Ghostscript, an interpreter for the PostScript language and for PDF. Ghostscript can be used as a raster image processor (RIP) for raster computer printers – it helps converting PostScript language files or Portable Document Format (PDF) files to many raster formats. The raster format is usually a page bitmap which can then be sent to an output device such as a printer or display. Anyway, many of the printers today are having PostScript embedded.

This will enable user to view PostScript language files on displays, and print them on printers that do not have PostScript language capability built in.

Ghostscript is also able to convert PostScript language files to PDF (with some limitations) and vice versa. A number of utility scripts like ps2pdf are available to convert a PostScript document to PDF.

There are other utility scripts besides ps2pdf, including pdf2ps, ps2epsi and ps2ascii. These applications call Ghostscript with the appropriate set of options.

Ghostscript is also used as a general engine inside other applications like CutePDF Writer, a virtual printer software.

To get a brief help message of Ghostscript, execute the gs command with the -h or -? switch:

gs -h
gs -?

The output from invoking this command are

• the version and release information
• the general format of the command line
• a few of the most useful options
• the formats it can interpret
• the available output devices
• the search path
• the bug report address

Visit the Ghostscript web page at http://www.cs.wisc.edu/~ghost for more information about this great software!

Wireshark (used to be known as Ethereal) is a open source GUI network protocol analyzer freeware. As packet analysis is important in trouble shooting and managing network, Wireshark is use regularly by network professionals, security experts, developers, and educators around the world to see and understand raw protocols on the wire.

Typically a network administrator will use Wireshark to troubleshoot network problems, the network security engineers use it to examine security problems, developers use it to debug protocol implementations and students may use it to learn network protocol internals.

Wireshark is able to inspect hundreds of protocols, with more being added all the time. It lets you interactively browse packet data from a live network or from a previously saved capture file. Packets captured are displayed with very detailed protocol information.

Wireshark’s native capture file format is libpcap format, which is also the format used by tcpdump and various other tools.

Like other protocol analyzers, Wireshark’s main window shows 3 views of a packet. It shows a summary line, briefly describing what the packet is. The second view is showing packet details which allows user to drill down to exact protocol or field. Finally, a hex dump shows the user exactly what the packet looks like when it goes over the wire. Coloring rules can be applied to the packet list for quick, intuitive analysis. Below is an example of Wireshark’s main window after packets have been captured.

Live data can be read from devices such as Ethernet, Token Ring, IEEE 802.11, PPP/HDLC, ATM, Bluetooth, USB, Frame Relay, FDDI, and others.

Wireshark is also having the decryption support for many protocols, including IPsec, ISAKMP, Kerberos, SNMPv3, SSL/TLS, WEP, and WPA/WPA2.

The output of Wireshark can be exported to XML, PostScript, CSV, or plain text.

Wireshark is available in all major modern operating systems like Windows, Linux, OS X, Solaris, FreeBSD, NetBSD, and many others. Installation process for Wireshark is fairly simple. For Windows system, you will need to install WinPcap capture driver (it is built into the Wireshark installation package) together with Wireshark as packet capturing in Wireshark is performed with the pcap library. WinPcap interacts with Windows OS to capture raw packet data, apply filters, and switch the network interface in and out of promiscuous mode.

You may download Wireshark from the official Wireshark web page.

FreeOTFE is an open source freeware uses for disk encryption for PCs and PDAs.

Like TrueCrypt, you can create virtual disks on your PC/PDA using this tool. The virtual disk is encrypted using AES, Blowfish and other cyphers. However, it operates exactly like a normal disk – any data written to it is securely encrypted before being stored on your computer’s hard drive.

On a PC, the theoretical maximum volume size you can create for FreeOTFE virtual disk is 2^64 bytes (16777216 TB; 17179869184 GB). But bear in mind that FAT/FAT32 file system cannot support files larger than (4GB – 1 byte).

You may also use FreeOTFE to mount a volume file located on a network server. Security is also take care in this case – all data read/written to that volume will be sent over the network in encrypted form.

Like TrueCrypt, you do not need to install it. This is ideal for use on a USB stick. The best thing about FreeOTFE is the source code is available for free. Last but not least, be careful, never forget the password you use to create volume in this freeware. If you lost it, you are not able to get your data back!

By the way, you may download this excellent tool at it’s homepage.

Mac MakeUp is a freeware that allows us to change the physical address (MAC Address) of a PC (MAC address spoofing). As for the current version (1.95d), it support Windows 2003, XP, 2000 and Vista.

It is quite easy to change the PC network adapter MAC address, simply select the PC network adapter, type the new MAC or delete the current one and enable it. You can use a new physical address of your choice, Randomly generate an address, or get a new one with the help of this tool – you can select the OID part according to your prefer Manufacturer. For example, if you select the address from Cisco, it would be something like: 00059b123456.

This is a tool that is very helpful if you like to test if the firewall or proxy is filtering network access through the MAC address. Even though your network adapter do not has the option to change the MAC address as in its property, you can use this tool to perform this network changes for you.

By the way, addresses changes are permanent until you decide to remove the new address.

Three new security tools freeware are added to the 88 Best Freeware list today.

Details for each of these three freeware will be introduced in the near future. Anyway, basically

1. Wireshark is a network protocol analyzer which was formerly called Ethereal. This is a very powerful tool use in capturing packets on the network.
2. NMap is a port scanner tool for Windows. You may use NMap in testing the range of ports open on a particular network device and subsequently know if any vulnerability is associated with it.
3. Eraser is use to securely delete files from your hard disk. It will completely remove data from your hard drive by overwriting the drive several times with selected pattern strings.

Wireshark and Nmap are mostly use in network system trouble shooting. These two security tools also popularly used in education institution to show students on how the network work. Eraser is mostly use in protecting the security of information in your personal computer.

Adobe Reader, a product from adobe.com, is a freeware that lets you view and print PDF files. As the open standard for worldwide electronic document distribution, Adobe PDF files preserve all the formatting, the graphics and the colors of the original document. As such, user can transfer documents from one media to another without losing important formatting or the document becoming completely garbled. The document itself is platform independent.

It is very easy to use Adobe Reader. A user may use it to view, search, digitally sign, verify, print, and collaborate on Adobe PDF files. However, the free Adobe Reader cannot be used to create PDF files. You may like to use freeware like CutePDF Writer to do that instead.

Due to its big size, the start up of this freeware takes a few more seconds. Anyway, though there are other PDF readers available that may take up less space or work at slightly faster speeds, none offer as much of a tool set as Adobe Reader does. Adobe Reader has remained at the top of the list since creation. You may download this excellent software from Adobe.

TrueCrypt is a free open-source disk encryption software for Windows Vista/XP, Mac OS X, and Linux

The best feature that I found with TrueCrypt is it can create a virtual encrypted disk within a file and mounts it as a real disk. Files that is stored in this encrypted disk are automatically encrypted or decrypted on-the-fly and transparent to user.

TrueCrypt can also encrypts an entire partition or storage device such as USB flash drive or hard drive.

The other feature that I never try with TrueCrypt is the Encryption of a partition or drive where Windows is installed (pre-boot authentication).

No data stored on an TrueCrypt encrypted volume can be read (decrypted) without having the correct password or correct encryption key. Until decrypted, a TrueCrypt volume appears to be nothing more than a series of random numbers.

The encryption algorithms supported by TrueCrypt includes AES-256, Serpent, and Twofish. Additionally, five different combination of cascaded algorithms are available: AES-Twofish, AES-Twofish-Serpent, Serpent-AES, Serpent-Twofish-AES and Twofish-Serpent. The cryptographic hash functions used by TrueCrypt are RIPEMD-160, SHA-512, and Whirlpool.

From information security point of view, it is a good practice to protect your sensitive data with encryption software. TrueCrypt offers this excellent function to us freely!