[1] RFC 2985 - PKCS #9: Selected Object Classes and Attribute Types Version 2.0 ( 版) http://tools.ietf.org/html/rfc2985
[2] RFC 2985 - Status of this memo () https://tools.ietf.org/html/rfc2985
[3] RFC 7894 - Alternative Challenge Password Attributes for Enrollment over Secure Transport () https://tools.ietf.org/html/rfc7894