Generating jwt signing ECDSA256 key

1. Generating private key in pem format:

openssl ecparam -genkey -name prime256v1 -noout -out accula-private.pem

2. Converting it to pkcs8 der, so we could read it in java using PKCS8EncodedKeySpec:

openssl pkcs8 -topk8 -inform PEM -outform DER -in accula-private.pem -out accula-private.der -nocrypt

3. Generating public key in pem format using previously generated private key at first step:

openssl ec -in accula-private.pem -pubout -out accula-public.pem

4. Converting it to x509 der, so we could read it in java using X509EncodedKeySpec:

openssl pkey -in accula-public.pem -pubin -outform der -out accula-public.der