How the Private Space keeps secrets

Where it is stored

Each item — its name, account and content together — is encrypted with AES-256-GCM, using Apple’s CryptoKit and a fresh random nonce every time, and kept in a table of its own.

It never enters ordinary history, the search index, thumbnails or backups. Without the key, all that can be read is how many items there are and the day each was made.

The key

A random 256-bit key in your Mac’s keychain: this Mac only, not synced. SSPaste holds it in memory only between unlocking and locking. There is no separate master password.

Unlocking and locking

macOS confirms it is you, with Touch ID or your login password. Anyone who knows this Mac’s login password can unlock the Space.

It locks after 1, 5 or 15 minutes without use (5 unless you change it), and at once when the screen locks, the Mac sleeps or SSPaste quits.

Moving a clip in

When you move something from your history into the Private Space, it is encrypted, and the original is removed from history, the search index, stored data and thumbnails; the space it occupied in the database is overwritten.

If you copy the same text again later, it is recorded like anything else.

Pasting

What you paste is marked as concealed, so SSPaste itself and most clipboard tools do not record it, and it is cleared from the clipboard after about a minute.

During that minute it is plain text on the system clipboard, and other programs running on your Mac can read it.

What it does not protect against

Someone using your Mac while the Space is unlocked, and software able to read SSPaste’s memory.

Losing the key: on another Mac, or after the keychain is reset, the old database cannot be opened. Export first.

Taking your secrets with you

Export… writes an unencrypted CSV in the column format of the system’s Passwords app, which 1Password and Bitwarden also import. SSPaste warns you before it writes the file.