Asymmetric cryptography

A hash algorithm is a basic technique in asymmetric cryptography it is an irreversible mathematical function that yields a certain value when used with a data file. For example, used with a document it always yields the same value but it is impossible to calculate the document from the hash value. 

The basic idea is to apply the principles of the bank s safety deposit box to an IT solution for safeguarding electronic patient records. For the provision of services for sealed/locked records, the asymmetric cryptography technology, also known as public key cryptography, can be exploited as the base technology for implementation of a system managing the sensitive information in a sealed or locked state, for protection of privacy and for prevention of identity theft in the electronic information age. 

In asymmetric cryptography, the locks are referred to as public keys, and the keys for the locks are referred to as private keys. 

This asymmetric cryptography approach also protects the existence of the electronic record by storing the record identifier in an encrypted format. This is achieved by encrypting the electronic record identifier with the record owner s private key. Therefore only the ones who have access to the public key of the record owner can access the record identifier. 

The secure electronic data vault services described in the previous section exploit the public key infrastructure (PKI) based on the RSA cryptography,1 but in a nontraditional way using a new approach in the asymmetric cryptography. The concept of the RSA cryptography for secure exchange of an elec-... 

An asymmetric cryptography developed by R. Rivest, A Shamir, and L. Adleman. 

CSIC is demonstrated as a proof of concept by using it to find public and private keys for the RSA asymmetric cryptography system (Cormen et ak, 2001). The algorithm used in CSIC is a multi-objective genetic algorithm (Coello, Lamont, Veldhuizen, 2007). The human users will use CSIC through Amazon s Mechanical Turk service. 

As an analogy, think of the following scenario You manufacture multiple locks and an only key for those locks then you distribute the locks to your friends but keep the only key for yourself. When one of your friends wants to send you a secret letter, she will put the letter in a box and lock the box with your lock. Once it is locked, even your friend no longer can open the box because she does not have the key for the lock and because you have the only key for the lock. Therefore the box can be delivered safely to you even if you use some untrusted third party (e.g., courier, postman) for delivery. Only you can open the box with the only key you keep. Conversely, if you want to send a secret letter to your friend, you put your letter in a box and lock it with your friend s lock. Once locked, even you cannot unlock the box because your friend has the only key for the box. Consequently you are assured that only your friend can read your secret letter. Even if the box is misdelivered to someone else, the content of your letter is still kept secret because the box can be only opened by your friend, the friend you intended to access the secret letter. The key advantage of this asymmetric-key cryptography or public-key cryptography is that secret keys are kept with their owners and do not ever need to be shared with anyone else. 

Often, Ke = that is, the encryption and decryption keys are identical, and in this case we refer to it simply as the key or the secret key. This is called symmetric or secret key cryptography. In contrast, in asymmetric or public key cryptography, the encryption keys and decryption keys are different from each other, and only the decryption key needs to be kept secret. In public key cryptography, the decryption key is also sometimes called the secret key. 

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