Encryption
Encryption
So far we've seen that all video conferencing applications send their data over the Internet, from one IP address to another, and they send the video using UDP packets. It is theoretically possible to intercept these packets and eavesdrop. To prevent this from happening the packets can be encrypted.
Encryption is the process of transforming information (plaintext) using an algorithm (cipher) to make it unreadable to anyone (ciphertext) except those possessing special knowledge (key). "lbh cebonoyl erpnyy ebg13" is an example, which is what "you probably recall rot13" looks like if you apply the rotate 13 algorithm and replace each letter with the letter 13 places to the right.
While the 56 bit DES algorithm has seen use modern video conferencing equipment uses 128 or 256 bit AES (Advanced Encryption Standard). According to the mathematicians it is impossible to crack AES with current technology. The 128 bit and 256 bit notation references the key length. Each extra bit doubles the complexity so 128 bit AES is 2^72 more complex than DES. That' s 4,722,366,482,869,645,213,696 times in decimal. 256 bit DES is 2^200 which is roughly 2 followed by 60 zeros. It's a much bigger number but you would be right to ask Q: Does that matter?. A: No.
- Skype uses 256 bit AES and you can't switch it off.
- H.323 equipment can connect without encryption or with 128 bit or 256 bit AES. Encryption will only occur if both endpoints support it. On some endpoints it can be difficult/impossible to know if the connection is encrypted or not.
