Merge pull request #68 from zama-ai/updates-encrypted-erc20

refactor: updates EncryptedERC20 and other versions inheriting

.husky/pre-commit

@@ -1 +1,2 @@
 pnpm --no-install prettier:check
+pnpm --no-install lint:sol

contracts/test/utils/TestEncryptedErrors.sol

@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: BSD-3-Clause-Clear
+pragma solidity ^0.8.24;
+
+import "fhevm/lib/TFHE.sol";
+import { EncryptedErrors } from "../../utils/EncryptedErrors.sol";
+import { MockZamaFHEVMConfig } from "fhevm/config/ZamaFHEVMConfig.sol";
+
+contract TestEncryptedErrors is MockZamaFHEVMConfig, EncryptedErrors {
+    constructor(uint8 totalNumberErrorCodes_) EncryptedErrors(totalNumberErrorCodes_) {
+        for (uint8 i; i <= totalNumberErrorCodes_; i++) {
+            /// @dev It is not possible to access the _errorCodeDefinitions since it is private.
+            TFHE.allow(TFHE.asEuint8(i), msg.sender);
+        }
+    }
+
+    function errorChangeIf(
+        einput encryptedCondition,
+        einput encryptedErrorCode,
+        bytes calldata inputProof,
+        uint8 indexCode
+    ) external returns (euint8 newErrorCode) {
+        ebool condition = TFHE.asEbool(encryptedCondition, inputProof);
+        euint8 errorCode = TFHE.asEuint8(encryptedErrorCode, inputProof);
+        newErrorCode = _errorChangeIf(condition, indexCode, errorCode);
+        _errorSave(newErrorCode);
+        TFHE.allow(newErrorCode, msg.sender);
+    }
+
+    function errorChangeIfNot(
+        einput encryptedCondition,
+        einput encryptedErrorCode,
+        bytes calldata inputProof,
+        uint8 indexCode
+    ) external returns (euint8 newErrorCode) {
+        ebool condition = TFHE.asEbool(encryptedCondition, inputProof);
+        euint8 errorCode = TFHE.asEuint8(encryptedErrorCode, inputProof);
+        newErrorCode = _errorChangeIfNot(condition, indexCode, errorCode);
+        _errorSave(newErrorCode);
+        TFHE.allow(newErrorCode, msg.sender);
+    }
+
+    function errorDefineIf(
+        einput encryptedCondition,
+        bytes calldata inputProof,
+        uint8 indexCode
+    ) external returns (euint8 errorCode) {
+        ebool condition = TFHE.asEbool(encryptedCondition, inputProof);
+        errorCode = _errorDefineIf(condition, indexCode);
+        _errorSave(errorCode);
+        TFHE.allow(errorCode, msg.sender);
+    }
+
+    function errorDefineIfNot(
+        einput encryptedCondition,
+        bytes calldata inputProof,
+        uint8 indexCode
+    ) external returns (euint8 errorCode) {
+        ebool condition = TFHE.asEbool(encryptedCondition, inputProof);
+        errorCode = _errorDefineIfNot(condition, indexCode);
+        _errorSave(errorCode);
+        TFHE.allow(errorCode, msg.sender);
+    }
+
+    function errorGetCodeDefinition(uint8 indexCodeDefinition) external view returns (euint8 errorCode) {
+        errorCode = _errorGetCodeDefinition(indexCodeDefinition);
+    }
+
+    function errorGetCodeEmitted(uint256 errorId) external view returns (euint8 errorCode) {
+        errorCode = _errorGetCodeEmitted(errorId);
+    }
+
+    function errorGetCounter() external view returns (uint256 countErrors) {
+        countErrors = _errorGetCounter();
+    }
+
+    function errorGetNumCodesDefined() external view returns (uint8 totalNumberErrorCodes) {
+        totalNumberErrorCodes = _errorGetNumCodesDefined();
+    }
+}

contracts/token/ERC20/EncryptedERC20.sol

@@ -2,7 +2,10 @@
 pragma solidity ^0.8.24;
 
 import "fhevm/lib/TFHE.sol";
+
+import { IERC20Errors } from "@openzeppelin/contracts/interfaces/draft-IERC6093.sol";
 import { IEncryptedERC20 } from "./IEncryptedERC20.sol";
+import { TFHEErrors } from "../../utils/TFHEErrors.sol";
 
 /**
  * @title       EncryptedERC20
@@ -12,10 +15,9 @@ import { IEncryptedERC20 } from "./IEncryptedERC20.sol";
  *              and setting allowances, but uses encrypted data types.
  *              The total supply is not encrypted.
  */
-abstract contract EncryptedERC20 is IEncryptedERC20 {
+abstract contract EncryptedERC20 is IEncryptedERC20, IERC20Errors, TFHEErrors {
     /// @notice used as a placehoder in Approval and Transfer events to comply with the official EIP20
     uint256 internal constant _PLACEHOLDER = type(uint256).max;
-
     /// @notice Total supply.
     uint64 internal _totalSupply;
 
@@ -31,11 +33,6 @@ abstract contract EncryptedERC20 is IEncryptedERC20 {
     /// @notice A mapping of the form mapping(account => mapping(spender => allowance)).
     mapping(address account => mapping(address spender => euint64 allowance)) internal _allowances;
 
-    /**
-     * @notice Error when the `sender` is not allowed to access a value.
-     */
-    error TFHESenderNotAllowed();
-
     /**
      * @param name_ Name of the token.
      * @param symbol_ Symbol.
@@ -151,6 +148,14 @@ abstract contract EncryptedERC20 is IEncryptedERC20 {
     }
 
     function _approve(address owner, address spender, euint64 amount) internal virtual {
+        if (owner == address(0)) {
+            revert ERC20InvalidApprover(owner);
+        }
+
+        if (spender == address(0)) {
+            revert ERC20InvalidSpender(spender);
+        }
+
         _allowances[owner][spender] = amount;
         TFHE.allowThis(amount);
         TFHE.allow(amount, owner);
@@ -184,11 +189,11 @@ abstract contract EncryptedERC20 is IEncryptedERC20 {
 
     function _transferNoEvent(address from, address to, euint64 amount, ebool isTransferable) internal virtual {
         if (from == address(0)) {
-            revert SenderAddressNull();
+            revert ERC20InvalidSender(from);
         }
 
         if (to == address(0)) {
-            revert ReceiverAddressNull();
+            revert ERC20InvalidReceiver(to);
         }
 
         /// Add to the balance of `to` and subract from the balance of `from`.

contracts/token/ERC20/IEncryptedERC20.sol

@@ -22,16 +22,6 @@ interface IEncryptedERC20 {
      */
     event Transfer(address indexed from, address indexed to, uint256 errorId);
 
-    /**
-     * @notice Returned when receiver is address(0).
-     */
-    error ReceiverAddressNull();
-
-    /**
-     * @notice Returned when sender is address(0).
-     */
-    error SenderAddressNull();
-
     /**
      * @notice Sets the `encryptedAmount` as the allowance of `spender` over the caller's tokens.
      */

contracts/token/ERC20/extensions/EncryptedERC20WithErrors.sol

@@ -30,8 +30,8 @@ abstract contract EncryptedERC20WithErrors is EncryptedERC20, EncryptedErrors {
     }
 
     /**
-     * @param name_ Name of the token.
-     * @param symbol_ Symbol.
+     * @param name_     Name of the token.
+     * @param symbol_   Symbol.
      */
     constructor(
         string memory name_,
@@ -43,7 +43,7 @@ abstract contract EncryptedERC20WithErrors is EncryptedERC20, EncryptedErrors {
      */
     function transfer(address to, euint64 amount) public virtual override returns (bool) {
         _isSenderAllowedForAmount(amount);
-        /// Check whether the owner has enough tokens.
+        /// @dev Check whether the owner has enough tokens.
         ebool canTransfer = TFHE.le(amount, _balances[msg.sender]);
         euint8 errorCode = _errorDefineIfNot(canTransfer, uint8(ErrorCodes.UNSUFFICIENT_BALANCE));
         _errorSave(errorCode);
@@ -53,15 +53,6 @@ abstract contract EncryptedERC20WithErrors is EncryptedERC20, EncryptedErrors {
         return true;
     }
 
-    function getErrorCodeForTransferId(uint256 transferId) public view virtual returns (euint8) {
-        return _errorGetCodeEmitted(transferId);
-    }
-
-    function _transfer(address from, address to, euint64 amount, ebool isTransferable) internal override {
-        _transferNoEvent(from, to, amount, isTransferable);
-        emit Transfer(from, to, _errorGetCounter() - 1);
-    }
-
     /**
      * @notice See {IEncryptedERC20-transferFrom}.
      */
@@ -73,21 +64,37 @@ abstract contract EncryptedERC20WithErrors is EncryptedERC20, EncryptedErrors {
         return true;
     }
 
+    /**
+     * @notice            Returns the error for a transfer id.
+     * @param transferId  Transfer id. It can read from the `Transfer` event.
+     * @return errorCode  Encrypted error code.
+     */
+    function getErrorCodeForTransferId(uint256 transferId) public view virtual returns (euint8 errorCode) {
+        errorCode = _errorGetCodeEmitted(transferId);
+    }
+
+    function _transfer(address from, address to, euint64 amount, ebool isTransferable) internal override {
+        _transferNoEvent(from, to, amount, isTransferable);
+        /// @dev It was incremented in _saveError.
+        emit Transfer(from, to, _errorGetCounter() - 1);
+    }
+
     function _updateAllowance(
         address owner,
         address spender,
         euint64 amount
     ) internal virtual override returns (ebool isTransferable) {
         euint64 currentAllowance = _allowance(owner, spender);
-        /// Make sure sure the allowance suffices.
+        /// @dev It checks whether the allowance suffices.
         ebool allowedTransfer = TFHE.le(amount, currentAllowance);
         euint8 errorCode = _errorDefineIfNot(allowedTransfer, uint8(ErrorCodes.UNSUFFICIENT_APPROVAL));
-        /// Make sure the owner has enough tokens.
+        /// @dev It checks that the owner has enough tokens.
         ebool canTransfer = TFHE.le(amount, _balances[owner]);
         ebool isNotTransferableButIsApproved = TFHE.and(TFHE.not(canTransfer), allowedTransfer);
         errorCode = _errorChangeIf(
-            isNotTransferableButIsApproved, // should indeed check that spender is approved to not leak information
-            // on balance of `from` to unauthorized spender via calling reencryptTransferError afterwards
+            isNotTransferableButIsApproved,
+            /// @dev Should indeed check that spender is approved to not leak information.
+            ///      on balance of `from` to unauthorized spender via calling reencryptTransferError afterwards.
             uint8(ErrorCodes.UNSUFFICIENT_BALANCE),
             errorCode
         );