pkcs11 — archive

[Robert Relyea]

On 04/12/2013 01:41 PM, Michael StJohns wrote: On 4/12/2013 1:23 AM, Peter Gutmann wrote: There's really no need for this since the implementation can pretty trivially generate the CKA_PUBLIC_KEY_INFO from information it already has CKA_VALUE for DSA, CKA_MODULUS etc for RSA, and so on. Actually - no. Both the public and private keys for RSA are derived from two randomly generated primes p and q. There are three common models for storing private key info - { n, d } modulus and private exponent, { n, d, p, q } modulus, private exponent, generator primes, and finally the Chinese Remainder Theorem form (which also contains the generator primes). As far as I can tell from perusing the math, you can't get from a { n, d} private key to the public key as you need p-1 and q-1 to generate it. [Not a crypto mathematician, but the math seems simple enough to follow]. You can't get p and q from just {n, d}, or RSA would be basically broken. That is why most storage of RSA keys include {e} the public exponent, with the public key. Even if you don't store {e}, the likelihood that e is one of the (5) known Fermat primes is pretty high, and it's pretty easy to check if you are right. If e isn't stored and it's not one of the (5) Fermat primes, I think it's probably OK to punt. So I added this to the C_CreateObject stuff to support pushing a key pair where you only have the { n, d } values. The FIPS guidance requires verifying correspondence between public and private keys and I think it makes sense to enforce this here. EC doesn't have this problem as the public key is { k * G } where k is the private key and G is the generator point on the curve. I haven't looked at DH, DSA or KEA as of yet. (Or GOST for that matter). These are the same as EC except they are y = g^x mod p, x is the private key g and p are the domain parameters and y is the public key. Mike --------------------------------------------------------------------- To unsubscribe from this mail list, you must leave the OASIS TC that generates this mail. Follow this link to all your TCs in OASIS at: https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php Attachment: smime.p7s Description: S/MIME Cryptographic Signature