libsecp256k1 on Linux

Notes about getting libsecp256k1 to work with Electrum on Linux.

1. Using package manager

On recent versions of Ubuntu/Debian, libsecp256k1 should be available through the package manager:

sudo apt-get install libsecp256k1-0

Electrum should be able to find the .so file and use it.

2. How library is searched for

The command Electrum uses to find the library, on Linux, is the following:

import ctypes; ctypes.cdll.LoadLibrary('libsecp256k1.so.0')

If the library does not seem to be picked up by Electrum, consider opening a python interpreter to see for yourself.

3. If you compile libsecp256k1 yourself

If you compile from source, the .so files are typically placed in /usr/local/lib.

Unfortunately, ctypes.cdll.LoadLibrary does not seem to find them there.

Two workarounds:

Set LD_LIBRARY_PATH env var

You can set the LD_LIBRARY_PATH environment variable. Start Electrum like this:

LD_LIBRARY_PATH=/usr/local/lib electrum