pyinstaller生成EXE文件报错：Multibackend cannot be initialized with no backends

环境：

win7_64x
python3.5

脚本使用了paramiko模块。用PYINSTALLER生成EXE的时候报错：

Unknown exception: Multibackend cannot be initialized with no backends. If you are seeing this error when trying to use default_backend() please try uninstalling and reinstalling cryptography.

网友写了一个补丁。加入脚本就能解决：

def patch_crypto_be_discovery():

    """
    Monkey patches cryptography's backend detection.
    Objective: support pyinstaller freezing.
    """

    from cryptography.hazmat import backends

    try:
        from cryptography.hazmat.backends.commoncrypto.backend import backend as be_cc
    except ImportError:
        be_cc = None

    try:
        from cryptography.hazmat.backends.openssl.backend import backend as be_ossl
    except ImportError:
        be_ossl = None

    backends._available_backends_list = [
        be for be in (be_cc, be_ossl) if be is not None
    ]

然后在脚本开头调用就可以了~

patch_crypto_be_discovery()

貌似是依赖的cryptography模块的问题。没怎么看懂。反正解决了~ PS:网上不少安装paramiko的。好象都是去哪里下载。我是直接PIP INSTALL直接搞定的。没什么问题，包括pyinstaller:

pip install paramiko
pip install pyinstaller