errInvalidInternalSealAlgorithm = Errorf("The internal seal algorithm is invalid and not supported")
)

// errOutOfEntropy indicates that the a source of randomness (PRNG) wasn't able
// to produce enough random data. This is fatal error and should cause a panic.

// It must never be stored in plaintext.
type ObjectKey [32]byte

// GenerateKey generates a unique ObjectKey from a 256 bit external key
// and a source of randomness. If random is nil the default PRNG of the
// system (crypto/rand) is used.
func GenerateKey(extKey []byte, random io.Reader) (key ObjectKey) {
	if random == nil {
		random = rand.Reader
	}
	if len(extKey) != 32 { // safety check