Digital Bangladesh

Imagine that you are writing a letter in a post card for your friend. Since a post card is open, anybody can read what you have written. The post man can read it.
Just like the information in post card, email content is also open. Anybody can read it. The email you send goes through many computers and routers. It is possible that those computer and router users can read your email just for fun or even purposely.
Not only in Internet, even in your own network other people can read your emails. Anyone can use the notebook to connect to the network and sniff on the data packets in the network. He or she can use software such as ‘Protocol Analyzers’, ‘Network Monitors’, or ‘Sniffers’ to accomplish this task.
Your friend, colleague or even your spouse can use the ‘Cracker’ or ‘Spyware’ to install in your computer and steal your email password. Then they can use this password and download your emails to their computer.
‘Key logger’ software can be used to capture key strokes. Then they can capture the keys that you type and the keylogger will send this data to the cracker. They can get details such as credit card and passwords.
You may think that using keylogger one can just read the emails that you send to others. But its not true. The spyware is capable of taking screen shots of your desktop and send to the hacker. So when you are viewing your emails, the spyware can take picture of your screen and send back to the hacker.
How to make your emails safe?
If you do not want your email to be read by hackers while the email is on the way in the Internet then you can encrypt your email before sending. So your information will be converted to 0s and 1s in binary format and it will be encrypted using a 64 bit, 128 bit or 256 bit key. The recipient should decrypt it and read the email.
If the same key is used to encrypt and decrypt then it is called symmetric cryptography. You can also different keys for encrypting and decrypting which is called ‘Asymmetric cryptography’ or public private keys cryptography.
One can get a public and a private key from a CA (Certification Authority). The public key can be given to all while the private key has to be kept secretly. This is how the cryptography works.
If A wants to send an emails to B. Then A will use the public key of B and encrypt the email and send to B. Then B will use his private key to decrypt the email and read. Even if someone else gets hold of the email other than B, he or she cannot read it since they don’t have the private key of B to decrypt the email.