I want to use an EC key for ECDH and ECDSA too. Using the same key does compromise the security of the key in a cryptographic / mathematical sense? I read a lot in this theme, but I found nothing exact. I know that the usage of the same key for encryption and for signing is not recommended (because of encryption keys must be escrowed, and signing keys must not be escrowed), but is there any mathematical/cryptographic reason to use different keys? (Only in Elliptic curve cryptography of course). Is there an RFC or something formal paper about this? (A haven't found any)
I want to generate an EC key on a HSM, but I can't enable SIGN, and DERIVE at the same time. (I think that's because the HSM generates an ECDSA key in the precending case, and an ECDH key in the latter case, and don't know what to do if they are enabled in the same time). But I can generate an EC key with openssl without so much as to know if I want to use it for ECDH, or ECDSA purposes. Is there any workaround for that? Can I generate a general EC key on the HSM?