5.3 KiB
BLS threshold signature
An implementation of BLS threshold signature
Support architectures
- Windows Visual Studio / MSYS2(MinGW-w64)
- Linux
- macOS
- Android
- iOS
- WebAssembly
Support languages
- Go
- C#
Installation Requirements
Create a working directory (e.g., work) and clone the following repositories.
mkdir work
cd work
git clone git://github.com/herumi/mcl.git
git clone git://github.com/herumi/bls.git
git clone git://github.com/herumi/cybozulib_ext ; for only Windows
News
-
rename blsGetGeneratorOfG{1 or 2} to blsGetGeneratorOfPublicKey
-
add blsSetETHserialization(1) to use ETH serialization for BLS12-381
-
Support swap of G1 and G2 for Go (-tags bn384_256_swapg)
-
blsInit() is not thread safe (pthread is not used)
-
-tags option for Go bindings is always necessary
- use -tags bn384_256 for BLS12-381
-
support Android
-
(Break backward compatibility) The suffix
_dy
of library name is removed and bls*.a requires libmcl.so set LD_LIBRARY_PATH to the directory. -
-tags option for Go bindings
- -tags bn256
- -tags bn384_256
- -tags bn384
-
Support swap of G1 and G2
make BLS_SWAP_G=1
then G1 is assigned to PublicKey and G2 is assigned to Signature.
-
Build option without GMP
make MCL_USE_GMP=0
-
Build option without OpenSSL
make MCL_USE_OPENSSL=0
-
Build option to specify
mcl
directorymake MCL_DIR=<mcl directory>
-
(old) libbls.a for C++ interface(bls/bls.hpp) is removed Link
lib/libbls256.a
orlib/libbls384.a
to usebls/bls.hpp
according to MCLBN_FP_UNIT_SIZE = 4 or 6.
Build and test for Linux
To make and test, run
cd bls
make test
To make sample programs, run
make sample_test
Build and test for Windows
- make static library and use it
mklib
mk -s test\bls_c384_test.cpp
bin\bls_c384_test.exe
- make dynamic library and use it
mklib dll
mk -d test\bls_c384_test.cpp
bin\bls_c384_test.exe
Build for Android
see readme.md
Build for iOS
cd bls
make gomobile
Library
- libbls256.a/libbls256.so ; for BN254 compiled with MCLBN_FP_UNIT_SIZE=4
- libbls384.a/libbls384.so ; for BN254/BN381_1/BLS12_381 compiled with MCLBN_FP_UNIT_SIZE=6
- libbls384_256.a/libbls384_256.so ; for BN254/BLS12_381 compiled with MCLBN_FP_UNIT_SIZE=6 and MCLBN_FR_UNIT_SIZE=4
See mcl/include/curve_type.h
for curve parameter
Remark for static library
If there are both a shared library both and static library having the same name in the same directory, then the shared library is linked. So if you want to link a static library, then remove the shared library in the directory.
API
Basic API
BLS signature
e : G2 x G1 -> Fp12 ; optimal ate pairing over BN curve
Q in G2 ; fixed global parameter
H : {str} -> G1
s in Fr: secret key
sQ in G2; public key
s H(m) in G1; signature of m
verify ; e(sQ, H(m)) = e(Q, s H(m))
C
blsInit(MCL_BLS12_381, MCLBN_COMPILED_TIME_VAR); // use BLS12-381
blsSignatureVerifyOrder(0); // disable to check the order of a point in deserializing
blsPublicKeyVerifyOrder(0);
blsSetETHserialization(1); // obey ETH serialization
C++
void bls::init();
Initialize this library. Call this once to use the other api.
void SecretKey::init();
Initialize the instance of SecretKey. s
is a random number.
void SecretKey::getPublicKey(PublicKey& pub) const;
Get public key sQ
for the secret key s
.
void SecretKey::sign(Sign& sign, const std::string& m) const;
Make sign s H(m)
from message m.
bool Sign::verify(const PublicKey& pub, const std::string& m) const;
Verify sign with pub and m and return true if it is valid.
e(sQ, H(m)) == e(Q, s H(m))
Secret Sharing API
void SecretKey::getMasterSecretKey(SecretKeyVec& msk, size_t k) const;
Prepare k-out-of-n secret sharing for the secret key.
msk[0]
is the original secret key s
and msk[i]
for i > 0 are random secret key.
void SecretKey::set(const SecretKeyVec& msk, const Id& id);
Make secret key f(id) from msk and id where f(x) = msk[0] + msk[1] x + ... + msk[k-1] x^{k-1}.
You can make a public key f(id)Q
from each secret key f(id) for id != 0 and sign a message.
void Sign::recover(const SignVec& signVec, const IdVec& idVec);
Collect k pair of sign f(id) H(m)
and id
for a message m and recover the original signature s H(m)
for the secret key s
.
PoP (Proof of Possesion)
void SecretKey::getPop(Sign& pop) const;
Sign pub and make a pop s H(sQ)
bool Sign::verify(const PublicKey& pub) const;
Verify a public key by pop.
Check the order of a point
deserializer functions check whether a point has correct order and the cost is heavy for especially G2. If you do not want to check it, then call
void blsSignatureVerifyOrder(false);
void blsPublicKeyVerifyOrder(false);
cf. subgroup attack
Go
make test_go
WASM(WebAssembly)
mkdir ../bls-wasm
make bls-wasm
License
modified new BSD License http://opensource.org/licenses/BSD-3-Clause
Author
MITSUNARI Shigeo(herumi@nifty.com)