13 questions linked to/from How does RSA signature verification work?
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### Do I really need to use the same private/public key pair in RSA?

So I'm making an Android application, I need my application to be only able to scan my own generated QR codes, and I want to make sure that nobody else can generate fake ones. The data isn't sensitive,...
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### Derive a secret from an RSA private key

What I want to do is deterministically derive a secure key from an RSA private key, such that the RSA private key cannot be derived from the secure key. The first approach that came to mind was ...
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### What is the verification algorithm for verifying RSA signatures?

I am not able to find much information how how to verify RSA signatures. I have three values. Message = "Launch a missile." public key: ...
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### How exactly does plaintext become ciphertext?

I'm having a hard time finding out how PlainText becomes Ciphertext. I understand that I do the following: PlainText -> RSA/AES/Whatever -> Ciphertext Can ...
1 vote
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### Calculate if a digital signature is valid

In the book An Introduction to Mathematical Cryptography, it mentions a section on digital signatures and a theoretical example. I am having difficulty understanding the book and I was wondering if ...
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### What is the probability of attacking SHA1 used in RSA signature with small exponent?

There is RSA signature check which has following properties: RSA modulus N which is 2048-bit RSA public exponent equal 41 (0x29) Genuine Signature uses EMSA-PKCS1-v1_5 padding of SHA1 hash, however ...
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### RSA signature send signature with encrypted message?

What is the correct procedure in sending an authenticated message, I've been researching and have been getting different answers, such as hash-then-sign [1], [2] , sign-then-encrypt [3] (but the link ...
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### Can I use asymmetric encryption for more powerful write-protection?

I have a game that I am developing which uses a locally-stored internal database. It does not matter to me whether a user can read the file (which, to me, means I don't need a symmetric cipher), but I ...
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### How does the signature checking work in DKIM?

As far as I understand DKIM works like this: DKIM is not used to encrypt anything, the only purpose is to mark mails that are not really sent from the claimed domain as spam. the DKIM-enabled sending ...
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### Encrypt with private key decrypt with public key

I want to sign and transmit a short message, which contains a few simple hashes. My objective is not to prevent an attacker from inserting a fake message, but to ensure that the attacker cannot define ...
1 vote
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### Given N and e in RSA and the ability to get signature s for any message m, can you find the value of the private key d?

Given N and e in RSA and the ability to get signature s for any message m ($s=m^d \mod{n}$), can you find the value of the private key d?
I am trying to learn about RSA digital signatures, and have a question about the verification process. My understanding of the set-up is the following: The signer chooses two secret primes $p$ and $q$,...