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implement detached signature generation for pk_calc_signature #6727

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Merged
merged 1 commit into from
Apr 2, 2025
Merged

implement detached signature generation for pk_calc_signature #6727

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59 changes: 45 additions & 14 deletions src/pgp.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,18 +4,21 @@ use std::collections::{BTreeMap, HashSet};
use std::io::{BufRead, Cursor};

use anyhow::{Context as _, Result};
use chrono::SubsecRound;
use deltachat_contact_tools::EmailAddress;
use pgp::armor::BlockType;
use pgp::composed::{
Deserializable, KeyType as PgpKeyType, Message, MessageBuilder, SecretKeyParamsBuilder,
SignedPublicKey, SignedPublicSubKey, SignedSecretKey, StandaloneSignature, SubkeyParamsBuilder,
TheRing,
ArmorOptions, Deserializable, KeyType as PgpKeyType, Message, MessageBuilder,
SecretKeyParamsBuilder, SignedPublicKey, SignedPublicSubKey, SignedSecretKey,
StandaloneSignature, SubkeyParamsBuilder, TheRing,
};
use pgp::crypto::ecc_curve::ECCCurve;
use pgp::crypto::hash::HashAlgorithm;
use pgp::crypto::sym::SymmetricKeyAlgorithm;
use pgp::packet::{SignatureConfig, SignatureType, Subpacket, SubpacketData};
use pgp::types::{
CompressionAlgorithm, KeyDetails, Password, PublicKeyTrait, SignatureBytes, StringToKey,
CompressionAlgorithm, KeyDetails, KeyVersion, Password, PublicKeyTrait, SecretKeyTrait,
SignatureBytes, StringToKey,
};
use rand::thread_rng;
use tokio::runtime::Handle;
Expand Down Expand Up @@ -280,21 +283,49 @@ pub async fn pk_encrypt(
.await?
}

/// Signs `plain` text using `private_key_for_signing`.
/// Produces a detached signature for `plain` text using `private_key_for_signing`.
pub fn pk_calc_signature(
plain: Vec<u8>,
private_key_for_signing: &SignedSecretKey,
) -> Result<String> {
let mut rng = thread_rng();
let signature = MessageBuilder::from_bytes("", plain)
.sign(
&**private_key_for_signing,
Password::empty(),
HASH_ALGORITHM,
)
.to_armored_string(&mut rng, Default::default())?;
let rng = thread_rng();

let mut config = match private_key_for_signing.version() {
KeyVersion::V4 => SignatureConfig::v4(
SignatureType::Binary,
private_key_for_signing.algorithm(),
private_key_for_signing.hash_alg(),
),
KeyVersion::V6 => SignatureConfig::v6(
rng,
SignatureType::Binary,
private_key_for_signing.algorithm(),
private_key_for_signing.hash_alg(),
)?,
v => anyhow::bail!("unsupported key version {:?}", v),
};

Ok(signature)
config.hashed_subpackets = vec![
Subpacket::regular(SubpacketData::IssuerFingerprint(
private_key_for_signing.fingerprint(),
))?,
Subpacket::critical(SubpacketData::SignatureCreationTime(
chrono::Utc::now().trunc_subsecs(0),
))?,
];
config.unhashed_subpackets = vec![Subpacket::regular(SubpacketData::Issuer(
private_key_for_signing.key_id(),
))?];

let signature = config.sign(
&private_key_for_signing.primary_key,
&Password::empty(),
plain.as_slice(),
)?;

let sig = StandaloneSignature::new(signature);

Ok(sig.to_armored_string(ArmorOptions::default())?)
}

/// Decrypts the message with keys from the private key keyring.
Expand Down
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