[openssl-dev] [openssl-users] pkeyutl does not invoke hash?

[Dr. Stephen Henson]

On Thu, Jan 14, 2016, Blumenthal, Uri - 0553 - MITLL wrote:

> On 1/14/16, 16:51 , "openssl-dev on behalf of Dr. Stephen Henson"
> <openssl-dev-bounces at openssl.org on behalf of steve at openssl.org> wrote:
> 
> >On Thu, Jan 14, 2016, Salz, Rich wrote:
> >
> >> Okay, how about this.  First, remove the NOTES subhead.  Add this to
> >>the end of the first paragraph:
> >> 
> >> 	This program does not hash the input data and requires the input data
> >> 	to be of the proper size, and must not be greater than the size of
> >> 	the public key field or modulus.  See dgst(1) for a unified
> >> 	Interace.
> >> 
> >
> >The comment about the public key field or modulus is only true for some
> >public
> >key algorithms (e.g. RSA).
> 
> Public key modulus would be true for RSA and DSA. Field would be true for
> ECDSA (and I daresay EdDSA). What other signatures do we have?

For RSA the maximum size depends on the padding mode and is typically
less than the modulus.

For ECDSA it can be exceed the field size: it is truncated in that case.

Steve.
--
Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: http://www.openssl.org