In Matrix specs: EncryptedFile.
Check what the spec tells us.
Required. A map from an algorithm name to a hash of the ciphertext, encoded as unpadded base64. Clients should support the SHA-256 hash, which uses the key "sha256".
Required. The Initialisation Vector used by AES-CTR, encoded as unpadded base64.
Required. A JSON Web Key object.
Required. The URL to the file.
Required. Version of the encrypted attachments protocol. Must be "v2".