[openssl-users] Converting a p12 or PEM formatted private key to a PKCS#1 format

Viktor Dukhovni openssl-users at dukhovni.org
Thu Sep 3 16:16:04 UTC 2015

On Thu, Sep 03, 2015 at 04:06:06PM +0000, Viktor Dukhovni wrote:
> On Thu, Sep 03, 2015 at 08:21:25AM -0700, tmcclure0501 wrote:
> > We have an embedded MQTT framework that we want to configure for mutual
> > authentication.  The framework is complaining that it needs a key format of
> > PKCS#1.  We have p12 and pem formats of the key.  Does openssl support
> > converting keys to the PKCS#1, if so what is the command? 
> I've never heard of a PKCS#1 key format, I'm only aware of
>     PKCS#8	- Private key
>     PKCS#12	- Private key and related certificates
> Consult the documentation for the product, this is not an OpenSSL
> question until at least the desired key format is known.

Perhaps what you're looking for is the legacy RSA key format (PEM
or DER encoded).


The "openssl rsa" command (unlike the "pkey" command) outputs RSA
keys in either DER or PEM formats.


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