[[exception]]
target = "https://www.rfc-editor.org/rfc/rfc9001#section-6.4"
quote = '''
An endpoint that successfully removes protection with old
keys when newer keys were used for packets with lower packet numbers
MUST treat this as a connection error of type KEY_UPDATE_ERROR.
'''
reason = '''
To reduce the possibility of a timing side channel, we do not attempt to remove protection from packets with old keys if the initial attempt failed.
'''