Generating 4096 bit key fails – why?

NIIBE Yutaka gniibe at
Mon Nov 2 03:04:35 CET 2015

On 10/31/2015 02:18 PM, Felix E. Klee wrote:
> See attachment.

Thank you for the attachment.

It failed when gpg frontend tried to change the key attribute for RSA-4096.

> 2015-10-31 06:05:38 scdaemon[1927] DBG: chan_5 <- SETATTR KEY-ATTR --force+1+1+rsa4096
> 2015-10-31 06:05:38 scdaemon[1927] DBG: chan_5 -> ERR 100663375 Invalid data <SCD>

Do you happened to have (and run) old scdaemon of 2.0?

In 2.1.x, this particular protocol has been changed to support ECC.
It was in the format (in the syntax of scanf):

	setattr key-attr --force %d %d %u

It was number, because we only supported RSA.

Now, it's in the format:

	setattr key-attr --force %d %d %s

It is now string, because we supports RSA and ECC.

The error seems to be occurred because of this format change.

Since SETATTR command uses percent-and-plus escaping, having '+' is no
problem (it means space).

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