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
}

	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 {

	// 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.

		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

	"github.com/minio/pkg/v3/sync/errgroup"
	"github.com/minio/sio"
)

func (er erasureObjects) getUploadIDDir(bucket, object, uploadID string) string {
	uploadUUID := uploadID
	uploadBytes, err := base64.RawURLEncoding.DecodeString(uploadID)
	if err == nil {
		slc := strings.SplitN(string(uploadBytes), ".", 2)
		if len(slc) == 2 {
			uploadUUID = slc[1]
		}
	}
	return pathJoin(er.getMultipartSHADir(bucket, object), uploadUUID)
}

				// Expires in 10 days.
				pp.SetExpires(UTCNow().AddDate(0, 0, 10))
			}

			tt.fv.Set("Policy", base64.StdEncoding.EncodeToString([]byte(pp.String())))

			policyBytes, err := base64.StdEncoding.DecodeString(base64.StdEncoding.EncodeToString([]byte(pp.String())))
			if err != nil {
				t.Fatal(err)
			}

			postPolicyForm, err := parsePostPolicyForm(bytes.NewReader(policyBytes))
			if err != nil {

			return "", errObjectTampered
		}
		if _, err := hex.DecodeString(object.ETag[:32]); err != nil {
			return "", errObjectTampered
		}
		if _, err := strconv.ParseInt(object.ETag[i+1:], 10, 32); err != nil {
			return "", errObjectTampered
		}
		return object.ETag, nil
	}

	etag, err := hex.DecodeString(object.ETag)
	if err != nil {
		return "", err
	}

		// We ensure it is rewritten without an index.
		// We compare this against the signature of the files stored without a version.

	if e.Type == ssekms && spaces {
		return crypto.ErrInvalidEncryptionKeyID
	}

	if e.Type == ssekms && GlobalKMS != nil {
		ctx := kms.Context{}
		if e.Context != "" {
			b, err := base64.StdEncoding.DecodeString(e.Context)
			if err != nil {
				return err
			}

			json := jsoniter.ConfigCompatibleWithStandardLibrary
			if err := json.Unmarshal(b, &ctx); err != nil {
				return err
			}
		}