Re: [ippm] Discussion on draft-brockners-ippm-ioam-data-integrity method 3 variant in @ietf110

[Tommy Pauly <[e-mail]>]

Thanks, that’d be great to see the variants of Method 3 like that!

Best,
Tommy

> On Mar 8, 2021, at 8:31 PM, Shwetha <[e-mail]> wrote:
> 
> My bad, it should be possible to reverse the process for validation and retrieve the previous signature in the reverse order. We will update the draft to have Method 3 with both symmetric/asymmetric variants.
> 
> Thanks,
> Shwetha
> 
> On Tue, Mar 9, 2021 at 7:07 AM Shwetha <[e-mail] <mailto:[e-mail]>> wrote:
> During the session 1 of ippm at IETF 110, it was suggested to consider introducing a variant of method 3 in  draft-brockners-ippm-ioam-data-integrity with asymmetric keys.
> 
> 
> When we were designing the methods to protect integrity of the entire IOAM data collected at each node, the node chains it's own node data with the signature from the previous node and overwrites the signature:
> Trace signature = sign([Trace Signature || its node_data_list[x] hash])
> 
> In the symmetric key case this operation can be validated by reversing the operation by the validator who has the shared secret from each node.
> However this will not work if nodes use their private keys to sign and validator has the public key to validate as it can only validate but not derive a specific node's signature to reverse the operation. 
> 
> So I think the space optimized  method to overwrite the signature at each node cannot be modified to use asymmetric keys easily. Will be happy to discuss ideas to create a space optimized asymmetric key based solution.
> 
> Thanks
> Shwetha
> 
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