  Cryptography promises four information security objectives, namely,
confidentiality, integrity, authenticity, and non-repudiation, to support
trillions of transactions annually in the digital economy. Efficient digital
signatures, ensuring the integrity, authenticity, and non-repudiation of data
with information-theoretical security are highly urgent and intractable open
problems in cryptography. Here, we propose a protocol of high-efficiency
quantum digital signatures using secret sharing, one-time universal$_2$
hashing, and the one-time pad. We just need to use a 384-bit key to sign
documents of up to $2^{64}$ lengths with a security bound of $10^{-19}$. If
one-megabit document is signed, the signature efficiency is improved by more
than $10^8$ times compared with previous quantum digital signature protocols.
Furthermore, we build the first all-in-one quantum secure network integrating
information-theoretically secure communication, digital signatures, secret
sharing, and conference key agreement and experimentally demonstrate this
signature efficiency advantage. Our work completes the cryptography toolbox of
the four information security objectives.
