Restore ECHConfig from keysets

main/commands/all/tls/ech.go

@@ -13,13 +13,14 @@ import (
 )
 
 var cmdECH = &base.Command{
-	UsageLine: `{{.Exec}} tls ech [--serverName (string)] [--pem]`,
+	UsageLine: `{{.Exec}} tls ech [--serverName (string)] [--pem] [-i "ECHSeverKeys (base64.StdEncoding)"]`,
 	Short:     `Generate TLS-ECH certificates`,
 	Long: `
 Generate TLS-ECH certificates.
 
 Set serverName to your custom string: {{.Exec}} tls ech --serverName (string)
 Generate into pem format: {{.Exec}} tls ech --pem
+Restore ECHConfigs from ECHSeverKeys: {{.Exec}} tls ech -i "ECHSeverKeys (base64.StdEncoding)"
 `, // Enable PQ signature schemes: {{.Exec}} tls ech --pq-signature-schemes-enabled
 }
 
@@ -27,7 +28,9 @@ func init() {
 	cmdECH.Run = executeECH
 }
 
-var input_pqSignatureSchemesEnabled = cmdECH.Flag.Bool("pqSignatureSchemesEnabled", false, "")
+var input_echSeverKeys = cmdECH.Flag.String("i", "", "ECHSeverKeys (base64.StdEncoding)")
+
+// var input_pqSignatureSchemesEnabled = cmdECH.Flag.Bool("pqSignatureSchemesEnabled", false, "")
 var input_serverName = cmdECH.Flag.String("serverName", "cloudflare-ech.com", "")
 var input_pem = cmdECH.Flag.Bool("pem", false, "True == turn on pem output")
 
@@ -40,21 +43,43 @@ func executeECH(cmd *base.Command, args []string) {
 	kem = hpke.DHKEM_X25519_HKDF_SHA256
 	// }
 
-	echKeySet, priv, err := tls.GenerateECHKeySet(0, *input_serverName, kem)
+	echConfig, priv, err := tls.GenerateECHKeySet(0, *input_serverName, kem)
 	common.Must(err)
 
-	configBytes, _ := tls.MarshalBinary(echKeySet)
+	var configBuffer, keyBuffer []byte
+	if *input_echSeverKeys == "" {
+		configBytes, _ := tls.MarshalBinary(echConfig)
 		var b cryptobyte.Builder
 		b.AddUint16LengthPrefixed(func(child *cryptobyte.Builder) {
 			child.AddBytes(configBytes)
 		})
-	configBuffer, _ := b.Bytes()
+		configBuffer, _ = b.Bytes()
 		var b2 cryptobyte.Builder
 		b2.AddUint16(uint16(len(priv)))
 		b2.AddBytes(priv)
 		b2.AddUint16(uint16(len(configBytes)))
 		b2.AddBytes(configBytes)
-	keyBuffer, _ := b2.Bytes()
+		keyBuffer, _ = b2.Bytes()
+	} else {
+		keySetsByte, err := base64.StdEncoding.DecodeString(*input_echSeverKeys)
+		if err != nil {
+			os.Stdout.WriteString("Failed to decode ECHSeverKeys: " + err.Error() + "\n")
+			return
+		}
+		keyBuffer = keySetsByte
+		KeySets, err := tls.ConvertToGoECHKeys(keySetsByte)
+		if err != nil {
+			os.Stdout.WriteString("Failed to decode ECHSeverKeys: " + err.Error() + "\n")
+			return
+		}
+		var b cryptobyte.Builder
+		for _, keySet := range KeySets {
+			b.AddUint16LengthPrefixed(func(child *cryptobyte.Builder) {
+				child.AddBytes(keySet.Config)
+			})
+		}
+		configBuffer, _ = b.Bytes()
+	}
 
 	if *input_pem {
 		configPEM := string(pem.EncodeToMemory(&pem.Block{Type: "ECH CONFIGS", Bytes: configBuffer}))