[strongSwan] Selecting proper encryption pairings

[Kostya Vasilyev]

Tom,

On Mon, Feb 18, 2019, at 9:31 PM, Tom Rymes wrote:
> Can anyone point me to some good information for which of the various 
> options should be paired together? I've done a fair amount of digging, 
> but it's always nice to have some confirmation that my interpretation is 
> accurate.
> 
> I am working with Strongswan and Windows Roadwarrior clients, and am 
> thus limited to (I have omitted some of the weaker options):
> 
> Encryption: AES128, AES192, AES256, GCMAES128, GCMAES192, GCMAES256
> 
> Integrity: SHA2_256, SHA2_384
> 
> Grouptype: MODP2048, ECP256, ECP384
> 
> 
> Which combinations of encryption and integrity options provides the best 
> possible security without wasting computational effort for each of the 
> grouptypes?
> 
> Many thanks,
> 
> Tom

Some useful links:

https://wiki.strongswan.org/projects/strongswan/wiki/SecurityRecommendations

https://wiki.strongswan.org/projects/strongswan/wiki/PublicKeySpeed

https://wiki.strongswan.org/projects/strongswan/wiki/IKEv2CipherSuites

Personally I'm using aes128-sha256-ecp256 - and would use AES GCM but my client side (a home-class Mikrotik) doesn't have hardware acceleration for AES GCM, only for AES CBC.

You may find this older discussion useful too:

https://lists.strongswan.org/pipermail/users/2015-April/007809.html

-- K