46 lines
2.5 KiB
Plaintext
46 lines
2.5 KiB
Plaintext
digraph {
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label="Matrix room key sharing algorithm"
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fontname="Fira Sans"
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ratio=0.5
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node [shape=box, colorscheme=paired6, style=filled, fillcolor=white, fontname="Fira Sans"]
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edge [fontname="Fira Sans"]
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/* Non-end states, additional checks needed. */
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verified_device_check [label="START\n\nIs this our own, verified device?", labelfontname="Fira Sans"]
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outbound_session_check [label="Outbound session exists?"]
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outbound_exists [label="Session previously previously_shared with this user ID/device ID pair?"]
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previously_shared [label="Requesting device sender (Curve25519) key matches the key we originally shared with?"]
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own_device_check [label="Is this our own device?"]
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/* End states */
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allow_verified [label="Share the entire session from the earliest known index.\n\nOk(None)", color=4, fillcolor=3]
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allow_limited [label="Share a limited session starting from index i, which is the index we previously shared at.\n\nOk(Some(i))", color=4, fillcolor=3]
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refuse_device_key_changed [label="Sender key changed, refuse to share.\n\nErr(KeyForwardDecision::ChangedSenderKey)", color=6, fillcolor=5]
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refuse_not_shared [label="Session was never shared with this device, refuse to share.\n\nErr(KeyForwardDecision::OutboundSessionNotShared)", color=6, fillcolor=5]
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refuse_untrusted_own_device [label="Our own device, but it is untrusted and we haven't previously shared with it. Refuse to share.\n\nErr(KeyForwardDecision::UntrustedDevice)", color=6, fillcolor=5]
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refuse_missing_outbound_session [label="Not our device and haven't previously shared with it. Refuse to share.\n\nErr(KeyForwardDecision::MissingOutboundSession)", color=6, fillcolor=5]
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/* Checks */
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/* Is this our own verified device? */
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verified_device_check -> allow_verified [label="Yes"]
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verified_device_check -> outbound_session_check [label="No"]
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/* Does the outbound session exist? */
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outbound_session_check -> outbound_exists [label="Yes"]
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outbound_session_check -> own_device_check [label="No"]
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/* Previously shared? */
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outbound_exists -> previously_shared [label="Yes"]
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outbound_exists -> refuse_not_shared [label="No"]
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/* Requesting device sender key matches key it was shared with? */
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previously_shared -> allow_limited [label="Yes"]
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previously_shared -> refuse_device_key_changed [label="No"]
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/* Is this our own device? */
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own_device_check -> refuse_untrusted_own_device [label="Yes"]
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own_device_check -> refuse_missing_outbound_session [label="No"]
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}
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