phantom is an extension for accessing distributed applications deployed on the Solana blockchain.
The extension injects an object into every website’s javascript context so that decentralized applications can interact with your wallet, and you can interact with the application.
Phantom also lets users create and manage their own identities (via private keys, mnemonics, and hardware wallets like Ledger), so when a decentralized application wants to perform a transaction and write to the blockchain, the user gets a secure interface to review the transaction, before approving or rejecting.
Because it adds functionality to the normal browser context, Phantom requires the permission to read and write to any webpage. Security is taken very seriously, and the Phantom code has been audited by top auditing firms.