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Can We Trust Cryptographic Software? Cryptographic Flaws in GNU Privacy Guard V1.2.3
Can We Trust Cryptographic Software? Cryptographic Flaws in GNU Privacy Guard v1.2.3 Phong Q. Nguyen CNRS/Ecole´ normale sup´erieure D´epartement d’informatique 45 rue d’Ulm, 75230 Paris Cedex 05, France. [email protected] http://www.di.ens.fr/˜pnguyen Abstract. More and more software use cryptography. But how can one know if what is implemented is good cryptography? For proprietary soft- ware, one cannot say much unless one proceeds to reverse-engineering, and history tends to show that bad cryptography is much more frequent than good cryptography there. Open source software thus sounds like a good solution, but the fact that a source code can be read does not imply that it is actually read, especially by cryptography experts. In this paper, we illustrate this point by examining the case of a basic In- ternet application of cryptography: secure email. We analyze parts of thesourcecodeofthelatestversionofGNUPrivacyGuard(GnuPGor GPG), a free open source alternative to the famous PGP software, com- pliant with the OpenPGP standard, and included in most GNU/Linux distributions such as Debian, MandrakeSoft, Red Hat and SuSE. We ob- serve several cryptographic flaws in GPG v1.2.3. The most serious flaw has been present in GPG for almost four years: we show that as soon as one (GPG-generated) ElGamal signature of an arbitrary message is released, one can recover the signer’s private key in less than a second on a PC. As a consequence, ElGamal signatures and the so-called ElGamal sign+encrypt keys have recently been removed from GPG. -
A History of End-To-End Encryption and the Death of PGP
25/05/2020 A history of end-to-end encryption and the death of PGP Hey! I'm David, a security engineer at the Blockchain team of Facebook (https://facebook.com/), previously a security consultant for the Cryptography Services of NCC Group (https://www.nccgroup.com). I'm also the author of the Real World Cryptography book (https://www.manning.com/books/real-world- cryptography?a_aid=Realworldcrypto&a_bid=ad500e09). This is my blog about cryptography and security and other related topics that I Ûnd interesting. A history of end-to-end encryption and If you don't know where to start, you might want to check these popular the death of PGP articles: posted January 2020 - How did length extension attacks made it 1981 - RFC 788 - Simple Mail Transfer Protocol into SHA-2? (/article/417/how-did-length- extension-attacks-made-it-into-sha-2/) (https://tools.ietf.org/html/rfc788) (SMTP) is published, - Speed and Cryptography the standard for email is born. (/article/468/speed-and-cryptography/) - What is the BLS signature scheme? (/article/472/what-is-the-bls-signature- This is were everything starts, we now have an open peer-to-peer scheme/) protocol that everyone on the internet can use to communicate. - Zero'ing memory, compiler optimizations and memset_s (/article/419/zeroing-memory- compiler-optimizations-and-memset_s/) 1991 - The 9 Lives of Bleichenbacher's CAT: New Cache ATtacks on TLS Implementations The US government introduces the 1991 Senate Bill 266, (/article/461/the-9-lives-of-bleichenbachers- which attempts to allow "the Government to obtain the cat-new-cache-attacks-on-tls- plain text contents of voice, data, and other implementations/) - How to Backdoor Di¸e-Hellman: quick communications when appropriately authorized by law" explanation (/article/360/how-to-backdoor- from "providers of electronic communications services di¸e-hellman-quick-explanation/) and manufacturers of electronic communications - Tamarin Prover Introduction (/article/404/tamarin-prover-introduction/) service equipment". -
CS 255: Intro to Cryptography 1 Introduction 2 End-To-End
Programming Assignment 2 Winter 2021 CS 255: Intro to Cryptography Prof. Dan Boneh Due Monday, March 1st, 11:59pm 1 Introduction In this assignment, you are tasked with implementing a secure and efficient end-to-end encrypted chat client using the Double Ratchet Algorithm, a popular session setup protocol that powers real- world chat systems such as Signal and WhatsApp. As an additional challenge, assume you live in a country with government surveillance. Thereby, all messages sent are required to include the session key encrypted with a fixed public key issued by the government. In your implementation, you will make use of various cryptographic primitives we have discussed in class—notably, key exchange, public key encryption, digital signatures, and authenticated encryption. Because it is ill-advised to implement your own primitives in cryptography, you should use an established library: in this case, the Stanford Javascript Crypto Library (SJCL). We will provide starter code that contains a basic template, which you will be able to fill in to satisfy the functionality and security properties described below. 2 End-to-end Encrypted Chat Client 2.1 Implementation Details Your chat client will use the Double Ratchet Algorithm to provide end-to-end encrypted commu- nications with other clients. To evaluate your messaging client, we will check that two or more instances of your implementation it can communicate with each other properly. We feel that it is best to understand the Double Ratchet Algorithm straight from the source, so we ask that you read Sections 1, 2, and 3 of Signal’s published specification here: https://signal. -
The Autonomous Surfer
Renée Ridgway The Autonomous Surfer CAIS Report Fellowship Mai bis Oktober 2018 GEFÖRDERT DURCH RIDGWAY The Autonomous Surfer Research Questions The Autonomous Surfer endeavoured to discover the unknown unknowns of alternative search through the following research questions: What are the alternatives to Google search? What are their hidden revenue models, even if they do not collect user data? How do they deliver divergent (and qualitative) results or knowledge? What are the criteria that determine ranking and relevance? How do p2p search engines such as YaCy work? Does it deliver alternative results compared to other search engines? Is there still a movement for a larger, public index? Can there be serendipitous search, which is the ability to come across books, articles, images, information, objects, and so forth, by chance? Aims and Projected Results My PhD research investigates Google search – its early development, its technological innovation, its business model of the past 20 years and how it works now. Furthermore, I have experimented with Tor (The Onion Router) in order to find out if I could be anonymous online, and if so, would I receive diver- gent results from Google with the same keywords. For my fellowship at CAIS I decided to first research search engines that were incorporated into the Tor browser as default (Startpage, Disconnect) or are the default browser now (DuckDuckGo). I then researched search engines in my original CAIS proposal that I had come across in my PhD but hadn’t had the time to research; some are from the Society of the Query Reader (2014) and others I found en route or on colleagues’ suggestions. -
Copyrighted Material
Stichwortverzeichnis A B Abstreitbarkeit 167 Bequemlichkeit 30 Adblocker 96 Bitcoin 110 – Adblock Plus 96 Blackberry 215 – Disconnect 96 Bookmarks siehe Favoriten – Ghostery 96 Browser 68, 75 – Privacy Badger 96 – Add-on 87, 90 – uBlock 97 – Apple Safari 77 Add-on – Cache 88 – Browser 87, 90 – Chromium 78 – E-Mail-Client 126 – Chronik 87 – Enigmail siehe Enigmail – Fingerprinting 85, 98 – GpgOL 137 – Google Chrome 77 – Mailvelope 130, 132 – HTML-Engine 80 – Thunderbird 139 – Hygiene 88 Adium 170 – Iceweasel 78 Advanced Programming Interface (API) 90, – Inkognito-Modus 86 182 – integrierte Suche 84 Android – Internet Explorer 77 – Android Privacy Guard (App) 156 – Konqueror 78 – K9 Mail (E-Mail-Client) 156 – Microsoft Edge 92 – OpenKeychain (App) 156 – Midori 78 – PGP 156 – Mosaic 68 – R2Mail2 (E-Mail-Client) 158 – Mozilla Firefox 68, 76 – S/MIME 156 – Netscape Navigator 68 Anonymität 206 COPYRIGHTED– Opera 77MATERIAL AOL Instant Messenger (AIM) 164 – Plug-in 87 Apple Mail – Prole (Identitäten) 87 – PGP 145 – Synchronisation von Einstellungen – S/MIME 155 86 Authentizierung 167, 169, 176, 179 – Web (Epiphany) 78 – Adium 172 Buffer Overow 82 – Multifaktor- 201 Bugs 82 – Pidgin 169 Bundesamt für Sicherheit in der Informations- Authentizität 29, 54, 56 technik (BSI) 215 233 Stichwortverzeichnis C – E-Mail-Adresse 119 Caesar-Chiffre 36 – Header 121 Certicate Authority siehe Zertizierungsstelle – Provider 129, 131, 139 Chain of Trust siehe Web of Trust – Server 122 Chaos Computer Club (CCC) 133 Eingangsverschüsselung 125 Chat 161 Electronic -
About Garlic and Onions a Little Journey…
About Garlic and Onions A little journey… Tobias Mayer, Technical Solutions Architect BRKSEC-2011 Cisco Webex Teams Questions? Use Cisco Webex Teams to chat with the speaker after the session How 1 Find this session in the Cisco Events Mobile App 2 Click “Join the Discussion” 3 Install Webex Teams or go directly to the team space 4 Enter messages/questions in the team space BRKSEC-2011 © 2020 Cisco and/or its affiliates. All rights reserved. Cisco Public 3 About Garlic and Onions We are all looking for privacy on the internet, for one or the other reason. This Session is about some technologies you can use to anonymise your network traffic, such as Tor (The Onion Router). The first part will give an introduction and explain the underlaying technology of Tor. We will take look at how you can not only use the Tor browser for access but also how the Tor network is working. We will learn how you can establish a Tor session and how we can find hidden websites and give examples of some websites...So we will enter the Darknet together. Beside Tor, we will also take a quick look at other techniques like I2P (Garlic Routing). In the last section we will make a quick sanity check what security technologies we can use to (maybe) detect such traffic in the network. This presentation is aimed at everyone who likes to learn about anonymization techniques and have a little bit of fun in the Darknet. BRKSEC-2011 © 2020 Cisco and/or its affiliates. All rights reserved. -
Gnu Privacy Guard (Gnupg) Mini Howto (Italiano)
Gnu Privacy Guard (GnuPG) Mini Howto (italiano) Brenno J.S.A.A.F. de Winter (inglese) <[email protected]>, Michael Fischer v. Mollard (tedesco) <[email protected]>, Arjen Baart (olandese) <[email protected]>, Cristian Riga- monti (italiano) <[email protected]> Versione 0.1.4 12 maggio 2003 Questo documento spiega come usare GNU Privacy Guard (GnuPG), un sistema di crittografia Open Source e compatibile con OpenPGP. Per mantenere il programma totalmente libero, si `eevitato l’uso di RSA e di altri algoritmi brevettati. Il documento originale `escritto in tedesco da Michael Fischer v. Mollard, questa traduzione italiana, a cura di Cristian Rigamonti, `ebasata sulla traduzione inglese del testo originale. Indice 1 Concetti 2 1.1 Crittografia a chiave pubblica .................................... 2 1.2 Firme digitali ............................................. 2 1.3 Rete di fiducia ............................................ 3 1.4 Limiti alla sicurezza ......................................... 3 2 Installazione 3 2.1 Sorgenti di GnuPG .......................................... 3 2.2 Configurazione ............................................ 4 2.3 Compilazione ............................................. 4 2.4 Installazione .............................................. 5 3 Uso delle chiavi 5 3.1 Creare una chiave ........................................... 5 3.2 Esportare le chiavi .......................................... 6 3.3 Importare le chiavi .......................................... 6 3.4 Revocare una chiave ........................................ -
Crypto Projects That Might Not Suck
Crypto Projects that Might not Suck Steve Weis PrivateCore ! http://bit.ly/CryptoMightNotSuck #CryptoMightNotSuck Today’s Talk ! • Goal was to learn about new projects and who is working on them. ! • Projects marked with ☢ are experimental or are relatively new. ! • Tried to cite project owners or main contributors; sorry for omissions. ! Methodology • Unscientific survey of projects from Twitter and mailing lists ! • Excluded closed source projects & crypto currencies ! • Stats: • 1300 pageviews on submission form • 110 total nominations • 89 unique nominations • 32 mentioned today The People’s Choice • Open Whisper Systems: https://whispersystems.org/ • Moxie Marlinspike (@moxie) & open source community • Acquired by Twitter 2011 ! • TextSecure: Encrypt your texts and chat messages for Android • OTP-like forward security & Axolotl key racheting by @trevp__ • https://github.com/whispersystems/textsecure/ • RedPhone: Secure calling app for Android • ZRTP for key agreement, SRTP for call encryption • https://github.com/whispersystems/redphone/ Honorable Mention • ☢ Networking and Crypto Library (NaCl): http://nacl.cr.yp.to/ • Easy to use, high speed XSalsa20, Poly1305, Curve25519, etc • No dynamic memory allocation or data-dependent branches • DJ Bernstein (@hashbreaker), Tanja Lange (@hyperelliptic), Peter Schwabe (@cryptojedi) ! • ☢ libsodium: https://github.com/jedisct1/libsodium • Portable, cross-compatible NaCL • OpenDNS & Frank Denis (@jedisct1) The Old Standbys • Gnu Privacy Guard (GPG): https://www.gnupg.org/ • OpenSSH: http://www.openssh.com/ -
The Double Ratchet Algorithm
The Double Ratchet Algorithm Trevor Perrin (editor) Moxie Marlinspike Revision 1, 2016-11-20 Contents 1. Introduction 3 2. Overview 3 2.1. KDF chains . 3 2.2. Symmetric-key ratchet . 5 2.3. Diffie-Hellman ratchet . 6 2.4. Double Ratchet . 13 2.6. Out-of-order messages . 17 3. Double Ratchet 18 3.1. External functions . 18 3.2. State variables . 19 3.3. Initialization . 19 3.4. Encrypting messages . 20 3.5. Decrypting messages . 20 4. Double Ratchet with header encryption 22 4.1. Overview . 22 4.2. External functions . 26 4.3. State variables . 26 4.4. Initialization . 26 4.5. Encrypting messages . 27 4.6. Decrypting messages . 28 5. Implementation considerations 29 5.1. Integration with X3DH . 29 5.2. Recommended cryptographic algorithms . 30 6. Security considerations 31 6.1. Secure deletion . 31 6.2. Recovery from compromise . 31 6.3. Cryptanalysis and ratchet public keys . 31 1 6.4. Deletion of skipped message keys . 32 6.5. Deferring new ratchet key generation . 32 6.6. Truncating authentication tags . 32 6.7. Implementation fingerprinting . 32 7. IPR 33 8. Acknowledgements 33 9. References 33 2 1. Introduction The Double Ratchet algorithm is used by two parties to exchange encrypted messages based on a shared secret key. Typically the parties will use some key agreement protocol (such as X3DH [1]) to agree on the shared secret key. Following this, the parties will use the Double Ratchet to send and receive encrypted messages. The parties derive new keys for every Double Ratchet message so that earlier keys cannot be calculated from later ones. -
Security Analysis of the Signal Protocol Student: Bc
ASSIGNMENT OF MASTER’S THESIS Title: Security Analysis of the Signal Protocol Student: Bc. Jan Rubín Supervisor: Ing. Josef Kokeš Study Programme: Informatics Study Branch: Computer Security Department: Department of Computer Systems Validity: Until the end of summer semester 2018/19 Instructions 1) Research the current instant messaging protocols, describe their properties, with a particular focus on security. 2) Describe the Signal protocol in detail, its usage, structure, and functionality. 3) Select parts of the protocol with a potential for security vulnerabilities. 4) Analyze these parts, particularly the adherence of their code to their documentation. 5) Discuss your findings. Formulate recommendations for the users. References Will be provided by the supervisor. prof. Ing. Róbert Lórencz, CSc. doc. RNDr. Ing. Marcel Jiřina, Ph.D. Head of Department Dean Prague January 27, 2018 Czech Technical University in Prague Faculty of Information Technology Department of Computer Systems Master’s thesis Security Analysis of the Signal Protocol Bc. Jan Rub´ın Supervisor: Ing. Josef Kokeˇs 1st May 2018 Acknowledgements First and foremost, I would like to express my sincere gratitude to my thesis supervisor, Ing. Josef Kokeˇs,for his guidance, engagement, extensive know- ledge, and willingness to meet at our countless consultations. I would also like to thank my brother, Tom´aˇsRub´ın,for proofreading my thesis. I cannot express enough gratitude towards my parents, Lenka and Jaroslav Rub´ınovi, who supported me both morally and financially through my whole studies. Last but not least, this thesis would not be possible without Anna who re- lentlessly supported me when I needed it most. Declaration I hereby declare that the presented thesis is my own work and that I have cited all sources of information in accordance with the Guideline for adhering to ethical principles when elaborating an academic final thesis. -
BRKSEC-2011.Pdf
#CLUS About Garlic and Onions A little journey… Tobias Mayer, Technical Solutions Architect BRKSEC-2011 #CLUS Me… CCIE Security #14390, CISSP & Motorboat driving license… Working in Content Security & TLS Security tmayer{at}cisco.com Writing stuff at “blogs.cisco.com” #CLUS BRKSEC-2011 © 2018 Cisco and/or its affiliates. All rights reserved. Cisco Public 3 Agenda • Why anonymization? • Using Tor (Onion Routing) • How Tor works • Introduction to Onion Routing • Obfuscation within Tor • Domain Fronting • Detect Tor • I2P – Invisible Internet Project • Introduction to Garlic Routing • Conclusion #CLUS BRKSEC-2011 © 2018 Cisco and/or its affiliates. All rights reserved. Cisco Public 4 Cisco Webex Teams Questions? Use Cisco Webex Teams (formerly Cisco Spark) to chat with the speaker after the session How 1 Find this session in the Cisco Events App 2 Click “Join the Discussion” 3 Install Webex Teams or go directly to the team space 4 Enter messages/questions in the team space Webex Teams will be moderated cs.co/ciscolivebot#BRKSEC-2011 by the speaker until June 18, 2018. #CLUS © 2018 Cisco and/or its affiliates. All rights reserved. Cisco Public 5 Different Intentions Hide me from Government! Hide me from ISP! Hide me from tracking! Bypass Corporate Bypass Country Access Hidden policies restrictions (Videos…) Services #CLUS BRKSEC-2011 © 2018 Cisco and/or its affiliates. All rights reserved. Cisco Public 6 Browser Identity Tracking does not require a “Name” Tracking is done by examining parameters your browser reveals https://panopticlick.eff.org #CLUS BRKSEC-2011 © 2018 Cisco and/or its affiliates. All rights reserved. Cisco Public 7 Proxies EPIC Browser #CLUS BRKSEC-2011 © 2018 Cisco and/or its affiliates. -
Authentication and Key Management Automation In
Authentication and Key Management Automation in Decentralized Secure Email and Messaging via Low-Entropy Secrets Itzel Vazquez Sandoval∗, Arash Atashpendar∗†, Gabriele Lenzini∗ ∗SnT, University of Luxembourg †itrust consulting, Luxembourg Email: {itzel.vazquezsandoval,gabriele.lenzini}@uni.lu, [email protected] Abstract—We revisit the problem of entity authentication in management, affecting email more acutely, is intertwined with decentralized end-to-end encrypted email and secure messaging authentication and the need for automating it has been known to propose a practical and self-sustaining cryptographic solution for a long time, e.g., see (Ruoti et al., 2018). based on password-authenticated key exchange (PAKE). This not only allows users to authenticate each other via shared low- Over the years, several methods have been established to entropy secrets, e.g., memorable words, without a public key tackle authentication, and indirectly key management: man- infrastructure or a trusted third party, but it also paves the ual validation, web of trust, public key infrastructure (PKI) way for automation and a series of cryptographic enhancements; and hierarchical validation, public key directories as well as improves security by minimizing the impact of human error and server-derived public keys such as identity-based encryption potentially improves usability. First, we study a few vulnera- bilities in voice-based out-of-band authentication, in particular (IBE). The set of viable candidates becomes much smaller a combinatorial attack against lazy users, which we analyze in once we consider a decentralized setting, i.e., without a PKI the context of a secure email solution. Next, we propose solving or a trusted third party (TTP).