Keep on top of the terms you should know about to keep your company safe and secure. We'll post one new term per week from our sister site If you have a security term you'd like to see defined, please email us at:

    Requires Free Membership to View

Link Encryption

Link encryption (sometimes called link level or link layer encryption) is the data security process of encrypting information at the data link level as it is transmitted between two points within a network. Data, which is plaintext in the host server, is encrypted when it leaves the host, decrypted at the next link (which may be a host or a relay point), and then reencrypted before it continues to the next link. Each link may use a different key or even a different algorithm for data encryption. The process is repeated until the data has reached the recipient.

Link encryption takes place in the lowest protocol layers (layers 1 and 2 in the OSI model). Because the process protects the message in transit, link encryption is very useful in situations where the security of the transmission line is not assured. However, because the message is decrypted at each host in the transmission path, vulnerability can arise at a link when the message must be transmitted between hosts that are not known to be secure.

Link encryption has been used successfully within organizations, including the military, where the security of each link can be assured. It isn't feasible over the Internet, because intermediate links are neither accessible nor secure.

This was first published in March 2001

There are Comments. Add yours.

TIP: Want to include a code block in your comment? Use <pre> or <code> tags around the desired text. Ex: <code>insert code</code>

REGISTER or login:

Forgot Password?
By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy
Sort by: OldestNewest

Forgot Password?

No problem! Submit your e-mail address below. We'll send you an email containing your password.

Your password has been sent to:

Disclaimer: Our Tips Exchange is a forum for you to share technical advice and expertise with your peers and to learn from other enterprise IT professionals. TechTarget provides the infrastructure to facilitate this sharing of information. However, we cannot guarantee the accuracy or validity of the material submitted. You agree that your use of the Ask The Expert services and your reliance on any questions, answers, information or other materials received through this Web site is at your own risk.