[−][src]Struct sequoia_openpgp::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 MessageLayer
s, where
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
Signature::level
.
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.
Trait Implementations
impl<'a> Debug for MessageStructure<'a>
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impl<'a> Deref for MessageStructure<'a>
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type Target = [MessageLayer<'a>]
The resulting type after dereferencing.
pub fn deref(&self) -> &Self::Target
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impl<'a> IntoIterator for MessageStructure<'a>
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type Item = MessageLayer<'a>
The type of the elements being iterated over.
type IntoIter = IntoIter<MessageLayer<'a>>
Which kind of iterator are we turning this into?
pub fn into_iter(self) -> Self::IntoIter
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Auto Trait Implementations
impl<'a> !RefUnwindSafe for MessageStructure<'a>
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impl<'a> Send for MessageStructure<'a>
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impl<'a> Sync for MessageStructure<'a>
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impl<'a> Unpin for MessageStructure<'a>
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impl<'a> !UnwindSafe for MessageStructure<'a>
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Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> Same<T> for T
type Output = T
Should always be Self
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,