Feature Request/Question - encrypt recipient file (part 2)

In the feature request https://github.com/FiloSottile/passage/issues/25 I suggested that it might be useful to store the recipient file encrypted on a shared storage as well, if you want to share the passwords with others and the shared storage is not trusted.

But every write operation would require decryption.

To avoid this the following idea might be useful:
A copy of the plaintext recipient file is stored locally (trusted storage) and the hash value of the encrypted recipient file. For each write operation the locally stored hash value is compared with the hash value of the encrypted recipient file stored on the shared storage. If they match, the locally stored plaintext recipient file can be used (this results in less costs than a decryption). If not, decryption must be performed.