Struct sequoia_openpgp::packet::user_attribute::UserAttribute

pub struct UserAttribute { /* fields omitted */ }

Holds a UserAttribute packet.

See Section 5.12 of RFC 4880 for details.

Implementations

impl UserAttribute

pub fn new(subpackets: &[Subpacket]) -> Result<Self>

Returns a new UserAttribute packet.

Note: a valid UserAttribute has at least one subpacket.

pub fn hash_algo_security(&self) -> HashAlgoSecurity

The security requirements of the hash algorithm for self-signatures.

A cryptographic hash algorithm usually has three security properties: pre-image resistance, second pre-image resistance, and collision resistance. If an attacker can influence the signed data, then the hash algorithm needs to have both second pre-image resistance, and collision resistance. If not, second pre-image resistance is sufficient.

In general, an attacker may be able to influence third-party signatures. But direct key signatures, and binding signatures are only over data fully determined by signer. And, an attacker’s control over self signatures over User IDs is limited due to their structure.

These observations can be used to extend the life of a hash algorithm after its collision resistance has been partially compromised, but not completely broken. For more details, please refer to the documentation for HashAlgoSecurity.

pub fn value(&self) -> &[u8]

Gets the user attribute packet’s raw, unparsed value.

Most likely you will want to use subpackets() to iterate over the subpackets.

pub fn value_mut(&mut self) -> &mut Vec<u8>

Gets a mutable reference to the user attribute packet’s raw value.

pub fn subpackets(&self) -> SubpacketIterator<'_>

Iterates over the subpackets.

impl UserAttribute

pub fn bind(
    &self,
    signer: &mut dyn Signer,
    cert: &Cert,
    signature: SignatureBuilder
) -> Result<Signature>

Creates a binding signature.

The signature binds this user attribute to cert. signer will be used to create a signature using signature as builder. Thehash_algo defaults to SHA512, creation_time to the current time.

This function adds a creation time subpacket, a issuer fingerprint subpacket, and a issuer subpacket to the signature.

Examples

This example demonstrates how to bind this user attribute to a Cert. Note that in general, the CertBuilder is a better way to add userids to a Cert.

// Generate a Cert, and create a keypair from the primary key.
let (cert, _) = CertBuilder::new()
    .generate()?;
let mut keypair = cert.primary_key().key().clone()
    .parts_into_secret()?.into_keypair()?;
assert_eq!(cert.userids().len(), 0);

// Generate a user attribute and a binding signature.
let user_attr = UserAttribute::new(&[
    Subpacket::Image(
        Image::Private(100, vec![0, 1, 2].into_boxed_slice())),
])?;
let builder =
    signature::SignatureBuilder::new(SignatureType::PositiveCertification);
let binding = user_attr.bind(&mut keypair, &cert, builder)?;

// Now merge the user attribute and binding signature into the Cert.
let cert = cert.insert_packets(vec![Packet::from(user_attr),
                                   binding.into()])?;

// Check that we have a user attribute.
assert_eq!(cert.user_attributes().count(), 1);

pub fn certify<S, H, T>(
    &self,
    signer: &mut dyn Signer,
    cert: &Cert,
    signature_type: S,
    hash_algo: H,
    creation_time: T
) -> Result<Signature> where
    S: Into<Option<SignatureType>>,
    H: Into<Option<HashAlgorithm>>,
    T: Into<Option<SystemTime>>, 

Returns a certificate for the user attribute.

The signature binds this user attribute to cert. signer will be used to create a certification signature of type signature_type. signature_type defaults to SignatureType::GenericCertification, hash_algo to SHA512, creation_time to the current time.

This function adds a creation time subpacket, a issuer fingerprint subpacket, and a issuer subpacket to the signature.

Errors

Returns Error::InvalidArgument if signature_type is not one of SignatureType::{Generic, Persona, Casual, Positive}Certificate

Examples

This example demonstrates how to certify a userid.

// Generate a Cert, and create a keypair from the primary key.
let (alice, _) = CertBuilder::new()
    .add_userid("alice@example.org")
    .generate()?;
let mut keypair = alice.primary_key().key().clone()
    .parts_into_secret()?.into_keypair()?;

// Generate a Cert for Bob.
let user_attr = UserAttribute::new(&[
    Subpacket::Image(
        Image::Private(100, vec![0, 1, 2].into_boxed_slice())),
])?;
let (bob, _) = CertBuilder::new()
    .set_primary_key_flags(KeyFlags::empty().set_certification())
    .add_user_attribute(user_attr)
    .generate()?;

// Alice now certifies the binding between `bob@example.org` and `bob`.
let certificate =
    bob.user_attributes().nth(0).unwrap()
    .certify(&mut keypair, &bob, SignatureType::PositiveCertification,
             None, None)?;

// `certificate` can now be used, e.g. by merging it into `bob`.
let bob = bob.insert_packets(certificate)?;

// Check that we have a certification on the userid.
assert_eq!(bob.user_attributes().nth(0).unwrap()
           .certifications().count(),
           1);

Trait Implementations

impl Clone for UserAttribute

fn clone(&self) -> UserAttribute

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for UserAttribute

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

Formats the value using the given formatter.

impl From<UserAttribute> for Packet

fn from(s: UserAttribute) -> Self

Performs the conversion.

impl From<Vec<u8, Global>> for UserAttribute

fn from(u: Vec<u8>) -> Self

Performs the conversion.

impl Hash for UserAttribute

fn hash(&self, hash: &mut dyn Digest)

Updates the given hash with this object.

impl Hash for UserAttribute

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 IntoIterator for UserAttribute

Implement IntoIterator so that cert::insert_packets(sig) just works.

type Item = UserAttribute

The type of the elements being iterated over.

type IntoIter = Once<UserAttribute>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl Marshal for UserAttribute

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 UserAttribute

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 UserAttribute

fn cmp(&self, other: &UserAttribute) -> 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<'a> Parse<'a, UserAttribute> for UserAttribute

fn from_reader<R: 'a + Read + Send + Sync>(reader: R) -> Result<Self>

Reads from the given reader.

fn from_file<P: AsRef<Path>>(path: P) -> Result<T>

Reads from the given file.

fn from_bytes<D: AsRef<[u8]> + ?Sized + Send + Sync>(data: &'a D) -> Result<T>

Reads from the given slice.

impl PartialEq<UserAttribute> for UserAttribute

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

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

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

This method tests for !=.

impl PartialOrd<UserAttribute> for UserAttribute

fn partial_cmp(&self, other: &UserAttribute) -> 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 UserAttribute

impl StructuralEq for UserAttribute

impl StructuralPartialEq for UserAttribute