Struct sequoia_openpgp::packet::signature::subpacket::Subpacket

pub struct Subpacket { /* fields omitted */ }

Signature subpackets.

Most of a signature’s attributes are not stored in fixed fields, but in so-called subpackets. These subpackets are stored in a Signature’s so-called subpacket areas, which are effectively small key-value stores. The keys are subpacket tags (SubpacketTag). The values are well-structured (SubpacketValue).

In addition to their key and value, subpackets also include a critical flag. When set, this flag indicates to the OpenPGP implementation that if it doesn’t understand the subpacket, it must consider the signature to be invalid. (Likewise, if it isn’t set, then it means that it is safe for the implementation to ignore the subpacket.) This enables forward compatibility with security-relevant extensions.

It is possible to control how Sequoia’s higher-level functionality handles unknown, critical subpackets using a Policy object. Depending on the degree of control required, it may be sufficient to customize a StandardPolicy object using, for instance, the StandardPolicy::accept_critical_subpacket method.

The subpacket system is extensible in two ways. First, although limited, the subpacket name space is not exhausted. So, it is possible to introduce new packets. Second, one of the subpackets, the Notation Data subpacket (NotationData), is explicitly designed for adding arbitrary data to signatures.

Subpackets are described in Section 5.2.3.1 of RFC 4880.

Implementations

impl Subpacket

pub fn new(value: SubpacketValue, critical: bool) -> Result<Subpacket>

Creates a new Subpacket.

pub fn critical(&self) -> bool

Returns whether the critical bit is set.

pub fn tag(&self) -> SubpacketTag

Returns the Subpacket’s tag.

pub fn value(&self) -> &SubpacketValue

Returns the Subpacket’s value.

pub fn authenticated(&self) -> bool

Returns whether the information in this subpacket has been authenticated.

There are three ways a subpacket can be authenticated:

• It is in the hashed subpacket area and the signature has been verified.
• It is in the unhashed subpacket area and the information is self-authenticating and has been authenticated by Sequoia. This is can be done for issuer information and embedded Signatures.
• The subpacket has been authenticated by the user and marked as such using Subpacket::set_authenticated.

Note: The authentication is only valid in the context of the signature the subpacket is in. If the Subpacket is cloned, or a Subpacket is added to a SubpacketArea, the flag is cleared.

pub fn set_authenticated(&mut self, authenticated: bool) -> bool

Marks the information in this subpacket as authenticated or not.

See Subpacket::authenticated for more information.

Trait Implementations

impl Clone for Subpacket

fn clone(&self) -> Subpacket

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Subpacket

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for Subpacket

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl Marshal for Subpacket

fn serialize(&self, o: &mut dyn Write) -> Result<()>

Writes a serialized version of the object to o.

fn export(&self, o: &mut dyn Write) -> Result<()>

Exports a serialized version of the object to o.

impl MarshalInto for Subpacket

fn serialized_len(&self) -> usize

Computes the maximal length of the serialized representation.

fn serialize_into(&self, buf: &mut [u8]) -> Result<usize>

Serializes into the given buffer.

fn to_vec(&self) -> Result<Vec<u8>>

Serializes the packet to a vector.

fn export_into(&self, buf: &mut [u8]) -> Result<usize>

Exports into the given buffer.

fn export_to_vec(&self) -> Result<Vec<u8>>

Exports to a vector.

impl Ord for Subpacket

fn cmp(&self, other: &Subpacket) -> Ordering

This method returns an Ordering between self and other.

#[must_use]

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

#[must_use]

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

#[must_use]

fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl PartialEq<Subpacket> for Subpacket

fn eq(&self, other: &Subpacket) -> bool

This method tests for self and other values to be equal, and is used by ==.

#[must_use]

fn ne(&self, other: &Rhs) -> bool

This method tests for !=.

impl PartialOrd<Subpacket> for Subpacket

fn partial_cmp(&self, other: &Subpacket) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

#[must_use]

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

#[must_use]

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

#[must_use]

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

#[must_use]

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Eq for Subpacket