Comparing Implementations of Secure Messaging Protocols (Long Version) Christian Johansen , Aulon Mujaj , Hamed Arshad , Josef Noll Research Report 475, November 2017
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Course 5 Lesson 2
This material is based on work supported by the National Science Foundation under Grant No. 0802551 Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author (s) and do not necessarily reflect the views of the National Science Foundation C5L3S1 With the advent of the Internet, social networking, and open communication, a vast amount of information is readily available on the Internet for anyone to access. Despite this trend, computer users need to ensure private or personal communications remain confidential and are viewed only by the intended party. Private information such as a social security numbers, school transcripts, medical histories, tax records, banking, and legal documents should be secure when transmitted online or stored locally. One way to keep data confidential is to encrypt it. Militaries,U the governments, industries, and any organization having a desire to maintain privacy have used encryption techniques to secure information. Encryption helps to boost confidence in the security of online commerce and is necessary for secure transactions. In this lesson, you will review encryption and examine several tools used to encrypt data. You will also learn to encrypt and decrypt data. Anyone who desires to administer computer networks and work with private data must have some familiarity with basic encryption protocols and techniques. C5L3S2 You should know what will be expected of you when you complete this lesson. These expectations are presented as objectives. Objectives are short statements of expectations that tell you what you must be able to do, perform, learn, or adjust after reviewing the lesson. -
Chapter 12 Pretty Good Privacy (PGP)
Chapter 12 Pretty Good Privacy (PGP) With the explosively growing reliance on electronic mail for every conceivable pur- pose, there grows a demand for authentication and confidentiality services. Two schemes stand out as approaches that enjoy widespread use: Pretty Good Privacy (PGP) and Secure/Multipurpose Internet Mail Extension (S/MIME). The latter is a security en- hancement to the MIME Internet e-mail format standard, based on technology from RSA Data Security. Although both PGP and S/MIME are on an IETF standards track, it appears likely that S/MIME will emerge as the industry standard for commercial and organisational use, while PGP will remain the choice for personal e-mail security for many users. In this course we will only be looking at PGP. S/MIME is discussed in detail in the recommended text. 12.1 Background PGP is a remarkable phenomenon. Largely the effort of a single person, Phil Zimmer- mann, PGP provides a confidentiality and authentication service that can be used for electronic mail and file storage applications. In essence what Zimmermann has done is the following: 1. Selected the best cryptographic mechanisms (algorithms) as building blocks. 2. Integrated these algorithms into a general purpose application that is independent of operating system and processor and that is based on a small set of easy to use commands. 3. Made the package and its source code freely available via the Internet, bulletin boards, and commercial networks such as America On Line (AOL). 4. Entered into an agreement with a company (Viacrypt, now Network Associates) to provide a fully compatible low cost commercial version of PGP. -
An Advance Visual Model for Animating Behavior of Cryptographic Protocols
An Advance Visual Model for Animating Behavior of Cryptographic Protocols Mabroka Ali Mayouf Maeref1*, Fatma Alghali2, Khadija Abied2 1 Sebha University, Faculty of Science, Department of Computer Science, P. O. Box 18758 Sebha, Libya, Libyan. 2 Sebha University of Libya, Sebha, Libya. * Corresponding author. Tel.: 00218-925132935; email: [email protected] Manuscript submitted February 13, 2015; accepted July 5, 2015. doi: 10.17706/jcp.10.5.336-346 Abstract: Visual form description benefits from the ability of visualization to provide precise and clear description of object behavior especially if the visual form is extracted from the real world. It provides clear definition of object and the behavior of that object. Although the current descriptions of cryptographic protocol components and operations use a different visual representation, the cryptographic protocols behaviors are not actually reflected. This characteristic is required and included within our proposed visual model. The model uses visual form and scenario-based approach for describing cryptographic protocol behavior and thus increasing the ability to describe more complicated protocol in a simple and easy way. Key words: Animation, cryptographic protocols, interactive tool, visualization. 1. Introduction Cryptographic protocols (CPs) mostly combine both theory and practice [1], [2]. These cause protocol complexity describing and understanding. Therefore, separating the mathematical part from the protocol behavior should provide feeling of how the protocol works, thus increasing the ability to describe and to gain confidence in reflecting more complicated information about CPs, as well as to generate interest to know about other more complex protocol concepts. Several researchers realized the use of visual model and animation techniques to reflect the explanation of the learning objectives and their benefits [3]-[11]. -
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. -
Schluss Mit Facebook: Fünf Whatsapp-Alternativen Im Überblick
https://futurezone.at/apps/schluss-mit-facebook-fuenf-whatsapp-alternativen-im-ueberblick/400529764 Apps 23.06.2019 Schluss mit Facebook: Fünf WhatsApp-Alternativen im Überblick Es gibt viele Gründe, WhatsApp abzulehen. Die richtige Messaging-Alternative zu finden, ist aber alles andere als leicht. Es gibt kaum eine App, die im Leben so vieler Menschen eine Rolle spielt wie Whatsapp. 2009 von Jan Koum und Brian Acton gegründet, entwickelte sich der Dienst rasant zu einer Konkurrenz für SMS und andere Messenger, die auf veraltete Protokolle setzten. Zu Beginn war die Anwendung nicht mehr als eine Art schwarzes Brett für Statusmeldungen. Nutzer konnten ihre Gedanken posten, Freunde hatten die Möglichkeit, diese Meldungen zu lesen. Mit der Zeit verwandelten die Entwickler ihre Erfindung in einen Kurznachrichtendienst. Die Vorteile von Whatsapp damals lagen auf der Hand: plattformübergreifende Kommunikation mit dem Smartphone und das auch noch kostenlos. Eine einfache Registrierung und der ebenfalls mögliche Austausch von Fotos und Videos taten das Übrige dazu. Seitdem ist viel Zeit vergangen und in der Welt von WhatsApp hat sich einiges getan. Nach der Übernahme durch Facebook für 19 Milliarden US-Dollar entstanden bei so manchem Nutzer Sorgenfalten. Der Umgang mit Nutzerdaten durch das soziale Netzwerk wurde schon damals kritisch beäugt. Befürchtungen, dass WhatsApp ein ähnliches Schicksal droht, waren alles andere als unbegründet. Zusicherungen, dass sich nichts verändert und die beiden Erfinder das Ruder in der Hand behalten würden, sollten besorgte Nutzer beruhigen. Auch die Implementierung von End-to-End-Verschlüsselung brachte etwas Ruhe. Mittlerweile sind die Gründer aus Unzufriedenheit nicht mehr bei Facebook am Werk, der Zuckerberg-Konzern hat mit der Verschmelzung seiner Plattformen begonnen und bald soll auch Werbung in der App erscheinen. -
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. -
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/ -
A Matter of Security, Privacy and Trust
A matter of security, privacy and trust: A study of the principles and values of encryption in New Zealand Michael Dizon Ryan Ko Wayne Rumbles Patricia Gonzalez Philip McHugh Anthony Meehan Acknowledgements This study was funded by grants from the New Zealand Law Foundation and the University of Waikato. We would like to express our gratitude to our project collaborators and members of the Advisory Board – Prof Bert-Jaap Koops (Tilburg University), Prof Lyria Bennett Moses (UNSW Sydney), Prof Alana Maurushat (Western Sydney University), and Associate Professor Alex Sims (University of Auckland) – for their support as well as feedback on specific parts of this report. We would also like to thank Patricia Gonzalez, Joseph Graddy, Philip McHugh, Anthony Meehan, Jean Murray and Peter Upson for their valuable research assistance and other contributions to this study. Michael Dizon, Ryan Ko and Wayne Rumbles Principal investigators December 2019 Executive summary Cybersecurity is crucial for ensuring the safety and well-being of the general public, businesses, government, and the country as a whole. New Zealand has a reasonably comprehensive and well-grounded legal regime and strategy for dealing with cybersecurity matters. However, there is one area that deserves further attention and discussion – encryption. Encryption is at the heart of and underpins many of the technologies and technical processes used for computer and network security, but current laws and policies do not expressly cover this significant technology. The principal objective of this study is to identify the principles and values of encryption in New Zealand with a view to informing future developments of encryption- related laws and policies. -
Encryption and Anonymity Follow-Up Report
PALAIS DES NATIONS • 1211 GENEVA 10, SWITZERLAND www.ohchr.org • TEL: +41 22 917 9000 • FAX: +41 22 917 9008 • E-MAIL: [email protected] Mandate of the Special Rapporteur on the promotion and protection of the right to freedom of opinion and expression Research Paper 1/2018 June 2018 Encryption and Anonymity follow-up report Contents I. INTRODUCTION ............................................................................................................................... 2 II. TRENDS IN STATE RESTRICTIONS ON ENCRYPTION AND ANONYMITY .............................. 3 A. An Overview of State Obligations ........................................................................................................... 3 B. State practice: examples and concerns ..................................................................................................... 4 (i) Bans on Use and Dissemination of Encryption Tools ......................................................................... 5 (ii) Licensing and Registration Requirements .......................................................................................... 5 (iii) Intentional Weakening of Encryption ................................................................................................ 5 (iv) Government Hacking ......................................................................................................................... 7 (v) Mandatory Data Localization and Key Escrows ................................................................................. 8 (vi) -
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. -
Communication and Security Survey Results from US, UK and German Business Leaders
The most secure collaboration platform. Communication and Security Survey results from US, UK and German business leaders Communication and Security Survey | wire.com | February 2019 1 An introduction Every year we ask executives about key topics - this year we chose to focus on communication, security, privacy, and regulation as these have been hot topics in 2018. We asked more than 300 executives from US and Europe about their views on these topics. In addition, please find at the end of this presentation my personal predictions for 2019. We trust you will enjoy the report. Morten Brøgger · CEO Best regards, Morten Brøgger Chief Executive Officer at Wire Communication and Security Survey | wire.com | February 2019 2 Are we still secure? Many organizations have been a …. want their organization to be more proactive victim of a cyberattack and not a 81% in the ways it protects its sensitive information, single respondent disagreed that communication, and/or data. cybersecurity is a major challenge for businesses. Yet while the challenges posed by cybersecurity are understood …. believe security and compliance are key by businesses, some organizations 79% parameters when selecting cloud business aren’t doing enough to prepare. In crisis solutions. situations, in particular, businesses have gaps in their ability to communicate internally and externally in a safe and secure way. …. of organizations don’t have or are unsure if they 38% have, a plan in case of a security breach. …. of respondents said it would be useful to be 83% able to extend a company's secure communication infrastructure to business partners and customers Communication and Security Survey | wire.com | February 2019 3 Emails are popular, Email remains a popular communication to changes in instant messaging but are they tool yet business leaders spend too technology, an overwhelming number much of their time using it. -
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.