  Threshold signatures are a fundamental cryptographic primitive used in many
practical applications. As proposed by Boneh and Komlo (CRYPTO'22), TAPS is a
threshold signature that is a hybrid of privacy and accountability. It enables
a combiner to combine t signature shares while revealing nothing about the
threshold t or signing quorum to the public and asks a tracer to track a
signature to the quorum that generates it. However, TAPS has three
disadvantages: it 1) structures upon a centralized model, 2) assumes that both
combiner and tracer are honest, and 3) leaves the tracing unnotarized and
static. In this work, we introduce Decentralized, Threshold, dynamically
Accountable and Private Signature (DeTAPS) that provides decentralized
combining and tracing, enhanced privacy against untrusted combiners (tracers),
and notarized and dynamic tracing. Specifically, we adopt Dynamic Threshold
Public-Key Encryption (DTPKE) to dynamically notarize the tracing process,
design non-interactive zero knowledge proofs to achieve public verifiability of
notaries, and utilize the Key-Aggregate Searchable Encryption to bridge TAPS
and DTPKE so as to awaken the notaries securely and efficiently. In addition,
we formalize the definitions and security requirements for DeTAPS. Then we
present a generic construction and formally prove its security and privacy. To
evaluate the performance, we build a prototype based on SGX2 and Ethereum.
