title: Unable to install secp256k1 for pythereum?
body: <p>the error I am getting is below. I have installed the dependencies required for pythereum by:</p>
  
  <pre><code>brew install --force pkg-config libffi autoconf automake libtool openssl
  </code></pre>
  
  <p>and the response I am getting is</p>
  
  <pre><code>Warning: pkg-config-0.29.1_2 already installed
  Warning: libffi-3.0.13 already installed, it's just not linked.
  Warning: autoconf-2.69 already installed
  Warning: automake-1.15 already installed
  Warning: libtool-2.4.6_1 already installed
  Warning: openssl-1.0.2k already installed, it's just not linked.
  </code></pre>
  
  <p>I then try to link the unlinked libraries:</p>
  
  <pre><code>(ENV) Madhavs-MacBook-Air:pyethereum madhavsharma$ brew unlink libffi &amp;&amp; brew link --force libffi
  Unlinking /usr/local/Cellar/libffi/3.0.13... 0 symlinks removed
  Linking /usr/local/Cellar/libffi/3.0.13... 10 symlinks created
  </code></pre>
  
  <p>However, when trying to link openssl, I get this</p>
  
  <pre><code>(ENV) Madhavs-MacBook-Air:pyethereum madhavsharma$ brew unlink openssl &amp;&amp; brew link --force openssl
  Unlinking /usr/local/Cellar/openssl/1.0.2k... 0 symlinks removed
  Warning: Refusing to link: openssl
  Linking keg-only openssl means you may end up linking against the insecure,
  deprecated system OpenSSL while using the headers from Homebrew's openssl.
  Instead, pass the full include/library paths to your compiler e.g.:
    -I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib
  </code></pre>
  
  <p>I am not entirely sure how I should account for this message,and I am not sure why there is a download error as I have pasted below. Any general guidance on installing pythereum would be appreciated.</p>
  
  <pre><code>(ENV) My-computer:pyethereum user$ pip3 install -r requirements.txt 
  Collecting https://github.com/ethereum/ethash/tarball/master (from -r requirements.txt (line 9))
    Downloading https://github.com/ethereum/ethash/tarball/master (76kB)
      100% |████████████████████████████████| 81kB 540kB/s 
  Collecting bitcoin (from -r requirements.txt (line 1))
    Using cached bitcoin-1.1.42.tar.gz
  Collecting pysha3 (from -r requirements.txt (line 2))
    Using cached pysha3-1.0.2.tar.gz
  Collecting PyYAML (from -r requirements.txt (line 3))
    Using cached PyYAML-3.12.tar.gz
  Collecting repoze.lru (from -r requirements.txt (line 4))
    Using cached repoze.lru-0.6.tar.gz
  Collecting pbkdf2 (from -r requirements.txt (line 5))
    Using cached pbkdf2-1.3.tar.gz
  Collecting pycryptodome&gt;=3.3.1 (from -r requirements.txt (line 6))
    Using cached pycryptodome-3.4.5.tar.gz
  Collecting scrypt (from -r requirements.txt (line 7))
    Using cached scrypt-0.8.0.tar.gz
  Collecting rlp&gt;=0.4.4 (from -r requirements.txt (line 8))
    Using cached rlp-0.4.7.tar.gz
  Collecting secp256k1 (from -r requirements.txt (line 10))
    Using cached secp256k1-0.13.2.tar.gz
      Complete output from command python setup.py egg_info:
      0.29.1
      Download error on https://pypi.python.org/simple/pytest-runner/: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749) -- Some packages may not be found!
      Couldn't find index page for 'pytest-runner' (maybe misspelled?)
      Download error on https://pypi.python.org/simple/: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:749) -- Some packages may not be found!
      No local packages or working download links found for pytest-runner==2.6.2
      Traceback (most recent call last):
        File "&lt;string&gt;", line 1, in &lt;module&gt;
        File "/private/var/folders/c7/m5bh8s6d7nn1prj5x4dk6lp00000gn/T/pip-build-s_ta8_h3/secp256k1/setup.py", line 295, in &lt;module&gt;
          "Topic :: Security :: Cryptography"
        File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/distutils/core.py", line 108, in setup
          _setup_distribution = dist = klass(attrs)
        File "/Users/madhavsharma/Desktop/pyethereum/ENV/lib/python3.6/site-packages/setuptools/dist.py", line 315, in __init__
          self.fetch_build_eggs(attrs['setup_requires'])
        File "/Users/madhavsharma/Desktop/pyethereum/ENV/lib/python3.6/site-packages/setuptools/dist.py", line 361, in fetch_build_eggs
          replace_conflicting=True,
        File "/Users/madhavsharma/Desktop/pyethereum/ENV/lib/python3.6/site-packages/pkg_resources/__init__.py", line 850, in resolve
          dist = best[req.key] = env.best_match(req, ws, installer)
        File "/Users/madhavsharma/Desktop/pyethereum/ENV/lib/python3.6/site-packages/pkg_resources/__init__.py", line 1122, in best_match
          return self.obtain(req, installer)
        File "/Users/madhavsharma/Desktop/pyethereum/ENV/lib/python3.6/site-packages/pkg_resources/__init__.py", line 1134, in obtain
          return installer(requirement)
        File "/Users/madhavsharma/Desktop/pyethereum/ENV/lib/python3.6/site-packages/setuptools/dist.py", line 429, in fetch_build_egg
          return cmd.easy_install(req)
        File "/Users/madhavsharma/Desktop/pyethereum/ENV/lib/python3.6/site-packages/setuptools/command/easy_install.py", line 659, in easy_install
          raise DistutilsError(msg)
      distutils.errors.DistutilsError: Could not find suitable distribution for Requirement.parse('pytest-runner==2.6.2')
  
      ----------------------------------------
  Command "python setup.py egg_info" failed with error code 1 in /private/var/folders/c7/m5bh8s6d7nn1prj5x4dk6lp00000gn/T/pip-build-s_ta8_h3/secp256k1/
  </code></pre>