Linked Questions

1 vote
0 answers
123 views

RSA algorithm assignment [duplicate]

Alice wants to share a symmetric key with Bob. She encrypts the small (64-bit) secret key $K$ with Bob’s public RSA key $(n,e)$ by padding it with zeroes to 2048 bits (the length of n) and computing $$...
0 votes
0 answers
50 views

RSA PADDING WITH e=3 [duplicate]

I have a ciphertext which has been padded with spaces from left the message is 31 bytes long and e = 3 how can I recover the message with python code .
0 votes
0 answers
35 views

How to falsify RSA signature with known message [duplicate]

I have a question about the RSA signature. Let's say Alice has $(d,n)$ as the private key and $(e,n)$ as the public key. In order to sign a message $m$, Alice computes $y = m^d \bmod n$ and sends $(m,...
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58 votes
3 answers
49k views

Definition of textbook RSA

What is the definition of textbook or "raw" RSA? What are some of the properties of textbook RSA? How does it differ from other schemes based on RSA?
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24 votes
2 answers
12k views

Is RSA encryption with a private key the same as signature generation?

It is often said that RSA encryption of a cryptographic hash with a private key is the same as signing (signature generation). And that verification consists of decryption using a public key. Is RSA ...
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12 votes
3 answers
3k views

Is RSA padding needed for single recipient, one-time, unique random message?

I want a way to encrypt files using this process: https://crypto.stackexchange.com/a/15 . That is: generate a random password, use that to AES-encrypt a file, and use an RSA public key to encrypt the ...
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9 votes
1 answer
7k views

ECDH or RSA more secure for symmetric key wrapping?

Suppose a message is encrypted with a symmetric block cipher with a random key. RSA is often used to wrap the symmetric key using the recipient's public key. In this case, the size of the message is ...
9 votes
2 answers
687 views

Which attacks are possible against raw/textbook NTRU encryption?

In the same fashion that these questions about attacks to textbook RSA and ECC, I was wondering what are the immediate drawbacks of applying NTRU Encryption directly, without any padding scheme, such ...
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3 votes
2 answers
2k views

Toy public/private key example open to frequency analysis?

I've been looking at an online Public Key Encryption Example (summarized below). It seems to me that choosing cyphertext = plaintext^(key) mod n would produce the ...
-1 votes
1 answer
8k views

Why plain RSA encryption does not achieve CPA-security?

Why plain RSA encryption does not achieve CPA-security?
3 votes
1 answer
3k views

Why is RSA-2048 max input 245 bytes?

I can see that the message (after padding) should not be 256 bytes because it might be bigger than the modulus of RSA. So I think that the message should be 255 bytes, but I saw posts that says the ...
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4 votes
1 answer
2k views

What use is the signature without the message under RSA?

Using RSA for signing & verification, is there a way to take a valid signature for an unknown message, and for someone else to generate a valid signature using a different key against the valid ...
3 votes
3 answers
320 views

Is RSA in decline across the board?

From what I gather from the internet (source), the recommended practice for 2019 and beyond is to avoid RSA and use ECDH and ECDSA. Is this the general case?
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1 vote
1 answer
2k views

OpenSSL RSA same plaintext but different ciphertext

how OpenSSL RSA work ? I generate public (n,e) and private key (n,d) then I encypted a file by : ...
2 votes
2 answers
685 views

Can RSA signing be implemented on top of RSA encryption/decryption?

I need to use RSA-SHA256 signing. Unfortunately not all Microsoft CryptoAPI providers support that. It's possible that I might get a handle to a CryptoAPI provider that can just encrypt/decrypt with ...
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