What the Monzero patch adds to Cake Wallet

Cake Wallet is an open-source, non-custodial wallet for Monero and a number of other coins, published as cake-tech/cake_wallet on GitHub. The patch this site describes adds Monzero (XMZ) to it as a new wallet type. It is our patch: the people who write this site prepared it. It is not in any version of Cake Wallet that has been released, and it has not been submitted yet — the pull request guide has where it stands.

Built on the Wownero integration

Cake Wallet already carries another Monero-family coin, Wownero, in a package called cw_wownero. The Monzero package, cw_monzero, is a copy of it with the names changed — Wownero to Monzero, WOW to XMZ — and the app's Monzero glue is a copy of its Wownero glue. The pull request text gives the reason: a reviewer can diff the two packages file by file and see only what differs. Wownero's own 14-word seed code is left out; Monzero uses Monero's standard word lists only.

What it adds

The wallet package. cw_monzero runs on the Monzero library from monero_c, the project Cake Wallet builds its Monero-family wallets from. It holds the wallet service and the wallet, accounts and subaddresses, transaction history, unspent coins, the balance, pending transactions, the mnemonic word lists in ten languages and the connection to a node.

The coin. In Cake Wallet's shared core: a wallet type called Monzero, a currency called XMZ with 11 decimal places, card designs for the balance screen, a payment link of the form monzero:<address>?tx_amount=, and a way to estimate a block height from a date when a wallet is restored.

The app. Monzero is handled everywhere Wownero is: creating and restoring wallets, sending and fees, unspent coins, accounts and addresses, the dashboard and the menu, QR codes, contacts and settings. Addresses are checked against the pattern of a Monzero address, which starts with F and is 95 characters long, or 106 for an integrated address. A transaction's details link to the block explorer on monzero.org. A settings migration, number 73, adds the Monzero node list and makes node.monzero.org on port 6175 the default; the nodes guide has what that connection is.

Exchange. No exchange provider in Cake Wallet trades XMZ, so for a Monzero wallet the exchange screen falls back to a Monero-to-Bitcoin pair.

Icons. Placeholders — a dark circle with an M — until the official Monzero logo replaces them.

The build. Scripts that build the Monzero library, libmonzero_wallet2_api_c, from monero_c, and on macOS a step that copies the libraries it was linked against next to it so that it loads inside the sandboxed app. The build guide has how that went.

Where it follows Monero instead

Copying Wownero brought three things that are right for Wownero and wrong for a coin people are meant to keep using. Three of the six commits replace them with what Cake Wallet does for Monero.

Opening a wallet. Wownero is deprecated in Cake Wallet, so its code throws a deprecation error every time a wallet is opened. Copied as it was, a Monzero wallet could be created and never opened again. Dart's static analysis found it. The second commit opens Monzero wallets normally and, if that fails, retries the way the Monero code does — restore the cache files, then remove the cache, then give up — instead of Wownero's retry with no limit.

The end of a sync. The sync listener copied from Wownero lacks two fixes the Monero code received, Cake Wallet pull requests 2377 and 3575. In the app, a Monzero wallet reopened after a full sync could stay at “Attempting sync”. The fifth commit ports the Monero logic: wait while the node's height still reads 0, take the higher of the node's height and the wallet's, and report again every five ticks even when nothing has changed.

Seeds. Cake Wallet has no BIP39 for Wownero; it has BIP39 for Monero. The sixth commit gives Monzero the Monero BIP39 code unchanged, so a new Monzero wallet can have a classic 25-word seed or a BIP39 phrase. Polyseed is not offered for new Monzero wallets; the restore screen still accepts a Polyseed, as before, though restoring one has not been tested. That choice has a consequence for anyone who also holds Monero, and the BIP39 guide explains it.