diff --git a/crypto/crypto.go b/crypto/crypto.go
new file mode 100644
index 0000000..ba4d38c
--- /dev/null
+++ b/crypto/crypto.go
@@ -0,0 +1,89 @@
+package crypto
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/sha256"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/pem"
+	"fmt"
+	"log"
+)
+
+// HashToken hashes a token using SHA-256.
+func HashToken(token string) string {
+	hash := sha256.Sum256([]byte(token))
+	return hex.EncodeToString(hash[:])
+}
+
+// VerifyToken compares a plaintext token with a stored hash.
+func VerifyToken(token, storedHash string) bool {
+	return HashToken(token) == storedHash
+}
+
+func main() string {
+	// 1. Generiere einen privaten Schlüssel
+	privateKey, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		log.Fatalf("Fehler beim Generieren des privaten Schlüssels: %v", err)
+	}
+
+	// 2. Extrahiere den öffentlichen Schlüssel
+	publicKey := &privateKey.PublicKey
+
+	// 3. Beispieltext zum Verschlüsseln
+	plainText := "Dies ist ein geheimer String!"
+
+	// 4. Verschlüssle den Text mit dem öffentlichen Schlüssel
+	encryptedBytes, err := rsa.EncryptPKCS1v15(rand.Reader, publicKey, []byte(plainText))
+	if err != nil {
+		log.Fatalf("Fehler beim Verschlüsseln: %v", err)
+	}
+
+	// Kodierung des verschlüsselten Textes in Base64 für Lesbarkeit
+	encryptedString := base64.StdEncoding.EncodeToString(encryptedBytes)
+	fmt.Println("Verschlüsselter Text (Base64):", encryptedString)
+
+	// 5. Entschlüssle den Text mit dem privaten Schlüssel
+	decryptedBytes, err := rsa.DecryptPKCS1v15(rand.Reader, privateKey, encryptedBytes)
+	if err != nil {
+		log.Fatalf("Fehler beim Entschlüsseln: %v", err)
+	}
+
+	// 6. Gib den entschlüsselten Text aus
+	decryptedString := string(decryptedBytes)
+	fmt.Println("Entschlüsselter Text:", decryptedString)
+
+	// 7. (Optional) Exportiere und Importiere die Schlüssel
+	privateKeyPEM := exportPrivateKeyToPEM(privateKey)
+	fmt.Println("\nPrivate Key (PEM):\n", privateKeyPEM)
+
+	publicKeyPEM := exportPublicKeyToPEM(publicKey)
+	fmt.Println("\nPublic Key (PEM):\n", publicKeyPEM)
+	return ""
+}
+
+// Funktion, um den privaten Schlüssel in PEM-Format zu exportieren
+func exportPrivateKeyToPEM(privateKey *rsa.PrivateKey) string {
+	privateKeyBytes := x509.MarshalPKCS1PrivateKey(privateKey)
+	privateKeyPEM := pem.EncodeToMemory(&pem.Block{
+		Type:  "RSA PRIVATE KEY",
+		Bytes: privateKeyBytes,
+	})
+	return string(privateKeyPEM)
+}
+
+// Funktion, um den öffentlichen Schlüssel in PEM-Format zu exportieren
+func exportPublicKeyToPEM(publicKey *rsa.PublicKey) string {
+	publicKeyBytes, err := x509.MarshalPKIXPublicKey(publicKey)
+	if err != nil {
+		log.Fatalf("Fehler beim Exportieren des öffentlichen Schlüssels: %v", err)
+	}
+	publicKeyPEM := pem.EncodeToMemory(&pem.Block{
+		Type:  "PUBLIC KEY",
+		Bytes: publicKeyBytes,
+	})
+	return string(publicKeyPEM)
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..8edbeed
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module git.send.nrw/sendnrw/sendnrwlib
+
+go 1.23.1
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..06ab7d0
--- /dev/null
+++ b/main.go
@@ -0,0 +1 @@
+package main
diff --git a/netproto/netproto.go b/netproto/netproto.go
new file mode 100644
index 0000000..790829b
--- /dev/null
+++ b/netproto/netproto.go
@@ -0,0 +1,96 @@
+package netproto
+
+import (
+	"encoding/base64"
+)
+
+type MainHeader struct {
+	Version          uint8             `json:"version"`
+	Meta             map[string]string `json:"meta"`
+	ExtensionHeaders []ExtensionHeader `json:"extension_headers"`
+}
+
+const (
+	MainHeaderVersion1 = 1
+)
+
+const (
+	ExtensionHeaderType_Source            uint8 = 1 /* https://git.send.nrw/sendnrw/sendnrwlib/issues/1 */
+	ExtensionHeaderType_Destination       uint8 = 2 /* https://git.send.nrw/sendnrw/sendnrwlib/issues/1 */
+	ExtensionHeaderType_PayloadDefinition uint8 = 3
+	ExtensionHeaderType_Protocol          uint8 = 4
+	ExtensionHeaderType_Control           uint8 = 5 /*Steuerbefehle wie Download, Upload, ...*/
+	ExtensionHeaderType_Crypto            uint8 = 6 /*Hinweis auf eine Verschlüsselung*/
+	ExtensionHeaderType_Validation        uint8 = 7 /*Hinweis auf eine Validierung oder Checksum*/
+	ExtensionHeaderType_Routing           uint8 = 8 /*Hinweis auf eine Routing-Information*/
+)
+
+func GenerateEHT1(IPv4, IPv6, Port string) ExtensionHeader {
+	return ExtensionHeader{
+		Type: ExtensionHeaderType_Source,
+		Meta: map[string]string{"version": "1.0"},
+		Data: map[string]string{"ipv4": IPv4, "ipv6": IPv6, "port": Port},
+	}
+}
+
+func GenerateEHT2(IPv4, IPv6, Port string) ExtensionHeader {
+	return ExtensionHeader{
+		Type: ExtensionHeaderType_Destination,
+		Meta: map[string]string{"version": "1.0"},
+		Data: map[string]string{"ipv4": IPv4, "ipv6": IPv6, "port": Port},
+	}
+}
+
+func GenerateEHT3(PayloadMime, PayloadLength, PayloadChecksum string) ExtensionHeader {
+	return ExtensionHeader{
+		Type: ExtensionHeaderType_PayloadDefinition,
+		Meta: map[string]string{"version": "1.0"},
+		Data: map[string]string{"payloadmime": PayloadMime, "payloadlength": PayloadLength, "payloadchecksum": PayloadChecksum},
+	}
+}
+
+func GenerateEHT4(ProtocolName, ProtocolVersion, ProtocolOID string) ExtensionHeader {
+	return ExtensionHeader{
+		Type: ExtensionHeaderType_Protocol,
+		Meta: map[string]string{"version": "1.0"},
+		Data: map[string]string{"protocolname": ProtocolName, "protocolversion": ProtocolVersion, "protocoloid": ProtocolOID},
+	}
+}
+
+func GenerateEHT7(Checksum string) ExtensionHeader {
+	return ExtensionHeader{
+		Type: ExtensionHeaderType_Validation,
+		Meta: map[string]string{"version": "1.0"},
+		Data: map[string]string{"checksum": Checksum},
+	}
+}
+
+func GenerateMH(Version uint8, Flag string) MainHeader {
+	return MainHeader{
+		Version: Version,
+		Meta:    map[string]string{"version": "1.0", "flag": Flag},
+	}
+}
+
+func EncodeB64(input string) (string, error) {
+	return base64.StdEncoding.EncodeToString([]byte(input)), nil
+}
+
+func DecodeB64(input string) (string, error) {
+	d, err := base64.StdEncoding.DecodeString(input)
+	if err != nil {
+		return "", err
+	}
+	return string(d), nil
+}
+
+type ExtensionHeader struct {
+	Type uint8             `json:"type"`
+	Meta map[string]string `json:"meta"`
+	Data map[string]string `json:"data"`
+}
+
+type NetworkProtocol struct {
+	Header  MainHeader `json:"header"`
+	Payload string     `json:"payload"`
+}