Do you write down sensitive data on the back of a postcard? Why not? Because you know, that anyone dealing with the mail underway; postal workers, the delivery guy, or anyone peaking in your mailbox, can read it. The same goes for e-mail, except then it’s done electronically in a matter of seconds.
Why do you put an email in an envelope? Breaking a sealed envelope is a felony in most countries. The solution for emails is even harder to break through, it is called encryption.
And you are probably familiar with your bank sending you sensitive information in a security envelope. They do this, so that even in a sealed envelope, you can’t hold it against the light to read the contents. But how would you know that your bank was the actual sender? That is where for emails, a digital signature come in. It allows you to verify who sent it.
