Category Archives: English

New Blog Design

Today I had to upgrade PHP on my hosting server. My terribly oudated and insecure WordPress version was incompatible with the new PHP and thus had to be upgraded, too. Lots of new features… maybe this is going to make me post more often  🙂

I also changed the blog’s design, giving it a nice contemporary template. Hope you like it.

Close button in iOS app?

dont quit programmaticallyApple is quite strict about their Human Interface Guidelines for iOS devices. Complying with these guidelines is not always easy though. Much of what Apple states in the guidelines is open to interpretation. It’s a guideline, after all. Lots of statements such as “in general…”, “if possible…”, “in most cases”.

Apple’s developer support avoids clear answers on questions about the guidelines. If your question is a tricky one, they will much rather refer back to the guideline or recommend you simply submit you app and give it a try. Continue reading

Color blindness and accessibility

color blindness testIn an effort to meet accessibility requirements, I was looking for tools to check whether users with a variety of color blindness conditions can actually use our websites. Posters and brochures can already be difficult to read for color blind people. On web sites another dimension is added to this problem because certain features may be rendered useless by choosing a bad color palette. Colored links for example, if not underlined, may not be seen as links because they appear to be of the same color as all other text. Continue reading

Website standards

PAS124In April 2008, the British Standards Institute has published PAS 124, a best practice approach to implementing, maintaining, and managing standards compliant websites. PAS 124 helps organizations deploy web site standards. So if you are involved with the planning or building of web sites, this document is a must read. Being one of my focus areas, website standards are part of my daily work. As a member of the review panel for PAS 124 I got my hands on the document very early, and I have been using it ever since. Continue reading

Free encryption software (2)
File encryption on USB flash drives

Free encryption softwareI am a PGP user since 1996 and I still use Ståle Schumacher’s international DOS version 2.63i to encrypt files on my USB flash drives. All I need is PGP’s small exectutable file (pgp.exe, 237.737 kb). On first use, PGP will create a second small file that contains some random seed data for the encryption. With this minimal setup, PGP will warn you about a missing configuration file, but this does not affect the strength of encryption. The USB drive on my key ring contains an encrypted passwords file and pgp.exe, providing easy access to the many cryptic passwords I use. All I need is one strong master pass phrase to decrypt the file and get instant access to more passwords than I could ever remember.

I insert the USB drive and open a command prompt window (Start > Run > cmd).

PGP file encryption:

pgp -c filename

PGP file decryption:

pgp filename.pgp

PGP 2.36i in action

In conventional -c encryption mode PGP uses a symmetric block encryption algorithm (IDEA) with a key size of 128 bits. Together with a good pass phrase this is really strong encryption.

Don’t forget to securely delete the plaintext file afterwards:

pgp -w filename

Since this version of PGP was developed for DOS, it only supports 8 character file names (8.3).

PGP 2.63i is still available from Ståle’s site  [download].

Back in 1996 I contributed the “self-sign FAQ” to the PGP community.

Other Flash drive encrytion options for Windows, Mac and Linux

Many different free and commercial PGP versions and clones are available. See,, and I still use PGP 2.63i because it is an easy-to-use lightweight program that provides strong encryption and can be put on any device by simply copying one small file.

Truecrypt in “Traveller Mode” can be used to create an encrypted file container on Flash memory. Truecrypt is free and provides super strong encryption, too. However, you need to have administrator privileges on all machines that you decrypt the container on. I’m not an admin on my machine at work but need access to the passwords on my keyring there, too.

Some USB drives (SanDisk, Kingston, IronKey) have hardware encryption built in, but when it comes to encryption, I prefer to stay away from proprietary implementations.

Free encryption software (1): Introduction

Free encryption software (3): Hard disc encryption

Free encryption software (4): GNU Privacy Guard