Hi Tero, Thank you for the feed back, my understanding is that we have a a consensus that Transform ID is the preferred way. I will update the draft accordingly and post a new version next week.
BR, Daniel On Fri, Jun 17, 2016 at 9:41 AM, Tero Kivinen <[email protected]> wrote: > Daniel Migault writes: > > Regarding the negotiation of the use of the implicit IV three ways have > been > > proposed. Currently it seems that the consensus is more encline to define > > Transform IDs. However, it has been raised that Transform Attributes > might be > > a better protocol design choice. > > My personal preference is for Transform IDs. > > > I would like to understand if there are any guidance whether using > attributes > > is preferred to ID or vice versa and if there is any preference in using > > IMPLICIT IV Transform ID versus an IMPLICIT IV Transform Attribute. > > Both with Transform IDs and Transform Attributes you need to duplicate > each cipher support things. The payload would be either: > > SA Payload > | > +-- Proposal #1 ( Proto ID = ESP(3), SPI size = 4, > | | 7 transforms, SPI = 0x052357bb ) > | | > | +-- Transform ENCR ( Name = ENCR_AES_CBC ) > | | +-- Attribute ( Key Length = 128 ) > | | > | +-- Transform ENCR ( Name = ENCR_AES_CBC ) > | | +-- Attribute ( Key Length = 192 ) > | | > | +-- Transform ENCR ( Name = ENCR_AES_CBC ) > | | +-- Attribute ( Key Length = 256 ) > | | > | +-- Transform INTEG ( Name = AUTH_HMAC_SHA1_96 ) > | +-- Transform INTEG ( Name = AUTH_AES_XCBC_96 ) > | +-- Transform ESN ( Name = ESNs ) > | +-- Transform ESN ( Name = No ESNs ) > | > +-- Proposal #2 ( Proto ID = ESP(3), SPI size = 4, > | 6 transforms, SPI = 0x35a1d6f2 ) > | > +-- Transform ENCR ( Name = AES-GCM with a 8 octet ICV ) > | +-- Attribute ( Key Length = 128 ) > | > +-- Transform ENCR ( Name = AES-GCM with a 8 octet ICV ) > | +-- Attribute ( Key Length = 256 ) > | > +-- Transform ENCR ( Name = AES-GCM with a 8 octet ICV Implicit IV ) > | +-- Attribute ( Key Length = 128 ) > | > +-- Transform ENCR ( Name = AES-GCM with a 8 octet ICV Implicit IV ) > | +-- Attribute ( Key Length = 256 ) > | > +-- Transform ESN ( Name = ESNs ) > +-- Transform ESN ( Name = No ESNs ) > > Or: > > SA Payload > | > +-- Proposal #1 ( Proto ID = ESP(3), SPI size = 4, > | | 7 transforms, SPI = 0x052357bb ) > | | > | +-- Transform ENCR ( Name = ENCR_AES_CBC ) > | | +-- Attribute ( Key Length = 128 ) > | | > | +-- Transform ENCR ( Name = ENCR_AES_CBC ) > | | +-- Attribute ( Key Length = 192 ) > | | > | +-- Transform ENCR ( Name = ENCR_AES_CBC ) > | | +-- Attribute ( Key Length = 256 ) > | | > | +-- Transform INTEG ( Name = AUTH_HMAC_SHA1_96 ) > | +-- Transform INTEG ( Name = AUTH_AES_XCBC_96 ) > | +-- Transform ESN ( Name = ESNs ) > | +-- Transform ESN ( Name = No ESNs ) > | > +-- Proposal #2 ( Proto ID = ESP(3), SPI size = 4, > | 6 transforms, SPI = 0x35a1d6f2 ) > | > +-- Transform ENCR ( Name = AES-GCM with a 8 octet ICV ) > | +-- Attribute ( Key Length = 128 ) > | > +-- Transform ENCR ( Name = AES-GCM with a 8 octet ICV ) > | +-- Attribute ( Key Length = 256 ) > | > +-- Transform ENCR ( Name = AES-GCM with a 8 octet ICV ) > | +-- Attribute ( Key Length = 128 ) > | +-- Attribute ( Implicit = Yes ) > | > +-- Transform ENCR ( Name = AES-GCM with a 8 octet ICV ) > | +-- Attribute ( Key Length = 256 ) > | +-- Attribute ( Implicit = Yes ) > | > +-- Transform ESN ( Name = ESNs ) > +-- Transform ESN ( Name = No ESNs ) > > where missing Implicit would mean same as Implicit = No. > > The Transform ID version provides more compact encoding, and I think > it is cleaner. > > If transform attribute version is used, that would provide easy way to > expand this for every cipher we have, i.e. including > ENCR_CAMELLIA_CCM, i.e. if we just say it is allowed for > ENCR_CAMELLIA_CCM too, then it can use it. For the Transform ID option > we need to allocate separate ID for ENCR_CAMELLIA_CCM_IIV to allow it > using implicit IV. > > Transform IDs are fairly cheap, and I think it is better that we > explictly mention which ciphers can use this, and doing this by > allocating separate number for them is clean way of indicating that. > Otherwise we need table listing which attributes are allowed with > which cipher... > -- > [email protected] > > _______________________________________________ > IPsec mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/ipsec >
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