Linked Questions

23 votes
4 answers
7k views

If the public key can't be used for decrypting something encrypted by the private key, then how do digital signatures work?

I'm learning asymmetric encryption in the use case of ssl/tls protocol. I can understand that the public key (like a padlock) can encrypt (lock) something and only the private key can decrypt (open)...
Aaron Shen's user avatar
15 votes
4 answers
3k views

Why should I sign data that's already encrypted? [duplicate]

My question is about the difference between signing and encrypting. Why would you still sign something if you are already going to PKI encrypt it? Doesn't the PKI encryption inherently provide ...
Jaap's user avatar
  • 167
18 votes
2 answers
5k views

Trying to understand RSA and it's terminology?

I get the gist of RSA but I'm mostly self taught so sometimes the phrases I picked to describe something don't match up with the widely accepted terminology. I'm trying to remedy this. I'm working ...
Corey Ogburn's user avatar
9 votes
3 answers
5k views

What happens when I encrypt something with my RSA Public Key?

I know encrypting something with my private key is used for signing. To prove that the message is indeed coming from me. But what about if I sign something with my public key? That would mean that ...
Áron Pop Adorján's user avatar
9 votes
3 answers
7k views

Is encrypting data with a private key dangerous?

I have been reviewing code for various internal apps that handle secure transmission of data with external systems. These follow the following process: RSA encrypt data with 3rd party public key RSA ...
user avatar
7 votes
3 answers
6k views

Digital Signature and Verification?

AFAIK , When Alice wants to write a message to Bob -- she uses Bob's public key and encrypt the message - and then Bob - using his private key - use to decrypt it. So public key is used to decrypt ...
Royi Namir's user avatar
3 votes
2 answers
2k views

With GPG, can you "decrypt" a file that hasn’t been encrypted?

In reading about asymmetric encryption a while ago, I remember reading that you could "decrypt" an unencrypted file with your private key, then others (anyone) could "encrypt" it with your public key ...
lukejanicke's user avatar
5 votes
2 answers
2k views

Encrypt with private and decrypt with public

Above picture is captured from iOS Security overview at page 25. The path encrypt with public and decrypt with private makes sense. But the other path, encrypt with private and decrypt with public to ...
Saran's user avatar
  • 153
3 votes
1 answer
2k views

What signature and certificate signing is all about

I know that X.509 certificate signing process includes creating a CSR (certificate signing request) and then the following happens: Some data's from the certificate to be signed hash is computed ...
Joe D's user avatar
  • 143
5 votes
2 answers
370 views

Understanding digitial certifications

q1) Does that mean that every time information is exchanged, both the original data + digital certification is sent? Meaning data + signature for each and every exchange. q2) Can any kind soul here ...
Noob's user avatar
  • 501
2 votes
2 answers
2k views

How do clients extract the public key from a self-signed certificate?

I have gone over: Why do we need to sign the self-signed certificate? Basic self-signed certificate questions Is a self-signed SSL certificate much better than nothing? I am new to cryptography and ...
Sheel Pancholi's user avatar
1 vote
1 answer
932 views

Does RSA encryption always pad small amounts of data to some larger size?

If I encrypt 160 bits (20 bytes) of data using an RSA 1024 private key, will the result always be 128 bytes? This seems to be the case in my experiements, but I want to be sure. For example, /bin/...
lwood's user avatar
  • 75
0 votes
1 answer
362 views

How to obtain body from RSA signed document without verifying signature?

According to my understanding of computational cryptology, the body of a signed document can be retrieved disregarding whether or not the signature is authentic. However, I cannot apply this ...
Jonathan Ginsburg's user avatar
0 votes
2 answers
288 views

Software Signing Standards

Is there a software signing certificates standard, officially or by popularity? As I understand the SSL/TLS/https certificates rules are specified by the RFCs. Mixed use of servers and clients from ...
minghua's user avatar
  • 165
-1 votes
1 answer
108 views

Digital signature from hashing encrypted webpage

I'm studying for the Security+ exam with the help of Total Seminars' Udemy course and in one video they claim that a digital signature is generated by encrypting a message with the sender's private ...
Retsek's user avatar
  • 101

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