Re: additively computing SHA hash

2010-06-14 Thread Steffen DETTMER
* Subra Aswathanarayanan wrote on Mon, Jun 07, 2010 at 20:44 -0400: >Both of you mention that OpenSSL doesn't provide such an interface. >May be this question is not appropriate for this forum, but do you >know of any such simpler libraries that I might be able to use? If it is just S

Re: additively computing SHA hash

2010-06-08 Thread Dr. Stephen Henson
On Tue, Jun 08, 2010, Jason Fister wrote: > Stephen, > Thanks for your solution. > > >Well I'd add the BIG disclaimer that will NOT work in future when OpenSSL > >structures are made opaque and almost certainly will fail if you have an > >ENGINE. > > Understood. I am new to openssl and I am rea

Re: additively computing SHA hash

2010-06-08 Thread Jason Fister
Stephen, Thanks for your solution. >Well I'd add the BIG disclaimer that will NOT work in future when OpenSSL >structures are made opaque and almost certainly will fail if you have an >ENGINE. Understood. I am new to openssl and I am reading up about 'ENGINE's in openssl. When you say it will fa

Re: additively computing SHA hash

2010-06-08 Thread Dr. Stephen Henson
On Mon, Jun 07, 2010, Subra Aswathanarayanan wrote: > Steve/Victor, > > >You mean you want to do: > >SHA1(A) > >and later do: > >SHA1(A || B) > >without including A again? > > That is correct. Thats exactly what I want to do. > > >You need to serialize, save and restore the intermediate state o

Re: additively computing SHA hash

2010-06-08 Thread Subra Aswathanarayanan
Steve/Victor, >You mean you want to do: >SHA1(A) >and later do: >SHA1(A || B) >without including A again? That is correct. Thats exactly what I want to do. >You need to serialize, save and restore the intermediate state of >the digest before you call "final" if you need to be able to append >mor

Re: additively computing SHA hash

2010-06-07 Thread Victor Duchovni
On Mon, Jun 07, 2010 at 04:07:06PM -0400, Jason Fister wrote: > Hello folks, > > I have a service to which people can send data. My service then stores the > data and returns the SHA checksum for the data back to the client. I also > store the checksum I computed and the offset at which it was co

Re: additively computing SHA hash

2010-06-07 Thread Dr. Stephen Henson
On Mon, Jun 07, 2010, Jason Fister wrote: > Hello folks, > > I have a service to which people can send data. My service then stores the > data and returns the SHA checksum for the data back to the client. I also > store the checksum I computed and the offset at which it was computed as > part of

additively computing SHA hash

2010-06-07 Thread Jason Fister
Hello folks, I have a service to which people can send data. My service then stores the data and returns the SHA checksum for the data back to the client. I also store the checksum I computed and the offset at which it was computed as part of the metadata. I want to allow clients to send append r