bitcoin-s/secp256k1jni/README.md

Secp256k1jni

This project gives people a convenient way to use libsecp256k1 on the JVM without compiling natives themselves.

Currently we have support for natives on

1. linux 32 bit
2. linux 64 bit
3. mac osx 64 bit

This uses a zero depdency library called native-lib-loader. The does the appropriate loading of the library onto your classpath to be accessed. To tell if you have access to libsecp256k1 you can do the following

sbt:root> project secp256k1jni
[info] Set current project to bitcoin-s-secp256k1jni (in build file:/home/chris/dev/bitcoin-s-core/)
sbt:bitcoin-s-secp256k1jni> console
[info] Starting scala interpreter...
Welcome to Scala 2.12.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_191).
Type in expressions for evaluation. Or try :help.

scala> import org.bitcoin.Secp256k1Context;

scala> Secp256k1Context.isEnabled()
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
res0: Boolean = true

Adding secp256k1jni to your project

To add bitcoin-s-secp256k1jni to your project you add it like this

"org.bitcoins" % "bitcoin-s-secp256k1jni" % "0.0.1"

or with maven

<dependency>
  <groupId>org.bitcoins</groupId>
  <artifactId>bitcoin-s-secp256k1jni</artifactId>
  <version>0.0.1</version>
</dependency>

Using secp256k1

The file NativeSecp256k1.java contains basic functionality for

1. Verifying digital signatures
2. Producing digital signatures
3. Computing a public key from a private key
4. tweaking keys
5. Checking public key validity

Binaries

The binaries provided here are PGP signed, to give at least some assurances that nothing funny has happened to them.

macOS 64 bit

bitcoin-s/secp256k1jni/natives/osx_64 $ find -type f -exec sha256sum {} \; | \
        sort -k 2 | sha256sum | cut --fields 1 --delimiter=" " | \
        gpg --clearsign --output hashed-dir.sig --detach-sig

bitcoin-s/secp256k1jni/natives/osx_64 $ cat hashed-dir.sig
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

341d768b915d989db82c1fb94b29faec9509ad45e30a27c217feb121747789ce
-----BEGIN PGP SIGNATURE-----

iQEzBAEBCgAdFiEEcQE9FyWyvvLjrwybHk0b2DvgrM0FAlxPHuQACgkQHk0b2Dvg
rM07EwgApXWPlVKMDP7Z8RQhhDmlnycTJxFaw315TH2IKDMEtCA0mBGY8UOy7jis
ZtQEyUQdspBnLW6RHeEBhkDlQzjMS3G4K2T2D1r2eL4vXf7dnZ2CUSy7N9Gd8Lsy
Tcdi9a/GSyFu1RCtmklCZ75/oECPlmNctdOY30+5FDIfWIcTHqKebfDstTqeYGbd
0+U5N2xDI/07g5jCF1EsgiqvFkXZEjI/44xlxWon6GtbiYR/n+MHzgwBi5XqNs2p
0t3Tvx5NbJiVVn7K2ThQFaW4ap/bqggZh1ddT/v2Wq0BH+UX6b6Abrq0tD5+ZPst
5+tz19oEa9XK+X/DDkFrT4WEMDpyIw==
=CauS
-----END PGP SIGNATURE-----

bitcoin-s/secp256k1jni/natives/osx_64 $ gpg --verify hashed-dir.sig
gpg: Signature made Mon 28 Jan 2019 04:25:24 PM CET
gpg:                using RSA key 71013D1725B2BEF2E3AF0C9B1E4D1BD83BE0ACCD
gpg: Good signature from "Torkel Rogstad <torkel@suredbits.com>" [ultimate]

Linux 32 bit

TODO

Linux 64 bit

TODO

Windows 64 bit

To build binaries for windows, you need to cross compile them from a linux machine. This can be done with the following commands. The origin of these commands comes from ACINQ

$ sudo apt install g++-mingw-w64-x86-64
$ sudo update-alternatives --config x86_64-w64-mingw32-g++ # Set the default mingw32 g++ compiler option to posix.

# this is needed to compile shared libraries, otherwise you'll get:
# libtool: warning: undefined symbols not allowed in x86_64-w64-mingw32 shared libraries; building static only
$ echo "LDFLAGS = -no-undefined" >> Makefile.am
$ ./configure --host=x86_64-w64-mingw32 --enable-experimental --enable-module_ecdh --enable-jni && make clean && make CFLAGS="-std=c99"
cp ./.libs/libsecp256k1-0.dll ../src/main/resources/fr/acinq/native/Windows/x86_64/secp256k1.dll

Windows 64 bit signature

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

510f864a2d5d5ec238aa8e3653d01e3c027caef810797c494fc22e8f6fd8fe84  libsecp256k1-0.dll
-----BEGIN PGP SIGNATURE-----
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=2mZ8
-----END PGP SIGNATURE-----