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Last updated on September 13, 2025

RSA Calculator

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Calculators are reliable tools for solving simple mathematical problems and advanced calculations like cryptography. Whether you’re securing data, encrypting messages, or learning about cryptographic algorithms, calculators will make your life easy. In this topic, we are going to talk about RSA calculators.

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What is RSA Calculator?

An RSA calculator is a tool to perform calculations related to RSA encryption and decryption. Since RSA involves complex mathematical operations, the calculator helps to perform tasks like key generation, encryption, and decryption efficiently.

 

This calculator makes RSA processes much easier and faster, saving time and effort.

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How to Use the RSA Calculator?

Given below is a step-by-step process on how to use the calculator:

 

Step 1: Enter the prime numbers: Input the two large prime numbers into the given fields for key generation.

 

Step 2: Click on generate: Click on the generate button to create the public and private keys.

 

Step 3: Use the keys: Use the keys for encryption or decryption of messages.

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How to Calculate RSA Encryption?

To perform RSA encryption, there is a simple formula that the calculator uses. The RSA encryption formula uses a public key made of two components: the modulus (n) and the public exponent (e).

 

Ciphertext = Plaintext^e mod n This formula allows encrypting a plaintext message into ciphertext using the recipient's public key.

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Tips and Tricks for Using the RSA Calculator

When using an RSA calculator, there are a few tips and tricks that we can use to make it a bit easier and avoid mistakes:

 

  • Consider using large prime numbers to enhance security.
     
  • Remember that the modulus (n) is the product of the two prime numbers.
     
  • Use the private key for decryption, which is comprised of the modulus and the private exponent (d).
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Common Mistakes and How to Avoid Them When Using the RSA Calculator

We may think that when using a calculator, mistakes will not happen. But it is possible to make mistakes when using a calculator.

Mistake 1

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Using small prime numbers for key generation

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Ensure you use sufficiently large prime numbers to enhance encryption security.

 

Small primes make the encryption susceptible to brute force attacks.

Mistake 2

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Forgetting to verify the public and private keys

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After generating the keys, verify them to ensure they match the intended security parameters and can encrypt and decrypt correctly.

Mistake 3

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Incorrectly interpreting the modulus and exponent values

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The modulus (n) is critical for both keys, and the exponents (e for public and d for private) must be correctly used in encryption and decryption.

Mistake 4

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Relying on the calculator for all security aspects

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While calculators help with calculations, they don't account for other security measures like secure storage of keys and secure transmission of messages.

Mistake 5

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Assuming all calculators can handle all encryption scenarios

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Not all calculators handle every encryption scenario.

 

Verify that the calculator supports the specific operations you require.

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RSA Calculator Examples

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Problem 1

How do you encrypt a message with RSA if the public key is (n=3233, e=17) and the plaintext is 65?

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Use the formula: Ciphertext = Plaintext^e mod n Ciphertext = 65^17 mod 3233 = 2790 So, the encrypted message is 2790.

Explanation

By raising 65 to the power of 17 and taking modulo 3233, we obtain the encrypted message 2790.

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Problem 2

Decrypt a message with RSA if the private key is (n=3233, d=2753) and the ciphertext is 2790.

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Use the formula: Plaintext = Ciphertext^d mod n Plaintext = 2790^2753 mod 3233 = 65 So, the decrypted message is 65.

Explanation

Raising 2790 to the power of 2753 and taking modulo 3233 gives us the original plaintext message, 65.

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Problem 3

If you want to generate RSA keys with prime numbers 61 and 53, what is the modulus (n)?

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Calculate the modulus: n = p * q n = 61 * 53 = 3233 So, the modulus is 3233.

Explanation

Multiplying the two primes, 61 and 53, gives the modulus 3233, used in both the public and private keys.

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Problem 4

How do you find the totient (φ) for the prime numbers 61 and 53?

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Calculate the totient: φ(n) = (p-1) * (q-1) φ(n) = (61-1) * (53-1) = 3120 So, the totient is 3120.

Explanation

Subtracting 1 from each prime and multiplying the results gives us the totient, 3120.

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Problem 5

What is the public exponent (e) if the totient (φ) is 3120 and e is chosen as 17?

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Ensure e is coprime with φ: gcd(17, 3120) = 1 So, 17 is a valid public exponent.

Explanation

The greatest common divisor of e (17) and φ (3120) is 1, confirming that 17 is a suitable choice for the public exponent.

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FAQs on Using the RSA Calculator

1.How do you calculate RSA encryption?

Use the formula Ciphertext = Plaintext^e mod n with the public key components.

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2.What makes a strong RSA key?

Using large prime numbers for key generation increases security against brute force attacks.

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3.Why is the modulus important in RSA?

The modulus (n) is the product of two primes and is used in both public and private keys.

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4.How do I use an RSA calculator?

Input the required parameters and perform key generation, encryption, or decryption as needed.

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5.Is the RSA calculator accurate?

The calculator provides accurate results based on mathematical operations but ensure proper security practices.

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Glossary of Terms for the RSA Calculator

  • RSA Calculator: A tool used for performing calculations related to RSA encryption and decryption.

 

  • Modulus (n): The product of two prime numbers used in RSA key generation.

 

  • Public Key: A key used for encrypting messages, consisting of the modulus and public exponent.

 

  • Private Key: A key used for decrypting messages, consisting of the modulus and private exponent.

 

  • Ciphertext: The encrypted form of a plaintext message, unreadable without decryption.
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Seyed Ali Fathima S

About the Author

Seyed Ali Fathima S a math expert with nearly 5 years of experience as a math teacher. From an engineer to a math teacher, shows her passion for math and teaching. She is a calculator queen, who loves tables and she turns tables to puzzles and songs.

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Fun Fact

: She has songs for each table which helps her to remember the tables

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