return key, ErrInvalidCustomerKey
	}
	keyMD5, err := base64.StdEncoding.DecodeString(h.Get(xhttp.AmzServerSideEncryptionCustomerKeyMD5))
	if md5Sum := md5.Sum(clientKey); err != nil || !bytes.Equal(md5Sum[:], keyMD5) {
		return key, ErrCustomerKeyMD5Mismatch
	}
	copy(key[:], clientKey)
	return key, nil
}

// UnsealObjectKey extracts and decrypts the sealed object key

	if err != nil {
		b.Fatal(err)
	}

	// get text data generated for number of bytes equal to object size.
	textData := generateBytesData(objSize)
	// generate md5sum for the generated data.
	// md5sum of the data to written is required as input for PutObject.

	md5hex := getMD5Hash(textData)
	sha256hex := ""

	// benchmark utility which helps obtain number of allocations and bytes allocated per ops.

				log.Println("SKIPPED: Objects encrypted with SSE-C do not have md5sum as ETag:", objFullPath(object))
				continue
			}
			if v, ok := object.UserMetadata["X-Amz-Server-Side-Encryption"]; ok && v == "aws:kms" {
				log.Println("SKIPPED: encrypted with SSE-KMS do not have md5sum as ETag:", objFullPath(object))
				continue
			}
			parts := 1
			multipart := false

		},
		{
			name:     "2",
			metadata: map[string]string{"content-type": "application/octet-stream", "etag": "de75a98baf2c6aef435b57dd0fc33c86", "x-amz-storage-class": "REDUCED_REDUNDANCY", "md5sum": "abcde"},
			keys:     []string{"etag", "md5sum"},
			want:     map[string]string{"content-type": "application/octet-stream", "x-amz-storage-class": "REDUCED_REDUNDANCY"},
		},
		{
			name:     "3",

func tryDecryptETag(key []byte, encryptedETag string, sses3 bool) string {
	// ETag for SSE-C or SSE-KMS encrypted objects need not be content MD5Sum.While encrypted
	// md5sum is stored internally, return just the last 32 bytes of hex-encoded and
	// encrypted md5sum string for SSE-C
	if !sses3 {
		return encryptedETag[len(encryptedETag)-32:]
	}
	var objectKey crypto.ObjectKey
	copy(objectKey[:], key)

		h.Reset()
		_, err = io.Copy(h, gr)
		if err != nil {
			t.Fatalf("Test %d: Failed to calculate md5sum of the object: %v", i+1, err)
		}
		gr.Close()
		foundHash := h.Sum(nil)

		if !bytes.Equal(foundHash, expectedHash) {
			t.Fatalf("Test %d: Expected data to have md5sum = `%x`, found `%x`", i+1, expectedHash, foundHash)
		}
	}

type CopyObjectResponse struct {
	XMLName      xml.Name `xml:"http://s3.amazonaws.com/doc/2006-03-01/ CopyObjectResult" json:"-"`
	LastModified string   // time string of format "2006-01-02T15:04:05.000Z"
	ETag         string   // md5sum of the copied object.
}

// CopyObjectPartResponse container returns ETag and LastModified of the successfully copied object
type CopyObjectPartResponse struct {

	return errors.New(part.Error)
}

// CompleteMultipartUpload - completes an ongoing multipart
// transaction after receiving all the parts indicated by the client.
// Returns an md5sum calculated by concatenating all the individual
// md5sums of all the parts.
//
// Implements S3 compatible Complete multipart API.

		Name:        fi.TransitionedObjName,
		VersionID:   fi.TransitionVersionID,
		Status:      fi.TransitionStatus,
		FreeVersion: fi.TierFreeVersion(),
		Tier:        fi.TransitionTier,
	}

	// etag/md5Sum has already been extracted. We need to
	// remove to avoid it from appearing as part of
	// response headers. e.g, X-Minio-* or X-Amz-*.
	// Tags have also been extracted, we remove that as well.

	// this is required even to assert the copied object,
	bytesData := []struct {
		byteData []byte
		md5sum   string
	}{
		{byteData: generateBytesData(6 * humanize.KiByte)},
	}
	h := md5.New()
	h.Write(bytesData[0].byteData)
	bytesData[0].md5sum = hex.EncodeToString(h.Sum(nil))

	buffers := []*bytes.Buffer{
		new(bytes.Buffer),
		new(bytes.Buffer),
	}