pgpfan:expire
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| pgpfan:expire [2023/08/24 00:30] – Separate background clearer b.walzer | pgpfan:expire [2023/09/20 15:17] (current) – [What does key expiry mean to the user?] good example b.walzer | ||
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| A signing key allows a user to produce a signature that authenticates a message or document or a software archive in some context dependent way. | A signing key allows a user to produce a signature that authenticates a message or document or a software archive in some context dependent way. | ||
| - | I am not really sure what expiry could mean for the case of loss of the secret part of the key. In a paper context, a signature or seal is still considered valid even if the technical means to create such marks no longer exists. Even if you lose your pen or stamp, signatures made with the pen or stamp are still binding and relevant. In a PGP context, only the public part of the key is required to verify a signature. Expiring that public part seems arbitrary and pointless. It would just be confusing if all the already received email from a particular correspondent suddenly started showing up as anonymous (unsigned). It would make no sense for a signed software archive to suddenly be not signed. Signing key expiry goes against normal cultural assumption. | + | I am not really sure what expiry could mean for the case of loss of the secret part of the key. In a paper context, a signature or seal is still considered valid even if the technical means to create such marks no longer exists. Even if you lose your pen or stamp, signatures made with the pen or stamp are still binding and relevant. In a PGP context, only the public part of the key is required to verify a signature. Expiring that public part seems arbitrary and pointless. It would just be confusing if all the already received email from a particular correspondent suddenly started showing up as anonymous (unsigned). It would make no sense for a signed software archive to suddenly be not signed((Here a user asks if signing key expiry is a problem and receives no definite answer: [[https:// |
| It might make sense for implementations to ignore expiry dates on keys used for verifying a signature and thus avoid the question of meaning in the first place. | It might make sense for implementations to ignore expiry dates on keys used for verifying a signature and thus avoid the question of meaning in the first place. | ||
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| Where the receiver and the sender are the same entity then that entity can choose whatever key they want, whenever they want. So encryption key expiry doesn' | Where the receiver and the sender are the same entity then that entity can choose whatever key they want, whenever they want. So encryption key expiry doesn' | ||
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| + | So the point of this section is that key expiry only makes sense for encryption keys and then only for very rare circumstances. Default key expiry is likely to cause more trouble than it is worth. | ||
| ====How TLS is different==== | ====How TLS is different==== | ||
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| //< | //< | ||
| - | Instead it turned out that the problem was that the PGP keys had expired. Since this was instant messaging we couldn' | + | Instead it turned out that the problem was that the PGP keys had expired. |
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| + | Since this was instant messaging we couldn' | ||
| I wondered how someone not particularly interested in the technical details of key expiry would manage when they encountered it. This is what is what the user needs to be able to do: | I wondered how someone not particularly interested in the technical details of key expiry would manage when they encountered it. This is what is what the user needs to be able to do: | ||
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| I am not all that sure about the idea behind this. It seems that there is some thought that PGP key expiry might help a user keep their cryptography more up to date. When the user updates their key expiry time that might be a good time to also update their cryptography preferences but they might be distracted by, you know, the fact that their key(s) expired. If the implementation is set up to help/remind them then we have to ask the question: why wait for key expiry to do that? The implementation knows what encryption preferences and methods are in use. It could bring up the subject at any time, not some years in the future when the key gets around to expiring. | I am not all that sure about the idea behind this. It seems that there is some thought that PGP key expiry might help a user keep their cryptography more up to date. When the user updates their key expiry time that might be a good time to also update their cryptography preferences but they might be distracted by, you know, the fact that their key(s) expired. If the implementation is set up to help/remind them then we have to ask the question: why wait for key expiry to do that? The implementation knows what encryption preferences and methods are in use. It could bring up the subject at any time, not some years in the future when the key gets around to expiring. | ||
| - | How often does this sort of thing need to be updated anyway? My CAST5 encrypted files from 20 years ago are still secure today. Currently there does not seem to be any good reasons | + | How often does this sort of thing need to be updated anyway? My CAST5 encrypted files from 20 years ago are still secure today. Currently there does not seem to be any good reason |
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| + | [[pgpfan: | ||
| + | [[em: | ||
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pgpfan/expire.1692837015.txt.gz · Last modified: 2023/08/24 00:30 by b.walzer