Skip to main content
Cryptography

Return to Question

Added another reason why CMS is confusing
Source Link
Finlay Weber
Finlay Weber
  • 504
  • 1
  • 3
  • 12

I am really confused over PKCS. I saw this question but I do not have enough reputation to leave a comment so I am asking a new question to clarify.

I am trying to understand what exactly PKCS and in extension what CMS is. I have stumbled on the line from the RFC mentioned in the aforementioned question.

This syntax is used to digitally sign, digest, authenticate, or encrypt arbitrary message content.

How can a syntax be used to digitally sign stuff?!! I can understand if it states it is a syntax used to describe digitally signed stuff...but signing? how can a syntax be used to sign?

This all tie into my confusion with PKCS/CMS and x509. I understand that x509 is a standard that describes what should make up a certificate, how is this different from PKCS/CMS?

Edit

The Wikipedia entry for CMS does not also help. For example it says:

It [CMS] can be used by cryptographic schemes and protocols to digitally sign, digest, authenticate or encrypt any form of digital data.

Okay is CMS an encryption algorithm like RSA? No!! so why then say it is a protocol used to digitally sign or encrypt stuff?

I am really confused over PKCS. I saw this question but I do not have enough reputation to leave a comment so I am asking a new question to clarify.

I am trying to understand what exactly PKCS and in extension what CMS is. I have stumbled on the line from the RFC mentioned in the aforementioned question.

This syntax is used to digitally sign, digest, authenticate, or encrypt arbitrary message content.

How can a syntax be used to digitally sign stuff?!! I can understand if it states it is a syntax used to describe digitally signed stuff...but signing? how can a syntax be used to sign?

This all tie into my confusion with PKCS/CMS and x509. I understand that x509 is a standard that describes what should make up a certificate, how is this different from PKCS/CMS?

I am really confused over PKCS. I saw this question but I do not have enough reputation to leave a comment so I am asking a new question to clarify.

I am trying to understand what exactly PKCS and in extension what CMS is. I have stumbled on the line from the RFC mentioned in the aforementioned question.

This syntax is used to digitally sign, digest, authenticate, or encrypt arbitrary message content.

How can a syntax be used to digitally sign stuff?!! I can understand if it states it is a syntax used to describe digitally signed stuff...but signing? how can a syntax be used to sign?

This all tie into my confusion with PKCS/CMS and x509. I understand that x509 is a standard that describes what should make up a certificate, how is this different from PKCS/CMS?

Edit

The Wikipedia entry for CMS does not also help. For example it says:

It [CMS] can be used by cryptographic schemes and protocols to digitally sign, digest, authenticate or encrypt any form of digital data.

Okay is CMS an encryption algorithm like RSA? No!! so why then say it is a protocol used to digitally sign or encrypt stuff?

changed PKCS7 to PKCS
Source Link
Finlay Weber
Finlay Weber
  • 504
  • 1
  • 3
  • 12

How is PKCS7PKCS a syntax to digitally sign, digest, authenticate, or encrypt arbitrary message content

I am really confused over PKCS7PKCS. I saw this question but I do not have enough reputation to leave a comment so I am asking a new question to clarify.

I am trying to understand what exactly PKCS7PKCS and in extension what CMS is. I have stumbled on the line from the RFC mentioned in the aforementioned question.

This syntax is used to digitally sign, digest, authenticate, or encrypt arbitrary message content.

How can a syntax be used to digitally sign stuff?!! I can understand if it states it is a syntax used to describe digitally signed stuff...but signing? how can a syntax be used to sign?

This all tie into my confusion with PKCS7PKCS/CMS and x509. I understand that x509 is a standard that describes what should make up a certificate, how is this different from PKCS7PKCS/CMS?

How is PKCS7 a syntax to digitally sign, digest, authenticate, or encrypt arbitrary message content

I am really confused over PKCS7. I saw this question but I do not have enough reputation to leave a comment so I am asking a new question to clarify.

I am trying to understand what exactly PKCS7 and in extension what CMS is. I have stumbled on the line from the RFC mentioned in the aforementioned question.

This syntax is used to digitally sign, digest, authenticate, or encrypt arbitrary message content.

How can a syntax be used to digitally sign stuff?!! I can understand if it states it is a syntax used to describe digitally signed stuff...but signing? how can a syntax be used to sign?

This all tie into my confusion with PKCS7/CMS and x509. I understand that x509 is a standard that describes what should make up a certificate, how is this different from PKCS7/CMS?

How is PKCS a syntax to digitally sign, digest, authenticate, or encrypt arbitrary message content

I am really confused over PKCS. I saw this question but I do not have enough reputation to leave a comment so I am asking a new question to clarify.

I am trying to understand what exactly PKCS and in extension what CMS is. I have stumbled on the line from the RFC mentioned in the aforementioned question.

This syntax is used to digitally sign, digest, authenticate, or encrypt arbitrary message content.

How can a syntax be used to digitally sign stuff?!! I can understand if it states it is a syntax used to describe digitally signed stuff...but signing? how can a syntax be used to sign?

This all tie into my confusion with PKCS/CMS and x509. I understand that x509 is a standard that describes what should make up a certificate, how is this different from PKCS/CMS?

Source Link
Finlay Weber
Finlay Weber
  • 504
  • 1
  • 3
  • 12

How is PKCS7 a syntax to digitally sign, digest, authenticate, or encrypt arbitrary message content

I am really confused over PKCS7. I saw this question but I do not have enough reputation to leave a comment so I am asking a new question to clarify.

I am trying to understand what exactly PKCS7 and in extension what CMS is. I have stumbled on the line from the RFC mentioned in the aforementioned question.

This syntax is used to digitally sign, digest, authenticate, or encrypt arbitrary message content.

How can a syntax be used to digitally sign stuff?!! I can understand if it states it is a syntax used to describe digitally signed stuff...but signing? how can a syntax be used to sign?

This all tie into my confusion with PKCS7/CMS and x509. I understand that x509 is a standard that describes what should make up a certificate, how is this different from PKCS7/CMS?