Add script for signing messages from specific address (#4582)

* Add script for signing messages from specific address
* use bitcoin-cli to check address
* add CHANGES

CHANGES.md

@@ -1,5 +1,6 @@
 ## What's new in Version 1.11.1 of RaspiBlitz?
 
+- New: config.scripts/lnd.signaddress.sh to easy sign messages on addresses on LND [details](https://github.com/raspiblitz/raspiblitz/issues/4540)
 - Update: Specter Desktop 2.0.4 with reactivated UPDATE option [details](https://github.com/cryptoadvance/specter-desktop/releases/tag/v2.0.4)
 - Remove: Tallycoin-Connect [see service shutdown](https://x.com/djbooth007/status/1784409117563720082)
 - Remove: IP2Tor Shoplist [details](https://github.com/raspiblitz/raspiblitz/issues/4589)

home.admin/config.scripts/lnd.signaddress.sh

@@ -0,0 +1,50 @@
+#!/bin/bash
+
+# This script allows users to sign a message from a specific Bitcoin address
+# either by generating a new address or using an existing one.
+
+# Ask if a new address should be generated or an existing one should be entered
+read -p "Do you want to generate a new address? (y/n) " generate_new
+
+# 1.a. If generating a new address, ask for the address type
+if [ "$generate_new" == "y" ]; then
+    echo "Generate a wallet new address. Address-types has to be one of:"
+    echo "1. p2wkh:  Pay to witness key hash"
+    echo "2. np2wkh: Pay to nested witness key hash"
+    echo "3. p2tr:   Pay to taproot pubkey"
+    read -p "Enter the address type (1-3 or string): " address_type
+    case "$address_type" in
+        1|"p2wkh")
+            address_type="p2wkh"
+            ;;
+        2|"np2wkh")
+            address_type="np2wkh"
+            ;;
+        3|"p2tr")
+            address_type="p2tr"
+            ;;
+        *)
+            echo "Error: Invalid address type."
+            exit 1
+            ;;
+    esac
+    address=$(lncli newaddress $address_type)
+    address_variable=$(echo $address | jq -r '.address')
+else
+    # 1.b. Check if the manually entered address is valid
+    read -p "Enter the existing address: " address
+    if ! bitcoin-cli validateaddress "$address" | grep -q "isvalid\": true"; then
+        echo "Error: The entered address is not valid."
+        exit 1
+    fi
+    address_variable=$address
+fi
+# 2. Ask for the message to sign and save it to a variable
+read -p "Enter the message to sign: " message_to_sign
+
+# 3. Execute the lncli wallet addresses signmessage command
+signature_js=$(lncli wallet addresses signmessage --address $address_variable --msg "$message_to_sign")
+signature=$(echo $signature_js | jq -r '.signature')
+echo "The address is: $address_variable"
+echo "The message to sign is: $message_to_sign"
+echo "The signature is: $signature"