Seyvd is a Mac backup app that encrypts your files locally with AES-256-GCM before uploading anything to S3-compatible cloud storage. Your storage provider never receives readable data. No account or third-party key service is involved.
How encrypted backup works on Mac
Seyvd encrypts at the chunk level before any data leaves your Mac:
- your passphrase derives a master key through PBKDF2-SHA256 with 600,000 iterations
- files are split into fixed-size chunks
- each chunk is encrypted individually with AES-256-GCM using a key derived from the master key
- metadata including file names and folder structure is encrypted separately
- the storage provider receives only opaque encrypted blobs
Your backup repository stays private even if the storage account is compromised. There is no server-side decryption path.
Why encrypt before uploading
Server-side encryption protects against physical disk theft at the data center. It does not protect against provider access, account compromise or legal requests directed at the storage service.
Client-side encryption means:
- your provider stores data it cannot read or inspect
- a compromised storage account exposes only encrypted content
- no third party holds decryption keys for your backups
No account and no key escrow
Seyvd does not require a separate account or registration. You bring your own S3-compatible storage bucket and your own passphrase. Credentials stay in the macOS Keychain.
There is no key escrow and no recovery service, so nobody else can decrypt your backups. Keep your passphrase and Recovery Kit safe.
When client-side encryption matters
Client-side encryption fits when you want to:
- back up to cloud storage without trusting the provider with file contents
- keep sensitive documents, code or project files private at rest
- use S3-compatible storage without giving up confidentiality
- keep encryption out of the provider’s hands
If you also want backups to run without manual effort, read about scheduled cloud backups. For the full overview, visit the main Seyvd page.