[Busec] busec tomorrow! Luke Valenta (Wed 10am)

Sharon Goldberg goldbe at cs.bu.edu
Tue Nov 1 19:24:36 EDT 2016

We continue to have weekly busec talks. Tomorrow, Luke Valenta from UPenn
will talk about factoring 512-bit RSA keys and their prevalence in the
wild. And the week after that, George Bissias from UMass Amherst will talk
about Bitcoin security. And the week after that, Amir Houmansadr is on the
calendar to talk about TBD.

All talks on Wednesdays at 10am with lunch to follow. See you there!


BUsec Calendar:  http://www.bu.edu/cs/busec/
The busec seminar gratefully acknowledges the support of BU's Center for
Reliable Information Systems and Cyber Security (RISCS).

Factoring As A Service
Speaker: Luke Valenta (UPenn)
Wednesday Nov 2, 10am
Hariri Institute (111 Cummington St, Boston MA 02215)

The difficulty of integer factorization is fundamental to modern
cryptographic security using RSA encryption and signatures.  Although a
512-bit RSA modulus was first factored in 1999, 512-bit RSA remains
surprisingly common in practice across many cryptographic protocols.
Popular understanding of the difficulty of 512-bit factorization does not
seem to have kept pace with developments in computing power.  In this
paper, we optimize the CADO-NFS and Msieve implementations of the number
field sieve for use on the Amazon Elastic Compute Cloud platform, allowing
a non-expert to factor 512-bit RSA public keys in under four hours for
$75.  We go on to survey the RSA key sizes used in popular protocols,
finding hundreds or thousands of deployed 512-bit RSA keys in DNSSEC,

Double-Spend Attack Analysis and an Improved Network Architecture for
George Bissias. (UMass)
Wednesday Nov 9, 10am
Hariri Institute (111 Cummington St, Boston MA 02215)

We contribute two complementary analyses to increase Bitcoin’s security,
efficiency, and transparency. First, we present a novel economic evaluation
of the double-spend attack with and without a contemporaneous eclipse
attack. We derive and validate a mathematical model focused on the value of
transactions that can be secured. Our model quantifies the importance of
each factor that determines the attack’s success. Our model also quantifies
the threat posed by eclipse-based double-spend attacks.

Second, we design and evaluate a replacement for Bitcoin’s inefficient,
opaque network architecture comprised of a high-degree, random graph of
peers. In our approach, called Canary, peers submit transactions directly
to miners, who announce new blocks and transactions via self-managed,
one-way trees of peers. Canary uses byte-efficient status report messages
that, like canaries in a coal mine, allow peers to detect both malicious
miners and eclipse attacks almost immediately. Canary’s structured topology
reduces total overhead traffic significantly, e.g., to about 30% of the
cost of the current topology.

Amir Houmansadr (UMass)
Wednesday Nov 16, 10am
Hariri Institute (111 Cummington St, Boston MA 02215)

Sharon Goldberg
Computer Science, Boston University
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