private boolean verifyNative(
      final Bytes data, final SECPSignature signature, final SECPPublicKey pub) {

    return libSECP256R1.verify(
        data.toArrayUnsafe(),
        signature.getR().toByteArray(),
        signature.getS().toByteArray(),
        pub.getEncoded());
  }
SECP256R1 is using the non-deterministic implementation of K calculation (standard)

@return an instance of RandomDSAKCalculator
crypto/algorithms/src/main/java/org/hyperledger/besu/crypto/SECP256R1.java