What format are certificates in when exported/dragged from OS X Keychain By LotusshaneyJanuary 28, 2016Tech They are in DER format, even though they have a .cer extension ! To view the contents use openssl x509 -in MYCERT.der -inform der -text To convert them to a normal TXT Cert openssl x509 -in MYCERT.der -inform der -out MYCERT_OUT.cer