Privy is a small and fast utility for password-protecting secret data such as API keys, cryptocurrency wallets, or seeds for digital signatures.Say for example you are using GnuPG. You are about to sign a message but it first requires your password. Does your password become the input to instantiate your private key? No, it is first hashed by a secure key derivation function. That hash then becomes the input to a symmetric cipher such as AES which then decrypts your stored private key. That is what Privy does.