A DESCRIPTION OF THE PROBLEM :
When connecting to an internal device with a JDK17 and TLS v1.2, the handshake fails with this error:

No supported CertificateVerify signature algorithm for EC key

My key uses the EC "secp256r1", and the negociated signature algorithm is "ecdsa_secp384r1_sha384". The CertificateVerity stage fails because the "ecdsa_secp384r1_sha384" can't be used with the named group "secp256r1". I see in the log:

Ignore the signature algorithm (ecdsa_secp384r1_sha384), unsupported EC parameter spec: secp256r1

cf https://github.com/openjdk/jdk/blob/master/src/java.base/share/classes/sun/security/ssl/SignatureScheme.java#L503

When I try to connect to this device with openssl and the same certificate/pkey, It works without any issue.
In tlsv1.2, it seem to be legal to use ecdsa_secp384r1_sha384 with a secp256r1 key (but not in tlsv1.3)



FREQUENCY : always