Often, when stumbling upon the.sig format, people wonder what it is. The second question, which arises immediately after the first one, is: "How to open the sig extension?".
What is sig?
The sig extension (signature) is a digital signature file format. Most commonly used in documentation sent via email. For a simple user, this format may occur once or twice, but in a commercial environment it is not uncommon.

Despite the scary name and perhaps not entirely clear explanation, sig is a text file, just like txt or doc (docx). It contains information about the sender of the letter (usually the company name, sender's name, contacts, etc.), is edited by him (and therefore can also contain all sorts of quotes, advertising calls, and anything else) and is automatically attached to the letter.
How to open.sig extension?
Although most people associate mail with mail-th and gmail-th, those who, on duty, constantly intersect with it, use special softwarecomplexes - mail programs. They are multifunctional and, among other things, open sig extensions. How to open a letter with a similar extension from such software? The most popular services are:
- Microsoft Outlook - included in an extended set of office software packages from Microsoft.
- Eudopa is a common mail client in the West with an English-only interface. The advantage is that it works with both Windows and Apple MacOS.
- Mozilla ThunderBird, Opera Mail - developing mail programs from well-known browsers.
Which mail program to choose - the subject of a new article. If you are guided only by the criterion "how to open a sig-extension", any, even the simplest mail client, will do.

Other programs
To create digital signatures there is a program "CryptoARM" - with free and paid versions. Through it,.sig files are opened and created. For encryption in "CryptoARM" standard Windows cryptographic providers are used, so it is easy and simple. The software has no advantages over the method described below for a simple layman, but beginner cryptographers will be interested in it.
If you do not want to install a new program
The good old "Notepad" comes to the rescue - with this program, if desired, you can even open a picture (although its text encoding is unlikely to be to anyone's taste), let alone a text file.sig.
How to open anything for free?Notepad, of course! So the digital signature files are opened through it, and created, and edited. In the last two cases, the main thing is not to forget to enter the name of the corresponding extension after the file name when saving.
Finally
Curious users, of course, are advised to look through the "Notepad" what the.sig file is, but in reality it is not as interesting as it might seem at first. This is an auxiliary file and does not carry information for the recipient of the letter.