do better documentation on how to set a default password

docker/Dockerfile

@@ -35,6 +35,7 @@ RUN apt-get update && \
 
 RUN \
 # Set initial admin password : "docker" (encoded with custom yacy md5 function net.yacy.cora.order.Digest.encodeMD5Hex())
+# > java -classpath classes net.yacy.cora.order.Digest -strfhex "admin:The YaCy access is limited to administrators. If you don't know the password, you can change it using <yacy-home>/bin/passwd.sh <new-password>:docker"
 	sed -i "/adminAccountBase64MD5=/c\adminAccountBase64MD5=MD5:e672161ffdce91be4678605f4f4e6786" /opt/yacy_search_server/defaults/yacy.init && \
 # Intially enable HTTPS : this is the most secure option for remote administrator authentication
 	sed -i "/server.https=false/c\server.https=true" /opt/yacy_search_server/defaults/yacy.init && \
@@ -46,7 +47,7 @@ RUN \
 # Expose HTTP and HTTPS default ports
 EXPOSE 8090 8443
 
-# Set data volume : yacy data and configuration will persist aven after container stop or destruction
+# Set data volume : yacy data and configuration will persist even after container stop or destruction
 VOLUME ["/opt/yacy_search_server/DATA"]
 
 # Next commands run as yacy as non-root user for improved security

source/net/yacy/cora/order/Digest.java

@@ -26,6 +26,7 @@ import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.RandomAccessFile;
+import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.Queue;
@@ -132,7 +133,7 @@ public class Digest {
     	    digest.reset(); // they should all be reseted but anyway; this is safe
     	}
         byte[] keyBytes;
-        keyBytes = UTF8.getBytes(key);
+        keyBytes = key.getBytes(StandardCharsets.UTF_8);
         digest.update(keyBytes);
         final byte[] result = digest.digest();
         digest.reset(); // to be prepared for next