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The spectrum of threats and types of attackers targeting corporate business information systems are growing, creating security concerns for businesses. At the same time, public and private standards applied toward information protection are becoming increasingly stringent. In this environment, businesses are paying increased attention to new measures that enhance security. Quantum Cryptography is an emerging security technology that may offer some new protection measures.
Cryptography
Cryptography is a centuries-old method of communicating sensitive information between two parties in such a way that a third party is restricted from obtaining it. For example, Rose and Fred need to communicate sensitive information. Rose uses an algorithm, called a cipher, to convert the message into unintelligible cipher text (encryption), which can then be sent through an open channel. Fred receives the message and must apply a matching cipher to convert the message back into plain text (decryption). The ciphers are controlled by a set of parameters, called a key. The key is a tool used to encrypt and decrypt. Quantum Cryptography is centered around this key. Both parties, Fred and Rose, must have a key.
There are two types of Cryptography, Public Key Cryptography and Private Key Cryptography. The method in which the keys are distributed is the differentiator. The simplest and the most ancient form of key sharing uses private keys. Private Key Cryptography uses identical keys for encryption and decryption. Rose takes a message, puts it in a safe box, locks it with a key, and ships the box to Fred. Fred uses the same key to unlock the message. The issue is that two keys are needed in separate locations. Frequent and reliable key distribution is needed with this type of cryptography. If the key were compromised, it would be difficult to replace.
Public Key Cryptography was ushered into existence by the computer age. With this method, different keys are used for encryption and decryption. Encryption is done with a publicly announced key, which encrypts with bits. Today, 128 bit encryption is being used. Decryption is completed using a private key, which is not shared. The idea is that individuals looking to receive encrypted messages send out encryption keys publicly, while keeping private keys for themselves. The secrecy of the keys relies on computational complexity of certain hard mathematical problems. However, mathematics is constantly advancing. Someone could develop an algorithm that could break or solve the current mathematical problem. In addition, eavesdropping on the key is currently not detectable. That means that users do not know if someone is tampering with their keys. Quantum key distribution can help solve some of these issues.
Architecturally, quantum technology enhances Private Key Cryptology by making the exercise of key sharing difficult to compromise. On a high level, quantum-based transmissions can exist only in uncompromised networks where no third party connections are made. If a quantumbased transmission is wiretapped, it is designed to cease to exist.
Quantum Key Distribution
Quantum Cryptography has nothing to do with the process of encryption by itself. Quantum Cryptography is focused on the actual transmission of the private key from the party that encoded the message to the party that is going to decode it. When applied to cryptography, quantum technology exists in the form of Quantum Key Distribution (QKD) protocol. Proposed in 1984 by two IBM engineers, quantum physics enables the basic principles of QKD operation.
In the case of quantum cryptography, particles used to transfer information are called quantum bits (qubits). An important quality of these particles is that they can only be measured once and in a pre-set manner (basis). Measurement actually destroys qubits; therefore, measurement only takes place one time. The party doing the measurement has to be aware of the basis (measurement manner) of qubits beforehand. A measurement executed with the wrong basis will create uneven results that won't be useful to encode a message.
If qubits are used as information carriers, they are designed to transport information only once, and to the party intended as the recipient of the exchange. In any other scenario the information should get lost. To set this up, parties would have to be in agreement as to which basis they are going to be using to measure the traffic, and use a reliable line that would enable a single measurement take place. From quantum concepts flows the IEEE protocol.
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