pkcs#是“Personal Information Exchange Syntax”,在第一部分的“Introduction”中,提到“This standard describes a transfer syntax for personal identity information, including private keys, certificates, miscellaneous secrets, and extensions. Machines, applications, browsers, Internet kiosks, and so on, that support this standard will allow a user to import, export, and exercise a single set of personal identity information”。简单的说,它包含证书和私钥,并允许口令保护。
pkcs#7是“Cryptographic Message Syntax Standard”,在第一部分的“Scope”中,提到“This standard describes a general syntax for data that may have cryptography applied to it, such as digital signatures and digital envelopes”。简单的说,它规定了加密、签名等消息的语法格式,当然了,证书作为消息的一部分,也可以同时传递。