This means that if the data owner would like to search for particular information, then the data would need to be retrieved and decrypted a very costly operation, which limits the usability of the cloud to merely be used as a data storage centre. Homomorphic Encryption systems are used to perform operations on encrypted data without knowing the private key (without decryption), the client is the only holder of the secret key. When we decrypt the result of any operation, it is the same as if we had carried out the calculation on the raw data. Definition: An encryption is homomorphic, if: from Enc(a) and Enc(b) it is possible to compute Enc(f (a, b)), where f can be: +, ×, ⊕ and without using the private key. For plaintexts P1 and P2 and corresponding ciphertext C1 and C2, a homomorphic encryption scheme permits meaningful computation of P1 Θ P2 from C1 and C2 without revealing P1 or P2.The cryptosystem is additive or multiplicative homomorphic depending upon the operation Θ which can be addition or multiplication.
It should be computationally infeasible to derive the plaintext from the cipher text without knowledge of the decryption key. 2. It should be computationally infeasible to derive the cipher text from the plaintext without knowledge of the encryption key. Modern encryption systems are obtained from one of two basic systems: symmetric key (sometimes called shared key) systems, and asymmetric key (often called public key) systems. An encryption process the sender and receiver share a single and common key that is used to encrypt and decrypt the message, then is called as symmetric key systems.
Since symmetric cryptography uses the same key for enciphering and deciphering, a person has to use creative and difficult means to prevent someone from intercepting the key. If a third party were to intercept the key, they could use it to decipher anything it was used to encipher. A solution to this problem is public key cryptography which uses asymmetric cryptography to transport symmetric keys.
Does the government's plan to limit encryption have an adverse effect on the citizens' rights to free speech, protection from unlawful searches and seizures, or self-incrimination? There are many terms which have been introduced by the field of encryption. Each of these terms are need to understand this discussion. Plaintext is the original document to be transmitted or stored on a computer system. Ciphertext is the encrypted document.
5. CPSR: Electronic Privacy Principles 6. Daniel Lin, Michael C. Loui, "Taking the Byte Out of Cookies: Privacy, Consent, and the Web" Computers and Society, June 1998. 7. Herman T. Tavani, James H. Moor "Privacy Protection, Control of Information, and Privacy-Enhancing Technologies", Computers and Society, March 2001 8.
Can we trust the Internet? People have been working with coding words and numbers to send secret messages or to keep information private for a very long time. For example, about two thousand years ago, Julius Caesar encrypted the alphabet, called the Caesar Cipher, to send messages. So that even if his enemies intercepted the messages, they wouldn’t be able to read them. However, his simple encryption wasn’t effective because it was easy to decipher; therefore mathematicians and other scholars work hard to find other complicated encryptions.
Using the manual the Allies created a replica, allowing any code to be read. Looking back on this, we can learn how easy it is to screw up a theoretically perfect cipher through human error. The word cryptography comes from the Greek word of kryptos, meaning hidden. The idea behind cryptograph is to allow two people to communicate in secret without others reading or altering the message. Even if an outside person somehow intercepts this message, they will not be able to translate it into readable form effectively ending any leak of information.