Re: Luks encrpted disk with a blake2b checksumed btrfs fs is better than cryptsetup --integrity option ??

On 20 Jun 2025 18:58 +0000, from [email protected]:
> Here is a quote from the dev in the gitlab issue :
> 
>> If you are using AES-XTS and a cryptographic hash for the checksum (such as SHA2 or Blake2b), this should (barring filesystem bugs) provide integrity protection.  In fact, it will provide vastly stronger protection than dm-integrity can, because it does protect against replay attacks due to the CoW nature of the filesystem: my understanding (which could be mistaken!) is that the whole filesystem is a Merkle tree rooted at the superblock.  At least theoretically, dm-crypt + ZFS or BTRFS + SHA-2 or Blake2b hashes should be safe against an outright malicious block device.  By “should”, I mean that I would consider it to be a security vulnerability if the attacker could do anything other than roll the entire device back to an earlier version.  Of course, the ZFS, BTRFS, and dm-crypt developers may disagree
> 

Better for what use case?

-- 
Michael Kjörling
🔗 https://michael.kjorling.se