THE NEXT FUTURE becomes THE REALITY NOW

Thank @yuhan6665 for testing

main/commands/all/commands.go

@@ -15,5 +15,6 @@ func init() {
 		// cmdConvert,
 		tls.CmdTLS,
 		cmdUUID,
+		cmdX25519,
 	)
 }

main/commands/all/x25519.go

@@ -0,0 +1,63 @@
+package all
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+	"fmt"
+	"io"
+
+	"github.com/xtls/xray-core/main/commands/base"
+	"golang.org/x/crypto/curve25519"
+)
+
+var cmdX25519 = &base.Command{
+	UsageLine: `{{.Exec}} x25519 [-i "private key (base64.RawURLEncoding)"]`,
+	Short:     `Generate key pair for x25519 key exchange`,
+	Long: `
+Generate key pair for x25519 key exchange.
+
+Random: {{.Exec}} x25519
+
+From private key: {{.Exec}} x25519 -i "private key (base64.RawURLEncoding)"
+`,
+}
+
+func init() {
+	cmdX25519.Run = executeX25519 // break init loop
+}
+
+var input_base64 = cmdX25519.Flag.String("i", "", "")
+
+func executeX25519(cmd *base.Command, args []string) {
+	var output string
+	var err error
+	var privateKey []byte
+	var publicKey []byte
+	if len(*input_base64) > 0 {
+		privateKey, err = base64.RawURLEncoding.DecodeString(*input_base64)
+		if err != nil {
+			output = err.Error()
+			goto out
+		}
+		if len(privateKey) != curve25519.ScalarSize {
+			output = "Invalid length of private key."
+			goto out
+		}
+	}
+	if privateKey == nil {
+		privateKey = make([]byte, curve25519.ScalarSize)
+		if _, err = io.ReadFull(rand.Reader, privateKey); err != nil {
+			output = err.Error()
+			goto out
+		}
+	}
+	if publicKey, err = curve25519.X25519(privateKey, curve25519.Basepoint); err != nil {
+		output = err.Error()
+		goto out
+	}
+	output = fmt.Sprintf("Private key: %v\nPublic key: %v",
+		base64.RawURLEncoding.EncodeToString(privateKey),
+		base64.RawURLEncoding.EncodeToString(publicKey))
+out:
+	fmt.Println(output)
+}