The majority of encryption today uses asymmetric encryption. That means encryption techniques rely on the use of secure keys. To use an example, if you want to send encrypted instructions to your bank (such as to pay your broadband bill), your computer uses the publicly available key issued by the bank to encode the message. The bank then uses a different private key that only it has to decipher the message.
Key-based encryption is safe because it takes immense amounts of computing power to guess the details of the private key. Encryption methods today mostly fight off hacking by using long encryption keys – the latest standard is a key consisting of at least 2048 bits.
Unfortunately, the current decryption methods won’t stay safe for much longer. It seems likely that quantum computers will soon have the capability of cracking today’s encryption keys. This is possible since quantum computers can perform thousands of simultaneous calculations and could cut down the time needed to crack an encryption key from months or years down to hours. Once a quantum computer can do that, then no current encryption scheme is safe. The first targets for hackers with quantum computers will probably be big corporations and government agencies, but it probably won’t take long to turn the technology to hack into bank accounts.
Today’s quantum computers are not yet capable of cracking today’s encryption keys, but computing experts say that it’s just a matter of time. This is what is prompting Verizon and other large ISPs to look for a form of encryption that can withstand hacks from quantum computers.
Quantum key distribution (QKD) uses a method of encryption that might be unhackable. Photons are sent one at a time through a fiber optic transmission to accompany an encrypted message. If anybody attempts to intercept or listen to the encrypted stream the polarization of the photons is impacted and the recipient of the encrypted message instantly knows the transmission is no longer safe. The theory is that this will stop hackers before they know enough to crack into and analyze a data stream.
The Verizon trial added a second layer of security using a quantum random number generator. This technique generates random numbers and constantly updates the decryption keys in a way that can’t be predicted.
Verizon and others have shown that these encryption techniques can be performed over existing fiber optics lines without modifying the fiber technology. There was a worry in early trials of the technology that new types of fiber transmission gear would be needed for the process.
For now, the technology required for quantum encryption is expensive, but as the price of quantum computer chips drops, this encryption technique ought to become affordable and be available to anybody that wants to encrypt a transmission.