![]() ![]() For given n and e, there is unique number d. Private Key d is calculated from p, q, and e. Interestingly, though n is part of the public key, difficulty in factorizing a large prime number ensures that attacker cannot find in finite time the two primes (p & q) used to obtain n. The pair of numbers (n, e) form the RSA public key and is made public. In other words two numbers e and (p – 1)(q – 1) are coprime. There must be no common factor for e and (p − 1)(q − 1) except for 1. Number e must be greater than 1 and less than (p − 1)(q − 1). For strong unbreakable encryption, let n be a large number, typically a minimum of 512 bits. The process followed in the generation of keys is described below −Ĭalculate n=p*q. Generation of RSA Key PairĮach person or a party who desires to participate in communication using encryption needs to generate a pair of keys, namely public key and private key. We will see two aspects of the RSA cryptosystem, firstly generation of key pair and secondly encryption-decryption algorithms. The system was invented by three scholars Ron Rivest, Adi Shamir, and Len Adleman and hence, it is termed as RSA cryptosystem. ![]() It remains most employed cryptosystem even today. This cryptosystem is one the initial system. We discuss them in following sections − RSA Cryptosystem There are three types of Public Key Encryption schemes. In fact, intelligent part of any public-key cryptosystem is in designing a relationship between two keys. Though private and public keys are related mathematically, it is not be feasible to calculate the private key from the public key. Generally, this type of cryptosystem involves trusted third party which certifies that a particular public key belongs to a specific person or entity only.Įncryption algorithm is complex enough to prohibit attacker from deducing the plaintext from the ciphertext and the encryption (public) key. Some assurance of the authenticity of a public key is needed in this scheme to avoid spoofing by adversary as the receiver. Receiver needs to publish an encryption key, referred to as his public key. This is a property which set this scheme different than symmetric encryption scheme.Įach receiver possesses a unique decryption key, generally referred to as his private key. The most important properties of public key encryption scheme are −ĭifferent keys are used for encryption and decryption. The process of encryption and decryption is depicted in the following illustration − This gave rise to the public key cryptosystems. The symmetric key was found to be non-practical due to challenges it faced for key management. With the spread of more unsecure computer networks in last few decades, a genuine need was felt to use cryptography at larger scale. Symmetric cryptography was well suited for organizations such as governments, military, and big financial corporations were involved in the classified communication. Unlike symmetric key cryptography, we do not find historical use of public-key cryptography. ![]()
0 Comments
Leave a Reply. |