gokey allows secret recovery from a seed file without the master password

In gokey versions <0.2.0,
a flaw in the seed decryption logic resulted in passwords incorrectly
being derived solely from the initial vector and the AES-GCM
authentication tag of the key seed.

This issue has been fixed in gokey version 0.2.0. This is a breaking change. The fix has invalidated any passwords/secrets that were derived from the seed file (using the -s option). Even if the input seed file stays the same, version 0.2.0 gokey will generate different secrets.

Impact
This vulnerability impacts generated keys/secrets using a seed file as an entropy input (using the -s option). Keys/secrets generated just from the master password (without the -s
option) are not impacted. The confidentiality of the seed itself is
also not impacted (it is not required to regenerate the seed itself).
Specific impact includes:

• keys/secrets generated from a seed file may have lower entropy: it
  was expected that the whole seed would be used to generate keys (240
  bytes of entropy input), where in vulnerable versions only 28 bytes was
  used

• a malicious entity could have recovered all passwords, generated
  from a particular seed, having only the seed file in possession without
  the knowledge of the seed master password

Patches
The code logic bug has been fixed in gokey version 0.2.0
and above. Due to the deterministic nature of gokey, fixed versions
will produce different passwords/secrets using seed files, as all seed
entropy will be used now.

System secret rotation g…