Toshiba Succeeds in Transmitting 500 GB of Human Genome Using Quantum Cryptography

Toshiba and Tohoku University, Quantum Cryptography Tohoku Medical Megabank Organization announced on January 14 that the world’s first successful transmission of about 500 GB of human genome data to a facility about 7 km away using “ quantum cryptography ”  can detect eavesdropping and is said to be highly secure. The company is expected to start business with quantum cryptography soon.

In the experiment, a transmitter and a receiver for quantum cryptography were installed on the Seiryo Campus of Tohoku University and the Toshiba Life Science Analysis Center and the equipment was connected with a 7-kilometer optical fiber. Light (photon) carrying bit information is emitted from the transmitter. The company’s quantum cryptography technology can transmit data at over 10Mbps over a distance of 7km. This speed is the fastest in the world as of 2018.

In quantum cryptography, only the “common key” used for encryption and decryption is transmitted on the quantum path (quantum key transmission). The actual data to be sent is originally encrypted using a common key, and then sent over a normal dedicated line (several Gbps). Since the common key uses the same length as the real data, the transmission time of the quantum path is the time required for decoding the real data as it is.

Schematic diagram of quantum cryptography communication Only the key is transmitted in the quantum path, and the data encrypted with the key is sent over the conventional line.

What Toshiba and Tohoku University have been working on this time is the transmission of about 500 GB of genomic data for 24 people (about 500 GB to 700 GB). Conventionally, to exchange sensitive and huge medical data safely, it was stored on a secure HDD or the like, and then physically carried by the person to the destination. If this could be replaced by quantum cryptography, confidential information could be sent more efficiently.

Toshiba’s quantum cryptographic communication is fast at about 10Mbps, which is slower than conventional communication. Therefore, the research team focused on the analysis time of the genome. It takes time to determine the nucleotide sequence using a “next-generation sequencer” that analyzes genomic data from DNA extracted from cells. It took about 59 hours to analyze the transmitted genome data (30 times for 24 people).

If it is a conventional means of transport carried by a person, it is necessary to wait for the analysis to be completed and save it to the HDD before starting to carry it. However, with quantum cryptography communication, the fragment data under analysis can be sent. Based on this idea, a method of sequentially sending fragment data of about several hundred MB in parallel with genome analysis was adopted, and it was said that all data transmission was completed in about 2 minutes after the analysis was completed.

Photons are the smallest unit of light of a certain wavelength and cannot be further divided. For this reason, if the key data is intercepted in the middle of the route, the key data will not reach the intended recipient, and eavesdropping will be detected. Even if an attacker attempts to copy the intercepted key data to the intended recipient after the interception, quantum mechanics has a “ non-duplicatable theorem ”. It cannot be sent to the recipient. The eavesdropping is discovered here because the receiver can match the quantum state with the sender after receiving the photon.

Since the encrypted actual data itself is transmitted via the classical route (normal non-quantum route), the encrypted data can be intercepted without depending on the sender / receiver. However, since Toshiba uses a method called “ one-time pad encryption ”, which disposes of a common key with the same length as real data for each communication and replaces it with a new key, it collects multiple encrypted data by interception and Even if the algorithm of the quantum computer is used, the encrypted data cannot be decrypted.

Thus, Toshiba’s quantum cryptography guarantees informationistic security by combining quantum key transmission and one-time pad cryptography.