Don't use Cert to build signer and decryptor.

Rename decryptor/signer/authenticator getters.
Add alternatives that don't require PublicKey parameter.

openpgp-card-sequoia/examples/test.rs

@@ -163,15 +163,13 @@ fn main() -> Result<(), Box<dyn Error>> {
             .user_card()
             .expect("We just validated, this should not fail");
 
-        let cert = Cert::from_file(TEST_KEY_PATH)?;
+        let _cert = Cert::from_file(TEST_KEY_PATH)?;
         let msg = std::fs::read_to_string(TEST_ENC_MSG).expect("Unable to read file");
 
         println!("Encrypted message:\n{}", msg);
 
         let sp = StandardPolicy::new();
-        let d = user.decryptor(&cert, &|| {
+        let d = user.decryptor(&|| println!("Touch confirmation needed for decryption"))?;
-            println!("Touch confirmation needed for decryption")
-        })?;
         let res = sq_util::decryption_helper(d, msg.into_bytes(), &sp)?;
 
         let plain = String::from_utf8_lossy(&res);
@@ -194,11 +192,11 @@ fn main() -> Result<(), Box<dyn Error>> {
         // Use Sign access to card
         let mut sign = open.signing_card().expect("just verified");
 
-        let cert = Cert::from_file(TEST_KEY_PATH)?;
+        let _cert = Cert::from_file(TEST_KEY_PATH)?;
 
         let text = "Hello world, I am signed.";
 
-        let signer = sign.signer(&cert, &|| {})?;
+        let signer = sign.signer(&|| {})?;
         let sig = sq_util::sign_helper(signer, &mut text.as_bytes())?;
 
         println!("Signature from card:\n{}", sig)

openpgp-card-sequoia/src/card.rs

@@ -7,7 +7,6 @@
 use sequoia_openpgp::cert::amalgamation::key::ValidErasedKeyAmalgamation;
 use sequoia_openpgp::packet::key::SecretParts;
 use sequoia_openpgp::types::{HashAlgorithm, SymmetricAlgorithm};
-use sequoia_openpgp::Cert;
 
 use openpgp_card::algorithm::{Algo, AlgoInfo, AlgoSimple};
 use openpgp_card::card_do::{
@@ -15,13 +14,13 @@ use openpgp_card::card_do::{
     ExtendedLengthInfo, Fingerprint, HistoricalBytes, KeyGenerationTime, Lang, PWStatusBytes,
     SecuritySupportTemplate, Sex, TouchPolicy,
 };
+use openpgp_card::crypto_data::PublicKeyMaterial;
 use openpgp_card::{Error, KeySet, KeyType, OpenPgpTransaction};
 
 use crate::decryptor::CardDecryptor;
 use crate::signer::CardSigner;
 use crate::util::{public_to_fingerprint, vka_as_uploadable_key};
 use crate::PublicKey;
-use openpgp_card::crypto_data::PublicKeyMaterial;
 
 /// Representation of an opened OpenPGP card in its base state (i.e. no
 /// passwords have been verified, default authorization applies).
@@ -340,13 +339,40 @@ pub struct User<'app, 'open> {
 impl<'app, 'open> User<'app, 'open> {
     pub fn decryptor(
         &mut self,
-        cert: &Cert,
         touch_prompt: &'open (dyn Fn() + Send + Sync),
     ) -> Result<CardDecryptor<'_, 'app>, Error> {
-        CardDecryptor::new(&mut self.oc.opt, cert, touch_prompt)
+        let pk = crate::util::key_slot(self.oc, KeyType::Decryption)?
+            .expect("Couldn't get decryption pubkey from card");
+
+        Ok(CardDecryptor::with_pubkey(
+            &mut self.oc.opt,
+            pk,
+            touch_prompt,
+        ))
+    }
+
+    pub fn decryptor_from_public(
+        &mut self,
+        pubkey: PublicKey,
+        touch_prompt: &'open (dyn Fn() + Send + Sync),
+    ) -> CardDecryptor<'_, 'app> {
+        CardDecryptor::with_pubkey(&mut self.oc.opt, pubkey, touch_prompt)
     }
 
     pub fn authenticator(
+        &mut self,
+        touch_prompt: &'open (dyn Fn() + Send + Sync),
+    ) -> Result<CardSigner<'_, 'app>, Error> {
+        let pk = crate::util::key_slot(self.oc, KeyType::Authentication)?
+            .expect("Couldn't get authentication pubkey from card");
+
+        Ok(CardSigner::with_pubkey_for_auth(
+            &mut self.oc.opt,
+            pk,
+            touch_prompt,
+        ))
+    }
+    pub fn authenticator_from_public(
         &mut self,
         pubkey: PublicKey,
         touch_prompt: &'open (dyn Fn() + Send + Sync),
@@ -364,16 +390,18 @@ pub struct Sign<'app, 'open> {
 impl<'app, 'open> Sign<'app, 'open> {
     pub fn signer(
         &mut self,
-        cert: &Cert,
         touch_prompt: &'open (dyn Fn() + Send + Sync),
-    ) -> std::result::Result<CardSigner<'_, 'app>, Error> {
+    ) -> Result<CardSigner<'_, 'app>, Error> {
         // FIXME: depending on the setting in "PW1 Status byte", only one
         // signature can be made after verification for signing
 
-        CardSigner::with_cert(&mut self.oc.opt, cert, touch_prompt)
+        let pk = crate::util::key_slot(self.oc, KeyType::Signing)?
+            .expect("Couldn't get signing pubkey from card");
+
+        Ok(CardSigner::with_pubkey(&mut self.oc.opt, pk, touch_prompt))
     }
 
-    pub fn signer_from_pubkey(
+    pub fn signer_from_public(
         &mut self,
         pubkey: PublicKey,
         touch_prompt: &'open (dyn Fn() + Send + Sync),

openpgp-card-sequoia/src/decryptor.rs

@@ -9,13 +9,11 @@ use openpgp::crypto::SessionKey;
 use openpgp::packet;
 use openpgp::parse::stream::{DecryptionHelper, MessageStructure, VerificationHelper};
 use openpgp::types::{Curve, SymmetricAlgorithm};
-use openpgp::Cert;
 use sequoia_openpgp as openpgp;
 
 use openpgp_card::crypto_data::Cryptogram;
-use openpgp_card::{Error, OpenPgpTransaction};
+use openpgp_card::OpenPgpTransaction;
 
-use crate::sq_util;
 use crate::PublicKey;
 
 pub struct CardDecryptor<'a, 'app> {
@@ -30,41 +28,15 @@ pub struct CardDecryptor<'a, 'app> {
 }
 
 impl<'a, 'app> CardDecryptor<'a, 'app> {
-    /// Try to create a CardDecryptor.
+    pub(crate) fn with_pubkey(
-    ///
-    /// An Error is returned if no match between the card's decryption
-    /// key and a (sub)key of `cert` can be made.
-    pub fn new(
         ca: &'a mut OpenPgpTransaction<'app>,
-        cert: &Cert,
+        public: PublicKey,
         touch_prompt: &'a (dyn Fn() + Send + Sync),
-    ) -> Result<CardDecryptor<'a, 'app>, Error> {
+    ) -> CardDecryptor<'a, 'app> {
-        // Get the fingerprint for the decryption key from the card.
+        Self {
-        let ard = ca.application_related_data()?;
+            ca,
-        let fps = ard.fingerprints()?;
+            public,
-        let fp = fps.decryption();
+            touch_prompt,
-
-        if let Some(fp) = fp {
-            // Transform into Sequoia Fingerprint
-            let fp = openpgp::Fingerprint::from_bytes(fp.as_bytes());
-
-            if let Some(eka) = sq_util::get_subkey_by_fingerprint(cert, &fp)? {
-                let public = eka.key().clone();
-                Ok(Self {
-                    ca,
-                    public,
-                    touch_prompt,
-                })
-            } else {
-                Err(Error::InternalError(format!(
-                    "Failed to find (sub)key {} in cert",
-                    fp
-                )))
-            }
-        } else {
-            Err(Error::InternalError(
-                "Failed to get the decryption key's Fingerprint from the card".to_string(),
-            ))
         }
     }
 }

openpgp-card-sequoia/src/lib.rs

@@ -67,13 +67,8 @@
 //! open.verify_user(b"123456")?;
 //! let mut user = open.user_card().expect("This should not fail");
 //!
-//! // Get decryptor (`cert` must contain a public key that corresponds
+//! // Get decryptor
-//! // to the key material on the card)
+//! let decryptor = user.decryptor(&|| { println!("Touch confirmation needed for decryption") });
-//! # use sequoia_openpgp::cert::CertBuilder;
-//! # let (cert, _) =
-//! #   CertBuilder::general_purpose(None, Some("alice@example.org"))
-//! #       .generate()?;
-//! let decryptor = user.decryptor(&cert, &|| { println!("Touch confirmation needed for decryption") });
 //!
 //! // Perform decryption operation(s)
 //! // ..
@@ -110,13 +105,8 @@
 //! open.verify_user_for_signing(b"123456")?;
 //! let mut user = open.signing_card().expect("This should not fail");
 //!
-//! // Get signer (`cert` must contain a public key that corresponds
+//! // Get signer
-//! // to the key material on the card)
+//! let signer = user.signer(&|| println!("Touch confirmation needed for signing"));
-//! # use sequoia_openpgp::cert::CertBuilder;
-//! # let (cert, _) =
-//! #   CertBuilder::general_purpose(None, Some("alice@example.org"))
-//! #       .generate()?;
-//! let signer = user.signer(&cert, &|| println!("Touch confirmation needed for signing"));
 //!
 //! // Perform signing operation(s)
 //! // ..

openpgp-card-sequoia/src/signer.rs

@@ -11,9 +11,8 @@ use openpgp::types::{Curve, PublicKeyAlgorithm};
 use sequoia_openpgp as openpgp;
 
 use openpgp_card::crypto_data::Hash;
-use openpgp_card::{Error, OpenPgpTransaction};
+use openpgp_card::OpenPgpTransaction;
 
-use crate::sq_util;
 use crate::PublicKey;
 
 pub struct CardSigner<'a, 'app> {
@@ -31,40 +30,6 @@ pub struct CardSigner<'a, 'app> {
 }
 
 impl<'a, 'app> CardSigner<'a, 'app> {
-    /// Try to create a CardSigner.
-    ///
-    /// An Error is returned if no match between the card's signing
-    /// key and a (sub)key of `cert` can be made.
-    pub(crate) fn with_cert(
-        ca: &'a mut OpenPgpTransaction<'app>,
-        cert: &openpgp::Cert,
-        touch_prompt: &'a (dyn Fn() + Send + Sync),
-    ) -> Result<CardSigner<'a, 'app>, Error> {
-        // Get the fingerprint for the signing key from the card.
-        let ard = ca.application_related_data()?;
-        let fps = ard.fingerprints()?;
-        let fp = fps.signature();
-
-        if let Some(fp) = fp {
-            // Transform into Sequoia Fingerprint
-            let fp = openpgp::Fingerprint::from_bytes(fp.as_bytes());
-
-            if let Some(eka) = sq_util::get_subkey_by_fingerprint(cert, &fp)? {
-                let key = eka.key().clone();
-                Ok(Self::with_pubkey(ca, key, touch_prompt))
-            } else {
-                Err(Error::InternalError(format!(
-                    "Failed to find (sub)key {} in cert",
-                    fp
-                )))
-            }
-        } else {
-            Err(Error::InternalError(
-                "Failed to get the signing key's Fingerprint from the card".to_string(),
-            ))
-        }
-    }
-
     pub(crate) fn with_pubkey(
         ca: &'a mut OpenPgpTransaction<'app>,
         public: PublicKey,

openpgp-card-sequoia/src/util.rs

@@ -29,11 +29,13 @@ use sequoia_openpgp::types::{HashAlgorithm, SymmetricAlgorithm};
 use openpgp_card::algorithm::{Algo, Curve};
 use openpgp_card::card_do::{Fingerprint, KeyGenerationTime};
 use openpgp_card::crypto_data::{CardUploadableKey, PublicKeyMaterial};
-use openpgp_card::{Error, KeyType, OpenPgpTransaction};
+use openpgp_card::{Error, KeyType};
 
 use crate::card::Open;
+use crate::decryptor::CardDecryptor;
 use crate::privkey::SequoiaKey;
-use crate::{decryptor, signer, PublicKey};
+use crate::signer::CardSigner;
+use crate::PublicKey;
 
 /// Create a Cert from the three subkeys on a card.
 /// (Calling this multiple times will result in different Certs!)
@@ -85,7 +87,7 @@ pub fn make_cert<'app>(
             }
             if let Some(mut sign) = open.signing_card() {
                 // Card-backed signer for bindings
-                let mut card_signer = sign.signer_from_pubkey(key_sig.clone(), touch_prompt);
+                let mut card_signer = sign.signer_from_public(key_sig.clone(), touch_prompt);
 
                 let signing_bsig: Packet = sub_dec
                     .bind(&mut card_signer, &cert, signing_builder)?
@@ -116,7 +118,7 @@ pub fn make_cert<'app>(
             }
             if let Some(mut sign) = open.signing_card() {
                 // Card-backed signer for bindings
-                let mut card_signer = sign.signer_from_pubkey(key_sig.clone(), touch_prompt);
+                let mut card_signer = sign.signer_from_public(key_sig.clone(), touch_prompt);
 
                 // Temporary version of the cert
                 let cert = Cert::try_from(pp.clone())?;
@@ -159,7 +161,7 @@ pub fn make_cert<'app>(
 
             if let Some(mut sign) = open.signing_card() {
                 // Card-backed signer for bindings
-                let mut card_signer = sign.signer_from_pubkey(key_sig, touch_prompt);
+                let mut card_signer = sign.signer_from_public(key_sig, touch_prompt);
 
                 // Temporary version of the cert
                 let cert = Cert::try_from(pp.clone())?;
@@ -238,7 +240,7 @@ pub fn public_key_material_and_fp_to_key(
 }
 
 /// Get a PublicKey representation for a key slot on the card
-pub fn key_slot(open: &mut Open, kt: KeyType) -> Result<Option<PublicKey>> {
+pub fn key_slot(open: &mut Open, kt: KeyType) -> Result<Option<PublicKey>, Error> {
     // FIXME: only read these once, if multiple subkeys are retrieved from the card
     let times = open.key_generation_times()?;
     let fps = open.fingerprints()?;
@@ -425,17 +427,9 @@ pub fn vka_as_uploadable_key(
     Box::new(sqk)
 }
 
-/// FIXME: this fn is used in card_functionality, but should be removed
+pub fn sign(s: CardSigner, input: &mut dyn io::Read) -> Result<String> {
-pub fn sign(
-    card_tx: &'_ mut OpenPgpTransaction<'_>,
-    cert: &Cert,
-    input: &mut dyn io::Read,
-    touch_prompt: &(dyn Fn() + Send + Sync),
-) -> Result<String> {
     let mut armorer = armor::Writer::new(vec![], armor::Kind::Signature)?;
     {
-        let s = signer::CardSigner::with_cert(card_tx, cert, touch_prompt)?;
-
         let message = Message::new(&mut armorer);
         let mut message = Signer::new(message, s).detached().build()?;
 
@@ -450,20 +444,11 @@ pub fn sign(
     String::from_utf8(buffer).context("Failed to convert signature to utf8")
 }
 
-/// FIXME: this fn is used in card_functionality, but should be removed
+pub fn decrypt(d: CardDecryptor, msg: Vec<u8>, p: &dyn Policy) -> Result<Vec<u8>> {
-pub fn decrypt(
-    card_tx: &'_ mut OpenPgpTransaction<'_>,
-    cert: &Cert,
-    msg: Vec<u8>,
-    touch_prompt: &(dyn Fn() + Send + Sync),
-    p: &dyn Policy,
-) -> Result<Vec<u8>> {
     let mut decrypted = Vec::new();
     {
         let reader = io::BufReader::new(&msg[..]);
 
-        let d = decryptor::CardDecryptor::new(card_tx, cert, touch_prompt)?;
-
         let db = DecryptorBuilder::from_reader(reader)?;
         let mut decryptor = db.with_policy(p, None, d)?;