explain public key cryptography. Public Key Cryptography is based on asymmetric cryptography, so first let us talk about symmetric cryptography. CryptographyYour front door is usually locked by a key. This key unlocks & locks your front door. With symmetric cryptography, you have one key which you use to unlock and lock things.Only people with the key or a copy of the key can unlock the door. Now, imagine you’re on holiday in Bali. You want to invite your friend around to look after your cat ? while you’re on the beautiful beaches ?️.Before the holiday, you give your friend the (...)

    #hacking #security #programming #computer-science

  • CounterMail - protecting your privacy - encrypted pgp email webmail

    CounterMail is a secure and easy to use online email service, designed to provide maximum security and privacy without any unnecessary complexity.

    You can access your email account at any time, from anywhere in the world. Your account will always be encrypted and anonymous.

    An Interview with Simon Persson - Founder of Secure Email Provider CounterMail - Unfinished ManUnfinished Man

    We are under Swedish jurisdiction and swedish laws, Sweden still have better privacy laws than many other countries
    We don’t log IP-addresses
    You can pay anonymously if you follow our instructions, or simply just use Bitcoin
    Incoming email will be encrypted to your public key, which means no emails will be stored as plaintext on our server, only in encrypted format
    Web based OpenPGP encryption with no possibility to disable the end-to-end encryption, passwords and decrypted texts is never sent to our server
    We have an USB-key option, which gives you two factor authentication, and increased protection
    Our webmail server do not have any hard drives, only CD-ROM, which means no “leakage” to any hard drive is possible
    Our customers never have any direct connection to our mailserver, regardless how they connect to their account, IMAP/SMTP/webmail always connects to a diskless server (tunnel)
    You can delete the private key from our server (but we recommend this only for advanced users, your private key is always encrypted on our server anyway)
    We have an additional encryption layer to protect against man-in-the-middle attacks

    If anyone can find any other established provider that have all our privacy and security features, we will give that person $10k as a reward!

    #sécurité #vie_privée #email

  • Generating #rsa Private and Public Keys

    We use SSH, HTTPS, etc., on a daily basis. These programs depend on RSA asymmetric key encryption and decryption for providing #security.Asymmetric key encryption involves two keys, public key and private key. Public key is used for encrypting the message and Private key is used for decrypting the message.In this post, we will look into how a public key and private key pair are generated using simple mathematics.We will use small numbers for simplicity.Public Key ( e, n )Public key is made up of two numbers called e and n.Generation of nGenerate two prime numbers.Prime number 1, p = 7Prime number 2, q = 17n = p x qn = 7 x 17 = 119Thus n = 119Generation of eCompute totient of n, ϕ(n) = ( p -1) x (q -1)Choose a random prime number that has a greatest common divisor (gcd) of 1 with ϕ(n)ϕ(n) = ( 7 — 1 (...)

    #public-key-cryptography #cryptography #public-key

  • Why Signal and not Threema ? : signal

    Signal is open source, Threema is not, so that disqualifies Threema as a secure app in my opinion. You could as well continue using WhatsApp since it’s also end to end encrypted but closed source. Wire is another great alternative, and it’s German.

    Hacker erklären, welche Messenger-App am sichersten ist - Motherboard

    C’est en allemand, mais c’est valable sans égard de la langue que vous utilisez pour votre communication.
    – La communication sécurisée en ligne doit obligatoirement passer par une app et un prootocole open source.
    – Il vous faut un système qui exclue ou rend très difficile la collection de métatdonnées par des tiers.
    – Votre système de communication « voice » et « chat » doit fonctionner avec des clients smartphome et desktop si vous voulez entretenir un fil de commmunication indépendamment du type d’appareil à votre disposition.

    Passons sur les exigences plus poussées, je ne vois que Signal qui satisfait tous ces besoins. Après on peut toujours utiliser plusieurs « messenger apps » afin de rester au courant des « updates » de tout le monde - à l’exception des apps de Facebook (Whatsapp), Wechat et Google parce que leur utilistion constitue une menace de votre vie privée simplement par l’installation sur votre portable.

    Roland Schilling (33) und Frieder Steinmetz (28) haben vor sechs Jahren begonnen, an der TU Hamburg unter anderem zu dieser Frage zu forschen. In einer Zeit, als noch niemand den Namen Edward Snowden auch nur gehört hatte, brüteten Schilling und Steinmetz bereits über die Vor- und Nachteile verschiedener Verschlüsselungsprotokolle und Messenger-Apps. So haben sie beispielsweise im vergangenen Jahr geschafft, die Verschlüsselung von Threema per Reverse Engineering nachzuvollziehen.

    Ihre Forschung ist mittlerweile zu einer Art Aktivismus und Hobby geworden, sagen die beiden: Sie wollen Menschen außerhalb von Fachkreisen vermitteln, wie elementar die Privatsphäre in einer Demokratie ist. Im Interview erklären sie, auf was man bei der Wahl des Messengers achten soll, welche App in punkto Sicherheit nicht unbedingt hält, was sie verspricht und warum Kreditinstitute sich über datenhungrige Messenger freuen.
    Roland Schilling: Bei mir ist es anders. Ich bringe die Leute einfach dazu, die Apps zu benutzen, die ich auch nutze. Das sind ausschließlich Threema, Signal und Wire. Wenn Leute mit mir reden wollen, dann klappt das eigentlich immer auf einer von den Dreien.
    Frieder: ... Signal und WhatsApp etwa setzen auf die gleiche technische Grundlage, das Signal-Protokoll, unterscheiden sich aber in Nuancen. Threema hat ein eigenes, nicht ganz schlechtes Protokoll, das aber beispielsweise keine ‘Perfect Forward Secrecy’ garantiert. Die Technik verhindert, dass jemand mir in der Zukunft meinen geheimen Schlüssel vom Handy klaut und damit meine gesamte verschlüsselte Kommunikation entschlüsseln kann, die ich über das Handy geführt habe. Signal und WhatsApp haben das.
    Roland: Ein gutes Messenger-Protokoll ist Open Source und ermöglicht damit Forschern und der Öffentlichkeit, eventuell bestehende Schwachstellen zu entdecken und das Protokoll zu verbessern. Leider gibt es auf dem Messenger-Markt auch viele Angebote, die ihre vorgebliche „Verschlüsselung“ diesem Prozess entziehen und geheim halten, oder das Protokoll zwar veröffentlichen, aber auf Kritik nicht eingehen.

    Secure WhatsApp Alternatives – Messenger Comparison

    Threema and Telegram under Control of Russia’s Government ?

    WhatsApp Exploited by NSA and US Secret Services?
    Go to the profile of Vadim An
    Vadim An
    Mar 7, 2018
    This is the end of era centralized communication!

    The 2017/2018 years are hot and saturated with cybersecurity challenges. Almost every week, a major media source reported hacking incidents or backdoor exploits in popular communication and messaging services. Some of which granted government agents unauthorized access to private and confidential information from within the communications industry.

    According to mass-media reports, one of the most popular Swiss secure messaging apps Threema moved under the control of the Russian government and has been listed in the official registry with a view to controlling user communications.

    This can be seen on regulatory public website

    This knockout news was commented by Crypviser — innovative German developer of the most secure instant communication platform based on Blockchain technologies, of the point of view, what does it mean for millions of Threema users?

    To answer this question, let’s understand the requirements for getting listed in this registry as an “information-dissemination organizers” according to a new Russian federal law, beginning from 01 June 2018.

    The law requires that all companies listed in internet regulator’s registry must store all users’ metadata (“information about the arrival, transmission, delivery, and processing of voice data, written text, images, sounds, or other kinds of action”), along with content of correspondence, voice call records and make it accessible to the Russian authorities. Websites can avoid the hassle of setting aside this information by granting Russian officials unfettered, constant access to their entire data stream.

    This is very bad news for Threema users. Threema officials have reported that they are not aware of any requirements to store, collect, or provide information. Maybe not yet though since there is still some time until 01 June 2018 when the new law kicks in and Threema will be obligated to provide direct access to sensitive user’s data.

    It’s possible that Threema is fully aware of this despite claiming otherwise. They may realize that the most popular messenger in Russia, Telegram, has been under pressure since refusing to officially cooperate with Russian secret services. If Russia takes steps to block Telegram as a result, then Threema would become the next best alternative service. That is assuming they’re willing to violating the security and privacy rights of its users by giving in to the new law’s requirements.

    Based on the reports of Financial Time magazine, the Telegram founder agreed to register their app with Russian censors by the end of June 2017. This, however; is not a big loss for Telegram community because of the lack of security in Telegram to date. During the last 2 years, its security protocol has been criticized many times and many security issues were found by researchers. Although there is no direct evidence showing that Telegram has already cooperated with the Russian government or other governments, these exploitable bugs and poor security models make Telegram users vulnerable victims to hackers and secret services of different countries.

    The same security benchmark issues have been explored in the biggest communication app WhatsApp. The security model of WhatsApp has been recognized as vulnerable by the most reputed cryptographic experts and researchers worldwide. According to the Guardian, a serious “backdoor” was found in encryption. More specifically, the key exchange algorithm.

    A common security practice in encrypted messaging services involves the generation and store of a private encryption key offline on the user’s device. And only the public key gets broadcasted to other users through the company’s server. In the case of WhatsApp, we have to trust the company that it will not alter public key exchange mechanism between the sender and receiver to perform man-in-the-middle attack for snooping of users encrypted private communication.

    Tobias Boelter, security researcher from the University of California, has reported that WhatsApp’s end-to-end encryption, based on Signal protocol, has been implemented in a way that if WhatsApp or any hacker intercepts your chats, by exploiting trust-based key exchange mechanism, you will never come to know if any change in encryption key has occurred in the background.

    The Guardian reports, “WhatsApp has implemented a backdoor into the Signal protocol, giving itself the ability to force the generation of new encryption keys for offline users and to make the sender re-encrypt messages with new keys and send them again for any messages that have not been marked as delivered. The recipient is not made aware of this change in encryption.”

    But on the other hand, the developer of Signal messaging app Open Whisper Systems says, ”There is no WhatsApp backdoor”, “it is how cryptography works,” and the MITM attack “is endemic to public key cryptography, not just WhatsApp.”

    It’s worth noting that none of the security experts or the company itself have denied the fact that, if required by the government, WhatsApp can intercept your chats. They do say; however, WhatsApp is designed to be simple, and users should not lose access to messages sent to them when their encryption key is changed. With this statement, agrees on a cybersecurity expert and CTO of Crypviser, Vadim Andryan.

    “The Man-in-the-Middle attack threat is the biggest and historical challenge of asymmetric cryptography, which is the base of end-to-end encryption model. It’s hard to say, is this “backdoor” admitted intentionally or its became on front due lack of reliable public — key authentication model. But it definitely one of the huge disadvantages of current cryptographic models used for secure instant communication networks, and one of the main advantage of Crypviser platform.”

    Crypviser has introduced a new era of cryptography based on Blockchain technologies. It utilizes Blockchain to eliminate all threats of Man-in-the-Middle attack and solves the historical public key encryption issue by using decentralized encryption keys, exchanges, and authorization algorithms. The authentication model of Crypviser provides public key distribution and authorization in peer-to-peer or automated mode through Blockchain.

    After commercial launch of Crypviser unified app, ”messenger” for secure social communication will be available on the market in free and premium plans. The free plan in peer-to-peer authentication mode requires user interaction to check security codes for every new chat and call. The full-featured premium plan offers Blockchain based automated encryption model and powerful professional security features on all levels.

    You can see the comperisation table of Crypviser with centralized alternatives in the below table

    #internet #communication #sécurité #vie_privée

  • The Crypto Anarchist Manifesto
    Précurseur de la très romatique Declaration of the Independence of Cyberspace et du Manifeste du web indépendant plus raisonnable et pragmatique le manifeste des anars cryptograhiques sera encore d’actualité en 2019.

    From: (Timothy C. May)
    Subject: The Crypto Anarchist Manifesto
    Date: Sun, 22 Nov 92 12:11:24 PST

    Cypherpunks of the World,

    Several of you at the “physical Cypherpunks” gathering yesterday in Silicon Valley requested that more of the material passed out in meetings be available electronically to the entire readership of the Cypherpunks list, spooks, eavesdroppers, and all. <Gulp>

    Here’s the “Crypto Anarchist Manifesto” I read at the September 1992 founding meeting. It dates back to mid-1988 and was distributed to some like-minded techno-anarchists at the “Crypto ’88” conference and then again at the “Hackers Conference” that year. I later gave talks at Hackers on this in 1989 and 1990.

    There are a few things I’d change, but for historical reasons I’ll just leave it as is. Some of the terms may be unfamiliar to you...I hope the Crypto Glossary I just distributed will help.

    (This should explain all those cryptic terms in my .signature!)

    –-Tim May


    The Crypto Anarchist Manifesto
    Timothy C. May <>

    A specter is haunting the modern world, the specter of crypto anarchy.

    Computer technology is on the verge of providing the ability for individuals and groups to communicate and interact with each other in a totally anonymous manner. Two persons may exchange messages, conduct business, and negotiate electronic contracts without ever knowing the True Name, or legal identity, of the other. Interactions over networks will be untraceable, via extensive re- routing of encrypted packets and tamper-proof boxes which implement cryptographic protocols with nearly perfect assurance against any tampering. Reputations will be of central importance, far more important in dealings than even the credit ratings of today. These developments will alter completely the nature of government regulation, the ability to tax and control economic interactions, the ability to keep information secret, and will even alter the nature of trust and reputation.

    The technology for this revolution—and it surely will be both a social and economic revolution—has existed in theory for the past decade. The methods are based upon public-key encryption, zero-knowledge interactive proof systems, and various software protocols for interaction, authentication, and verification. The focus has until now been on academic conferences in Europe and the U.S., conferences monitored closely by the National Security Agency. But only recently have computer networks and personal computers attained sufficient speed to make the ideas practically realizable. And the next ten years will bring enough additional speed to make the ideas economically feasible and essentially unstoppable. High-speed networks, ISDN, tamper-proof boxes, smart cards, satellites, Ku-band transmitters, multi-MIPS personal computers, and encryption chips now under development will be some of the enabling technologies.

    The State will of course try to slow or halt the spread of this technology, citing national security concerns, use of the technology by drug dealers and tax evaders, and fears of societal disintegration. Many of these concerns will be valid; crypto anarchy will allow national secrets to be trade freely and will allow illicit and stolen materials to be traded. An anonymous computerized market will even make possible abhorrent markets for assassinations and extortion. Various criminal and foreign elements will be active users of CryptoNet. But this will not halt the spread of crypto anarchy.

    Just as the technology of printing altered and reduced the power of medieval guilds and the social power structure, so too will cryptologic methods fundamentally alter the nature of corporations and of government interference in economic transactions. Combined with emerging information markets, crypto anarchy will create a liquid market for any and all material which can be put into words and pictures. And just as a seemingly minor invention like barbed wire made possible the fencing-off of vast ranches and farms, thus altering forever the concepts of land and property rights in the frontier West, so too will the seemingly minor discovery out of an arcane branch of mathematics come to be the wire clippers which dismantle the barbed wire around intellectual property.

    Arise, you have nothing to lose but your barbed wire fences!

    Timothy C. May | Crypto Anarchy: encryption, digital money, | anonymous networks, digital pseudonyms, zero
    408-688-5409 | knowledge, reputations, information markets,
    W.A.S.T.E.: Aptos, CA | black markets, collapse of governments.
    Higher Power: 2^756839 | PGP Public Key: by arrangement.

    #internet #cryptographie

  • A 101 Noob Intro to Understanding Smart Contracts on #hyperledger Fabric

    How do I get started with dapp (decentralized app) development on Hyperledger Fabric Platform?This is the question I get every time I do a talk about Hyperledger Fabric. So this post will serve as my official answer to those that have asked in the past, and those that will ask in the future ⏳. I will outline my favorite material that has helped me get a good grasp on Hyperledger Fabric, and #blockchain in general. I will first start with general blockchain concepts as implemented by Bitcoin and then move towards more specific Hyperledger reading materials. Having a solid understanding of how Bitcoin works, and the public key cryptography that Bitcoin uses to transact securely without double-spending is essential to understanding how Hypereledger works.Blockchain 101☕️+ ?= understanding (...)

    #ethereum #smart-contracts #dapps

  • Today we’re launching Address Verification, full PGP support, and a public key server! Now ProtonMail is even more convenient to use and secure against attacks. Learn more: …

    Today we’re launching Address Verification, full PGP support, and a public key server! Now ProtonMail is even more convenient to use and secure against attacks. Learn more: …

  • How to Create Your #identity Effortlessly on a #blockchain

    This paid story is brought to you by SafebitYou can create a social identity for yourself by creating a profile on a social networking site like Facebook. You can use that identity to seamlessly signup on Medium. You don’t have to re-enter first name, last name, etc. Medium integrates Facebook APIs and transfers your information with your consent.But, what about creating your identity on the blockchain?Creating an identity on a blockchain is not easy. Consider a #bitcoin wallet, you need to generate a private key and a public key. But, look at this public key, does it speak for you?897c59e1c04dab8748f7f9a2e2c7fd96d16bf700d389ba4153dba3d1bebdccf9You need an identity that communicates your personality or individuality.@BlockchainCoderNow compare this identity with the public key. (...)

    #blockchain-identity #identity-on-blockchain

  • Trust model of #bitcoin — part I

    Bitcoin is a decentralized form of digital currency based on a system of trust underpinned by cryptographic puzzles such as various properties of Elliptic curves. Without delving too much into the mathematical aspect of it, let’s see how the Bitcoin trust system is built. To properly grasp the key ideas in this post, profound knowledge of #cryptography is not needed. But, it is expected that you have the basic understanding of a private and public key.“Where do I sign?”Each time you want to authorize a payment, you’re asked for some sort of verification. The purpose of the verification is that once you’ve authorized a deal under your name, it is irreversible. Of course, there are cases where you might want to add a clause that the payment has to go in the other direction if certain conditions (...)

    #trust-model-of-bitcoin #transactions #protocol


    JUST A FEW years ago, sending encrypted messages was a challenge. Just to get started, you had to spend hours following along with jargon-filled tutorials, or be lucky enough to find a nerd friend to teach you. The few that survived this process quickly hit a second barrier: They could only encrypt with others who had already jumped through the same hoops. So even after someone finally set up encrypted email, they couldn’t use it with most of the people they wanted to send encrypted emails to.

    The situation is much better today. A number of popular apps have come along that make encryption as easy as texting. Among the most secure is Signal, open-source software for iOS and Android that has caught on among activists, journalists, and others who do sensitive work. And probably the most popular is WhatsApp, a Facebook-owned platform with encryption setup derived from Signal. For me, the spread of encrypted chat apps means that, with very few exceptions, all of my text messages — with friends, family, or for work — are end-to-end encrypted, and no one even has to understand what a “public key” is.

    But there is a major issue with both Signal and WhatsApp: Your account is tied to your phone number.

  • Blockchain can help prevent DDoS attacks

    Several products such as #Blockstack, #Nebulis and #Maidsafe are facilitating the decentralisation of the Domain Name System (DNS).
    This would make it much more difficult to launch attacks such as the one suffered by Dyn DNS.

    “By using the Bitcoin blockchain to bind the name to a public key and DNS information, Blockstack allows anyone to register a name while simultaneously ensuring that only the name’s owner can control it."
    “If the Dyn attackers wanted to knock websites offline in Blockstack, they would have to attack either the individual sites or attack the Bitcoin network itself. Even then, all the Dyn attackers could do is slow down name updates,”

    Another project similar to the Blockstack vision is a platform called Nebulis, which uses Ethereal under the hood. [...] The difference is, this platform uses IPFS as a replacement for HTTP and utilizes the Ethereum blockchain for DNS capabilities.

    Maidsafe focuses on removing centralised servers and creates an encrypted distributed framework across a peer-to-peer network.

    #decentralisation #decentralised

  • Upgrade your SSH keys for you own security. Bye bye DSA, welcome Ed25519

    Whether you’re a software developer or a sysadmin, I bet you’re using SSH keys. Pushing your commits to Github or managing your Unix systems, it’s best practice to do this over SSH with public key authentication rather than passwords. However, as time flies, many of you are using older keys and not aware of the need to generate fresh ones to protect your privates much better. In this post I’ll demonstrate how to transition to an Ed25519 key smoothly, why you would want this and show some tips and tricks on the way there.

    Tl;dr: Generate your new key with ssh-keygen -o -a 100 -t ed25519, specify a strong passphrase and read further if you need a smooth transition.

    I’m planning to publish some more posts on SSH tips & tricks, so keep an eye on my blog for more. This post will focus (...)

  • GCHQ already had developed an “insecure by design” end-to-end phone encryption protocol (as opposed to link encryption) that contains a backdoor: MIKEY-SAKKE, as discovered by University College London researcher Steven J. Murdoch

    He describes this in a quite interesting (and lengthy) article on his appropriately called blog:

    access to private keys would be provided by companies operating communication networks, and so may be more vulnerable to hacking, intimidation of employees or insider abuse, as well as allowing less oversight.


    The design of MIKEY-SAKKE is motivated by the desire to allow undetectable and unauditable mass surveillance, which may be a requirement in exceptional scenarios such as within government departments processing classified information.


    MIKEY-SAKKE is the latest example to raise questions over the policy of many governments, including the UK, to put intelligence agencies in charge of protecting companies and individuals from spying, given the conflict of interest it creates.

    RFC 6509 : MIKEY-SAKKE: Sakai-Kasahara Key Encryption in Multimedia Internet KEYing (MIKEY)

    This document describes the Multimedia Internet KEYing-Sakai-Kasahara Key Encryption (MIKEY-SAKKE), a method of key exchange that uses Identity-based Public Key Cryptography (IDPKC) to establish a shared secret value and certificateless signatures to provide source authentication. MIKEY-SAKKE has a number of desirable features, including simplex transmission, scalability, low-latency call setup, and support for secure deferred delivery.

    #privacy #surveillance
    #backdoor #key-escrow

  • There’s No DRM in JPEG—Let’s Keep It That Way | Electronic Frontier Foundation

    We encourage the JPEG committee to continue work on an open standards based Public Key Infrastructure (PKI) architecture for JPEG images that could meet some of the legitimate use cases for improved privacy and security, in an open, backwards-compatible way. However, we warn against any attempt to use the file format itself to enforce the privacy or security restrictions that its metadata describes, by locking up the image or limiting the operations that can be performed on it.

    #jpeg #copyright_madness #images_diffusion #DRM

  • Torrent clients and BitTorrent Sync can be leveraged for DrDoS attacks

    In this paper, we demonstrate that the BitTorrent protocol family is vulnerable to distributed reflective denial-of-service (DRDoS) attacks. Specifically, we show that an attacker can exploit BitTorrent protocols (Micro Transport Protocol (uTP), Distributed Hash Table (DHT), Message Stream Encryption (MSE))and BitTorrent Sync (BTSync) to reflect and amplify traffic from peers.

    We validate the efficiency, robustness and evadability of the exposed BitTorrent vulnerabilities in a P2P lab testbed. We further substantiate the lab results by crawling more than 2.1 million IP addresses over Mainline DHT (MLDHT) and analyzing more than 10,000 BitTorrent handshakes. Our experiments reveal that an attacker is able to exploit BitTorrent peers to amplify the traffic up to a factor of 50 times and in case of BTSync up to 120 times.

    Additionally, we observe that the most popular BitTorrent clients are the most vulnerable ones. (uTorrent, Mainline Vuze)


    We showed that anattack is quite difficult to circumvent, as the found vulnerabilities can only be defended with a DPI firewall. In case of a MSE handshake, it is even harder to detect the attack, since the packet contains a high entropy payload with a public key and random data.

    The paper:

    BitTorrent Inc has been notified about the vulnerabilities and patched some in a recent beta release. For now, however, uTorrent is still vulnerable to a DHT attack. Vuze was contacted as well but has yet to release an update according to the researcher.

    Arstechnica also wrote about it:

    En Français :

    #DDoS #DrDoS

  • Think Lavabit overreacted ? Think again: there is now proof that FBI extorts root certificates from companies. Cryptography is only as good as the PKI’s physical security and its political environment.

    For those that don’t remember, Lavabit was Edward Snowden’s email provider, and they shut down their fucking business rather than cooperating with a court order they claimed “would make them complicit in crimes against the American people.” They were bound by a gag order and threatened with jail if they violated it.

    Today they won a victory in court and were able to get the secret court order unsealed, and holy shit is it a doozy: the ACLU’s Chris Soghoian called it “the nuclear option.” The court order revealed the US government demanded Lavabit turn over their root SSL certificate, something that allows them to monitor the traffic of every user of the service. Security researchers have argued for years over whether the government would be so heavy-handed as to try this, but there has never been any proof that they actually do, as no one has ever challenged such an order in court.

    If a government can force a company to turn over the SSL keys, it breaks the trust model for the entire internet. Everything from google to facebook to skype to your bank is only encrypted by SSL keys, and if the FBI can force Lavabit to hand over their SSL key, they can bet your ass they did the same thing to Google. People don’t understand how big this is from an internet trust model. This story changes everything. No US company that relies on SSL encryption can be trusted with sensitive data, which is what lavabit asserted in their “farewell address” and people thought was an overreaction."

  • Trsst: a distributed secure blog platform for the open web

    Looks and feels like Twitter but built for the open web: encrypted and anonymized and decentralized; and only you hold the keys.

    From a technical perspective:

    • Each user’s client generates a keystore with a keypair for each account. Each account maps to a blog. The account’s public key is the unique identifier.
    • The account keypair is also a bitcoin address, making each trsst client effectively a bitcoin wallet, whether the user realizes it or utilizes it or not.
    • A user posts entries to an account either publicly or privately. Public posts are signed with your private key; private posts are encrypted with the recipient’s public key.
    • Each post contains the message digest of the previous post so you can verify that no posts are modified or missing. We call this the blogchain.
    • You publish your posts by pushing them to one or more servers that are participating in the syndication network. Servers serve up portions of your blogchain as an RSS feed.
    • Following means subscribing to an account’s RSS feed using their public key as an identifier. This is how you see private messages meant for you.
    • Any server in the syndication network can serve the feed to you, fetching it from cache or from other servers in order to route around network congestion or firewalls and blacklists.

    The obvious risk is that this ends up as vaporware.


    cc @stephane

  • Schleuder - Mails et mailing-lists chiffrées

    Schleuder is a gpg-enabled mailinglist with remailer-capabilities. It is designed to serve as a tool for group communication: subscribers can communicate encrypted (and pseudonymously) among themselves, receive emails from non-subscribers and send emails to non-subscribers via the list. Schleuder takes care of all de- and encryption, stripping of headers, formatting conversions, etc. Further schleuder can send out its own public key upon request and receive administrative commands by email.

    #gpg #mail #outils