What is
encryption?
In very basic terms,
encryption is a way to send a message in
code. The only person who can decode the message is the person with
the correct key; to anyone else, the message looks like a random
series of letters, numbers, and characters.
Encryption is
especially important if you are trying to send
sensitive information that other people should not be able to
access. Because email messages are sent over the internet and might be
intercepted by an attacker, it is important to add an additional layer
of security to sensitive information.
How is it
different from digital signatures?
Like digital
signatures, public-key encryption utilizes software such
as PGP, converts information with mathematical algorithms, and relies
on public and private keys, but there are differences:
The
purpose of encryption is confidentiality—concealing the
content of the message by translating it into a code. The purpose of
digital signatures is integrity and authenticity—verifying
the
sender of a message and indicating that the content has not been
changed. Although encryption and digital signatures can be used
independently, you can also sign an encrypted message.
When you
sign a message, you use your private key, and anybody
who has your public key can verify that the signature is valid (see
Understanding
Digital Signatures for more information). When you encrypt a
message, you use the public key for the person you're sending it to,
and his or her private key is used to decrypt the message. Because
people should keep their private keys confidential and should protect
them with passwords, the intended recipient should be the only one who
is able to view the information.
How does
encryption work?
- Obtain the
public key for the person you want to be able to read
the information. If you get the key from a public key ring, contact
the person directly to confirm that the series of letters and numbers
associated with the key is the correct fingerprint.
- Encrypt
the email message using their public key. Most email
clients have a feature to easily perform this task.
- When the
person receives the message, he or she will be able to
decrypt it.
Authors: Mindi
McDowell
| Copyright
2004 Carnegie Mellon University.
