masterkey is a simple, secure password manager written in Go. It uses xchacha20poly1305 for authenticated encryption and argon2id for key derivation. It stores credentials given a location, where each credential is represented by a Username and a Password. Locations, Usernames, and Passwords are always encrypted using a argon2id key derived from the input passphrase. Unlike password-store and a few other password managers, an attacker with access to the encrypted database can not discern exactly how many passwords are stored, the labels (locations) for the passwords, or the usernames associated with the passwords.
Install masterkey either by downloading a release or using go get:
go get github.com/avahowell/masterkey
Now create your vault, in this example we'll create it at ./vault.db. New vaults are created using the -new flag, existing vaults can be opened by simplly omitting the -new flag.
Next, launch the terminal UI using masterkey vault.db, or use masterkey -repl vault.db to use the developer shell which has a bit more functionality.
Note that as with all password managers, your vault is only as secure as your master password. Use a strong, high entropy master password to protect your credentials.