Using libgcrypt on large files

Moritz Schulte mo at
Thu Feb 24 06:37:56 CET 2005

On Wed, Feb 23, 2005 at 10:41:20PM +0100, Ralf H wrote:

> 2) What can I do if the file is really large and will not fit into
> memory? My approach will obviously fail, as I need everything in
> 'data' :(. Is there a way to hash a file in little portions, so I can
> read in buffers and update my signatures in a loop?

No, no: *hash* your file; with gcry_md_*() functions.  And then, sign
the *hash value* (optionally with pkcs1) - not the file data itself.
Have a look at the Libgcrypt manual,


Moritz Schulte
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