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List:       ms-cryptoapi
Subject:    Re: KP_KEYLEN lies?
From:       Jeff Spelman <jeffspel () MICROSOFT ! COM>
Date:       1997-12-18 16:04:28
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Slava
  When enumerating the algorithms with PP_ENUMALGS the CSP should return the
default key length which is supported.
Thanks, Jeff

> -----Original Message-----
> From: Bronislav Kavsan [SMTP:bkavsan@IRE-MA.COM]
> Sent: Wednesday, December 17, 1997 6:24 PM
> To:   CryptoAPI@LISTSERV.MSN.COM
> Subject:      Re: KP_KEYLEN lies?
>
> Another key-length related question: what values does PP_ENUMALGS return
> for
> variable key lengths algorithms - both symmetric (e.g.RC5, 40-128) and
> public(e.g.RSA 512-...)?
>
> Jeff Spelman wrote:
>
> > Ferrell
> >    You are correct.  The Microsoft Provider is counting the parity bits
> on
> > the DES keys when CryptGetKeyParam is called with KP_KEYLEN.  Thanks for
> > pointing this out!  Please note that 3DES and 3DES two key are also
> > currently wrong.  I will fix this in future releases.
> > Thanks, Jeff
> >
> > > -----Original Message-----
> > > From: Ferrell Moultrie [SMTP:fmoultrie@ISS.NET]
> > > Sent: Wednesday, December 17, 1997 9:10 AM
> > > To:   CryptoAPI@LISTSERV.MSN.COM
> > > Subject:      KP_KEYLEN lies?
> > >
> > > Hi:
> > >   I'm generating a DES symmetric key using CryptGenKey() using the
> > > Enhanced
> > > RSA CSP installed with IE 4.01. Querying the provider with
> > > CryptGetProvParam(PP_ENUMALGS) returns the expected response that the
> > > symmetric key length is 56 bits. Unfortunately,
> > > CryptGetKeyParam(KP_KEYLEN)
> > > returns that the key size is 64 bits -- which I don't believe. This
> same
> > > call on a RC2 or RC4 key returns the proper value (128 bits). Is there
> any
> > > way to fix this other than to examine ALG_ID prior to making the
> KP_KEYLEN
> > > request and simply hard-coding the 'right' answer? Also, any
> information
> > > on
> > > whether this is broken for all providers, for any other algorithms,
> etc.?
> > > Thanks!
> > > Ferrell
> > >
> > > --------------------------------------------------
> > > Ferrell Moultrie        Internet Security Systems (ISS)
> > > FMoultrie@iss.net   770-522-4865 (voice)  770-395-1972 (fax)
> > >
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