.cadenas and .age formats

cadenas can encrypt in two formats. When decrypting, the format is detected automatically.

	.cadenas (default)	.age
Password derivation	Argon2id (64 MiB, 3 passes)	scrypt (2¹⁸)
Encryption	XChaCha20-Poly1305, 64 KiB chunks	ChaCha20-Poly1305, 64 KiB chunks
Readable by	cadenas	cadenas, age, rage
Independent audit	not yet	the age format is widely reviewed and used

Which one?

• .cadenas for everyday use. Argon2id makes every password guess expensive, GPUs included.
• .age if the file must open with other tools, or if you want an already widely reviewed format. On the command line: cadenas lock --age file.

Either way, any change to the encrypted file is detected: a tampered or truncated file is refused, never half decrypted.

What stays visible

The content is encrypted, but not:

• the file name, if it keeps its original name (report.pdf.cadenas). cadenas lock --hide-name stores the file in an archive with a neutral name;
• the approximate file size.

age compatibility

• cadenas reads password-encrypted age files, including the "armored" form (age -a).
• age files encrypted to a public key are not supported: cadenas only handles passwords.
• The scrypt work factor is capped at 18, age's default. A file created by age with a higher work factor (19 to 22) does not open with cadenas.

What if cadenas disappears one day?

Your files stay readable. The .cadenas format is fully specified and only uses standard primitives: any developer can write a program to read it. The .age format decrypts with age or rage, without cadenas.