- From: Wan-Teh Chang <wtc@google.com>
- Date: Fri, 24 Aug 2012 18:04:21 -0700
- To: Ryan Sleevi <sleevi@google.com>, "David McGrew (mcgrew)" <mcgrew@cisco.com>
- Cc: Web Cryptography Working Group <public-webcrypto@w3.org>
Ryan, Thank you for the info. I found the guidance you quoted in RFC 3447 for RSAES-OAEP and EMSA-PSS. The recommendation is repeated in RFC 4055 Section 3.1 for RSASSA-PSS keys: When signing, it is RECOMMENDED that the parameters, except for possibly saltLength, remain fixed for all usages of a given RSA key pair. I did not find similar language that recommends using a fixed hash algorithm for a given signing key in X9.62-2005 and FIPS 186-3. Also, RFC 5480 still uses the completely unrestricted id-ecPublicKey algorithm identifier for ECDSA keys. So it seems that these standards and RFCs, especially for ECDSA keys, still allow key algorithms to be less restrictive/specific than crypto operation algorithms. In PKCS #11, key algorithms and crypto operation algorithms come from two namespaces -- CKK_xxx for key types and CKM_xxx for mechanisms. The implication is that this kind of "tainting" will need to be maintained by the user agents, and it would be difficult to migrate key tainting from one computer to another for keys in smart cards unless the smart cards themselves carry key tainting information. Wan-Teh
Received on Saturday, 25 August 2012 01:04:48 UTC