(1) Basic data: data that is unencrypted and does not contain attachments such as hash or digital signature.

(2) Enhanced data: The data has been encrypted or included as an attachment, or both. Enhanced content is compressed into another content in one form.

The PKCS#7 standard defines various content types, including:

Data: byte or octet string.

Signature design: data and encrypted data summary. Information digest is the result of hash algorithm (the term digest and hash have the same definition). Use message digest to ensure that the original message has not been tampered with during transmission and to confirm the identity of the sender.

Encapsulate data: Ciphertext plus public key can decrypt data. In this way, the content of the message is confidential to everyone, and the receiver is a trusted receiver.

Signature and encrypted data: content encrypted with public key and double encrypted message digest.

Summary data: data plus message summary.

Separation of encrypted data: In this case, the public key of encrypted data must be transmitted through other mechanisms.