Decrypting RSA: Using d_K, d_p, d_q, M_p, M_q and x_p,x_q to Prove y^d=x mod n

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In summary, the conversation discusses the RSA encryption algorithm and how it uses modular arithmetic to encrypt and decrypt messages. It introduces the variables d_K, n, d_p, d_q, M_p, M_q, x_p, x_q, and x, and explains their roles in the encryption process. Finally, it shows how to use Fermat's theorem and Chinese Remainder Theorem to prove that y^d = x mod n.
  • #1
hope2009
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0
In RSA: d_K (y)=y^d mod n and n=pq. Define

d_p=d mod(p-1)

d_q=d mod(q-1)
Let

M_p=q^(-1) mod p
M_q=p^(-1) mod q
And

x_p=y^(d_p ) mod p
x_q=y^(d_q ) mod q
x=M_p qx_p+M_q px_q mod n

Show that y^d=x mod n
any help would be appraciated, thanks
 
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  • #2
homework eh?

use fermat's thm to prove y^d = y^(d_p) mod p (same for q)
show x = x_p mod p (same for q)
then use CRT to solve for x
 

FAQ: Decrypting RSA: Using d_K, d_p, d_q, M_p, M_q and x_p,x_q to Prove y^d=x mod n

1. What is RSA encryption and why is it important?

RSA encryption is a form of public-key cryptography that is widely used to secure digital communications, such as online transactions and sensitive data transfers. It is important because it allows for secure communication between two parties without the need for a shared secret key.

2. How does RSA encryption work?

RSA encryption uses two keys - a public key and a private key - to encrypt and decrypt messages. The public key is used to encrypt messages, while the private key is used to decrypt them. The two keys are mathematically related but cannot be derived from each other, ensuring the security of the communication.

3. What is the role of d_K, d_p, d_q, M_p, M_q, x_p, and x_q in RSA decryption?

These variables are used in the decryption process of RSA encryption. d_K is the private key, while d_p and d_q are derived from it and are used in the Chinese Remainder Theorem (CRT) to speed up the decryption process. M_p and M_q are the modular multiplicative inverses of x_p and x_q, respectively, and are also used in the CRT. x_p and x_q are calculated using the Extended Euclidean Algorithm.

4. How do these variables help prove that y^d = x mod n?

In RSA decryption, y is the ciphertext, d is the private key, x is the plaintext, and n is the product of two large prime numbers. By using the CRT and the modular exponentiation algorithm, computing y^d mod n can be broken down into smaller, more manageable calculations involving the variables mentioned above. This allows for a more efficient and accurate way to prove the correctness of the decryption process.

5. What are the potential risks or vulnerabilities of using RSA encryption?

While RSA encryption is generally considered secure, there are some potential risks and vulnerabilities to be aware of. These include attacks on the underlying mathematical algorithms, flaws in the implementation of the encryption system, and the risk of someone obtaining the private key through physical or digital theft. It is important to regularly update and strengthen the security measures in place to mitigate these risks.

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