Due to the implementation of "deriveVaultKey", prior to version 7.10, the generated vault key would always have the last 16 bytes predetermined to be "arfoobarfoobarfo".

This issue happens because "deriveVaultKey" calls "retrieveCloudKey" (which will always return "foobarfoobarfoobarfoobarfoobarfo" as the key), and then merges the 32byte randomly generated key with this key (by takeing 16bytes from each, see "mergeKeys").

This makes the key a lot weaker.

This issue does not persist in devices that were initialized on/after version 7.10, but devices that were initialized before that and updated to a newer version still have this issue.

Roll an update that enforces the full 32bytes key usage.

Affected: Go: github.com/lf-edge/eve

### Impact

The deriveVaultKey function calls retrieveCloudKey which always returns "foobarfoobarfoobarfoobarfoobarfo". When merged with the randomly generated 32-byte key using mergeKeys (16 bytes from each), the last 16 bytes are always "arfoobarfoobarfo". This enables an attacker with physical access to the EVE-OS device to attempt to brute force the remaining 128 bits of key.

### Patches

Fixed in 7.10 and 8.12.1-lts

### Workarounds

None