parse:: stream:: MessageStructure
Communicates the message structure to the VerificationHelper.
A valid OpenPGP message contains one literal data packet with
optional encryption, signing, and compression layers freely
combined on top. This structure is passed to
VerificationHelper::check for verification.
The most common structure is an optionally encrypted, optionally compressed, and optionally signed message, i.e. if the message is encrypted, then the encryption is the outermost layer; if the message is signed, then the signature group is the innermost layer. This is a sketch of such a message:
[ encryption layer: [ compression layer: [ signature group: [ literal data ]]]]
However, OpenPGP allows encryption, signing, and compression
operations to be freely combined (see Section 11.3 of RFC 4880).
This is represented as a stack of
signatures of the same level (i.e. those over the same data:
either directly over the literal data, or over other signatures
and the literal data) are grouped into one layer. See also
Consider the following structure. This is a set of notarizing signatures N over a set of signatures S over the literal data:
[ signature group: [ signature group: [ literal data ]]]
The notarizing signatures N are said to be of level 1, i.e. signatures over the signatures S and the literal data. The signatures S are level 0 signatures, i.e. signatures over the literal data.
OpenPGP's flexibility allows adaption to new use cases, but also presents a challenge to implementations and downstream users. The message structure must be both validated, and possibly communicated to the application's user. Note that if compatibility is a concern, generated messages must be restricted to a narrow subset of possible structures, see this test of unusual message structures.
impl<'a> Debug for MessageStructure<'a>[src]
impl<'a> Deref for MessageStructure<'a>[src]
type Target = [MessageLayer<'a>]
The resulting type after dereferencing.
impl<'a> IntoIterator for MessageStructure<'a>[src]
impl<'a> !RefUnwindSafe for MessageStructure<'a>
impl<'a> !Send for MessageStructure<'a>
impl<'a> !Sync for MessageStructure<'a>
impl<'a> Unpin for MessageStructure<'a>
impl<'a> !UnwindSafe for MessageStructure<'a>
impl<I> IntoIterator for I where[src]
The type of the elements being iterated over.
type IntoIter = I
Which kind of iterator are we turning this into?
type Error = Infallible
The type returned in the event of a conversion error.