Topic: Digital Signatures Date: 31st August 2009

1. Presentation on Digital Signatures…!

5. Private key encryption is essentially the same as a secret code that the two computers must each know in order to decode the information. The code would provide the key to decoding the message. Think of it like this. You create a coded message to send to a friend where each letter is substituted by the letter that is second from it. So "A" becomes "C" and "B" becomes "D". You have already told a trusted friend that the code is "Shift by 2". Your friend gets the message and decodes it. Anyone else who sees the message will only see nonsense .

7. The key is based on a hash value. This is a value that is computed from a base input number using a hashing algorithm. The important thing about a hash value is that it is nearly impossible to derive the original input number without knowing the data used to create the hash value. Here's a simple example: Input number Hashing algorithm Hash value 10667 Input # x 143 1525381

9. Digital signatures are used to verify that a message or document was authored by a certain person, and that it was not altered or modified by anyone else. Encryption and digital signatures can be used together, or separately a message may be encrypted, but not digitally signed (only people with the key can read it, but the reader cannot be certain who actually wrote it)

12. For other keys, use the key to skip the specified number of letters. If the original message is CATS HAVE FUR then the encrypted version depends on the key as follows: (key = 1) DBUT IBWF GVS (key = 2) ECVU JCXG HWT (key = 3) FDWV KDYH IXU ...and so forth

16. To use digital signature software requires some initial setup: you will need a signing certificate. Digital signatures can help you save time and paper-handling costs. Example: If in your business you commonly sign documents or need to verify the authenticity of documents.

20. The formula depends on two inputs: the sequence of characters representing the electronic data to be signed, and a secret number referred to as a signature's private key, associated with the signing party and which only that party has access to. The resulting computed value, representing the digital signature, is then attached to the electronic data just as a paper signature becomes a part of a paper document.

22. Here, the formula depends on three inputs: The sequence of characters representing the supposedly originally signed electronic data, the public key of the signing party, and the value representing the supposedly authentic digital signature. The output of the formula is a simple answer: yes or no. 'Yes' signifies that the digital signature is indeed an authentic digital signature on the presented electronic data, and it is associated with the party linked to the public key being used.

25. • Evidence: In order for the document to have power, the originator has to prove he or she is the sole owner and executioner of the document. This is what the digital signature does. It provides the necessary evidence to those viewing the document that it is real and the person signing it is real. • Ceremony: Basically, any time a document is signed it is based on a ceremony or tradition of making the document legal. Without the signature, the document would not be validated as authentic and legal. Providing a digital signature proves that the signor is entering into a commitment voluntarily

26. • Approval : As is stated by law, when a document must be made legal, it needs to be approved in order for the information to be turned legal and acted on. By placing a digital signature on the document makes it this way. This way the document can be acted on in a legal way. • Efficiency: One thing the digital signature does is if saves time and money because the signature turns the document instead a legal transaction. This way no further inquiries are needed to verify or clarify the information on the document, as being legit or not.

30. The Advantages of using digital signatures include: • Imposter prevention: By using digital signatures you are eliminating the possibility of committing fraud by an imposter signing the document. Since the digital signature cannot be altered, this makes forging the signature impossible. • Message integrity: By having a digital signature you are in fact proving the document to be valid. You are assuring the recipient that the document is free from forgery or false information.

32. Q U E R I E s ?

33. Thank you & Signing off Silpa END