I think it's because RSA adds an object identifier (OID) to the hash before padding and signing. The OID describes the hash algorithm.
ECDSA apparently doesn't do that. I don't know DSA, but perhaps it's the same. > From: Lucas Martins <lucasgm...@gmail.com> > To: openssl-users@openssl.org > Date: 09/28/2011 06:31 PM > Subject: Why RSA considers Hash algorithm > Sent by: owner-openssl-us...@openssl.org > > I was looking libcrypto code, and found that DSA_sign and ECDSA_sign > ignore hash algorithm while RSA_sign do not. > > Are there any reason for this?
