Struct sequoia_openpgp::serialize::stream::Signer

source ·

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

Expand description

Signs a message.

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

Implementations§

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impl<'a> Signer<'a>

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pub fn new<S>(inner: Message<'a>, signer: S) -> Self
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 11.4 of RFC 4880), 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!");

source

pub fn with_template<S, T>(inner: Message<'a>, signer: S, template: T) -> Self
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()?;

source

pub fn detached(self) -> Self

Creates a signer for a detached signature.

Changes the Signer to create a detached signature (see Section 11.4 of RFC 4880). 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!")?;

source

pub fn cleartext(self) -> Self

Creates a signer for a cleartext signed message.

Changes the Signer to create a cleartext signed message (see Section 7 of RFC 4880). 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 7.1 of RFC 4880 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 4880).

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!");

source

pub fn add_signer<S>(self, signer: S) -> Self
where S: Signer + Send + Sync + 'a,

Adds an additional signer.

Can be used multiple times.

§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()?;

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pub fn add_intended_recipient(self, recipient: &Cert) -> Self

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()?;

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pub fn hash_algo(self, algo: HashAlgorithm) -> Result<Self>

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 hash selected using this method is not supported by a signer, a hash supported by the signer is selected instead.

§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()?;

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pub fn creation_time<T: Into<SystemTime>>(self, creation_time: T) -> Self

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()?;

source

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

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 11.3 of RFC 4880), literal data must be wrapped using the LiteralWriter. On the other hand, if you are creating a detached signature (see Section 11.4 of RFC 4880), 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()?;