Umbra is a protocol that defines a set of standards and a smart contract to allow stealth addresses on the Ethereum blockchain.  A stealth address allows a sender to send Ether or ERC20 tokens to an address controlled by the receiver without revealing the identity of the receiver. On-chain, the transaction appears to be a simple transfer to an unused address on the Ethereum network, while off-chain, the sender uses a public key to generate a new address by encrypting the data used to generate it. Umbra has processed more than 85,000 transactions across all networks since its launch in June 2021 and is a grant-funded public good project.