TABLE 1: S/MIME MIME Content-Type Extensions
MIME Content Type	MIME Subtype	S/MIME Type	S/MIME Service	Attachment Extension
Application	pkcs7-MIME	Signed data	Guarantees data integrity and authentication, and nonrepudiation; uses opaque signing	.p7m
		Enveloped data	Guarantees data confidentiality	.p7m
Multipart	signed	NA	Guarantees data integrity and authentication, and nonrepudiation; uses clear signing	NA
Application	pkcs7-signature	NA		.p7s