E2e impl guide: sign one-time keys

We now sign our one-time keys.
pull/977/head
Richard van der Hoff 8 years ago
parent 41a528c551
commit f0f6ea0cb3

@ -132,18 +132,18 @@ should construct a JSON object as follows:
{
"algorithms": ["m.olm.v1.curve25519-aes-sha2", "m.megolm.v1.aes-sha2"],
"device_id": "<deviceId>",
"device_id": "<device_id>",
"keys": {
"curve25519:<deviceId>": "<curve25519_key>",
"ed25519:<deviceId>": "<ed25519_key>"
"curve25519:<device_id>": "<curve25519_key>",
"ed25519:<device_id>": "<ed25519_key>"
},
"user_id: <userId>"
"user_id: <user_id>"
}
The object should be formatted as `Canonical
JSON <http://matrix.org/docs/spec/server_server/unstable.html#canonical-json>`__,
then signed with ``olm_account_sign``; the signature should be added to
the JSON as ``signatures.<userId>.ed25519:<deviceId>``.
the JSON as ``signatures.<user_id>.ed25519:<device_id>``.
The signed JSON is then uploaded via
``POST /_matrix/client/unstable/keys/upload``.
@ -168,7 +168,7 @@ maintain about half this number on the homeserver.
To generate new one-time keys:
* Call ``olm_account_generate_one_time_keys`` to generate new keys
* Call ``olm_account_generate_one_time_keys`` to generate new keys.
* Call ``olm_account_one_time_keys`` to retrieve the unpublished keys. This
returns a JSON-formatted object with the single property ``curve25519``,
@ -184,22 +184,60 @@ To generate new one-time keys:
}
}
* Construct a JSON object as follows:
* Each key should be signed with the account key. To do this:
* Construct a JSON object as follows:
.. code:: json
{
"key": "<curve25519_key>"
}
* Call ``olm_account_sign`` to calculate the signature.
* Add the signature should be added to the JSON as
``signatures.<user_id>.ed25519:<device_id>``.
* The complete key object should now look like:
.. code:: json
{
"key": "wo76WcYtb0Vk/pBOdmduiGJ0wIEjW4IBMbbQn7aSnTo",
"signatures": {
"@alice:example.com": {
"ed25519:JLAFKJWSCS": "dSO80A01XiigH3uBiDVx/EjzaoycHcjq9lfQX0uWsqxl2giMIiSPR8a4d291W1ihKJL/a+myXS367WT6NAIcBA"
}
}
}
* Aggregate all the signed one-time keys into a single JSON object as follows:
.. code:: json
{
"one_time_keys": {
"curve25519:<keyId>": "<curve25519_key>",
"signed_curve25519:<key_id>": {
"key": "<curve25519_key>",
"signatures": {
"<user_id>": {
"ed25519:<device_id>": "<signature>"
}
}
},
"signed_curve25519:<key_id>": {
...
},
...
}
}
* Upload the object via ``POST /_matrix/client/unstable/keys/upload``. (Unlike
the device keys, the one-time keys are **not** signed.
* Upload the object via ``POST /_matrix/client/unstable/keys/upload``.
* Call ``olm_account_mark_keys_as_published`` to tell the olm library not to
return the same keys from a future call to ``olm_account_one_time_keys``\.
return the same keys from a future call to ``olm_account_one_time_keys``.
Configuring a room to use encryption
------------------------------------
@ -407,20 +445,20 @@ object containing information on the device, as follows:
{
"algorithms": [...],
"device_id": "<deviceId>",
"device_id": "<device_id>",
"keys": {
"curve25519:<deviceId>": "<curve25519_key>",
"ed25519:<deviceId>": "<ed25519_key>"
"curve25519:<device_id>": "<curve25519_key>",
"ed25519:<device_id>": "<ed25519_key>"
},
"signatures": {
"<userId>": {
"ed25519:<deviceId>": "<signature>"
"ed25519:<device_id>": "<signature>"
},
},
"unsigned": {
"device_display_name": "<display name>"
},
"user_id: <userId>"
"user_id: <user_id>"
}
The client should first check the signature on this object. To do this,
@ -601,7 +639,7 @@ create a query object as follows:
{
"<user id>": {
"<device_id>": "curve25519",
"<device_id>": "signed_curve25519",
...
},
...
@ -617,15 +655,28 @@ This will return a result as follows:
{
"<user id>": {
"<device_id>": {
"curve25519:<key_id>": "<one-time key>"
"signed_curve25519:<key_id>": {
"key": "<curve25519_key>",
"signatures": {
"<user_id>": {
"ed25519:<device_id>": "<signature>"
}
}
},
},
...
},
...
}
The client should then pass this key, along with the Curve25519 Identity
key for the remote device, into ``olm_create_outbound_session``.
The client should first check the signatures on the signed key objects. As with
checking the signatures on the device keys, it should remove the ``signatures``
property, format the remainder as Canonical JSON, and pass the result into
``olm_ed25519_verify``, using the Ed25519 device key for the ``key`` parameter.
Provided the key object passes verification, the client should then pass the
key, along with the Curve25519 Identity key for the remote device, into
``olm_create_outbound_session``.
Handling membership changes
---------------------------

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