The crypto store is keyed by Matrix user ID, not device ID, so swapping in
a new access token (which mints a new device_id) silently inherits the
previous device's Olm account. That account's identity keys can never be
published under the new device ID, and the pickle key embeds the old
device ID anyway — the result is stale-key mismatches and cross-signing
signatures the homeserver refuses to replace, degrading E2EE in ways that
are hard to diagnose (peers silently withhold room keys).
_reset_crypto_store_if_device_changed() compares the store's persisted
device ID against the live one at connect time and wipes the store on
mismatch, so a fresh Olm account is generated for the new device instead
of reusing stale key material.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
ckaznocha
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