sum := r.md5.Sum(nil)
	return ETag(sum)
}

// VerifyError is an error signaling that a
// computed ETag does not match an expected
// ETag.
type VerifyError struct {
	Expected ETag
	Computed ETag
}

func (v VerifyError) Error() string {
	return fmt.Sprintf("etag: expected ETag %q does not match computed ETag %q", v.Expected, v.Computed)
}

// UUIDHash - use uuid to make md5sum

		{[]CompletePart{{ETag: "wrong-md5-hash-string"}}, "0deb8cb07527b4b2669c861cb9653607-1", ""},

		// Single CompletePart with valid MD5 hash string.
		{[]CompletePart{{ETag: "cf1f738a5924e645913c984e0fe3d708"}}, "10dc1617fbcf0bd0858048cb96e6bd77-1", ""},

		// Multiple CompletePart with valid MD5 hash string.

var stringTests = []struct {
	ETag   ETag
	String string
}{
	{ETag: ETag{59, 131, 239, 150, 56, 127, 20, 101}, String: "3b83ef96387f1465"},                                                                  // 0
	{ETag: ETag{59, 131, 239, 150, 56, 127, 20, 101, 95, 200, 84, 221, 195, 198, 189, 87}, String: "3b83ef96387f14655fc854ddc3c6bd57"},             // 1

	return partKey
}

// SealETag seals the etag using the object key.
// It does not encrypt empty ETags because such ETags indicate
// that the S3 client hasn't sent an ETag = MD5(object) and
// the backend can pick an ETag value.
func (key ObjectKey) SealETag(etag []byte) []byte {
	if len(etag) == 0 { // don't encrypt empty ETag - only if client sent ETag = MD5(object)
		return etag
	}
	var buffer bytes.Buffer

		// Test Case 3: if-match with wrong ETag
		// Even if the ETag doesn't match, we should still get read quorum error
		// because we can't read the object to check the condition.
		opts := ObjectOptions{
			UserDefined: map[string]string{
				xhttp.IfMatch: "wrong-etag",
			},
			CheckPrecondFn: func(oi ObjectInfo) bool {
				// Precondition fails if ETag doesn't match

// generates CopyObjectResponse from etag and lastModified time.
func generateCopyObjectResponse(etag string, lastModified time.Time) CopyObjectResponse {
	return CopyObjectResponse{
		ETag:         "\"" + etag + "\"",
		LastModified: amztime.ISO8601Format(lastModified.UTC()),
	}
}

// generates CopyObjectPartResponse from etag and lastModified time.

	PART_ETAG=$(echo "${UPLOAD_PART_OUT}" | jq '.ETag')
	if [ "${idx}" == 10 ]; then
		PARTS="${PARTS}{\"ETag\": ${PART_ETAG}, \"ChecksumSHA256\": \"${PART_CHKSUM}\", \"PartNumber\": ${idx}}"
	else
		PARTS="${PARTS}{\"ETag\": ${PART_ETAG}, \"ChecksumSHA256\": \"${PART_CHKSUM}\", \"PartNumber\": ${idx}},"
	fi
done

	for i := range key {
		key[i] = byte(i)
	}
	for i, etag := range sealUnsealETagTests {
		tag, err := hex.DecodeString(etag)
		if err != nil {
			t.Errorf("Test %d: failed to decode etag: %s", i, err)
		}
		sealedETag := key.SealETag(tag)
		unsealedETag, err := key.UnsealETag(sealedETag)
		if err != nil {
			t.Errorf("Test %d: failed to decrypt etag: %s", i, err)
		}
		if !bytes.Equal(unsealedETag, tag) {

			if _, ok := crypto.IsEncrypted(batch[i].UserDefined); ok {
				ETag, err := etag.Parse(batch[i].ETag)
				if err != nil {
					return err
				}
				if SSES3SinglePartObjects[i] {
					ETag, err = etag.Decrypt(keys[0][:], ETag)
					if err != nil {
						return err
					}
					keys = keys[1:]
				}
				batch[i].ETag = ETag.Format().String()
			}
		}
		objects = objects[N:]
	}
	return nil

func TestCanonicalizeETag(t *testing.T) {
	testCases := []struct {
		etag              string
		canonicalizedETag string
	}{
		{
			etag:              "\"\"\"",
			canonicalizedETag: "",
		},
		{
			etag:              "\"\"\"abc\"",
			canonicalizedETag: "abc",
		},
		{
			etag:              "abcd",
			canonicalizedETag: "abcd",
		},
		{
			etag:              "abcd\"\"",
			canonicalizedETag: "abcd",
		},
	}