refactor: Update authwit computation (#2651)

Fixes #2448

docs/docs/dev_docs/wallets/writing_an_account_contract.md

@@ -34,9 +34,9 @@ Public Key:  0x0ede151adaef1cfcc1b3e152ea39f00c5cda3f3857cef00decb049d283672dc71
 
 The important part of this contract is the `entrypoint` function, which will be the first function executed in any transaction originated from this account. This function has two main responsibilities: authenticating the transaction and executing calls. It receives a `payload` with the list of function calls to execute, and requests a corresponding auth witness from an oracle to validate it. You will find this logic implemented in the `AccountActions` module, which uses the `EntrypointPayload` struct:
 
-#include_code entrypoint yarn-project/aztec-nr/aztec/src/account.nr rust
+#include_code entrypoint yarn-project/aztec-nr/authwit/src/account.nr rust
 
-#include_code entrypoint-struct yarn-project/aztec-nr/aztec/src/entrypoint.nr rust
+#include_code entrypoint-struct yarn-project/aztec-nr/authwit/src/entrypoint.nr rust
 
 :::info
 Using the `AccountActions` module and the `EntrypointPayload` struct is not mandatory. You can package the instructions to be carried out by your account contract however you want. However, using these modules can save you a lot of time when writing a new account contract, both in Noir and in Typescript.

yarn-project/aztec-nr/authwit/Nargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "auth_wit"
+authors = ["aztec-labs"]
+compiler_version = "0.1"
+type = "lib"
+
+[dependencies]
+aztec = { path = "../aztec" }

yarn-project/aztec-nr/aztec/src/account.nr → yarn-project/aztec-nr/authwit/src/account.nr

@@ -1,8 +1,12 @@
+mod entrypoint;
+mod auth;
+
+use dep::aztec::context::{PrivateContext, PublicContext, Context};
+use dep::aztec::oracle::compute_selector::compute_selector;
+use dep::aztec::state_vars::{map::Map, public_state::PublicState};
+use dep::aztec::types::type_serialization::bool_serialization::{BoolSerializationMethods,BOOL_SERIALIZED_LEN};
+
 use crate::entrypoint::EntrypointPayload;
-use crate::context::{PrivateContext, PublicContext, Context};
-use crate::oracle::compute_selector::compute_selector;
-use crate::state_vars::{map::Map, public_state::PublicState};
-use crate::types::type_serialization::bool_serialization::{BoolSerializationMethods,BOOL_SERIALIZED_LEN};
 use crate::auth::IS_VALID_SELECTOR;
 
 struct AccountActions {

yarn-project/aztec-nr/authwit/src/auth.nr

@@ -0,0 +1,47 @@
+use dep::std::hash::pedersen_with_separator;
+
+use dep::aztec::{
+  context::{PrivateContext, PublicContext, Context},
+  constants_gen::{EMPTY_NULLIFIED_COMMITMENT, GENERATOR_INDEX__SIGNATURE_PAYLOAD},
+  types::address::AztecAddress,
+  abi::hash_args,
+};
+
+global IS_VALID_SELECTOR = 0xe86ab4ff;
+global IS_VALID_PUBLIC_SELECTOR = 0xf3661153;
+
+// @todo #2676 Should use different generator than the payload to limit probability of collisions.
+
+// Assert that `whom` have authorized `message_hash` with a valid authentication witness
+fn assert_valid_authwit(context: &mut PrivateContext, whom: AztecAddress, message_hash: Field) {
+  let result = context.call_private_function(whom.address, IS_VALID_SELECTOR, [message_hash])[0];
+  context.push_new_nullifier(message_hash, EMPTY_NULLIFIED_COMMITMENT);
+  assert(result == IS_VALID_SELECTOR, "Message not authorized by account");
+}
+
+// Assert that `whom` have authorized the current call with a valid authentication witness
+fn assert_current_call_valid_authwit(context: &mut PrivateContext, whom: AztecAddress) {
+  let args = [context.msg_sender(), context.this_address(), context.selector(), context.args_hash];
+  let message_hash = pedersen_with_separator(args, GENERATOR_INDEX__SIGNATURE_PAYLOAD)[0];
+  assert_valid_authwit(context, whom, message_hash);
+}
+
+// Assert that `whom` have authorized `message_hash` in a public context
+fn assert_valid_authwit_public(context: &mut PublicContext, whom: AztecAddress, message_hash: Field) {
+  let result = context.call_public_function(whom.address, IS_VALID_PUBLIC_SELECTOR, [message_hash])[0];
+  context.push_new_nullifier(message_hash, EMPTY_NULLIFIED_COMMITMENT);
+  assert(result == IS_VALID_SELECTOR, "Message not authorized by account");
+}
+
+// Assert that `whom` have authorized the current call in a public context
+fn assert_current_call_valid_authwit_public(context: &mut PublicContext, whom: AztecAddress) {
+  let args = [context.msg_sender(), context.this_address(), context.selector(), context.args_hash];
+  let message_hash = pedersen_with_separator(args, GENERATOR_INDEX__SIGNATURE_PAYLOAD)[0];
+  assert_valid_authwit_public(context, whom, message_hash);
+}
+
+// Compute the message hash to be used by an authentication witness 
+fn compute_authwit_message_hash<N>(caller: AztecAddress, target: AztecAddress, selector: Field, args: [Field; N]) -> Field {
+  let args_hash = hash_args(args);
+  pedersen_with_separator([caller.address, target.address, selector, args_hash], GENERATOR_INDEX__SIGNATURE_PAYLOAD)[0]
+}

yarn-project/aztec-nr/aztec/src/entrypoint.nr → yarn-project/aztec-nr/authwit/src/entrypoint.nr

@@ -1,9 +1,9 @@
-use crate::abi;
-use crate::types::vec::BoundedVec;
-use crate::context::PrivateContext;
-use crate::private_call_stack_item::PrivateCallStackItem;
-use crate::public_call_stack_item::PublicCallStackItem;    
-use crate::constants_gen::GENERATOR_INDEX__SIGNATURE_PAYLOAD;
+use dep::aztec::abi;
+use dep::aztec::types::vec::BoundedVec;
+use dep::aztec::context::PrivateContext;
+use dep::aztec::private_call_stack_item::PrivateCallStackItem;
+use dep::aztec::public_call_stack_item::PublicCallStackItem;    
+use dep::aztec::constants_gen::GENERATOR_INDEX__SIGNATURE_PAYLOAD;
 
 use dep::std::hash;
 

yarn-project/aztec-nr/authwit/src/lib.nr

@@ -0,0 +1,4 @@
+mod account;
+mod auth_witness;
+mod auth;
+mod entrypoint;

yarn-project/aztec-nr/aztec/src/hash.nr

@@ -24,12 +24,6 @@ fn sha256_to_field<N>(bytes_to_hash: [u8; N]) -> Field {
   hash_in_a_field
 }
 
-fn compute_message_hash<N>(args: [Field; N]) -> Field {
-  // @todo @lherskind We should probably use a separate generator for this, 
-  //                  to avoid any potential collisions with payloads.
-  pedersen_with_separator(args, GENERATOR_INDEX__SIGNATURE_PAYLOAD)[0]
-}
-
 fn compute_secret_hash(secret: Field) -> Field {
   // TODO(#1205) This is probably not the right index to use
   pedersen_with_separator([secret], GENERATOR_INDEX__L1_TO_L2_MESSAGE_SECRET)[0]

yarn-project/aztec-nr/aztec/src/lib.nr

@@ -1,10 +1,7 @@
 mod abi;
-mod account;
 mod address;
-mod auth;
 mod constants_gen;
 mod context;
-mod entrypoint;
 mod hash;
 mod log;
 mod messaging;

yarn-project/aztec-nr/aztec/src/oracle.nr

@@ -15,5 +15,4 @@ mod public_call;
 mod notes;
 mod storage;
 mod logs;
-mod compute_selector;
-mod auth_witness;
+mod compute_selector;

yarn-project/aztec.js/src/abis/ecdsa_account_contract.json

@@ -96,7 +96,7 @@
           "name": "payload",
           "type": {
             "kind": "struct",
-            "path": "aztec::entrypoint::EntrypointPayload",
+            "path": "authwit::entrypoint::EntrypointPayload",
             "fields": [
               {
                 "name": "function_calls",
@@ -105,7 +105,7 @@
                   "length": 4,
                   "type": {
                     "kind": "struct",
-                    "path": "aztec::entrypoint::FunctionCall",
+                    "path": "authwit::entrypoint::FunctionCall",
                     "fields": [
                       {
                         "name": "args_hash",

yarn-project/aztec.js/src/abis/schnorr_account_contract.json

@@ -84,7 +84,7 @@
           "name": "payload",
           "type": {
             "kind": "struct",
-            "path": "aztec::entrypoint::EntrypointPayload",
+            "path": "authwit::entrypoint::EntrypointPayload",
             "fields": [
               {
                 "name": "function_calls",
@@ -93,7 +93,7 @@
                   "length": 4,
                   "type": {
                     "kind": "struct",
-                    "path": "aztec::entrypoint::FunctionCall",
+                    "path": "authwit::entrypoint::FunctionCall",
                     "fields": [
                       {
                         "name": "args_hash",

yarn-project/aztec.js/src/abis/schnorr_single_key_account_contract.json

@@ -19,7 +19,7 @@
           "name": "payload",
           "type": {
             "kind": "struct",
-            "path": "aztec::entrypoint::EntrypointPayload",
+            "path": "authwit::entrypoint::EntrypointPayload",
             "fields": [
               {
                 "name": "function_calls",
@@ -28,7 +28,7 @@
                   "length": 4,
                   "type": {
                     "kind": "struct",
-                    "path": "aztec::entrypoint::FunctionCall",
+                    "path": "authwit::entrypoint::FunctionCall",
                     "fields": [
                       {
                         "name": "args_hash",

yarn-project/aztec.js/src/account/defaults/default_entrypoint.ts

@@ -46,7 +46,7 @@ export class DefaultAccountEntrypoint implements EntrypointInterface {
           name: 'payload',
           type: {
             kind: 'struct',
-            path: 'aztec::entrypoint::EntrypointPayload',
+            path: 'authwit::entrypoint::EntrypointPayload',
             fields: [
               {
                 name: 'function_calls',
@@ -55,7 +55,7 @@ export class DefaultAccountEntrypoint implements EntrypointInterface {
                   length: 4,
                   type: {
                     kind: 'struct',
-                    path: 'aztec::entrypoint::FunctionCall',
+                    path: 'authwit::entrypoint::FunctionCall',
                     fields: [
                       {
                         name: 'args_hash',

yarn-project/aztec.js/src/utils/authwit.ts

@@ -0,0 +1,24 @@
+import { AztecAddress, CircuitsWasm, GeneratorIndex } from '@aztec/circuits.js';
+import { pedersenPlookupCompressWithHashIndex } from '@aztec/circuits.js/barretenberg';
+import { FunctionCall, PackedArguments } from '@aztec/types';
+
+/**
+ * Compute an authentication witness message hash from a caller and a request
+ * H(caller: AztecAddress, target: AztecAddress, selector: Field, args_hash: Field)
+ * @param caller - The caller approved to make the call
+ * @param request - The request to be made (function call)
+ * @returns The message hash for the witness
+ */
+export const computeAuthWitMessageHash = async (caller: AztecAddress, request: FunctionCall) => {
+  const wasm = await CircuitsWasm.get();
+  return pedersenPlookupCompressWithHashIndex(
+    wasm,
+    [
+      caller.toField(),
+      request.to.toField(),
+      request.functionData.selector.toField(),
+      (await PackedArguments.fromArgs(request.args, wasm)).hash,
+    ].map(fr => fr.toBuffer()),
+    GeneratorIndex.SIGNATURE_PAYLOAD,
+  );
+};

yarn-project/aztec.js/src/utils/index.ts

@@ -4,3 +4,4 @@ export * from './l1_contracts.js';
 export * from './l2_contracts.js';
 export * from './abi_types.js';
 export * from './cheat_codes.js';
+export * from './authwit.js';

yarn-project/canary/src/uniswap_trade_on_l1_from_l2.test.ts

@@ -6,6 +6,7 @@ import {
   NotePreimage,
   TxHash,
   TxStatus,
+  computeAuthWitMessageHash,
   computeMessageSecretHash,
   createDebugLogger,
   createPXEClient,
@@ -14,7 +15,6 @@ import {
   sleep,
   waitForSandbox,
 } from '@aztec/aztec.js';
-import { FunctionSelector } from '@aztec/circuits.js';
 import { UniswapPortalAbi, UniswapPortalBytecode } from '@aztec/l1-artifacts';
 import { TokenBridgeContract, TokenContract, UniswapContract } from '@aztec/noir-contracts/types';
 
@@ -32,7 +32,7 @@ import {
 import { mnemonicToAccount } from 'viem/accounts';
 import { Chain, foundry } from 'viem/chains';
 
-import { deployAndInitializeTokenAndBridgeContracts, deployL1Contract, hashPayload } from './utils.js';
+import { deployAndInitializeTokenAndBridgeContracts, deployL1Contract } from './utils.js';
 
 const logger = createDebugLogger('aztec:canary');
 
@@ -335,15 +335,12 @@ describe('uniswap_trade_on_l1_from_l2', () => {
     // 4. Owner gives uniswap approval to unshield funds to self on its behalf
     logger('Approving uniswap to unshield funds to self on my behalf');
     const nonceForWETHUnshieldApproval = new Fr(2n);
-    const unshieldToUniswapMessageHash = await hashPayload([
-      uniswapL2Contract.address.toField(),
-      wethL2Contract.address.toField(),
-      FunctionSelector.fromSignature('unshield((Field),(Field),Field,Field)').toField(),
-      ownerAddress.toField(),
-      uniswapL2Contract.address.toField(),
-      new Fr(wethAmountToBridge),
-      nonceForWETHUnshieldApproval,
-    ]);
+    const unshieldToUniswapMessageHash = await computeAuthWitMessageHash(
+      uniswapL2Contract.address,
+      wethL2Contract.methods
+        .unshield(ownerAddress, uniswapL2Contract.address, wethAmountToBridge, nonceForWETHUnshieldApproval)
+        .request(),
+    );
     await ownerWallet.createAuthWitness(Fr.fromBuffer(unshieldToUniswapMessageHash));
 
     // 5. Swap on L1 - sends L2 to L1 message to withdraw WETH to L1 and another message to swap assets.

yarn-project/canary/src/utils.ts

@@ -1,6 +1,4 @@
 import { AztecAddress, EthAddress, Fr, TxStatus, Wallet } from '@aztec/aztec.js';
-import { CircuitsWasm, GeneratorIndex } from '@aztec/circuits.js';
-import { pedersenPlookupCompressWithHashIndex } from '@aztec/circuits.js/barretenberg';
 import { PortalERC20Abi, PortalERC20Bytecode, TokenPortalAbi, TokenPortalBytecode } from '@aztec/l1-artifacts';
 import { TokenBridgeContract, TokenContract } from '@aztec/noir-contracts/types';
 
@@ -136,16 +134,3 @@ export async function deployL1Contract(
 
   return EthAddress.fromString(receipt.contractAddress!);
 }
-
-/**
- * Hash a payload to generate a signature on an account contract
- * @param payload - payload to hash
- * @returns the hashed message
- */
-export const hashPayload = async (payload: Fr[]) => {
-  return pedersenPlookupCompressWithHashIndex(
-    await CircuitsWasm.get(),
-    payload.map(fr => fr.toBuffer()),
-    GeneratorIndex.SIGNATURE_PAYLOAD,
-  );
-};

yarn-project/end-to-end/src/e2e_cross_chain_messaging.test.ts

@@ -1,12 +1,12 @@
-import { AccountWallet, AztecAddress } from '@aztec/aztec.js';
-import { Fr, FunctionSelector } from '@aztec/circuits.js';
+import { AccountWallet, AztecAddress, computeAuthWitMessageHash } from '@aztec/aztec.js';
+import { Fr } from '@aztec/circuits.js';
 import { EthAddress } from '@aztec/foundation/eth-address';
 import { DebugLogger } from '@aztec/foundation/log';
 import { TokenBridgeContract, TokenContract } from '@aztec/noir-contracts/types';
 import { TxStatus } from '@aztec/types';
 
 import { CrossChainTestHarness } from './fixtures/cross_chain_test_harness.js';
-import { delay, hashPayload, setup } from './fixtures/utils.js';
+import { delay, setup } from './fixtures/utils.js';
 
 describe('e2e_cross_chain_messaging', () => {
   let logger: DebugLogger;
@@ -107,14 +107,10 @@ describe('e2e_cross_chain_messaging', () => {
     // 4. Give approval to bridge to burn owner's funds:
     const withdrawAmount = 9n;
     const nonce = Fr.random();
-    const burnMessageHash = await hashPayload([
-      l2Bridge.address.toField(),
-      l2Token.address.toField(),
-      FunctionSelector.fromSignature('burn((Field),Field,Field)').toField(),
-      ownerAddress.toField(),
-      new Fr(withdrawAmount),
-      nonce,
-    ]);
+    const burnMessageHash = await computeAuthWitMessageHash(
+      l2Bridge.address,
+      l2Token.methods.burn(ownerAddress, withdrawAmount, nonce).request(),
+    );
     await user1Wallet.createAuthWitness(burnMessageHash);
 
     // 5. Withdraw owner's funds from L2 to L1
@@ -201,14 +197,10 @@ describe('e2e_cross_chain_messaging', () => {
 
     const withdrawAmount = 9n;
     const nonce = Fr.random();
-    const expectedBurnMessageHash = await hashPayload([
-      l2Bridge.address.toField(),
-      l2Token.address.toField(),
-      FunctionSelector.fromSignature('burn((Field),Field,Field)').toField(),
-      user1Wallet.getAddress().toField(),
-      new Fr(withdrawAmount),
-      nonce,
-    ]);
+    const expectedBurnMessageHash = await computeAuthWitMessageHash(
+      l2Bridge.address,
+      l2Token.methods.burn(user1Wallet.getAddress(), withdrawAmount, nonce).request(),
+    );
     // Should fail as owner has not given approval to bridge burn their funds.
     await expect(
       l2Bridge