diff --git a/.gitignore b/.gitignore
index bd53762..15c2965 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,5 @@
+external-signer-pkcs11
+vendor/
 # ---> Go
 # If you prefer the allow list template instead of the deny list, see community template:
 # https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..8ba444f
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,11 @@
+module git.hatter.ink/external-signer-pkcs11
+
+go 1.24.1
+
+require github.com/ThalesGroup/crypto11 v1.4.1
+
+require (
+	github.com/miekg/pkcs11 v1.1.1 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/thales-e-security/pool v0.0.2 // indirect
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..586781e
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,14 @@
+github.com/ThalesGroup/crypto11 v1.4.1 h1:6YR6aVL8LI8akReXKTEgxf+k0+b8wlV8Ra7tZnCG9y4=
+github.com/ThalesGroup/crypto11 v1.4.1/go.mod h1:vggvBwlVrqePDrooq/B32dMXlfEsdsFY+6YlSD7VOy0=
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/miekg/pkcs11 v1.1.1 h1:Ugu9pdy6vAYku5DEpVWVFPYnzV+bxB+iRdbuFSu7TvU=
+github.com/miekg/pkcs11 v1.1.1/go.mod h1:XsNlhZGX73bx86s2hdc/FuaLm2CPZJemRLMA+WTFxgs=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/thales-e-security/pool v0.0.2 h1:RAPs4q2EbWsTit6tpzuvTFlgFRJ3S8Evf5gtvVDbmPg=
+github.com/thales-e-security/pool v0.0.2/go.mod h1:qtpMm2+thHtqhLzTwgDBj/OuNnMpupY8mv0Phz0gjhU=
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..baa1788
--- /dev/null
+++ b/main.go
@@ -0,0 +1,94 @@
+package main
+
+import (
+	"crypto"
+	"crypto/rand"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+
+	"github.com/ThalesGroup/crypto11"
+)
+
+const (
+	EnvPkcs11Pin = "PKCS11_PIN"
+)
+
+type Pkcs11Key struct {
+	Library    string `json:"library"`
+	TokenLabel string `json:"token_label"`
+	Pin        string `json:"pin"`
+	KeyLabel   string `json:"key_label"`
+}
+
+func main() {
+	parameter := "ewogICJsaWJyYXJ5IjogIi91c3IvbG9jYWwvbGliL2xpYnlrY3MxMS5keWxpYiIsCiAgInRva2VuX2xhYmVsIjogIll1YmlLZXkgUElWICM1MDEwMjIwIiwKICAicGluIjogIiIsCiAgImtleV9sYWJlbCI6ICJQcml2YXRlIGtleSBmb3IgUElWIEF1dGhlbnRpY2F0aW9uIgp9Cg=="
+	message := "message"
+
+	parameterBytes, err := base64.StdEncoding.DecodeString(parameter)
+	if err != nil {
+		println("1", err.Error())
+		return
+	}
+	var pkcs11Key Pkcs11Key
+	err = json.Unmarshal(parameterBytes, &pkcs11Key)
+	if err != nil {
+		println("2", err.Error())
+		return
+	}
+
+	pin, err := getPin(pkcs11Key.Pin)
+	if err != nil {
+		println("3", err.Error())
+		return
+	}
+	config := &crypto11.Config{
+		Path:       pkcs11Key.Library,
+		TokenLabel: pkcs11Key.TokenLabel,
+		Pin:        pin,
+	}
+	keyLabel := pkcs11Key.KeyLabel
+
+	ctx, err := crypto11.Configure(config)
+	if err != nil {
+		println("4", err.Error())
+		return
+	}
+	defer ctx.Close()
+
+	privateKey, err := ctx.FindKeyPair(nil, []byte(keyLabel))
+	if err != nil {
+		println("5", err.Error())
+		return
+	}
+	publicKey := privateKey.Public()
+	publicKeyBytes, err := x509.MarshalPKIXPublicKey(publicKey)
+	if err != nil {
+		println("6", err.Error())
+		return
+	}
+	println(base64.StdEncoding.EncodeToString(publicKeyBytes))
+
+	hashed := sha256.Sum256([]byte(message))
+	signature, err := privateKey.Sign(rand.Reader, hashed[:], crypto.SHA256)
+	if err != nil {
+		println("7", err.Error())
+		return
+	}
+	fmt.Printf("%x\n", signature)
+}
+
+func getPin(pin string) (string, error) {
+	if pin != "" {
+		return pin, nil
+	}
+	envPin := os.Getenv(EnvPkcs11Pin)
+	if envPin != "" {
+		return envPin, nil
+	}
+	return "", errors.New("PIN is not set, set PIN: " + EnvPkcs11Pin)
+}