Check values are encrypted with FHE.isInitialized(..) (#81)

* Check values are encrypted with FHE.isInitialized(..)

* Remove changeset

* Calll FHE library with full name

* Set empty changeset

* Remove empty changeset

Author: james-toussaint

contracts/governance/utils/VotesConfidential.sol

@@ -164,7 +164,7 @@ abstract contract VotesConfidential is Nonces, EIP712, IERC6372 {
      */
     function _moveDelegateVotes(address from, address to, euint64 amount) internal virtual {
         CheckpointsConfidential.TraceEuint64 storage store;
-        if (from != to && euint64.unwrap(amount) != 0) {
+        if (from != to && FHE.isInitialized(amount)) {
             if (from != address(0)) {
                 store = _delegateCheckpoints[from];
                 euint64 newValue = store.latest().sub(amount);

contracts/token/ConfidentialFungibleToken.sol

@@ -231,7 +231,7 @@ abstract contract ConfidentialFungibleToken is IConfidentialFungibleToken {
         FHE.checkSignatures(requestId, signatures);
 
         euint64 requestHandle = _requestHandles[requestId];
-        require(euint64.unwrap(requestHandle) != 0, ConfidentialFungibleTokenInvalidGatewayRequest(requestId));
+        require(FHE.isInitialized(requestHandle), ConfidentialFungibleTokenInvalidGatewayRequest(requestId));
         emit EncryptedAmountDisclosed(requestHandle, amount);
 
         _requestHandles[requestId] = euint64.wrap(0);
@@ -288,7 +288,7 @@ abstract contract ConfidentialFungibleToken is IConfidentialFungibleToken {
             _totalSupply = ptr;
         } else {
             euint64 fromBalance = _balances[from];
-            require(euint64.unwrap(fromBalance) != 0, ConfidentialFungibleTokenZeroBalance(from));
+            require(FHE.isInitialized(fromBalance), ConfidentialFungibleTokenZeroBalance(from));
             (success, ptr) = TFHESafeMath.tryDecrease(fromBalance, amount);
             FHE.allowThis(ptr);
             FHE.allow(ptr, from);

contracts/utils/TFHESafeMath.sol

@@ -15,7 +15,7 @@ library TFHESafeMath {
      * and `updated` will be the original value.
      */
     function tryIncrease(euint64 oldValue, euint64 delta) internal returns (ebool success, euint64 updated) {
-        if (euint64.unwrap(oldValue) == 0) {
+        if (!FHE.isInitialized(oldValue)) {
             success = FHE.asEbool(true);
             updated = delta;
         } else {