[clap-v3-utils] Add `EncodableKeypair` trait and make `confirm_keypair_pubkey` generic (#31642)

* add `EncodableKeypair` trait

* implement `EncodableKeypair` for `Keypair`

* implement `EncodableKeypair` for `ElGamalKeypair

* make confirm pubkey functions generic

* fix a typo

* Update sdk/src/signer/keypair.rs

Co-authored-by: Trent Nelson <trent.a.b.nelson@gmail.com>

* Update clap-v3-utils/src/keypair.rs

Co-authored-by: Tyera <teulberg@gmail.com>

* fix a typo

---------

Co-authored-by: Trent Nelson <trent.a.b.nelson@gmail.com>
Co-authored-by: Tyera <teulberg@gmail.com>

clap-v3-utils/src/keypair.rs

@@ -30,7 +30,7 @@ use {
         pubkey::Pubkey,
         signature::{
             generate_seed_from_seed_phrase_and_passphrase, read_keypair, read_keypair_file,
-            EncodableKey, Keypair, NullSigner, Presigner, Signature, Signer,
+            EncodableKey, EncodableKeypair, Keypair, NullSigner, Presigner, Signature, Signer,
         },
     },
     solana_zk_token_sdk::encryption::{auth_encryption::AeKey, elgamal::ElGamalKeypair},
@@ -1004,23 +1004,11 @@ pub fn keypair_from_path(
 ) -> Result<Keypair, Box<dyn error::Error>> {
     let keypair = encodable_key_from_path(matches, path, keypair_name)?;
     if confirm_pubkey {
-        confirm_keypair_pubkey(&keypair);
+        confirm_encodable_keypair_pubkey(&keypair, "pubkey");
     }
     Ok(keypair)
 }
 
-fn confirm_keypair_pubkey(keypair: &Keypair) {
-    let pubkey = keypair.pubkey();
-    print!("Recovered pubkey `{pubkey:?}`. Continue? (y/n): ");
-    let _ignored = stdout().flush();
-    let mut input = String::new();
-    stdin().read_line(&mut input).expect("Unexpected input");
-    if input.to_lowercase().trim() != "y" {
-        println!("Exiting");
-        exit(1);
-    }
-}
-
 /// Loads an [ElGamalKeypair] from one of several possible sources.
 ///
 /// If `confirm_pubkey` is `true` then after deriving the keypair, the user will
@@ -1063,14 +1051,14 @@ pub fn elgamal_keypair_from_path(
 ) -> Result<ElGamalKeypair, Box<dyn error::Error>> {
     let elgamal_keypair = encodable_key_from_path(matches, path, elgamal_keypair_name)?;
     if confirm_pubkey {
-        confirm_elgamal_keypair_pubkey(&elgamal_keypair);
+        confirm_encodable_keypair_pubkey(&elgamal_keypair, "ElGamal pubkey");
     }
     Ok(elgamal_keypair)
 }
 
-fn confirm_elgamal_keypair_pubkey(keypair: &ElGamalKeypair) {
-    let elgamal_pubkey = keypair.public;
-    print!("Recovered ElGamal pubkey `{elgamal_pubkey:?}`. Continue? (y/n): ");
+fn confirm_encodable_keypair_pubkey<K: EncodableKeypair>(keypair: &K, pubkey_label: &str) {
+    let pubkey = keypair.encodable_pubkey().to_string();
+    println!("Recovered {pubkey_label} `{pubkey:?}`. Continue? (y/n): ");
     let _ignored = stdout().flush();
     let mut input = String::new();
     stdin().read_line(&mut input).expect("Unexpected input");
@@ -1175,7 +1163,7 @@ pub fn keypair_from_seed_phrase(
     let keypair: Keypair =
         encodable_key_from_seed_phrase(keypair_name, skip_validation, derivation_path, legacy)?;
     if confirm_pubkey {
-        confirm_keypair_pubkey(&keypair);
+        confirm_encodable_keypair_pubkey(&keypair, "pubkey");
     }
     Ok(keypair)
 }
@@ -1198,7 +1186,7 @@ pub fn elgamal_keypair_from_seed_phrase(
         legacy,
     )?;
     if confirm_pubkey {
-        confirm_elgamal_keypair_pubkey(&elgamal_keypair);
+        confirm_encodable_keypair_pubkey(&elgamal_keypair, "ElGamal pubkey");
     }
     Ok(elgamal_keypair)
 }

sdk/src/signer/keypair.rs

@@ -5,7 +5,7 @@ use {
         derivation_path::DerivationPath,
         pubkey::Pubkey,
         signature::Signature,
-        signer::{EncodableKey, Signer, SignerError},
+        signer::{EncodableKey, EncodableKeypair, Signer, SignerError},
     },
     ed25519_dalek::Signer as DalekSigner,
     ed25519_dalek_bip32::Error as Bip32Error,
@@ -140,6 +140,16 @@ impl EncodableKey for Keypair {
     }
 }
 
+impl EncodableKeypair for Keypair {
+    type Pubkey = Pubkey;
+
+    /// Returns the associated pubkey. Use this function specifically for settings that involve
+    /// reading or writing pubkeys. For other settings, use `Signer::pubkey()` instead.
+    fn encodable_pubkey(&self) -> Self::Pubkey {
+        self.pubkey()
+    }
+}
+
 /// Reads a JSON-encoded `Keypair` from a `Reader` implementor
 pub fn read_keypair<R: Read>(reader: &mut R) -> Result<Keypair, Box<dyn error::Error>> {
     let bytes: Vec<u8> = serde_json::from_reader(reader)?;

sdk/src/signer/mod.rs

@@ -155,6 +155,15 @@ pub trait EncodableKey: Sized {
     ) -> Result<Self, Box<dyn error::Error>>;
 }
 
+/// The `EncodableKeypair` trait extends `EncodableKey` for asymmetric keypairs, i.e. have
+/// associated public keys.
+pub trait EncodableKeypair: EncodableKey {
+    type Pubkey: ToString;
+
+    /// Returns an encodable representation of the associated public key.
+    fn encodable_pubkey(&self) -> Self::Pubkey;
+}
+
 #[cfg(test)]
 mod tests {
     use {super::*, crate::signer::keypair::Keypair};

zk-token-sdk/src/encryption/elgamal.rs

@@ -33,8 +33,8 @@ use {
         pubkey::Pubkey,
         signature::Signature,
         signer::{
-            keypair::generate_seed_from_seed_phrase_and_passphrase, EncodableKey, Signer,
-            SignerError,
+            keypair::generate_seed_from_seed_phrase_and_passphrase, EncodableKey, EncodableKeypair,
+            Signer, SignerError,
         },
     },
     std::convert::TryInto,
@@ -273,6 +273,14 @@ impl EncodableKey for ElGamalKeypair {
     }
 }
 
+impl EncodableKeypair for ElGamalKeypair {
+    type Pubkey = ElGamalPubkey;
+
+    fn encodable_pubkey(&self) -> Self::Pubkey {
+        self.public
+    }
+}
+
 /// Public key for the ElGamal encryption scheme.
 #[derive(Clone, Copy, Debug, Default, Deserialize, Eq, PartialEq, Serialize, Zeroize)]
 pub struct ElGamalPubkey(RistrettoPoint);