On 03/25/2017 09:40 AM, Hugo Landau wrote:
> Currently, when an order is created, authorizations are created for it,
> and challenges are created for each of those authorizations.
>
> If a challenge is failed once, the challenge comes to have status
> "invalid", as does the authorization containing it. The order containing
> the authorization becomes unfulfillable.
I agree that this is an issue; You and I talked about it previously in
the thread "New application flow and retries," but didn't get much
feedback from the rest of the group.

Note that authz's are recyclable, so the impact is not quite so bad as
you describe. But even if you just consider the CSR, each new-order is
fairly expensive. A minimum of 1k of storage for a CSR with a 2048-bit
RSA key. Under the current model, a client that is having validation
problems and retries repeatedly will consume at least 1k of database
space per try. As a result, CAs will likely need to limit new-order
creations rather strictly, which makes life harder for clients.

I think the way CAs traditionally handle this is as you suggest: by
making challenges retryable. Note that this implies that orders
typically never get invalidated, they just expire after some period of
time (or error out if there's a problem during issuance, like CAA). This
also implies that clients would potentially need to keep state across
invocations. Specifically, clients would need to store the private keys
used for extant orders, so if a subsequent run completes an order, the
client is able to use the resulting certificate.

What's your thought on the additional burden on clients?

What is the rest of the group's thoughts on whether we'd have to restart
WGLC for this?

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