Cybersecurity – Page 3

PSD2 Is In Trouble: Will It Survive?

This blog post has been coauthored with Karen Lewison

The 2nd Payment Services Directive (PSD2) of the European Union went into effect on September 14, but one of its most prominent provisions, the Strong Customer Authentication (SCA) requirement, was postponed until December 31, 2020 by an opinion dated 16 October 2019 of the European Banking Authority (EBA). The EBA cited pushback from the National Competent Authorities (NCAs) of the EU member countries as the reason for the postponement, and the fact that version 2 of the 3-D Secure protocol (3-D Secure 2) is not ready as a reason for the pushback.

PSD2 is supposed to be technology neutral, but the EBA has unequivocally endorsed 3-D Secure as the way to implement the SCA requirement for online credit card transactions, as stated in another opinion, dated 21 June 2019:

Will Cardholder Authentication Ever Come to the US?

This blog post has been coauthored with Karen Lewison

You may have heard that the EU is struggling to implement the Strong Customer Authentication (SCA) requirements of Payment Services Directive 2 (PSD2). The directive was issued four years ago, Regulatory Technical Standards (RTS) followed two years later, and the SCA requirements went into effect on September 14. But on October 16 the European Banking Authority (EBA) had to postpone enforcement until December 31, 2020, due to pushback from the National Competent Authorities (NCAs) of the EU member countries. In an opinion announcing the postponement, the EBA cited as a reason for the pushback the fact that 3-D Secure 2 (3DS2) is not ready.

The problems that the EBA is having with the SCA requirements have more to do with the bureaucratic formulation of the requirements in PSD2, than with the technical difficulty of providing strong security. We will discuss this in another post, but first we want to ask here whether cardholder authentication will ever come to the US.

3-D Secure 2 May Allow the Merchant to Impersonate the Cardholder

3-D Secure is a protocol that provides security for online credit card payments by redirecting the cardholder's browser to the web site of the bank that has issued the credit card, where the cardholder is authenticated by methods such as username-and-password or a one-time password. 3-D Secure is rarely used in the US because the cardholder authentication creates friction that may cause transaction abandonment, but it is used more frequently in other countries. The credit card networks have been working on a new version of the protocol, called 3-S Secure 2, where the issuing bank assesses fraud risk based on information received from the merchant through a back channel and waives authentication for low-risk transactions.

In a paper presented at HCII 2019 we showed that 3-D Secure 2 has serious privacy and usability issues and we proposed an alternative protocol that provides strong security without friction for all transactions by cryptographically authenticating the cardholder. We have now looked in more detail at a particular configuration of 3-D Secure 2 where the cardholder uses a native app instead of a browser to access the merchant's site, and we have found security flaws, described in detail in a technical report, that may allow a malicious merchant to impersonate the cardholder.

Pomcor Contributes Biometrics Chapter to HCI and Cybersecurity Handbook

Karen Lewison and I have contributed the chapter on Biometrics to the book Human-Computer Interaction and Cybersecurity Handbook, published by Taylor & Francis in the CRC Press series on Human Factors and Ergonomics. The editor of the paper, Abbas Moallem, has received the SJSU 2018 Author and Artist Award for the book.

Biometrics is a very complex topic because there are many biometric modalities, and different modalities use different technologies that require different scientific backgrounds for in-depth understanding. The chapter focuses on biometric verfication and packs a lot of knowledge in only 20 pages, which it organizes by identifying general concepts, matching paradigms and security architectures before diving into the details of fingerprint, iris, face and speaker verification, briefly surveying other modalities, and discussing several methods of combining modalities in biometric fusion. It emphasizes presentation attacks and mitigation methods that can be used in what will always be an arms race between impersonators and verifiers, and discusses the security and privacy implications of biometric technologies.

Feedback or questions about the chapter would be very welcome as comments on this post.

New Conference to Address the Human Aspects of Cybersecurity and Cryptography

Human factors are an essential aspect of cybersecurity. Take for example credit card payments on the web. A protocol for reducing fraud by authenticating the cardholder, 3-D Secure, was introduced by VISA in 1999 and adopted by other payment networks, but has seen limited deployment because of poor usability. Now 3-D Secure 2.0 attempts to reduce friction by asking the merchant to share privacy-sensitive customer information with the bank and giving up on cardholder authentication for transactions deemed low-risk based on that data. A protocol with better usability would provide better security without impinging on cardholder privacy.

But human factors are not limited to the usability of cybersecurity defenses. In biometric authentication, human factors are the very essence of the defense. Human factors are also of the essence in cybersecurity attacks such as phishing and social engineering attacks, and play a role in enabling or spreading attacks that exploit technical vulnerabilities.

The 1st International Conference on HCI for Cybersecurity, Privacy and Trust (HCI-CPT) recognizes the multifaceted role played by human factors in cybersecurity, and intends to promote research that views Human-Computer Interaction (HCI) as “a fundamental pillar for designing more secure systems”. A call for participation can be found here.

Storing Cryptographic Keys in Persistent Browser Storage

Update (March 5, 2025): This post, and the presentation at ICMC 2017, show how to use a browser as a credential wallet for same-device presentation. Section 12.4 in Chapter 12 of a book I'm writing with Sukhi Chuhan and Veronica Wojnas shows how it can also be used for cross-device presentation, and how a WebView component of a native app can be combined with a native code component to further support proximity presentation over BlueTooth or NFC.

This blog post is a companion to a presentation made at the 2017 International Cryptographic Module Conference and refers to the presentation slides, revised after the conference. Karen Lewison is a co-author of the presentation and of this blog post.

Slide 2: Key storage in web clients

Most Web applications today use TLS, thus relying on cryptography to provide a secure channel between client and server, and to authenticate the server to the client by means of a cryptographic credential, consisting of a TLS server certificate and its associated private key. But other uses of cryptography by Web applications are still rare. Client authentication still relies primarily on traditional username-and-password, one-time passwords, proof of possession of a mobile phone, biometrics, or combinations of two or more of such authentication factors. Web payments still rely on a credit card number being considered a secret. Encrypted messaging is on the rise, but is not Web-based.

A major obstacle to broader use of cryptography by Web applications is the problem of where to store cryptographic keys on the client side. Continue reading "Storing Cryptographic Keys in Persistent Browser Storage"

What kind of “encrypted fingerprint template” is used by MasterCard?

In a press release, MasterCard announced yesterday an EMV payment card that features a fingerprint reader. The release said that two trials have been recently concluded in South Africa and, after additional trials, a full roll out is expected this year.

In the United States, EMV chip cards are used without a PIN. The fingerprint reader is no doubt intended to fill that security gap. But any use of biometrics raises privacy concerns. Perhaps to address such concerns, the press release stated that a fingerprint template stored in the card is “encrypted”.

That's puzzling. If the template is encrypted, what key is used to decrypt it before use?

Revocable Biometrics Discussion at the Internet Identity Workshop

One thing I like about the Internet Identity Workshop (IIW) is its unconference format, which allows for impromptu sessions. A discussion during one session can raise an issue that deserves its own session, and an impromptu session can be called the same day or the following day to discuss it. A good example of this happened at the last IIW (IIW XXII), which was held on April 26-28, 2016 at the Computer History Museum in Mountain View, California.

During the second day of the workshop, a participant in a session drew attention to one of the dangers of using biometrics for authentication, viz. the fact that biometrics are not revocable. This is true in the sense that you cannot change at will the biometric features of the human body, and it is a strong reason for using biometrics sparingly; but I pointed out that there is something called “revocable biometrics”. Continue reading "Revocable Biometrics Discussion at the Internet Identity Workshop"

NSA’s FAQs Demystify the Demise of Suite B, but Fail to Explain One Important Detail

Last July, the National Security Agency (NSA) issued CNSS Advisory Memorandum 02-15, available at the Advisory Memoranda page, updating the list of cryptographic algorithms that can be used in National Security Systems (NSS). A subsequent document referred to the new algorithms as the Commercial National Security Algorithm Suite (CNSA Suite), which replaces Suite B. The transition to the CNSA Suite took place two months before a Suite B deadline to discontinue the use of RSA, DH and DSA and rely exclusively on ECC algorithms for public key cryptosystems. The subsequent document explained the motivation for the transition by saying that "the growth of elliptic curve use has bumped up against the fact of continued progress in the research on quantum computing, which has made it clear that elliptic curve cryptography is not the long term solution many once hoped it would be," and announced "preliminary plans" for a future transition to quantum-resistant algorithms.

This abrupt change of course, following many years of promoting ECC, took the cryptographic community by surprise. Continue reading "NSA’s FAQs Demystify the Demise of Suite B, but Fail to Explain One Important Detail"

Cryptographic Module Standards at a Crossroads after Snowden’s Revelations

Last week I participated in the third International Cryptographic Module Conference (ICMC), organized by the Cryptographic Module User Forum (CMUF), and concerned with the validation of cryptographic modules against government and international standards. You may think of cryptographic module validation as a dry topic, but it was quite an exciting conference, full of technical and political controversy. The technical controversy resulted from the fact that the standards are out of sync with current technology and it is not at all clear how they can be fixed. The political controversy resulted from the fact that, after Snowden's revelations, it is not at all clear who should try to fix them. The organizers signalled that they were not afraid of controversy by inviting as keynote speakers both Phil Zimmerman, creator of PGP and co-founder of Silent Circle, and Marianne Bailey, Deputy CIO for Cybersecurity at the US Department of Defense, besides well known expert Paul Kocher of SSL fame. I enjoyed an exchange between Zimmerman and Bailey on the imbalance between defense and offense at the NSA and its impact on cybersecurity. Continue reading "Cryptographic Module Standards at a Crossroads after Snowden’s Revelations"