#social 2020-08-12
2020-08-12 UTC
sl007, pukkamustard and rzr joined the channel
# 
djangz[m] Question about inbox forwarding:
# BradKoehn[m] This question exposes a flaw in the current implementations of AP: there is no mechanism to allow forwarded messages to be verified. In email, DKIM can be used to guarantee that forwarded messages are authentic; no such capability exists in AP, and http-signatures can only be used to insure that the forwarder is valid, not that the original message is valid.
# djangz[m] I understand the concept, but the implementation details are scant.
# djangz[m] Should my server resend the original Create activity, what would http signature be based on?
# BradKoehn[m] * This question exposes a flaw in the current implementations of AP: there is no mechanism to allow forwarded messages to be verified. In email, DKIM can be used to guarantee that forwarded messages are authentic; no such capability exists in AP, and http-signatures can only be used to insure that the forwarder is valid, and cannot insure the forwarded message is valid.
# djangz[m] right
# djangz[m] so the current implementations use their own signatures in the header, even though it conflicts with the activity sig?
# BradKoehn[m] Implementations have no choice but to generate their own signatures, as http-signatures are time-based, and re-using a signature from another system would only work as a race condition.
# BradKoehn[m] A brief search for an alternative yielded JSF, but I've no idea if it's practicable. https://cyberphone.github.io/doc/security/jsf.html
# BradKoehn[m] Using something like JSF, an implementation could preserve the signature from the originating system, wrap that message in a new `Create` or `Forward` activity and sign that from the forwarding system, and both could co-exist in the same message.
# BradKoehn[m] (`Forward` being a new, non-AP activity)
# nightpool[m] Brad Koehn: djangz isn't this just what ld-signatures are currently used for?
# djangz[m] That would make sense!
# BradKoehn[m] nightpool (IRC): it looks to be about the same; I haven't seen them in use.
# nightpool[m] mastodon uses ld-signatures for inbox forwarding currently
# nightpool[m] Pleroma does not sign forwarded messages at all, it expects the receiving server to dereference the message to ensure its validity
sl007 and tantek joined the channel
# djangz[m] thanks @nigh
# djangz[m] * thanks nightpool !
Test and lain_soykaf joined the channel