curl -sSL https://get.rvm.io | bash -s stable
Downloading https://github.com/rvm/rvm/archive/1.26.11.tar.gz
Downloading https://github.com/rvm/rvm/releases/download/1.26.11/1.26.11.tar.gz.asc
gpg: failed to create temporary file `/home/cky/.gnupg/.#lk0x2518060.cky-pc.29930': 權限不夠
gpg: 金鑰區塊資源‘/home/cky/.gnupg/pubring.gpg’：例行錯誤
gpg: 於 2015年03月31日 星期二 05時52分13秒 CST 建立的簽名，使用 RSA，鑰匙 BF04FF17
gpg: 無法檢查簽章：找不到公鑰
Warning, RVM 1.26.0 introduces signed releases and automated check of signatures when GPG software found.
Assuming you trust Michal Papis import the mpapis public key (downloading the signatures).

GPG signature verification failed for '/home/cky/.rvm/archives/rvm-1.26.11.tgz' - 'https://github.com/rvm/rvm/releases/download/1.26.11/1.26.11. tar.gz.asc'!
try downloading the signatures:

    gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3

或 if it fails:

    command curl -sSL https://rvm.io/mpapis.asc | gpg --import -

the key can be compared with:

    https://rvm.io/mpapis.asc
    https://keybase.io/mpapis