Author: Francisco Corella

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”

Faster Modular Exponentiation in JavaScript

Modular exponentiation is the algorithm whose performance determines the performance and practicality of many public key cryptosystems, including RSA, DH and DSA. We have recently achieved a manyfold improvement in the performance of modular exponentiation in JavaScript over the implementation of modular exponentiation in the Stanford JavaScript Crypto Library (SJCL). JavaScript was originally intended for performing simple tasks in web pages, but it has grown into a sophisticated general purpose programming language used for both client and server computing, which is arguably the most important programming language today. Good performance of public key cryptography is difficult to achieve in JavaScript, because JavaScript is an interpreted language inherently slower than a compiled language such as C, and provides floating point arithmetic but no integer arithmetic. But fast JavaScript public key cryptography is worth the effort, because it may radically change the way cryptography is used in web applications. Continue reading “Faster Modular Exponentiation in JavaScript”

Has Bluetooth Become Secure?

Bluetooth has a bad reputation when it comes to security. Many vulnerabilities have been found over the years in the technology, and many successful attacks have been demonstrated against it. But the Bluetooth specification has also changed much over the years, and each revision of the specification has made substantial changes to the Bluetooth security protocols. Whether the latest protocols are secure is a question open to debate. This question is especially important when Bluetooth is used in emerging medical and Internet-of-Things applications where security flaws have safety implications. But it has also come up recently in the context of the Derived Credentials being standardized by NIST for authentication of Federal employees who use mobile devices.

(This is a continuation of the last two posts, which reported on the recent NIST Workshop on PIV-Related Special Publications. It is also the last of a seven-part series of posts discussing the public comments on Draft SP 800-157: Guidelines for Derived Personal Identity Verification (PIV) Credentials, and the final version of the publication. Links to all the posts in the series can be found here.)

Before tackling the question of whether Bluetooth is secure today, Continue reading “Has Bluetooth Become Secure?”

NIST Looks at EMV to Speed up Physical Access with PIV Contactless Cards

It takes US Federal employees four seconds to get a green light to enter a building after presenting a contactless PIV card to a reader, when using asymmetric cryptography for authentication. NIST is trying to speed this up, and is looking at EMV contactless payment cards for inspiration.

(This is a continuation of the previous post, where I reported on the recent NIST Workshop on PIV-Related Special Publications, and Part 6 of the ongoing series discussing the public comments on Draft NIST SP 800-157, Guidelines for Derived Personal Identity Verification (PIV) Credentials and the final version of the publication. Links to all the posts in the series can be found here.)

Federal employees have been using PIV cards to enter buildings for many years, and it has not been taking them four seconds to get the green light. But agencies are now transitioning from using a symmetric Card Authentication Key (CAK) to using an asymmetric CAK with an associated public key certificate, the asymmetric CAK being the private key component of an RSA or ECDSA key pair. Inclusion of the asymmetric CAK and associated certificate in PIV cards became mandatory in August 2013 with the publication of version 2 of the FIPS 201 standard (FIPS 201-2).

The motivation from transitioning from a symmetric to an asymmetric CAK is not to use fancier cryptography or to improve security, but rather Continue reading “NIST Looks at EMV to Speed up Physical Access with PIV Contactless Cards”

Highlights of the NIST Worshop on PIV-Related Special Publications

This is Part 5 of a series discussing the public comments on Draft NIST SP 800-157, Guidelines for Derived Personal Identity Verification (PIV) Credentials and the final version of the publication. Links to all the posts in the series can be found here.

On March 3-4, NIST held a Workshop on Upcoming Special Publications Supporting FIPS 201-2. The FIPS 201 standard, Personal Identity Verification (PIV) of Federal Employees and Contractors, leaves out many details to be specified in a large number of Special Publications (SPs). The purpose of the workshop was to discuss SPs being added or revised to achieve alignment with version 2 of the standard, FIPS 201-2, which was issued in September 2013. An agenda with links to the presentations and an archived webcast of the workshop are now available.

I attended the workshop, via webcast, mostly because some of the topics to be discussed were related to derived credentials. In this post I report on some of those topics, plus on three other topics that were quite interesting even though not directly related to derived credentials: (i) the resolution of a controversy on whether to use a pairing code to authenticate a computer or physical access terminal to the PIV card; (ii) the security of methods for physical access control, including new methods to be introduced in the next version of SP 800-116; and (iii) the difficulties caused by having to certify cryptographic modules to FIPS 140. Continue reading “Highlights of the NIST Worshop on PIV-Related Special Publications”

Biometrics and Derived Credentials

This is Part 4 of a series discussing the public comments on Draft NIST SP 800-157, Guidelines for Derived Personal Identity Verification (PIV) Credentials and the final version of the publication. Links to all the posts in the series can be found here.

As reviewed in Part 3, a PIV card carries two fingerprint templates for off-card comparison, and may also carry one or two additional fingerprint templates for on-card comparison, one or two iris images, and an electronic facial image. These biometrics may be used in a variety of ways, by themselves or in combination with cryptographic credentials, for authentication to a Physical Access Control System (PACS) or a local workstation. The fingerprint templates for on-card comparison can also be used to activate private keys used for authentication, email signing, and email decryption.

By contrast, neither the draft version nor the final version of SP 800-157 consider the use of any biometrics analogous to those carried in a PIV card for activation or authentication. Actually, they “implicitly forbid” the storage of such biometrics by the Derived PIV Application that manages the Derived PIV Credential, according to NIST’s response to comment 30 by Precise Biometrics.

But several comments requested or suggested the use of biometrics by the Derived PIV Application. In this post I review those comments, and other comments expressing concern for biometric privacy. Then I draw attention to privacy-preserving biometric techniques that should be considered for possible use in activating derived credentials.
Continue reading “Biometrics and Derived Credentials”

Biometrics in PIV Cards

This is Part 3 of a series discussing the public comments on Draft NIST SP 800-157, Guidelines for Derived Personal Identity Verification (PIV) Credentials and the final version of the publication. Links to all the posts in the series can be found here.

After Part 1 and Part 2, in this Part 3 I intended to discuss comments received by NIST regarding possible uses of biometrics in connection with derived credentials. But that requires explaining the use of biometrics in PIV cards, and as I delved into the details, I realized that this deserves a blog post of its own, which may be of interest in its own right. So in this post I will begin by reviewing the security and privacy issues raised by the use of biometrics, then I will recap the biometrics carried in a PIV card and how they are used.

Biometric security

When used for user authentication, biometrics are sometimes characterized as “something you are“, while a password or PIN is “something you know” and a private key stored in a smart card or computing device is “something you have“, “you” being the cardholder. However this is only an accurate characterization when a biometric sample is known to come from the cardholder or device user, which in practice requires the sample to be taken by, or at least in the presence of, a human attendant. How easy it was to dupe the fingerprint sensors in Apple’s iPhone (as demonstrated in this video) and Samsung’s Galaxy S5 (as demonstrated in this video) with a spoofed fingerprint shows how difficult it is to verify that a biometric sample is live, Continue reading “Biometrics in PIV Cards”

NIST Omits Encryption Requirement for Derived Credentials

This is Part 2 of a series of posts reviewing the public comments received by NIST on Draft SP800-157, Guidelines for Derived Personal Identity Verification (PIV) Credentials, their disposition, and the final version of the document. Links to all the posts in the series can be found here.

In the first post of this series I discussed how NIST failed to address many concerns expressed in the 400+ comments that it received on the guidelines for derived credentials published in March of last year as Draft Special Publication (SP) 800-157, including concerns about insufficient discussion of business need, lack of guidance, narrow scope, lack of attention to embedded solutions, and security issues. But I postponed a discussion of what I think is the most critical security problem in SP800-157: the lack of security of the so-called software tokens, a concern that was raised in comments including 111 by the Treasury, 291, 311 and 318 by ICAMSC, 406 by PrimeKey AB, 413 by NSA, and 424 by Exponent. This post focuses on that problem.

The concept of a software token, or software cryptographic module is defined in Draft NISTIR 7981 (Section 3.2.1) as follows:

Rather than using specialized hardware to store and use PIV keys, this approach stores the keys in flash memory on the mobile device protected by a PIN or password. Authentication operations are done in software provided by the application accessing the IT system, or the mobile OS.

What does it mean for the keys to be “protected by a PIN or password“?
Continue reading “NIST Omits Encryption Requirement for Derived Credentials”