http://wiki.cacert.org/FAQ/ImportRootCert#Android_Phones_.26_Tablets
name=$(openssl x509 -inform PEM -subject_hash_old -in cert.pem | head -1).0 # .0 を付けないと WebView で認識されない
cat cert.pem > $name
openssl x509 -inform PEM -text -in cert.pem -noout >> $name