private byte[] generateSessionNonce(final byte[] ecdh, final byte[] provisioningSalt) {
        final byte[] nonce = SecureUtils.calculateK1(ecdh, provisioningSalt, SecureUtils.PRSN);
        final ByteBuffer buffer = ByteBuffer.allocate(nonce.length - 3);
        buffer.put(nonce, 3, buffer.limit());
        return buffer.array();
    }
Calculate the Session nonce

@param ecdh             shared ECDH secret
@param provisioningSalt provisioning salt
@return sessionNonce
mesh/src/main/java/no/nordicsemi/android/mesh/provisionerstates/ProvisioningDataState.java