ECDSA, "plain" vs "non-plain"

To put this into the public record...  I asked some security folks at  
the IETF; their comment was that there is no known security difference  
between the two variants, which is useful to confirm.

For the ECDSA algorithms that we define so far, we actually *don't*  
use the ASN.1 sequence, in other words, we're going for the "plain"  
alternative anyway.  That, to me, suggests that we only coin  
identifiers for the "plain" variants of ECDSA-RIPEMD160 (and - 
whirlpool), and dont bother with the non-plain ones.

   http://www.w3.org/TR/xmldsig-core1/#sec-ECDSA

Regards,
--
Thomas Roessler, W3C  <tlr@w3.org>