MD5, err := hex.DecodeString(md5Hex)
	if err != nil {
		return nil, BadDigest{ // TODO(aead): Return an error that indicates that an invalid ETag has been specified
			ExpectedMD5:   md5Hex,
			CalculatedMD5: "",
		}
	}
	SHA256, err := hex.DecodeString(sha256Hex)
	if err != nil {

		t.Errorf("Expected size 4, got %d", r.ActualSize())
	}
	expectedMD5, err := hex.DecodeString("e2fc714c4727ee9395f324cd2e7f331f")
	if err != nil {
		t.Fatal(err)
	}
	if !bytes.Equal(r.MD5Current(), expectedMD5) {
		t.Errorf("Expected md5hex \"e2fc714c4727ee9395f324cd2e7f331f\", got %s", hex.EncodeToString(r.MD5Current()))
	}
	expectedSHA256, err := hex.DecodeString("88d4266fd4e6338d13b845fcf289579d209c897823b9217da3e161936f031589")
	if err != nil {

			t.Fatalf("Test %d: ciphertext mismatch: got %x - want %x", i, key.Ciphertext, test.Key.Ciphertext)
		}
	}
}

func mustDecodeB64(s string) []byte {
	b, err := base64.StdEncoding.DecodeString(s)
	if err != nil {
		panic(err)
	}
	return b

	}

	if item.Versioning != nil {
		configData, err := base64.StdEncoding.DecodeString(*item.Versioning)
		if err != nil {
			return wrapSRErr(err)
		}
		meta.VersioningConfigXML = configData
		meta.VersioningConfigUpdatedAt = item.UpdatedAt
	}

	if item.Tags != nil {
		configData, err := base64.StdEncoding.DecodeString(*item.Tags)
		if err != nil {
			return wrapSRErr(err)
		}

	// as Base64 encoding of a value is not unique:
	// For example "aGVsbG8=" and "aGVsbG8=\r" will result in the same byte slice.
	signature1, err := base64.StdEncoding.DecodeString(sig1)
	if err != nil {
		return false
	}
	signature2, err := base64.StdEncoding.DecodeString(sig2)
	if err != nil {
		return false
	}
	return subtle.ConstantTimeCompare(signature1, signature2) == 1
}

// Return canonical headers.

	fetchOwner = values.Get("fetch-owner") == "true"
	encodingType = values.Get("encoding-type")

	if token = values.Get("continuation-token"); token != "" {
		decodedToken, err := base64.StdEncoding.DecodeString(token)
		if err != nil {
			errCode = ErrIncorrectContinuationToken
			return
		}
		token = string(decodedToken)
	}
	return
}

// Parse bucket url queries for ?uploads

	}

	// Success.
	return totalWritten, nil
}

// returns deploymentID from uploadID
func getDeplIDFromUpload(uploadID string) (string, error) {
	uploadBytes, err := base64.RawURLEncoding.DecodeString(uploadID)
	if err != nil {
		return "", fmt.Errorf("error parsing uploadID %s (%w)", uploadID, err)
	}
	slc := strings.SplitN(string(uploadBytes), ".", 2)
	if len(slc) != 2 {

	v, ok := h["Content-Md5"]
	if !ok {
		return nil, nil
	}
	if v[0] == "" {
		return nil, errors.New("etag: content-md5 is set but contains no value")
	}
	b, err := base64.StdEncoding.Strict().DecodeString(v[0])
	if err != nil {
		return nil, err
	}
	if len(b) != md5.Size {
		return nil, errors.New("etag: invalid content-md5")
	}
	return ETag(b), nil
}

		if sha256Sum, ok := r.Form[xhttp.AmzContentSha256]; ok && len(sha256Sum) > 0 {
			contentSHA256, err = hex.DecodeString(sha256Sum[0])
			if err != nil {
				return ErrContentSHA256Mismatch
			}
		}
	} else if _, ok := r.Header[xhttp.AmzContentSha256]; !skipSHA256 && ok {
		contentSHA256, err = hex.DecodeString(r.Header.Get(xhttp.AmzContentSha256))
		if err != nil || len(contentSHA256) == 0 {
			return ErrContentSHA256Mismatch

		HighwayHash256S: "39c0407ed3f01b18d22c85db4aeff11e060ca5f43131b0126731ca197cd42313",
	}
	for algorithm := range bitrotAlgorithms {
		if !algorithm.Available() {
			continue
		}

		checksum, err := hex.DecodeString(checksums[algorithm])
		if err != nil {
			logger.Fatal(errSelfTestFailure, fmt.Sprintf("bitrot: failed to decode %v checksum %s for selftest: %v", algorithm, checksums[algorithm], err))
		}
		var (