Anon Fee for ABAR to BAR (#249)

src/components/finutils/src/bins/fn.rs

@@ -483,12 +483,7 @@ fn run() -> Result<()> {
                     wallet::public_key_from_bech32(addr).c(d!("invalid wallet address"))
                 })
             })?;
-        let fee_xfr_seckey = match m.value_of("fee-xfr-seckey") {
-            Some(path) => {
-                Some(fs::read_to_string(path).c(d!("Failed to read seckey file"))?)
-            }
-            None => None,
-        };
+        let fee_randomizer = m.value_of("fee-randomizer");
 
         if randomizer.is_none() {
             println!("{}", m.usage());
@@ -498,7 +493,7 @@ fn run() -> Result<()> {
                 randomizer.unwrap(),
                 dec_key,
                 &to,
-                fee_xfr_seckey.as_deref(),
+                fee_randomizer.unwrap(),
                 m.is_present("confidential-amount"),
                 m.is_present("confidential-type"),
             )

src/components/finutils/src/bins/fn.yml

@@ -555,6 +555,13 @@ subcommands:
             takes_value: true
             value_name: RANDOMIZER
             required: true
+        - fee-randomizer:
+            help: Randomizer for the FRA ABAR to pay fee
+            short: F
+            long: fee-randomizer
+            takes_value: true
+            value_name: FEE RANDOMIZER
+            required: true        
         - to-pubkey:
             help: base64-formated `XfrPublicKey` of the receiver
             short: t
@@ -568,12 +575,6 @@ subcommands:
             takes_value: true
             value_name: XFR WALLET ADDRESS
             required: true
-        - fee-xfr-seckey:
-            help: Xfr secret key for fee payment
-            long: fee-xfr-seckey
-            takes_value: true
-            value_name: XFR SECRET KEY
-            required: false
         - confidential-amount:
             help: mask the amount sent on the transaction log
             long: confidential-amount

src/components/finutils/src/common/mod.rs

@@ -37,6 +37,7 @@ use {
         parse_td_validator_keys,
     },
     zei::anon_xfr::{
+        anon_fee::ANON_FEE_MIN,
         keys::{AXfrKeyPair, AXfrPubKey},
         nullifier,
         structs::{AnonBlindAssetRecord, MTLeafInfo, OpenAnonBlindAssetRecordBuilder},
@@ -804,26 +805,27 @@ pub fn convert_bar2abar(
     let oar =
         utils::get_oar(&from, TxoSID(sid)).c(d!("error fetching open asset record"))?;
 
-    let r = utils::generate_bar2abar_op(&from, &to, TxoSID(sid), &oar, &enc_key)?;
+    let r = utils::generate_bar2abar_op(&from, &to, TxoSID(sid), &oar, &enc_key)
+        .c(d!("Bar to abar failed"))?;
 
     Ok(r)
 }
 
-/// Convert an ABAR to a BLind Asset Record
+/// Convert an ABAR to a Blind Asset Record
 pub fn convert_abar2bar(
     axfr_secret_key: String,
     r: &str,
     dec_key: String,
     to: &XfrPublicKey,
-    fee_xfr_seckey: Option<&str>,
+    fr: &str,
     confidential_am: bool,
     confidential_ty: bool,
 ) -> Result<()> {
     let from = wallet::anon_secret_key_from_base64(axfr_secret_key.as_str())
         .c(d!("invalid 'from-axfr-secret-key'"))?;
     let from_secret_key =
         wallet::x_secret_key_from_base64(dec_key.as_str()).c(d!("invalid dec_key"))?;
-    let fee_secret_key = restore_keypair_from_str_with_default(fee_xfr_seckey)?;
+    let from_public_key = XPublicKey::from(&from_secret_key);
 
     let r = wallet::randomizer_from_base58(r).c(d!())?;
     let randomized_from_pub_key = from.pub_key().randomize(&r);
@@ -860,14 +862,61 @@ pub fn convert_abar2bar(
         ));
     }
 
+    let fr = wallet::randomizer_from_base58(fr).c(d!())?;
+    let fee_randomized_key = from.pub_key().randomize(&fr);
+    let fee_axtxo_abar = utils::get_owned_abars(&fee_randomized_key).c(d!())?;
+    let fee_owner_memo = utils::get_abar_memo(&fee_axtxo_abar[0].0).c(d!())?.unwrap();
+    let fee_mt_leaf_info = utils::get_abar_proof(&fee_axtxo_abar[0].0)
+        .c(d!())?
+        .unwrap();
+
+    let fee_oabar = OpenAnonBlindAssetRecordBuilder::from_abar(
+        &fee_axtxo_abar[0].1,
+        fee_owner_memo,
+        &from,
+        &from_secret_key,
+    )
+    .unwrap()
+    .mt_leaf_info(fee_mt_leaf_info)
+    .build()
+    .unwrap();
+
+    let mut prng = ChaChaRng::from_entropy();
+    let out_fee_oabar = OpenAnonBlindAssetRecordBuilder::new()
+        .amount(fee_oabar.get_amount() - ANON_FEE_MIN)
+        .asset_type(fee_oabar.get_asset_type())
+        .pub_key(from.pub_key())
+        .finalize(&mut prng, &from_public_key)
+        .unwrap()
+        .build()
+        .unwrap();
+
     let art = match (confidential_am, confidential_ty) {
         (true, true) => AssetRecordType::ConfidentialAmount_ConfidentialAssetType,
         (true, false) => AssetRecordType::ConfidentialAmount_NonConfidentialAssetType,
         (false, true) => AssetRecordType::NonConfidentialAmount_ConfidentialAssetType,
         _ => AssetRecordType::NonConfidentialAmount_NonConfidentialAssetType,
     };
 
-    utils::generate_abar2bar_op(&oabar_in, &from, to, art, &fee_secret_key).c(d!())?;
+    utils::generate_abar2bar_op(&oabar_in, &fee_oabar, &out_fee_oabar, &from, to, art)
+        .c(d!())?;
+
+    println!(
+        "\x1b[31;01m Fee Remainder Randomizer: {}\x1b[00m",
+        wallet::randomizer_to_base58(&out_fee_oabar.get_key_rand_factor())
+    );
+    let mut file = fs::OpenOptions::new()
+        .append(true)
+        .create(true)
+        .open("owned_randomizers")
+        .expect("cannot open randomizers file");
+    std::io::Write::write_all(
+        &mut file,
+        ("\n".to_owned()
+            + &wallet::randomizer_to_base58(&out_fee_oabar.get_key_rand_factor()))
+            .as_bytes(),
+    )
+    .expect("randomizer write failed");
     Ok(())
 }
 

src/components/finutils/src/common/utils.rs

@@ -726,31 +726,36 @@ pub fn generate_bar2abar_op(
             input_record,
             enc_key,
         )
-        .c(d!())?;
+        .c(d!("Failed to generate operation bar to abar"))?;
 
-    let feeop = gen_fee_bar_to_abar(auth_key_pair, txo_sid).c(d!())?;
+    let feeop =
+        gen_fee_bar_to_abar(auth_key_pair, txo_sid).c(d!("Failed to generate fee"))?;
     builder.add_operation(feeop);
 
-    send_tx(&builder.take_transaction()).c(d!())?;
+    send_tx(&builder.take_transaction()).c(d!("Failed to submit Bar to Abar txn"))?;
     Ok(r)
 }
 
 #[inline(always)]
 #[allow(missing_docs)]
 pub fn generate_abar2bar_op(
     oabar_in: &OpenAnonBlindAssetRecord,
+    fee_oabar: &OpenAnonBlindAssetRecord,
+    out_fee_oabar: &OpenAnonBlindAssetRecord,
     from: &AXfrKeyPair,
     to: &XfrPublicKey,
     art: AssetRecordType,
-    fee_keypair: &XfrKeyPair,
 ) -> Result<()> {
     let mut builder: TransactionBuilder = new_tx_builder().c(d!())?;
     builder
         .add_operation_abar_to_bar(oabar_in, from, to, art)
         .c(d!())?;
 
-    let feeop = gen_fee_op(fee_keypair).c(d!())?;
-    builder.add_operation(feeop);
+    /* let feeop = gen_fee_op(fee_keypair).c(d!())?;
+    builder.add_operation(feeop); */
+    builder
+        .add_operation_anon_fee(fee_oabar, out_fee_oabar, from)
+        .c(d!())?;
 
     send_tx(&builder.take_transaction()).c(d!())?;
     Ok(())

src/components/finutils/src/txn_builder/mod.rs

@@ -7,7 +7,6 @@
 
 mod amount;
 
-use ledger::data_model::AbarToBarOps;
 use {
     credentials::CredUserSecretKey,
     crypto::basics::hybrid_encryption::XPublicKey,
@@ -17,9 +16,10 @@ use {
     ledger::{
         converter::ConvertAccount,
         data_model::{
-            AnonTransferOps, AssetRules, AssetTypeCode, BarToAbarOps, ConfidentialMemo,
-            DefineAsset, DefineAssetBody, IndexedSignature, IssueAsset, IssueAssetBody,
-            IssuerKeyPair, IssuerPublicKey, Memo, NoReplayToken, Operation, Transaction,
+            AbarToBarOps, AnonFeeOps, AnonTransferOps, AssetRules, AssetTypeCode,
+            BarToAbarOps, ConfidentialMemo, DefineAsset, DefineAssetBody,
+            IndexedSignature, IssueAsset, IssueAssetBody, IssuerKeyPair,
+            IssuerPublicKey, Memo, NoReplayToken, Operation, Transaction,
             TransactionBody, TransferAsset, TransferAssetBody, TransferType, TxOutput,
             TxoRef, TxoSID, UpdateMemo, UpdateMemoBody, ASSET_TYPE_FRA,
             BLACK_HOLE_PUBKEY, TX_FEE_MIN,
@@ -51,6 +51,7 @@ use {
     zei::{
         anon_xfr::{
             abar_to_bar::gen_abar_to_bar_note,
+            anon_fee::{gen_anon_fee_body, AnonFeeNote},
             bar_to_abar::gen_bar_to_abar_body,
             config::FEE_CALCULATING_FUNC,
             gen_anon_xfr_body,
@@ -562,6 +563,27 @@ impl TransactionBuilder {
         Ok(self)
     }
 
+    /// Add an operation to charge fee anonymously for ABAR to BAR transfer
+    #[allow(dead_code)]
+    pub fn add_operation_anon_fee(
+        &mut self,
+        input: &OpenAnonBlindAssetRecord,
+        output: &OpenAnonBlindAssetRecord,
+        input_keypair: &AXfrKeyPair,
+    ) -> Result<(&mut Self, AnonFeeNote)> {
+        let mut prng = ChaChaRng::from_entropy();
+        let user_params = UserParams::anon_fee_params(MERKLE_TREE_DEPTH)?;
+
+        let (body, keypairs) =
+            gen_anon_fee_body(&mut prng, &user_params, input, output, input_keypair)
+                .c(d!())?;
+        let note = AnonFeeNote::generate_note_from_body(body, keypairs).c(d!())?;
+        let inp = AnonFeeOps::new(note.clone(), self.no_replay_token).c(d!())?;
+        let op = Operation::AnonymousFee(Box::new(inp));
+        self.txn.add_operation(op);
+        Ok((self, note))
+    }
+
     /// Add an operation to transfer assets held in Anonymous Blind Asset Record.
     #[allow(dead_code)]
     pub fn add_operation_anon_transfer(
@@ -1426,17 +1448,14 @@ impl AnonTransferOperationBuilder {
 
         let fra_excess = fra_input_sum - fra_output_sum;
 
-        let boolean = estimated_fees > fra_excess;
-
-        let outcome = match boolean {
-            true => FEE_CALCULATING_FUNC(
+        if estimated_fees > fra_excess {
+            FEE_CALCULATING_FUNC(
                 self.inputs.len() as u32 + 1,
                 self.outputs.len() as u32 + 1,
-            ) as u64,
-            false => 0u64,
-        };
-
-        outcome
+            ) as u64
+        } else {
+            0u64
+        }
     }
 
     /// get_randomizers fetches the randomizers for the different outputs.

src/components/wasm/src/wasm.rs

@@ -66,6 +66,7 @@ use {
     wasm_bindgen::prelude::*,
     zei::{
         anon_xfr::{
+            anon_fee::ANON_FEE_MIN,
             keys::{AXfrKeyPair, AXfrPubKey},
             nullifier,
             structs::{
@@ -160,16 +161,6 @@ pub fn get_null_pk() -> XfrPublicKey {
 pub struct RandomizerStringArray {
     randomizers: Vec<String>,
 }
-/*
-#[wasm_bindgen]
-pub struct OBlindAssetRecord{
-    oabar: OpenAnonBlindAssetRecord,
-}
-
-impl OBlindAssetRecord{
-    pub fn get_oabar(&self) -> &OpenAnonBlindAssetRecord{&self.oabar}
-}
- */
 
 #[wasm_bindgen]
 /// Structure that allows users to construct arbitrary transactions.
@@ -560,6 +551,57 @@ impl TransactionBuilder {
         Ok(self)
     }
 
+    /// Adds an anon fee operation to transaction builder for abar to a bar.
+    ///
+    /// @param {AnonBlindAssetRecord} input - the ABAR to be used for fee
+    /// @param {OwnerMemo} owner_memo - the corresponding owner_memo of the fee ABAR
+    /// @param {MTLeafInfo} mt_leaf_info - the Merkle Proof of the ABAR
+    /// @param {AXfrKeyPair} from_keypair - the owners Anon Key pair
+    /// @param {XSecretKey} from_dec_key - the owners decryption key
+    pub fn add_operation_anon_fee(
+        mut self,
+        input: AnonBlindAssetRecord,
+        owner_memo: OwnerMemo,
+        mt_leaf_info: MTLeafInfo,
+        from_keypair: AXfrKeyPair,
+        from_dec_key: XSecretKey,
+    ) -> Result<TransactionBuilder, JsValue> {
+        let fee_oabar = OpenAnonBlindAssetRecordBuilder::from_abar(
+            &input,
+            owner_memo.memo,
+            &from_keypair,
+            &from_dec_key,
+        )
+        .c(d!())
+        .map_err(|e| JsValue::from_str(&format!("Could not add operation: {}", e)))?
+        .mt_leaf_info(mt_leaf_info.get_zei_mt_leaf_info().clone())
+        .build()
+        .c(d!())
+        .map_err(|e| JsValue::from_str(&format!("Could not add operation: {}", e)))?;
+
+        let mut prng = ChaChaRng::from_entropy();
+        let from_public_key = XPublicKey::from(&from_dec_key);
+        let rem_oabar = OpenAnonBlindAssetRecordBuilder::new()
+            .amount(fee_oabar.get_amount() - ANON_FEE_MIN)
+            .asset_type(fee_oabar.get_asset_type())
+            .pub_key(from_keypair.pub_key())
+            .finalize(&mut prng, &from_public_key)
+            .unwrap()
+            .build()
+            .unwrap();
+
+        self.get_builder_mut()
+            .add_operation_anon_fee(&fee_oabar, &rem_oabar, &from_keypair)
+            .c(d!())
+            .map_err(|e| {
+                JsValue::from_str(&format!("Could not add operation: {}", e))
+            })?;
+
+        let r = rem_oabar.get_key_rand_factor();
+        self.randomizers.push(r);
+        Ok(self)
+    }
+
     /// Returns a list of randomizer base58 strings as json
     pub fn get_randomizers(&self) -> JsValue {
         let r = RandomizerStringArray {
@@ -1732,9 +1774,6 @@ use rand_core::{CryptoRng, RngCore};
 use ring::pbkdf2;
 use std::num::NonZeroU32;
 use std::str;
-use zei::anon_xfr::config::FEE_CALCULATING_FUNC;
-use zei::xfr::structs::AssetType;
-//use ledger::store::LedgerState;
 
 #[wasm_bindgen]
 /// Returns bech32 encoded representation of an XfrPublicKey.
@@ -2114,9 +2153,8 @@ mod test {
 
     fn gen_oabar_and_keys<R: CryptoRng + RngCore>(
         prng: &mut R,
-        //amount: u64,
         amount: u64,
-        asset_type: AssetType,
+        asset_type: ZeiAssetType,
     ) -> (
         OpenAnonBlindAssetRecord,
         AXfrKeyPair,