On 3/17/21 7:22 PM, Viktor Dukhovni wrote:
On Wed, Mar 17, 2021 at 05:50:41PM -0400, Robert Moskowitz wrote:
I have created my X25519 pub/priv keypair with:
openssl genpkey -algorithm X25519\
-out $dir/private/$clientemail-X.key.$format
Are you sure you didn't want ed25519 instead? X25519 is a key agreement
menthod, not a signature method.
My limited understanding is that for encrypted S/MIME, and ECDH cert is
needed. Thus if ED25519 is used for signing said S/MIME, X25519 is used
for encrypting.
I have seen CA Cert policies for "Device Encryption Certificates" that
use: id-ecPublicKey {1 2 840 10045 2 1}; I need to talk to the CP
author more about this and what he sees the equiv Edward cert would look
like.
openssl req -config $dir/openssl-intermediate.cnf\
-key $dir/private/$clientemail-X.key.$format \
-subj "$DN" -new -out $dir/csr/$clientemail-X.csr.$format
which is what I used for ED25519 client certs. But I get an error:
140487683954496:error:0608D096:digital envelope
routines:EVP_PKEY_sign_init:operation not supported for this
keytype:crypto/evp/pmeth_fn.c:39:
Not surprising, why do you expect this to work?
Shooting from the hip, a bit. If I am going to have an X25519 cert,
then I need a csr and this is the command to make one. So try it and
see what it does. Not too well, it turns out.
Can someone point me to what I am missing?
Oh, and I am ASSuMEing that a CA cert of ED25519 signs an X25519 client
cert. Haven't found instructions on this, but it seems reasonable...
https://crypto.stackexchange.com/questions/27866/why-curve25519-for-encryption-but-ed25519-for-signatures
very familiar with this point and did look at this response during my
searches today.
I quite understand in TLS the use of EdDSA certs that allow
keyEncipherment and ?dataEncipherment? to permit an ECDHE exchange.
but my limited research claims that for S/MIME you can have an X25519
cert for static ECDH, rather than ephemeral, saving supposedly the
exchange of keys before sending encrypted S/MIME.
