add functions to generate mint/burn proofs from account infos

Author: samkim-crypto

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
@@ -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,
+        aes_key: &AeKey,
+        elgamal_keypair: &ElGamalKeypair,
+    ) -> Result<AeCiphertext, TokenError> {
+        let current_decrypted_supply = self.decrypt_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,
+        auditor_elgamal_pubkey: Option<&ElGamalPubkey>,
+        supply_elgamal_pubkey: &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() })
+    }
 }