# RSA algorithm: Working and Use Cases

## Introduction

Wondering what is RSA algorithm stands for and what is RSA algorithm in cryptography? Read this article thoroughly as this will define the RSA algorithm, RSA algorithm steps, RSA algorithm uses, working of RSA algorithm, and RSA algorithm advantages and disadvantages. RSA is the most common asymmetric cryptographic algorithm based on the mathematical fact that large primary numbers are easy to find and multiply, but they are not easy to handle.

Public and private companies are included. Mathematical analysis indicates that it will take about 70 years for assailants to discover the value of keys if the keys’ weight is 100 digits. In the RSA algorithm, the real difficulty is to pick and produce private and public keys. Both the public and private keys will encrypt a message in the RSA cryptography algorithm, and a message is decrypted with the other key used to encrypt a message. This attribute makes RSA the most common asymmetric algorithm in use as it provides a way to ensure that electronic messages and data storage are kept secret, complete, and accurate.

## 1. What is the RSA Algorithm?

Rivest Shamir Adleman is the RSA algorithm in full form. The algorithm was introduced in the year 1978. RSA algorithm is an algorithm of asymmetric encryption. Asymmetric means that two opposite keys are operating, and those are Private Key and Public Key. Now let us explain the RSA algorithm with an example:-

An example of asymmetric encryption:

A client sends its public key and asks for some information from the server.

The server encrypts the data using the public key of the client and offers encrypted data.

The customer receives and decrypts this information.

Nobody other than a browser will decode data because it is asymmetrical, except through a third party has a browser public key.

With the RSA algorithm examples, the principle of the RSA algorithm explained that the factoring of a big integer is difficult. There are two numbers in the public key where there are two large main numbers multiplied by one. Also, from the same two prime numbers comes a private key. Therefore the private key is compromised if anyone can factor in the high number.

Thus, the encryption strength depends solely on the key size, and whether the key size is double or triple, the encryption strength increases exponentially. RSA keys will typically be 1024 or 2048 bits long, but experts think 1024 bit keys will be broken quickly.

## 2. Why is the RSA Algorithm Used?

The application of the RSA algorithm derives its security from factoring the large integral elements, which are the product of two large numbers. It’s easy to multiple any of the figures. Still, the calculation of the initial primary numbers from the sum or variables is complicated because the time it takes even using supercomputers is the drawback of the RSA algorithm.

The most problematic feature of RSA cryptography is the public and private key generation algorithm. They primarily test algorithm generated using the Rabin Miller test, which are p and q, the two large numbers. A module, n, is computed by multiplying p and q. This number is used for a private and public key and provides the link between them is called the key length, and the length of the key is typically expressed in bits.

The public key is the n modulus and the e-public representative, which are typically set to 65537, as the number of people is not too high. The e-figure must not be a secretly chosen top number because the public key is universal to everyone.

The private key is the n modulus and the private exponent d, which can be used to find the multiplicative inverse for the totient of n using the expanded Euclidean algorithm.

## 3. How does RSA Algorithm Work?

Let us discuss the RSA algorithm steps with example:-

By choosing two primes: p=11 and q=13, Alice produces the RSA key. The modulus is n=p to the full size of 143. The block diagram of the RSA algorithm is n Ï•(n)=(p−1) x (q−1) = 120. It uses the extended Euclidean algorithm, which provides it’s 103, to measure its private key for RSA’s public key e.

Bob needs to send a cryptic message to Alice, M, to obtain his public RSA key (n, e) (143, 7). His direct text message is just number 9 and is encrypted as follows in ciphertext, C;

Me mod n = 97 mod 143 = 48 = C

Alice receives Bob’s message, and with the help of RSA, she decrypts it:

Cd mod n = 48103 mod 143 = 9 = M

Alice will need to create a hash — a message digest to Bob for her — to encode the hash value with the private RSA key to use RSA keys to sign the message digitally and to add the key to the message. Bob should then ensure that Alice has sent the message and that the hash value with its public key has not been decrypted. Only Alice will have been able to send it – verification and nonrepudiation – if this attribute matched the hash of the original letter, and this message is just the way it is written – honesty.

Alice must encrypt his message with a public Bob RSA key—confidentiality before giving Bob his message. A digital certificate provides information identifying the certificate holders, which includes the public key of the owner. With this message, RSA can edit and create their own RSA algorithm diagram.

## 4. Advantages of RSA Algorithm

(a) RSA is stronger than any other symmetric key algorithm, and the advantages of the RSA algorithm in cryptography are authenticity and privacy.

The disadvantage of the RSA algorithm:-

(b) It has got too much computation.

## Conclusion

The above article made you clear the concept of the RSA Algorithm and its uses and how it works.

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