# RSA application

#### Pycryptodome:

Pycryptodome is a python library about cryptography, see the documentation below: <https://www.pycryptodome.org/en/latest/> There is an example of RSA key generation with pycryptodome:

```python
from Crypto.Util.number import getPrime, bytes_to_long


def generate_keys():
    e = 0x10001    #public exponent e, we generally use this one by default
    while True:
        p = getPrime(512)
        q = getPrime(512)
        phi = (p - 1) * (q - 1)    #Euler's totient 
        d = pow(e, -1, phi)    #Private exponent d
        if d != -1:
            break

    n = p * q
    public_key = (n, e)
    private_key = (n, d)
    return public_key, private_key


def encrypt(plaintext: int, public_key) -> int:
    n, e = public_key
    return pow(plaintext, e, n)    #plaintext ** e mod n


def decrypt(ciphertext: int, private_key) -> int:
    n, d = private_key
    return pow(ciphertext, d, n)   #ciphertext ** d mod n


message = bytes_to_long(b"super_secret_message")
public_key, private_key = generate_keys()
ciphertext = encrypt(message, public_key)
plaintext = decrypt(ciphertext, private_key)
```

#### OpenSSL:

OpenSSL is a robust, commercial-grade, and full-featured toolkit for the Transport Layer Security (TLS) and Secure Sockets Layer (SSL) protocols. It is also a general-purpose cryptography library

#### OpenSSH:


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://cryptohack.gitbook.io/cryptobook/untitled/rsa-application.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.