Go Back   Computer Forums > General Computing > Hardware
Join Computer forums Today

Thread Tools Search this Thread Display Modes
Old 04-30-2009, 03:47 PM   #1
In Runtime
thomas49th's Avatar
Join Date: Sep 2005
Posts: 395
Default Encryption - Public and private keys, digital signature (message digests)

Hi, I was wondering about public and private keys with digital signatures

I thought that a private key can decrypt ciphered text that has been ciphered by a public key only, but a public key cannot decrypt text that has been encypted by a private?? Right?

That also implies that public keys cant decrypt public key messages? Only the private key right?

So my textbook says for creating digital signature:

when the message digest has been created (hashed), it is encrypted by the sender's private key, but then goes onto say that it's decrypted by the reciever's private key

The internet page here http://www.youdzone.com/signature.html says:

"decrypts the signature (using Bob's public key) changing it back into a message digest"

to get the message digest, but at the top of the page it says

"Either one of Bob's two keys can encrypt data, and the other key can decrypt that data."

so how can the public key be used to decrypt :\

Both ways don't make sense :\
Can someone tell me how it works?


1: Q6700 @ stock 3GHz 775 6GB-DDR800 ASROCK penryn 1600SLI, 1GB ATI RAEDON 5770 ~ 3TB internal;
2: 3.2Ghz Phenom 9550 Black ed 4GB-DDR3, ASUS skt AM3, HD 4850 512MB
3: Core i7 3.2GHz, 6GB DDR3, 512MB EN8800GT, 1TB Internal
4: Athlon 4000+ skt 939 6600GT 3GB
5: P4 3.4GHz, 3GB-DDR, ASUS skt 775, ATI RAEDON 9550
+ all my other lovely comp parts :)
thomas49th is offline   Reply With Quote
Old 04-30-2009, 08:55 PM   #2
Fully Optimized
vampist's Avatar
Join Date: Oct 2008
Location: USA
Posts: 2,404
Default Re: Encryption - Public and private keys, digital signature (message digests)

I don't know enough info on Hashes or the private keys to be able to answer your question. Although I will tell you that I have definitely peaked my interest. I have tomorrow off and then the weekend. RESEARCH! WOOT!
vampist is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off

All times are GMT -5. The time now is 07:11 PM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Friendly URLs by vBSEO 3.6.0