review fixes

Author: abcalphabet

token/confidential-transfer/proof-generation/src/lib.rs

@@ -10,6 +10,7 @@ pub mod burn;
 pub mod encryption;
 pub mod errors;
 pub mod mint;
+pub mod supply;
 pub mod transfer;
 pub mod transfer_with_fee;
 pub mod withdraw;

token/confidential-transfer/proof-generation/src/mint.rs

@@ -80,7 +80,7 @@ pub fn mint_split_proof_data(
         .ok_or(TokenProofGenerationError::IllegalAmountBitLength)?;
 
     // fresh mints are initialized with a zeroed decryptable_supply
-    // TODO: @samkim is there a better way to do this?
+    // TODO: don't clone here once AeCiphertext implement Copy in the zk-sdk
     let pod_decryptable_supply: PodAeCiphertext = current_decryptable_supply.clone().into();
     let current_decyptable_supply = if pod_decryptable_supply != PodAeCiphertext::default() {
         // decrypt the current supply

token/confidential-transfer/proof-generation/src/supply.rs

@@ -0,0 +1,31 @@
+use {
+    crate::errors::TokenProofGenerationError,
+    solana_zk_sdk::{
+        encryption::{
+            elgamal::{ElGamalCiphertext, ElGamalKeypair},
+            pedersen::PedersenOpening,
+        },
+        zk_elgamal_proof_program::proof_data::CiphertextCiphertextEqualityProofData,
+    },
+};
+
+pub fn supply_elgamal_pubkey_rotation_proof(
+    current_supply: u64,
+    supply_elgamal_keypair: &ElGamalKeypair,
+    new_supply_elgamal_keypair: &ElGamalKeypair,
+    current_supply_ciphertext: ElGamalCiphertext,
+) -> Result<CiphertextCiphertextEqualityProofData, TokenProofGenerationError> {
+    let new_supply_opening = PedersenOpening::new_rand();
+    let new_supply_ciphertext = new_supply_elgamal_keypair
+        .pubkey()
+        .encrypt_with(current_supply, &new_supply_opening);
+
+    Ok(CiphertextCiphertextEqualityProofData::new(
+        supply_elgamal_keypair,
+        new_supply_elgamal_keypair.pubkey(),
+        &current_supply_ciphertext,
+        &new_supply_ciphertext,
+        &new_supply_opening,
+        current_supply,
+    )?)
+}