We have previously mentioned that spam messages and malware use to increase when it’s Christmas time. That’s why our security tip #13 in this Christmas calendar is to improve your e-mail security. E-mail is insecure by default and should be seen more like a postcard, not a sealed envelope. To mitigate this you can use encryption, as well as signing the e-mail with a certificate so the receivers of your e-mails can be sure the mail really originated from you and not someone else. You can get a free personal digital signature from Comodo. You should also be sure to not send “Out of Office” replies to everyone outside your organization, as this means that spammers and attackers will see that the e-mail exists, and attackers could even use the fact that you are out of the office as a benefit when attacking.