The invention of the telegraph revolutionized long-distance communication by allowing messages to travel many miles practically instantaneously. However, the drawback of telegraphs compared to letters was that the required intermediaries for transmission also had access to the contents of a message. While a postman is unlikely to open and read a sealed letter, a telegraph clerk has no choice but to read what they are sending.

This affected the development of cryptographic techniques in two major ways. One, it prompted the general public to become more interested in cryptography. Even if their messages were not necessarily "secret" per se, most people are uncomfortable with the idea of a half-dozen people reading their private correspondences. Two, individuals and organizations that already encrypted their messages needed to amp up their security, because their messages would be viewed by more people and their messages would be easier to intercept via wire tapping. This spurred the adoption of the Vigenère cipher for telegraph communications because of the increased security it provided.

Similarly, in recent times, the concept of encryption has become more popular and the technique has become more refined in response to the increase in digital communications. As new technologies emerge, so may new cryptographic techniques.