IACR News item: 09 July 2025
Vivian Fang, Emma Dauterman, Akshay Ravoor, Akshit Dewan, Raluca Ada Popa
Transparency logs are critical for a wide range of
applications, from web certificates to end-to-end encrypted
messaging. Today, many transparency log designs exist for
various applications and workloads, and developers must
fully understand the design space to find the best design
for their needs. Worse, if a developer needs a transparency
log for an application and workload without an existing
transparency log, the developer (who might not be an expert)
must design a new log. To address these challenges, we
introduce the paradigm of a configurable transparency log,
which takes as input a description of the application work-
load and constraints of different entities and automatically
outputs a transparency log uniquely suited to the application.
We present the first configurable transparency log design,
LegoLog, which we implement and empirically evaluate end-
to-end for three specialized transparency logs. We also show
that LegoLog can express six different applications, and
we compare the asymptotic complexity of LegoLog and
existing transparency logs tailored to individual applications.
We find that configurability does not come at the cost of
performance: LegoLog can capture a variety of applications
while performing comparably to existing, special-purpose
transparency logs.
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