diff --git a/build.xml b/build.xml
index bc0b0d49..0706a637 100644
--- a/build.xml
+++ b/build.xml
@@ -648,7 +648,7 @@
 	<target name="portable" description="Build portable package" depends="revision">
 		<tar destfile="${dir.dist}/${release}-portable.tar.xz" compression="xz" longfile="posix" encoding="utf-8">
 			<tarfileset file="${path.fatjar}" fullpath="FileBot.jar" />
-			<tarfileset dir="${dir.installer}/portable" includes="*.exe, *.ini, *.cmd" />
+			<tarfileset dir="${dir.installer}/portable" includes="*.exe, *.ini, *.cmd, *.pub" />
 			<tarfileset dir="${dir.installer}/portable" includes="*.sh" filemode="755" />
 
 			<!-- include native libraries for all supported platforms -->
diff --git a/installer/portable/filebot.pub b/installer/portable/filebot.pub
new file mode 100644
index 00000000..b6355b02
--- /dev/null
+++ b/installer/portable/filebot.pub
@@ -0,0 +1,29 @@
+-----BEGIN PGP PUBLIC KEY BLOCK-----
+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+=Kug3
+-----END PGP PUBLIC KEY BLOCK-----
diff --git a/installer/portable/filebot.sh b/installer/portable/filebot.sh
old mode 100644
new mode 100755
diff --git a/installer/portable/install-filebot.sh b/installer/portable/install-filebot.sh
old mode 100644
new mode 100755
diff --git a/installer/portable/update-filebot.sh b/installer/portable/update-filebot.sh
old mode 100644
new mode 100755
index 14398975..6967bdfb
--- a/installer/portable/update-filebot.sh
+++ b/installer/portable/update-filebot.sh
@@ -21,37 +21,46 @@ APP_ROOT=`cd "$PRG_DIR" && pwd`
 cd "$WORKING_DIR"
 
 
-
 # update core application files
-JAR_XZ_FILE="$APP_ROOT/FileBot.jar.xz"
-JAR_XZ_URL="https://sourceforge.net/projects/filebot/files/filebot/HEAD/FileBot.jar.xz"
+PACKAGE_NAME="FileBot.jar.xz.gpg"
+PACKAGE_FILE="$APP_ROOT/$PACKAGE_NAME"
+PACKAGE_URL="https://sourceforge.net/projects/filebot/files/filebot/HEAD/$PACKAGE_NAME"
 
 # check if file has changed
-JAR_XZ_SHA1_EXPECTED=`curl --retry 5 "$JAR_XZ_URL/list" | egrep -o "[a-z0-9]{40}"`
-JAR_XZ_SHA1=`sha1sum $JAR_XZ_FILE | cut -d' ' -f1`
+PACKAGE_SHA1_EXPECTED=`curl --retry 5 "$PACKAGE_URL/list" | egrep -o "[a-z0-9]{40}"`
+PACKAGE_SHA1=`sha1sum $PACKAGE_FILE | cut -d' ' -f1`
 
-if [ -z "$JAR_XZ_SHA1_EXPECTED" ]; then
+if [ -z "$PACKAGE_SHA1_EXPECTED" ]; then
 	echo "SHA1 hash unknown"
 	exit 1
 fi
 
-if [ "$JAR_XZ_SHA1" == "$JAR_XZ_SHA1_EXPECTED" ]; then
-	echo "$JAR_XZ_FILE [SHA1: $JAR_XZ_SHA1]"
+if [ "$PACKAGE_SHA1" == "$PACKAGE_SHA1_EXPECTED" ]; then
+	echo "$PACKAGE_FILE [SHA1: $PACKAGE_SHA1]"
 	exit 0
 fi
 
-echo "Update $JAR_XZ_FILE"
-curl -L -o "$JAR_XZ_FILE" -z "$JAR_XZ_FILE" --retry 5 "$JAR_XZ_URL"	# FRS will redirect to (unsecure) HTTP download link
+echo "Update $PACKAGE_FILE"
+curl -L -o "$PACKAGE_FILE" -z "$PACKAGE_FILE" --retry 5 "$PACKAGE_URL"	# FRS will redirect to (unsecure) HTTP download link
 
 # check if file has been corrupted (or modified) in transit
-JAR_XZ_SHA1=`sha1sum $JAR_XZ_FILE | cut -d' ' -f1`
-echo "$JAR_XZ_FILE [SHA1: $JAR_XZ_SHA1]"
+PACKAGE_SHA1=`sha1sum $PACKAGE_FILE | cut -d' ' -f1`
+echo "$PACKAGE_FILE [SHA1: $PACKAGE_SHA1]"
 
-if [ "$JAR_XZ_SHA1" != "$JAR_XZ_SHA1_EXPECTED" ]; then
-	echo "SHA1 hash mismatch [SHA1: $JAR_XZ_SHA1_EXPECTED]"
-	rm -vf "$JAR_XZ_FILE"
+if [ "$PACKAGE_SHA1" != "$PACKAGE_SHA1_EXPECTED" ]; then
+	echo "SHA1 hash mismatch [SHA1: $PACKAGE_SHA1_EXPECTED]"
+	rm -vf "$PACKAGE_FILE"
 	exit 1
 fi
 
-# unpack new jar
-xz --decompress --force --keep "$JAR_XZ_FILE"
+
+# initialize gpg
+GPG_HOME="$APP_ROOT/.gpg"
+JAR_XZ_FILE="$APP_ROOT/FileBot.jar.xz"
+
+if [ -d "$GPG_HOME" ]; then
+	mkdir -p -m 700 "$GPG_HOME" && gpg --homedir "$GPG_HOME" --import "$APP_ROOT/filebot.pub"
+fi
+
+# verify signature and extract jar
+gpg --batch --yes --homedir "$GPG_HOME" --trusted-key "4E402EBF7C3C6A71" --output "$JAR_XZ_FILE" --decrypt "$PACKAGE_FILE" && xz --decompress --force "$JAR_XZ_FILE"