Unattended generation of an ECDSA key using gpg2

Short question

How do I specify an elliptic curve in a gpg2 v2.1.11 parameter file?

Long question

I have successfully used the following bash script to generate an RSA key using gpg2 v2.1.11:

#!/bin/bash

PUBRING_FILE=$(mktemp /tmp/pub.XXXXXX)
CONFIG_FILE=$(mktemp /tmp/config.XXXXXX)

cat >$CONFIG_FILE <<EOF
    Key-Type: DSA
    Key-Length: 1024
    Subkey-Type: RSA
    Subkey-Length: 2048
    Name-Real: Name
    Name-Comment: Comment
    Name-Email: Email
    Expire-Date: 0
    Passphrase: abc
    %pubring $PUBRING_FILE
EOF

gpg2 --quiet --batch --expert --full-gen-key $CONFIG_FILE

I want to use the same script to generate an ECDSA key. However, when I replace

Subkey-Type: RSA
Subkey-Length: 2048

with

Subkey-Type: ECDSA
Subkey-Length: 256

I get the following error

gpg: key generation failed: Unknown elliptic curve

My configuration file clearly omits the curve, but how can I include it? I.e., how do I specify an elliptic curve in a gpg2 v2.1.11 parameter file?

Unattended generation of an ECDSA key using gpg2

1 Answers