DSA signing using openssl CLI

dsa.sh

openssl dsaparam 1024 < /dev/random > dsa_param.pem
openssl gendsa dsa_param.pem -out dsa_priv.pem
openssl dsa -in dsa_priv.pem -pubout -out dsa_pub.pem
# DSA system now made up of: dsa_param.pem, dsa_pub.pem, dsa_priv.pem

echo "foobar" > foo.txt
openssl sha1 < foo.txt > foo.txt.sha1
openssl dgst -dss1 -sign dsa_priv.pem foo.txt.sha1 > foo.txt.sig
openssl dgst -dss1 -verify dsa_pub.pem -signature foo.txt.sig foo.txt.sha1