Link encryption

Link encryption is an approach to communications security that encrypts and decrypts all traffic at each end a communications line (e.g. a teletype circuit). It contrasts with end-to-end encryption where messages are encrypted by the sender at the point of origin and only decrypted by the intended receiver. Link encryption a couple of several advantages:

• encryption is automatic so there is less opportunity for human error
• if the communications link operates continuously, link encryption defeats traffic analysis

On the other hand, end-to-end encryption insures only authorized persons see plaintext.

Link encryption can be used with end-to-end systems by superencrypting the messages.

Bulk encryption refers to encrypting a large number of circuits at once, after they have been multiplexed.