[program-2022] Add functions to generate mint/burn proofs from account info (#7575)

Author: samkim-crypto

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

@@ -5,7 +5,6 @@ use {
     },
     solana_zk_sdk::{
         encryption::{
-            auth_encryption::{AeCiphertext, AeKey},
             elgamal::{ElGamalCiphertext, ElGamalKeypair, ElGamalPubkey},
             pedersen::Pedersen,
         },
@@ -28,15 +27,13 @@ pub struct MintProofData {
     pub ciphertext_validity_proof_data_with_ciphertext:
         CiphertextValidityProofWithAuditorCiphertext,
     pub range_proof_data: BatchedRangeProofU128Data,
-    pub new_decryptable_supply: AeCiphertext,
 }
 
 pub fn mint_split_proof_data(
     current_supply_ciphertext: &ElGamalCiphertext,
     mint_amount: u64,
     current_supply: u64,
     supply_elgamal_keypair: &ElGamalKeypair,
-    supply_aes_key: &AeKey,
     destination_elgamal_pubkey: &ElGamalPubkey,
     auditor_elgamal_pubkey: Option<&ElGamalPubkey>,
 ) -> Result<MintProofData, TokenProofGenerationError> {
@@ -161,6 +158,5 @@ pub fn mint_split_proof_data(
         equality_proof_data,
         ciphertext_validity_proof_data_with_ciphertext,
         range_proof_data,
-        new_decryptable_supply: supply_aes_key.encrypt(new_supply),
     })
 }

token/confidential-transfer/proof-tests/tests/proof_test.rs

@@ -222,21 +222,18 @@ fn test_mint_validity(mint_amount: u64, supply: u64) {
     let auditor_pubkey = auditor_keypair.pubkey();
 
     let supply_keypair = ElGamalKeypair::new_rand();
-    let supply_aes_key = AeKey::new_rand();
 
     let supply_ciphertext = supply_keypair.pubkey().encrypt(supply);
 
     let MintProofData {
         equality_proof_data,
         ciphertext_validity_proof_data_with_ciphertext,
         range_proof_data,
-        new_decryptable_supply: _,
     } = mint_split_proof_data(
         &supply_ciphertext,
         mint_amount,
         supply,
         &supply_keypair,
-        &supply_aes_key,
         destination_pubkey,
         Some(auditor_pubkey),
     )

token/program-2022/src/extension/confidential_mint_burn/account_info.rs

@@ -1,11 +1,16 @@
 use {
     super::ConfidentialMintBurn,
-    crate::error::TokenError,
+    crate::{
+        error::TokenError,
+        extension::confidential_transfer::{
+            ConfidentialTransferAccount, DecryptableBalance, EncryptedBalance,
+        },
+    },
     bytemuck::{Pod, Zeroable},
     solana_zk_sdk::{
         encryption::{
             auth_encryption::{AeCiphertext, AeKey},
-            elgamal::{ElGamalCiphertext, ElGamalKeypair},
+            elgamal::{ElGamalCiphertext, ElGamalKeypair, ElGamalPubkey},
             pedersen::PedersenOpening,
             pod::{
                 auth_encryption::PodAeCiphertext,
@@ -14,6 +19,10 @@ use {
         },
         zk_elgamal_proof_program::proof_data::CiphertextCiphertextEqualityProofData,
     },
+    spl_token_confidential_transfer_proof_generation::{
+        burn::{burn_split_proof_data, BurnProofData},
+        mint::{mint_split_proof_data, MintProofData},
+    },
 };
 
 /// Confidential Mint Burn extension information needed to construct a
@@ -43,7 +52,7 @@ impl SupplyAccountInfo {
     /// Computes the current supply from the decryptable supply and the
     /// difference between the decryptable supply and the ElGamal encrypted
     /// supply ciphertext
-    pub fn decrypt_current_supply(
+    pub fn decrypted_current_supply(
         &self,
         aes_key: &AeKey,
         elgamal_keypair: &ElGamalKeypair,
@@ -77,12 +86,12 @@ impl SupplyAccountInfo {
     /// `RotateSupplyElgamalPubkey` instruction
     pub fn generate_rotate_supply_elgamal_pubkey_proof(
         &self,
-        aes_key: &AeKey,
         current_supply_elgamal_keypair: &ElGamalKeypair,
         new_supply_elgamal_keypair: &ElGamalKeypair,
+        aes_key: &AeKey,
     ) -> Result<CiphertextCiphertextEqualityProofData, TokenError> {
         let current_supply =
-            self.decrypt_current_supply(aes_key, current_supply_elgamal_keypair)?;
+            self.decrypted_current_supply(aes_key, current_supply_elgamal_keypair)?;
 
         let new_supply_opening = PedersenOpening::new_rand();
         let new_supply_ciphertext = new_supply_elgamal_keypair
@@ -102,4 +111,98 @@ impl SupplyAccountInfo {
         )
         .map_err(|_| TokenError::ProofGeneration)
     }
+
+    /// Create a mint proof data that is split into equality, ciphertext
+    /// validity, and range proof.
+    pub fn generate_split_mint_proof_data(
+        &self,
+        mint_amount: u64,
+        current_supply: u64,
+        supply_elgamal_keypair: &ElGamalKeypair,
+        destination_elgamal_pubkey: &ElGamalPubkey,
+        auditor_elgamal_pubkey: Option<&ElGamalPubkey>,
+    ) -> Result<MintProofData, TokenError> {
+        let current_supply_ciphertext = self
+            .current_supply
+            .try_into()
+            .map_err(|_| TokenError::MalformedCiphertext)?;
+
+        mint_split_proof_data(
+            &current_supply_ciphertext,
+            mint_amount,
+            current_supply,
+            supply_elgamal_keypair,
+            destination_elgamal_pubkey,
+            auditor_elgamal_pubkey,
+        )
+        .map_err(|e| -> TokenError { e.into() })
+    }
+
+    /// Compute the new decryptable supply.
+    pub fn new_decryptable_supply(
+        &self,
+        mint_amount: u64,
+        elgamal_keypair: &ElGamalKeypair,
+        aes_key: &AeKey,
+    ) -> Result<AeCiphertext, TokenError> {
+        let current_decrypted_supply = self.decrypted_current_supply(aes_key, elgamal_keypair)?;
+        let new_decrypted_available_balance = current_decrypted_supply
+            .checked_add(mint_amount)
+            .ok_or(TokenError::Overflow)?;
+
+        Ok(aes_key.encrypt(new_decrypted_available_balance))
+    }
+}
+
+/// Confidential Mint Burn extension information needed to construct a
+/// `Burn` instruction.
+#[repr(C)]
+#[derive(Clone, Copy, Debug, Default, PartialEq, Pod, Zeroable)]
+pub struct BurnAccountInfo {
+    /// The available balance (encrypted by `encryption_pubkey`)
+    pub available_balance: EncryptedBalance,
+    /// The decryptable available balance
+    pub decryptable_available_balance: DecryptableBalance,
+}
+
+impl BurnAccountInfo {
+    /// Create the `ApplyPendingBalance` instruction account information from
+    /// `ConfidentialTransferAccount`.
+    pub fn new(account: &ConfidentialTransferAccount) -> Self {
+        Self {
+            available_balance: account.available_balance,
+            decryptable_available_balance: account.decryptable_available_balance,
+        }
+    }
+
+    /// Create a burn proof data that is split into equality, ciphertext
+    /// validity, and range proof.
+    pub fn generate_split_burn_proof_data(
+        &self,
+        burn_amount: u64,
+        source_elgamal_keypair: &ElGamalKeypair,
+        aes_key: &AeKey,
+        supply_elgamal_pubkey: &ElGamalPubkey,
+        auditor_elgamal_pubkey: Option<&ElGamalPubkey>,
+    ) -> Result<BurnProofData, TokenError> {
+        let current_available_balance_ciphertext = self
+            .available_balance
+            .try_into()
+            .map_err(|_| TokenError::MalformedCiphertext)?;
+        let current_decryptable_available_balance = self
+            .decryptable_available_balance
+            .try_into()
+            .map_err(|_| TokenError::MalformedCiphertext)?;
+
+        burn_split_proof_data(
+            &current_available_balance_ciphertext,
+            &current_decryptable_available_balance,
+            burn_amount,
+            source_elgamal_keypair,
+            aes_key,
+            auditor_elgamal_pubkey,
+            supply_elgamal_pubkey,
+        )
+        .map_err(|e| -> TokenError { e.into() })
+    }
 }