Tuesday, November 25, 2008

Digital Signature & SSL

A digital signature is an electronic signature that can be used to authenticate the identity of the sender of a message or the signer of a document, and possibly to ensure that the original content of the message or document that has been sent is unchanged. Digital signatures are easily transportable, cannot be imitated by someone else, and can be automatically time-stamped. A digital signature can be used with any kind of message, whether it is encrypted or not, simply so that the receiver can be sure of the sender's identity and that the message arrived intact. A digital certificate contains the digital signature of the certificate-issuing authority so that anyone can verify that the certificate is real.

Assume you were going to send some secret information to your superior officer in another town. You want to give him the assurance that it was unchanged from what you sent and that it is really from you.
You copy-and-paste the information into an e-mail note.
Using special software, you obtain a message hash (mathematical summary) of the information.
You then use a private key that you have previously obtained from a public-private key authority to encrypt the hash.
The encrypted hash becomes your digital signature of the message. (Note that it will be different each time you send a message.)
At the other end, your superior receives the message.
To make sure it's intact and from you, he makes a hash of the received message.
He then uses your public key to decrypt the message hash or summary.
If the hashes match, the received message is valid.

SSL:- Digital certificates encrypt data using Secure Sockets Layer (SSL) technology, the industry-standard method for protecting web communications developed by Netscape Communications Corporation. The SSL security protocol provides data encryption, server authentication, message integrity, and optional client authentication for a TCP/IP connection. Because SSL is built into all major browsers and web servers, simply installing a digital certificate turns on their SSL capabilities.
SSL comes in two strengths, 40-bit and 128-bit, which refer to the length of the "session key" generated by every encrypted transaction. The longer the key, the more difficult it is to break the encryption code. Most browsers support 40-bit SSL sessions, and the latest browsers, including Netscape Communicator 4.0, enable users to encrypt transactions in 128-bit sessions - trillions of times stronger than 40-bit sessions. Global companies that require international transactions over the web can use global server certificates program to offer strong encryption to their customers.
Security Center by VeriSign gives you access to a wealth of security resources, products, technologies, and news. Visit often for the latest information – because when it comes to protecting yourself on the Web, you can't be too careful.

1 comment:

Amber Salm said...

I have read about digital signatures many times but is not familiar with SSL. The detail shared gave me a basic idea and increased my curiosity to explore more about this concept.
digital signature software