Third, while they are cheap and easy to use, there is a lot of complex computing going on beneath the surface. To use a key, you type in a password, and the security program then scrambles or unscrambles the data. A key is made up of bits, which are single shards of digital information, zeroes or ones. The size of the key is essential to digital security. A second factor related to security is how keys are used.
Some security systems use a single key and password.
However, to exchange information with others, such as in an E-mail message, you first must share that password and key with the recipient. This, in itself, can be an insecure operation. For instance, if you call your associate and give them the password, eavesdroppers may hear it. With this plan, you exchange public keys with others, but you also must use a second, more secure, private key to encrypt and decrypt information, and that one is located only on your computer. A third method used by some programs for ensuring the security of E-mail messages is digital certificates, which are attached to the messages.