@Override
    protected void engineInitSign(PrivateKey privateKey) throws InvalidKeyException {
        key = verifyKey(OpenSSLKey.fromPrivateKey(privateKey));
        NativeRef.EVP_MD_CTX ctxLocal = new NativeRef.EVP_MD_CTX(NativeCrypto.EVP_MD_CTX_create());
        NativeCrypto.EVP_DigestSignInit(ctxLocal, 0, key.getNativeRef());
        this.ctx = ctxLocal;
    }
The current OpenSSL key we're operating on.
common/src/main/java/org/conscrypt/OpenSslSignatureEdDsa.java