Struct Signer 

pub struct Signer<'a> { /* private fields */ }

Signs a message.

Signs a message with every crypto::Signer added to the streaming signer.

Implementations

impl<'a> Signer<'a>

pub fn new<S>(inner: Message<'a>, signer: S) -> Result<Signer<'a>, Error>

where S: Signer + Send + Sync + 'a,

Creates a signer.

Signs the message with the given crypto::Signer. To create more than one signature, add more crypto::Signers using Signer::add_signer. Properties of the signatures can be tweaked using the methods of this type. Notably, to generate a detached signature (see Section 10.4 of RFC 9580), use Signer::detached. For even more control over the generated signatures, use Signer::with_template.

Examples

use std::io::{Read, Write};
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::{Message, Signer, LiteralWriter};
use openpgp::policy::StandardPolicy;

let p = &StandardPolicy::new();
let cert: Cert = // ...
let signing_keypair = cert.keys().secret()
    .with_policy(p, None).supported().alive().revoked(false).for_signing()
    .nth(0).unwrap()
    .key().clone().into_keypair()?;

let mut sink = vec![];
{
    let message = Message::new(&mut sink);
    let message = Signer::new(message, signing_keypair)?
        // Customize the `Signer` here.
        .build()?;
    let mut message = LiteralWriter::new(message).build()?;
    message.write_all(b"Make it so, number one!")?;
    message.finalize()?;
}

// Now check the signature.
struct Helper<'a>(&'a openpgp::Cert);
impl<'a> VerificationHelper for Helper<'a> {
    fn get_certs(&mut self, _: &[openpgp::KeyHandle])
                       -> openpgp::Result<Vec<openpgp::Cert>> {
        Ok(vec![self.0.clone()])
    }

    fn check(&mut self, structure: MessageStructure)
             -> openpgp::Result<()> {
        if let MessageLayer::SignatureGroup { ref results } =
            structure.iter().nth(0).unwrap()
        {
            results.get(0).unwrap().as_ref().unwrap();
            Ok(())
        } else { panic!() }
    }
}

let mut verifier = VerifierBuilder::from_bytes(&sink)?
    .with_policy(p, None, Helper(&cert))?;

let mut message = String::new();
verifier.read_to_string(&mut message)?;
assert_eq!(&message, "Make it so, number one!");

pub fn with_template<S, T>( inner: Message<'a>, signer: S, template: T, ) -> Result<Signer<'a>, Error>

where S: Signer + Send + Sync + 'a, T: Into<SignatureBuilder>,

Creates a signer with a given signature template.

Signs the message with the given crypto::Signer like Signer::new, but allows more control over the generated signatures. The given signature::SignatureBuilder is used to create all the signatures.

For every signature, the creation time is set to the current time or the one specified using Signer::creation_time, the intended recipients are added (see Signer::add_intended_recipient), the issuer and issuer fingerprint subpackets are set according to the signing key, and the hash algorithm set using Signer::hash_algo is used to create the signature.

Examples

use std::io::{Read, Write};
use sequoia_openpgp as openpgp;
use openpgp::types::SignatureType;
use openpgp::packet::signature;
use openpgp::serialize::stream::{Message, Signer, LiteralWriter};

let message = Message::new(&mut sink);
let message = Signer::with_template(
    message, signing_keypair,
    signature::SignatureBuilder::new(SignatureType::Text)
        .add_notation("issuer@starfleet.command", "Jean-Luc Picard",
                      None, true)?)?
    // Further customize the `Signer` here.
    .build()?;
let mut message = LiteralWriter::new(message).build()?;
message.write_all(b"Make it so, number one!")?;
message.finalize()?;

pub fn detached(self) -> Signer<'a>

Creates a signer for a detached signature.

Changes the Signer to create a detached signature (see Section 10.4 of RFC 9580). Note that the literal data must not be wrapped using the LiteralWriter.

This overrides any prior call to Signer::cleartext.

Examples

use std::io::Write;
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::{Message, Signer};
use openpgp::policy::StandardPolicy;

let p = &StandardPolicy::new();

let mut sink = vec![];
{
    let message = Message::new(&mut sink);
    let mut signer = Signer::new(message, signing_keypair)?
        .detached()
        // Customize the `Signer` here.
        .build()?;

    // Write the data directly to the `Signer`.
    signer.write_all(b"Make it so, number one!")?;
    // In reality, just io::copy() the file to be signed.
    signer.finalize()?;
}

// Now check the signature.
struct Helper<'a>(&'a openpgp::Cert);
impl<'a> VerificationHelper for Helper<'a> {
    fn get_certs(&mut self, _: &[openpgp::KeyHandle])
                       -> openpgp::Result<Vec<openpgp::Cert>> {
        Ok(vec![self.0.clone()])
    }

    fn check(&mut self, structure: MessageStructure)
             -> openpgp::Result<()> {
        if let MessageLayer::SignatureGroup { ref results } =
            structure.iter().nth(0).unwrap()
        {
            results.get(0).unwrap().as_ref().unwrap();
            Ok(())
        } else { panic!() }
    }
}

let mut verifier = DetachedVerifierBuilder::from_bytes(&sink)?
    .with_policy(p, None, Helper(&cert))?;

verifier.verify_bytes(b"Make it so, number one!")?;

pub fn cleartext(self) -> Signer<'a>

Creates a signer for a cleartext signed message.

Changes the Signer to create a cleartext signed message (see Section 7 of RFC 9580). Note that the literal data must not be wrapped using the LiteralWriter. This implies ASCII armored output, do not add an Armorer to the stack.

Note:

• The cleartext signature framework does not hash trailing whitespace (in this case, space and tab, see Section 7.2 of RFC 9580 for more information). We align what we emit and what is being signed by trimming whitespace off of line endings.

• That means that you can not recover a byte-accurate copy of the signed message if your message contains either a line with trailing whitespace, or no final newline. This is a limitation of the Cleartext Signature Framework, which is not designed to be reversible (see Section 7 of RFC 9580).

This overrides any prior call to Signer::detached.

Examples

use std::io::{Write, Read};
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::{Message, Signer};
use openpgp::policy::StandardPolicy;

let p = &StandardPolicy::new();

let mut sink = vec![];
{
    let message = Message::new(&mut sink);
    let mut signer = Signer::new(message, signing_keypair)?
        .cleartext()
        // Customize the `Signer` here.
        .build()?;

    // Write the data directly to the `Signer`.
    signer.write_all(b"Make it so, number one!")?;
    // In reality, just io::copy() the file to be signed.
    signer.finalize()?;
}

// Now check the signature.
struct Helper<'a>(&'a openpgp::Cert);
impl<'a> VerificationHelper for Helper<'a> {
    fn get_certs(&mut self, _: &[openpgp::KeyHandle])
                       -> openpgp::Result<Vec<openpgp::Cert>> {
        Ok(vec![self.0.clone()])
    }

    fn check(&mut self, structure: MessageStructure)
             -> openpgp::Result<()> {
        if let MessageLayer::SignatureGroup { ref results } =
            structure.iter().nth(0).unwrap()
        {
            results.get(0).unwrap().as_ref().unwrap();
            Ok(())
        } else { panic!() }
    }
}

let mut verifier = VerifierBuilder::from_bytes(&sink)?
    .with_policy(p, None, Helper(&cert))?;

let mut content = Vec::new();
verifier.read_to_end(&mut content)?;
assert_eq!(content, b"Make it so, number one!");

pub fn add_signer<S>(self, signer: S) -> Result<Signer<'a>, Error>

where S: Signer + Send + Sync + 'a,

Adds an additional signer.

Can be used multiple times.

Note that some signers only support a subset of hash algorithms, see [crate::crypto::Signer.acceptable_hashes]. If the given signer supports at least one hash from the current set of acceptable hashes, the signer is added and all algorithms not supported by it are removed from the set of acceptable hashes. Otherwise, an error is returned.

Examples

use std::io::Write;
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::{Message, Signer, LiteralWriter};


let message = Message::new(&mut sink);
let message = Signer::new(message, signing_keypair)?
    .add_signer(additional_signing_keypair)?
    .build()?;
let mut message = LiteralWriter::new(message).build()?;
message.write_all(b"Make it so, number one!")?;
message.finalize()?;

pub fn add_intended_recipient(self, recipient: &Cert) -> Signer<'a>

Adds an intended recipient.

Indicates that the given certificate is an intended recipient of this message. Can be used multiple times. This prevents Surreptitious Forwarding of encrypted and signed messages, i.e. forwarding a signed message using a different encryption context.

Examples

use std::io::Write;
use sequoia_openpgp as openpgp;
use openpgp::serialize::stream::{Message, Signer, LiteralWriter};

let recipient: Cert = // ...

let message = Message::new(&mut sink);
let message = Signer::new(message, signing_keypair)?
    .add_intended_recipient(&recipient)
    .build()?;
let mut message = LiteralWriter::new(message).build()?;
message.write_all(b"Make it so, number one!")?;
message.finalize()?;

pub fn hash_algo(self, algo: HashAlgorithm) -> Result<Signer<'a>, Error>

Sets the preferred hash algorithm to use for the signatures.

Note that some signers only support a subset of hash algorithms, see [crate::crypto::Signer.acceptable_hashes]. If the given algorithm is not supported by all signers, an error is returned.

Examples

use std::io::Write;
use sequoia_openpgp as openpgp;
use openpgp::types::HashAlgorithm;
use openpgp::serialize::stream::{Message, Signer, LiteralWriter};


let message = Message::new(&mut sink);
let message = Signer::new(message, signing_keypair)?
    .hash_algo(HashAlgorithm::SHA384)?
    .build()?;
let mut message = LiteralWriter::new(message).build()?;
message.write_all(b"Make it so, number one!")?;
message.finalize()?;

pub fn creation_time<T>(self, creation_time: T) -> Signer<'a>

where T: Into<SystemTime>,

Sets the signature’s creation time to time.

Note: it is up to the caller to make sure the signing keys are actually valid as of time.

Examples

use std::io::Write;
use sequoia_openpgp as openpgp;
use openpgp::types::Timestamp;
use openpgp::serialize::stream::{Message, Signer, LiteralWriter};
use openpgp::policy::StandardPolicy;

let p = &StandardPolicy::new();
let cert: Cert = // ...
let signing_key = cert.keys().secret()
    .with_policy(p, None).supported().alive().revoked(false).for_signing()
    .nth(0).unwrap()
    .key();
let signing_keypair = signing_key.clone().into_keypair()?;

let message = Message::new(&mut sink);
let message = Signer::new(message, signing_keypair)?
    .creation_time(Timestamp::now()
                   .round_down(None, signing_key.creation_time())?)
    .build()?;
let mut message = LiteralWriter::new(message).build()?;
message.write_all(b"Make it so, number one!")?;
message.finalize()?;

pub fn build(self) -> Result<Message<'a>, Error>

Builds the signer, returning the writer stack.

The most useful filter to push to the writer stack next is the LiteralWriter. Note, if you are creating a signed OpenPGP message (see Section 10.3 of RFC 9580), literal data must be wrapped using the LiteralWriter. On the other hand, if you are creating a detached signature (see Section 10.4 of RFC 9580), the literal data must not be wrapped using the LiteralWriter.

Examples

use std::io::Write;
use sequoia_openpgp as openpgp;
use openpgp::types::Timestamp;
use openpgp::serialize::stream::{Message, Signer};

let message = Message::new(&mut sink);
let message = Signer::new(message, signing_keypair)?
    // Customize the `Signer` here.
    .build()?;

Trait Implementations

impl<'a> Debug for Signer<'a>

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

Formats the value using the given formatter.

impl<'a> Write for Signer<'a>

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

Writes a buffer into this writer, returning how many bytes were written.

fn flush(&mut self) -> Result<(), Error>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize, Error>

Like write, except that it writes from a slice of buffers.

fn is_write_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Writer has an efficient write_vectored implementation.

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

Attempts to write an entire buffer into this writer.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

🔬This is a nightly-only experimental API. (write_all_vectored)

Attempts to write multiple buffers into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Writes a formatted string into this writer, returning any error encountered.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.