ElementR: Key Storage | When adding a new key to 4S the key encryption check is not added to the key info

[BillCarsonFr]

As per spec, when adding a new key to the secret storage the client must encrypt a "zero"/dummy secret to allow for key checks.
WebR is not doing it

Actual:

{
  "type": "m.secret_storage.key.abcdef",
  "content": {
    "algorithm": "m.secret_storage.v1.aes-hmac-sha2",
    "passphrase": { ... },
  }
} 

Expected:

{
  "type": "m.secret_storage.key.abcdef",
  "content": {
    "algorithm": "m.secret_storage.v1.aes-hmac-sha2",
    "passphrase": { ... },
    "iv": "2ZB0AAR+nsEoaX4owqA7ag==",
    "mac": "Wf6C9nDzIESogoikSW7uLJjDSU+BKtqpe/7tRMi/Y7E="
  }
} 

As a consequence if you try to use the key on EX (that is more strict) it will fail with (UnsupportedAlgorithm("m.secret_storage.v1.aes-hmac-sha2")) if you try to verifiy with a key generated from webR

[richvdh]

As per spec, when adding a new key to the secret storage the client must encrypt a "zero"/dummy secret to allow for key checks.

It is incorrect that it must do that. It is optional.