diff --git a/README.md b/README.md
index 042df25..e96a7e6 100644
--- a/README.md
+++ b/README.md
@@ -8,6 +8,11 @@ Cross compile:
 CGO_ENABLED=1 GOOS=linux GOARCH=amd64 CC="zig cc -target x86_64-linux" CXX="zig c++ -target x86_64-linux" go build  -o external-signer-pkcs11-linux-x86_64
 ```
 
+List private objects:
+```shell
+pkcs11-tool --module /usr/local/lib/libykcs11.dylib --login --list-objects --type privkey
+```
+
 
 ```shell
 external-signer-pkcs11 external_spec
diff --git a/main.go b/main.go
index 99f9c85..7d092de 100644
--- a/main.go
+++ b/main.go
@@ -2,14 +2,20 @@ package main
 
 import (
 	"crypto"
+	"crypto/ecdsa"
 	"crypto/rand"
+	"crypto/rsa"
 	"crypto/sha256"
+	"crypto/sha512"
 	"crypto/x509"
 	"encoding/base64"
 	"encoding/json"
 	"errors"
 	"fmt"
+	"net/url"
 	"os"
+	"reflect"
+	"strings"
 
 	"github.com/ThalesGroup/crypto11"
 	"github.com/urfave/cli/v2"
@@ -83,11 +89,14 @@ func innerMain() error {
 		Name:  "external-signer-pkc11",
 		Usage: "External signer PKCS#11",
 		Commands: []*cli.Command{
+			buildParameterDecodeCommand(),
+			buildParameterEncodeCommand(),
 			buildExternalSpecCommand(),
 			buildExternalPublicKeyCommand(),
 			buildExternalSignCommand(),
 		},
 		Action: func(ctx *cli.Context) error {
+			fmt.Println("External signer PKCS#11, specification: https://openwebstandard.org/rfc1")
 			return nil
 		},
 	}
@@ -98,6 +107,92 @@ func innerMain() error {
 	return nil
 }
 
+func buildParameterEncodeCommand() *cli.Command {
+	return &cli.Command{
+		Name:  "parameter_encode",
+		Usage: "Encode parameter, show PKCS#11 URIs: pkcs11-tool --module /usr/local/lib/libykcs11.dylib --login --list-objects --type privkey",
+		Flags: []cli.Flag{
+			&cli.StringFlag{
+				Name:     "uri",
+				Usage:    "PKCS#11 URI",
+				Required: true,
+			},
+			&cli.StringFlag{
+				Name:  "library",
+				Usage: "Library",
+			},
+			&cli.StringFlag{
+				Name:  "pin",
+				Usage: "PIN",
+			},
+		},
+		Action: func(ctx *cli.Context) error {
+			uri := ctx.String("uri")
+			library := ctx.String("library")
+			pin := ctx.String("pin")
+			if !strings.HasPrefix(uri, "pkcs11:") {
+				return fmt.Errorf("invalid uri: %s", uri)
+			}
+			if library == "" {
+				library = "/usr/local/lib/libykcs11.dylib"
+			}
+			uriMap := parseUri(uri)
+			pkcs11Key := Pkcs11Key{
+				Library:    library,
+				Pin:        pin,
+				TokenLabel: uriMap["token"],
+				KeyLabel:   uriMap["object"],
+			}
+			parameter, err := json.Marshal(&pkcs11Key)
+			if err != nil {
+				return nil
+			}
+			fmt.Println(base64.StdEncoding.EncodeToString(parameter))
+			return nil
+		},
+	}
+}
+
+func parseUri(uri string) map[string]string {
+	uriMap := map[string]string{}
+	pkcs11UriLeftPart := strings.TrimPrefix(uri, "pkcs11:")
+	keyValus := strings.Split(pkcs11UriLeftPart, ";")
+	for _, kv := range keyValus {
+		keyAndValue := strings.Split(kv, "=")
+		if len(keyAndValue) == 2 {
+			decodedValue, err := url.QueryUnescape(keyAndValue[1])
+			if err == nil {
+				uriMap[keyAndValue[0]] = decodedValue
+			} else {
+				uriMap[keyAndValue[0]] = keyAndValue[1]
+			}
+		}
+	}
+	return uriMap
+}
+
+func buildParameterDecodeCommand() *cli.Command {
+	return &cli.Command{
+		Name:  "parameter_decode",
+		Usage: "Decode parameter",
+		Flags: []cli.Flag{
+			&cli.StringFlag{
+				Name:     "parameter",
+				Usage:    "Parameter",
+				Required: true,
+			},
+		},
+		Action: func(ctx *cli.Context) error {
+			parameter := ctx.String("parameter")
+			pkcs11Key, err := parseParameter(parameter)
+			if err != nil {
+				return err
+			}
+			return printResponse(pkcs11Key)
+		},
+	}
+}
+
 func buildExternalSpecCommand() *cli.Command {
 	return &cli.Command{
 		Name:  "external_spec",
@@ -173,15 +268,54 @@ func buildExternalSignCommand() *cli.Command {
 		},
 		Action: func(ctx *cli.Context) error {
 			parameter := ctx.String("parameter")
+			alg := ctx.String("alg")
 			messageBase64 := ctx.String("message-base64")
-			// TODO check --alg
 			message, err := base64.StdEncoding.DecodeString(messageBase64)
 			if err != nil {
 				return fmt.Errorf("unmarshal --message-base64 failed: %v", err)
 			}
 			return tryWithPkcs11(parameter, true, func(privateKey crypto11.Signer) error {
-				hashed := sha256.Sum256(message)
-				signature, err := privateKey.Sign(rand.Reader, hashed[:], crypto.SHA256)
+				publicKey := privateKey.Public()
+
+				if ecdsaPublicKey, ok := publicKey.(*ecdsa.PublicKey); ok {
+					ecName := ecdsaPublicKey.Curve.Params().Name
+					es256Matches := alg == "ES256" && ecName == "P-256"
+					es384Matches := alg == "ES384" && ecName == "P-384"
+					es512Matches := alg == "ES512" && ecName == "P-521"
+
+					esMatches := es256Matches || es384Matches || es512Matches
+
+					if !esMatches {
+						return fmt.Errorf("algorithm mismatch %s vs %s", alg, ecName)
+					}
+				} else if _, ok := publicKey.(*rsa.PublicKey); ok {
+					rsValid := alg == "RS256" || alg == "RS384" || alg == "RS512"
+					if !rsValid {
+						return fmt.Errorf("rsa algorithm invalid %s", alg)
+					}
+				} else {
+					return fmt.Errorf("invalid public key type: %+v", reflect.TypeOf(publicKey))
+				}
+
+				var digest []byte
+				var hash crypto.Hash
+				if alg == "ES256" || alg == "RS256" {
+					digest32 := sha256.Sum256(message)
+					digest = digest32[:]
+					hash = crypto.SHA256
+				} else if alg == "ES384" || alg == "RS384" {
+					sha384 := crypto.SHA384.New()
+					digest = sha384.Sum(message)
+					hash = crypto.SHA384
+				} else if alg == "ES512" || alg == "RS512" {
+					digest64 := sha512.Sum512(message)
+					digest = digest64[:]
+					hash = crypto.SHA512
+				} else {
+					return fmt.Errorf("invalid algorithm: %s", alg)
+				}
+
+				signature, err := privateKey.Sign(rand.Reader, digest, hash)
 				if err != nil {
 					return fmt.Errorf("sign with private key failed: %v", err)
 				}