[question] What prevents a bearer from removing an offline attenuation blocks' caveat? about biscuit

[Geal]

the private key they get in the last block as not been used to sign anything yet.
let's say you have a 2-block token. You get:

Block 1:
- data 1
- public key 1
- signature = sign(root private key, data 1 + public key 1)

Block 2:
- data 2
- public key 2
- signature = sign(private key 1, data 2 + public key 2)

Last block:
- private key 2

When verifying a token, we check that the chain of signatures is ok, and the last step is verifying that the private key in the last block matches the public key signed in the preceding block.
If the last block is not present, verification will fail. If the private key does not match (because the preceding block was removed or modified), verification will fail too

[twitchyliquid64]

Ahhh, that makes sense. Thanks!

[Geal]

There's now some docs describing the crypto: https://www.biscuitsec.org/docs/reference/cryptography/