Category Archives: Open Source

How to set and use passwords in a safety way

Passwords are like underwear, you change them frequently. Do not share them and do not show them”

Well maybe some people like to show part of their underwear, but let’s say the previous statement suits most people. 😉

Nowadays we have to deal with hundreds of places where we have security access through a username and password. To use a different username and password is a suggestion that we have surely heard of, and probably tried, but when we have to remember access details for services we access everyday, a lot of people end up using the same username and password. Even if we use a strong password with upper and lower cases, numbers and signs, if one of these sites has a security problem (remember the cases of YahooLinkedIn and Dropbox, …) all the accounts using the same password will be jeopardised

So, it is clear that the most secure solution would be to use different, strong passwords for our accounts. But how can we deal with all this information?


One of the solutions is provided by password managers. This tool stores all of our passwords in an encrypted database and the only thing we have to do is to remember one strong password (a master password), usually incorporated within a long sentence. Once we have entered this password, we will be granted access to all the account details.

There are two types of password managers: the ones where the database is stored on servers and the other ones where we locally store the database. It is clear that the first ones are easy to use. We only have to create the database on their cloud and access from any device we want. You might be reluctant to hold your database on their servers, and you are probably right, because some providers were hacked into in the past, for example LastPass.

So we are going to focus on the password managers group where they do not provide a centralized database feature. That does not mean we are not able to use the same database in different devices but we have to use a cloud service to provide this synchronisation.

In this article I will explain how to setup and use the KeePass, the free, open source, light-weight, easy-to-use password manager, with a lot of awards. You can use it with Windows, Mac OSX, GNU/Linux, Android, iPhone/iPad, Windows Phone, Blackberry, Chrome… You can check the ports list here. As a cloud service I will use Mega and FolderSync Lite to synchronise the database to my mobile device and Keepass2Android Password Safe to get the database on my Android.

I will take for granted that you have already installed the KeePass version for your operating system, that you have some cloud service installed and that you have already created an account. The steps are the following:

Start KeePass and create the database

Start KeePass


The first time you will need to create a database


The system will ask for a name and a location. Remember to store them into the folder where the cloud service has been setup.


Create the Master password and the Key file

This is the MAIN and MOST important password, and the ONLY ONE you have to REMEMBER. It is a good idea to use a sentence instead of a word, use capital letters, numbers and special characters, like the one below:

My f4th3r w@s 4 great p3r$0n. 1 admire h1m!

As you can see, I am combining capital letters, numbers and especial characters, trying not to use the same pattern (I am not replacing all the vowels for numbers in all the words). It is a complex sentence, but you only need to remember this one. I recommend you to click on the 3 dots button to avoid repeating the sentence twice and ensure the Master password typed is the one you want.

IMPORTANT: In case you forget your Master password, you will not be able to open the database.

The estimated quality will show you how secure the password you have typed in is. Try to reach the 192 bits.


Key file (optional)

In case you want to setup an additional security level, you can create a Key file. You will need both (if checked is required), a master password and a key file to unlock the database. We have to specify where we want the Key file to be stored.


And then help the system generate random bits in order to increase the entropy of the computer. Move the mouse over the field until Generated bits bar reache 256 bits. Type random keys inside the Random keyboard input field. Then click OK button.


You can only check the “Key file” option, but I will not recommend it to you, as anyone who has your key file will be able to open the database. I suggest using Key file as an additional security level.createmp

Set database settings

Here we can set some database settings, like name, some description and additional parameters.


In case you are using the key file option, you can enable a change key reminder and an expiration date, to force that key to be changed. By default both settings are deactivated.


Once you click on the OK button, you will have the database opened and ready to create new entries. You have 2 samples.


Please, take into account that the database name in the main title window has an asterisk, meaning that the changes are not saved yet.

Adding a new entry

To add a new entry in the database, just click on the key button

The fill the main fields:

  • Title. Something to link with the account

  • User name. The user name of the account

  • Password: In case you want to ensure the password you are typing in, I will hardly recommend you to click on the 3 dots button


  • URL: The address of the site, in case the account is related to one website. If you write without the subdomain (www in the for example), this entry will be able to login inside any subdomain of, like, and so on.

Since there is no need to remember the password you have created, this is a good way to start using a strong password. Create strong passwords manually is not advisable, since maybe we have some (unconscious?) pattern, so it is better to delegate this task to the software. Just click on the key button and several options will be displayed.


In case you want to personalize due to some constraints on the password, just click on the “Open Password Generator…” option


Below you can set which type of character set you want to appear on the password. For a strongest password, I suggest enabling Upper and lower-cases, Digits, Special characters. Check the “Collect additional entropy” option which will show you the Entropy collection window we have already mentioned above.


Inside the Advanced tab you can specify some additional constraints. Like excluding the look-alike characters (Capital I and lower-cases L, vowels o and number 0…). You can also exclude some characters. Please remember that these options and rules may reduce the security of generated passwords.nocaracters

The Preview tab will show you some examples of the passwords generated matching the rules specified on the fist tab.


Clicking on the OK button will generate the password matching the options and rules. It is a good idea to specify inside the Notes field the email linked to the account, just in case you need to.


Now you have a database stored in a cloud service.

Browser integration in computer

The easiest way to be used in a trusted computer is by using a browser add-on. The one I use it is PassIFox, since I am using Mozilla Firefox as a main browser, but  chromeIPass can be used in case you use Chrome browser.


Following the instructions you will find the website to install and configure the add-on.

Once connected to your database, just visit the site where you have already set up an account, and in case the user name and password are not filled in automatically, click inside the username or password field and click with the right button. The “Fill User & Pass” option will appear.


Coming soon: (How to use KeePass with Android)

How to install and setup a PACS (dcm4chee)


Picture Archiving and Communication System (PACS) is a medical imaging technology which provides economical storage of and convenient access to images from multiple modalities (source machine types).

In our case we can use it to create pre-production environments to test PACS communications. For example, we can setup a PACS to send endoscopy images and retrieve radiology samples to an application.

We are going to use the dcm4chee open source solution from This is a JEE and JMX system which is deployed within the JBoss Application Server to provide a number of clinical services. It may be used for a variety of different purposes, the most popular being:

  1. a DICOM archive and image manager
  2. a PACS, when coupled with a viewer such as OsiriXK-PACSClearCanvasGinkgo CADx, etc.

As a host, trying to use always open source solutions, we are going to use a GNU/Linux operating system, specifically Kubuntu 14.04 LTS (Long Term Supported).

 As a database we are going to use PostgresSQL (9.3).

We can find installation instructions at dcm4chee page, but there are not always updated, so I will show all the steps for the current versions.

Installation of JDK

Although we can use the openjdk that comes with kubuntu, we are going to use the one from Oracle.

First we have to download the package from Oracle site:

And choose the one that fits our platform (x86 tar.gz in my case)

2014-11-27 17_19_48-Java SE Development Kit 8 - Downloads

Once decrompressed, just copy the folder to /usr/lib and add the following lines at the end of the ~/.bashrc file:

export JAVA_HOME
export PATH

We can check the version using the command “java -version”

$ java -version
java version “1.8.0_25”
Java(TM) SE Runtime Environment (build 1.8.0_25-b17)
Java HotSpot(TM) Server VM (build 25.25-b02, mixed mode)

Installation procedure

1. Download and extract the binary distribution package of dcm4chee:

We have to download the latest version of dcm4chee that is relevant to the database we want from sourceforgeIn our case, the postgres one.

2014-11-27 17_39_40-dcm4che, a DICOM Implementation in JAVA - Browse _dcm4chee_2.18

2. Download the binary distribution package of JBoss Application Server 4.2.3.GA

Download the binary distribution of JBoss 4.2.3.GA from here and extract it into a different directory.

Use neither JBoss 5 nor JBoss 6, because it is completely re-architected and is significantly different than the 4.2 line of JBoss! 

If you want to use JDK 5, don’t download JBoss for JDK 6 ( – use!

3. Copy files from JBoss to dcm4chee

Go to the dcm4chee-2.18.1-xxx/bin directory and execute the script, with the path of your JBoss as installation directory as a parameter.

For example, if we have JBoss downloaded in the same directory as dcm4chee:

dcm4chee-2.18.0-psql/bin$ sh ../../jboss-4.2.3.GA/

4. Install the Database Software and create the DCM4CHEE Database

Set permissions on Postgres database. The following setting will trust only connections from the localhost, which is reasonable for a development machine, but may need to be changed for production.

Edit the pg_hba.conf file in order to set the right permissions.

$ sudo vim /etc/postgresql/9.3/main/pg_hba.conf

Set a password for the postgres user

$export PGUSER=postgres
$createdb pacsdb
$psql pacsdb -f dcm4chee-psql-2.18.0/sql/create.psql

This will create all the database structure. Now we have to setup the database access from dcm4chee. In your dcm4chee installation, use a text editor to edit server/default/deploy/pacs-postgres-ds.xml and set the database password. This file controls the dcm4chee connections to the main archive application database.PostgressPWD

5. Deploy the Audit Record Repository (ARR)

The Audit Record Repository will help us track any movement in dcm4chee.

Starting with dcm4chee-2.12.0, the binary distribution package of the archive application does NOT include the dcm4chee Audit Record Repository (ARR) anymore. The ARR maintains an audit log of all transactions within the archive. This is necessary for HIPAA and IHE. Some dcm4chee deployment scenarios call for the deployment of the ARR in a standalone fashion because it acts as an ARR for more than one dcm4chee instance, or multiple applications which can take advantage of an external ARR. Commonly though it is deployed within the dcm4chee archive itself.

Download the latest version from soruceforge related with the database we have chosen (postgres in our case)

2014-11-27 19_28_29-dcm4che, a DICOM Implementation in JAVA - Browse _dcm4chee-arr_3.0

Go to the dcm4chee-*-xxx/bin directory and execute the script with the path of the dcm4chee-arr-* installation directory as parameter.

NOTE: Due to a bug, we have to modify two lines of the installer dcm4chee-2.18.psql/bin/

VERS=3.0.11 should be VERS=3.0.12


cp -v “$ARR_SERV” /lib/dcm4che-core-2.0.25.jar \ should be cp -v “$ARR_SERV” /lib/dcm4che-core-2.0.27.jar \


Now we can run the installer without problem.

dcm4chee-2.18.0-psql/bin$ sh ../../dcm4chee-arr-3.0.12-psql/

We have to create the arr database in Postgres and create the structure using the script from the dcm4chee-arr sql folder:

dcm4chee-arr-3.0.12-psql/sql$ psql arrdb -f dcm4chee-arr-psql.ddl

Now we have to set the ARR database acces. In your dcm4chee installation, use a text editor to edit server/default/deploy/arr-psql-ds.xml and set the database password. This file control the dcm4chee connections to the Audit Record Repository (ARR) database.


6. Set environment variable JAVA_HOME to JDK location

The dcm4chee startup/shutdown scripts depend on the JAVA_HOME environment variable in order to find the Java executables and libraries. For example, if your JDK is installed at “/usr/lib/jvm/jdk1.8.0_25” then that is the path to JAVA_HOME.

If you choose to add in the ~/.bashrc file, remember the PACS would not start unless you start the session.

7. Optional: Adjust maximum allocation of heap memory

Java programs run with a finite amount of memory allocated to them. If you anticipate high volumes of storage and retrievals, or very large datasets, you may want to increase the max (-Xmx) heap size of the Java process.

Linux/Unix/OSX: dcm4chee-2.xx-xxx/bin/run.conf

# Specify options to pass to the Java VM.
if [ "x$JAVA_OPTS" = "x" ]; then
JAVA_OPTS="-Xms128m -Xmx512m -XX:MaxPermSize=128m ..

according to available RAM and memory requirements of other processes on this node.

E.g.: if only 512 MB RAM are available, you should decrease the default value -Xmx512m to (e.g.) -Xmx300.

8. Test the installation

To test your installation, go to the dcm4chee-2.xx-xxx/bin directory and execute the script. Your output should look like the following and contains no error or exception messages:

 JBoss Bootstrap Environment
 JBOSS_HOME: /home/daniel/Downloads/dcm4chee-2.18.0-psql
 JAVA: /usr/lib/jvm/jdk1.8.0_25/bin/java
 JAVA_OPTS: -server -Xms128m -Xmx512m -XX:MaxPermSize=128m -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000 -Djboss.messaging.ServerPeerID=0 -Djava.awt.headless=true -Djava.library.path=/home/daniel/Downloads/dcm4chee-2.18.0-psql/bin/native
 CLASSPATH: /home/daniel/Downloads/dcm4chee-2.18.0-psql/bin/run.jar:/usr/lib/jvm/jdk1.8.0_25/lib/tools.jar
Java HotSpot(TM) Server VM warning: ignoring option MaxPermSize=128m; support was removed in 8.0
19:43:15,087 INFO [Server] Starting JBoss (MX MicroKernel)...
19:43:15,088 INFO [Server] Release ID: JBoss [Trinity] 4.2.3.GA (build: SVNTag=JBoss_4_2_3_GA date=200807181439)
19:43:15,089 INFO [Server] Home Dir: /home/daniel/Downloads/dcm4chee-2.18.0-psql
19:43:15,089 INFO [Server] Home URL: file:/home/daniel/Downloads/dcm4chee-2.18.0-psql/
19:43:15,090 INFO [Server] Patch URL: null
19:43:15,090 INFO [Server] Server Name: default
19:43:15,090 INFO [Server] Server Home Dir: /home/daniel/Downloads/dcm4chee-2.18.0-psql/server/default
19:43:15,090 INFO [Server] Server Home URL: file:/home/daniel/Downloads/dcm4chee-2.18.0-psql/server/default/
19:43:15,090 INFO [Server] Server Log Dir: /home/daniel/Downloads/dcm4chee-2.18.0-psql/server/default/log
19:43:15,090 INFO [Server] Server Temp Dir: /home/daniel/Downloads/dcm4chee-2.18.0-psql/server/default/tmp
19:43:15,091 INFO [Server] Root Deployment Filename: jboss-service.xml
19:43:15,359 INFO [ServerInfo] Java version: 1.8.0_25,Oracle Corporation
19:43:15,359 INFO [ServerInfo] Java VM: Java HotSpot(TM) Server VM 25.25-b02,Oracle Corporation
19:43:15,359 INFO [ServerInfo] OS-System: Linux 3.13.0-40-generic,i386
19:43:15,654 INFO [Server] Core system initialized
19:43:17,680 INFO [WebService] Using RMI server codebase: http://daniel-VirtualBox:8083/
19:43:17,682 INFO [Log4jService$URLWatchTimerTask] Configuring from URL: resource:jboss-log4j.xml
19:43:18,095 INFO [TransactionManagerService] JBossTS Transaction Service (JTA version) - JBoss Inc.
19:43:49,281 INFO [RequestListenerInterface] registered listener interface [RequestListenerInterface name=IActivePageBehaviorListener, method=public abstract void org.apache.wicket.behavior.IBehaviorListener.onRequest()]
19:43:49,281 INFO [Application] [WicketApplication] init: Wicket extensions initializer
19:43:49,281 INFO [WebApplication] [WicketApplication] Started Wicket version 1.4.22 in deployment mode
19:43:49,347 INFO [EARDeployer] Started J2EE application: file:/home/daniel/Downloads/dcm4chee-2.18.0-psql/server/default/deploy/dcm4chee-web-ear-3.0.4-psql.ear
19:43:49,378 INFO [ServerImpl] Start Server listening on
19:43:49,414 INFO [Http11Protocol] Starting Coyote HTTP/1.1 on http-
19:43:49,440 INFO [Http11Protocol] Starting Coyote HTTP/1.1 on http-8443
19:43:49,460 INFO [AjpProtocol] Starting Coyote AJP/1.3 on ajp-
19:43:49,472 INFO [ServerImpl] Start Server listening on
19:43:49,473 INFO [Server] JBoss (MX MicroKernel) [4.2.3.GA (build: SVNTag=JBoss_4_2_3_GA date=200807181439)] Started in 34s:379ms

9. Login into web interface

Connect to the Web Interface at http://localhost:8080/dcm4chee-web3/ of the archive using any Web Browser. You should get the User Login Screen. Login in using default Administrator account ‘admin’, with password ‘admin’.

2014-11-28 08_09_43-dcm4chee Login

2014-11-28 08_10_49-dcm4chee after login

10. Login to JMX Console

Connect to JBoss’s JMX Console at http://localhost:8080/jmx-console/ and login using also the Administrator account ‘admin’, with password ‘admin’.
Follow the link “group=ONLINE_STORAGE,service=FileSystemMgt” to the configuration page for File System Management service under the “dcm4chee.archive” heading.
Invoke the operation addRWFileSystem(), with argument dirPath specifying the directory, where the archive shall store received objects/images.

If no Storage File System is configured, the archive will auto-configure dcm4chee-2.xx.1-xxx/server/default/archive as Storage File System, when receiving the first object/image.

2014-11-28 08_11_35-dcm4chee logs

11. Optional: Change the default AE Title

Connect to JBoss’s JMX Console at http://localhost:8080/jmx-console/ and login using also the Administrator account ‘admin’, with password ‘admin’.

2014-11-28 08_12_25-dcm4chee Catalina

Follow the link “service=AE” to the configuration page for AE (Application Entity – a DICOM term for a DICOM node on the network) service under the “dcm4chee.archive” heading.
Invoke the operation update AETitle with the old AE Title (DCM4CHEE if unchanged from the default), and new AE Title as parameters.
This will update the following configurations:

  • update  the “retrieve AET” of file systems, associated to the current retrieve AET of this node
  • update “retrieve AETs” of all instances, series and studies that have files on these filesystems
  • update the entry for the “retrieve AE” in the AE Configuration
  • update the AE Title of all services listed by attribute OtherServiceAETitleAttributesToUpdate

12. Install as a service

If running as a service or daemon on any operating system, you should disable CONSOLE logging as noted here:ኳ

After verifying that the archive works, you may want to run it as a service so that it stays running even when you log out. If still running in the console window, you may stop the archive by Ctrl+C, and copy the init script to /etc/init.d/ and adjust it according your installation location of the archive and the JDK and under which user the archive application shall run.