Redundant zero address check in Bridge::registerKeyPairWithTransfer and Bridge::rotateToPublicKey

Two locations contain unreachable ZeroAddress() reverts that can never trigger due to prior guards.

Location 1, registerKeyPairWithTransfer

Inside the confirming logic, the code first checks that the outputAddress is non-zero:

if (ctx.confirming.outputAddress != address(0)) {

Then inside that same block, it checks again if the address is zero:

if (ctx.confirming.outputAddress == address(0))
    revert ZeroAddress();

This second check can never be true. If execution entered the block, it already means ctx.confirming.outputAddress != address(0). The inner revert is dead code.

Location 2, rotateToPublicKey

The code checks whether the derived owner address is zero:

if (existingOwnerAddress == address(0)) revert ZeroAddress();

However, this address is obtained from:

address existingOwnerAddress =
    getAddressFromPublicKey(ctx.unconfirmed.publicKey);

And getAddressFromPublicKey strictly enforces a 64-byte public key before hashing with keccak256. Getting address(0) would require the hash to end with 20 zero bytes, for a valid 64-byte input, the probability is ~1/2^160, which is practically impossible.

• Remove the redundant inner zero-address check in registerKeyPairWithTransfer.
• Remove the zero-address check in rotateToPublicKey.

YadaCoin, Confirmed.

Zealynx, Fixed.