Monday, 18 February 2013

What is a Digital Signature




After talking about the Basic Cryptography its the time to learn about the Digital signatures...!!!

A Digital Signature Certificate, like hand written signature, establishes the identity of the sender filing the documents through internet which sender can not revoke or deny. Accordingly, Digital Signature Certificate is a digital equivalent of a hand written signature which has an extra data attached electronically to any message or a document.
Digital Signature also ensures that no alterations are made to the data once the document has been digitally signed. A DSC is normally valid for 1 or 3 years, after which it can be renewed
A Digital Signature is a method of verifying the authenticity of an electronic document.


What is a Digital Signature Certificate...?

Digital signature certificates (DSC) are the digital equivalent (that is electronic format) of physical or paper certificates. Examples of physical certificates are drivers' licenses, passports or membership cards. Certificates serve as a proof of identity of an individual for a certain purpose; for example a driver's license identifies someone who can legally drive in a particular country. Likewise, a digital certificate can be presented electronically to prove your identity, to access information or services on the Internet or to sign certain documents digitally, properly implemented digital signatures are more difficult to forge than the handwritten type.

To digitally sign a document, you must have a digital ID. This unique identifier can obtained from various Certification Authorities on the Web, such as VeriSign and EchoSign. Once you have a digital ID, you can add register it with programs that support digital signatures, such as Adobe Acrobat and Microsoft Outlook. Then you can use the program's "Sign" feature to add your digital signature to documents.
The digital signature is simply a small block of data that is attached to documents you sign. It is generated from your digital ID, which includes both a private and public key. The private key is used to apply the signature to the document, while the public key is sent with the file. The public key contains encrypted code, also called a "hash," that verifies your identity.
Digital signatures can be used to certify or approve documents. Certifying signatures verify the document's creator and show that the document has not been altered since it was signed. Therefore, only the original creator of a document can add a certifying signature. Approval signatures can be added by anyone with a digital ID and are used to approve documents, track changes, and accept terms stated with a document.

                                                         Digitally Signed Word Document

            So if a document is once digitally signed then its difficult to tamper it by others...!
A digital signature scheme typically consists of three algorithms:
  • A key generation algorithm that selects a private key uniformly at random from a set of possible private keys. The algorithm outputs the private key and a corresponding public key.
  • A signing algorithm that, given a message and a private key, produces a signature.
  • A signature verifying algorithm that, given a message, public key and a signature, either accepts or rejects the message's claim to authenticity.
Two main properties are required. First, a signature generated from a fixed message and fixed private key should verify the authenticity of that message by using the corresponding public key. Secondly, it should be computationally infeasible to generate a valid signature for a party who does not possess the private key.


How Digital Signatures works...?

 Assume you were going to send the draft of a certain contract to your client in another town. You want to give your client the assurance that it was unchanged from what you sent and that it is really from you. Here then would be the process:
1. You copy-and-paste the contract (it’s a short one!) into an e-mail note.
2. Using special software, you obtain a message hash (mathematical summary) of the contract.
3. You then use a private key that you have previously obtained from a public-private key authority to encrypt the hash.
4. The encrypted hash becomes your digital signature of the message. (Note that it will be different each time you send a message.)

The disadvantages of using digital signatures involve the primary avenue for any business: money. This is because the business may have to spend more money than usual to work with digital signatures including buying certificates from certification authorities and getting the verification software..., any how nothing in this world is for free.... :)

Types of Digital Signatures :

Class 1: The use of digital ID’s for secure email enables the user to digitally sign and encrypt digital communication. The best way to secure and validate your email address is by using Class I Digital Signature. The recipient of the email will know that the content was kept confidential during transmission.

Class 2: Safe Solutions provides LRA (Local Registration Authority) for commencement of service, Class 2 certificate from the IT Department and ROC department. The Class 2 Digital certificates are electronic files that are used to identify people and resources over networks such as the internet.

Class 3: Class 3 Digital Signature recognizes people and resources over network and ensures encrypted communication between two parties. Safe Solutions provides LRA (Local Registration Authority) for commencement of service. The class 3 Digital Signature certificate recognizes people at E- procurement, E-Tender & E-actions.
The list of licensed CAs along with their contact information is available on the MCA porta...
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Sunday, 17 February 2013

What is Spam


After reviewing my post  Backtracking Emails I felt that I had missed to say something about Spams.., so here I'll be talking completely about spams, how it is made, why it is made and how to avoid it...!!!


Spam involving nearly identical messages sent to numerous recipients by email. Clicking on links in spam email may send users to phishing web sites or sites that are hosting malware. Spam email may also include malware as scripts or other executable file attachments. Definitions of spam usually include the aspects that email is unsolicited and sent in bulk.


How do they get my Email Id
Spammers collect email addresses from chatrooms, websites, customer lists, newsgroups, and viruses which harvest users' address books, and are sold to other spammers. They also use a practice known as "email appending" or "epending" in which they use known information about their target (such as a postal address) to search for the target's email address. Much of spam is sent to invalid email addresses. Spam averages 78% of all email sent. According to the Message Anti-Abuse Working Group, the amount of spam email was between 88–92% of email messages sent in the first half of 2010...!!!


How do they Spam

a. Appending: Similar to a telephone directory, here One will have the list of Name, Email Id and many more personal information's of clients. A spammer will get those details officially or unofficially...!!!

b. Image spam: This is one of the serious issue where texts and messages are stored in the attractive(erotic/beautiful/pornographic ) images and those images are uploaded to the popular websites, the one who clicks on it will be exploited by spammer as he can steal the host cookie..!!!

c. Blank spam: Blank spam is spam without any payload advertisements, but still it fits the definition of spam because of its nature as bulk and unsolicited email...!!!

 

 So what are the effects of Spam

 a. Every time a "spammer" sends out email spam, the entire Internet community has to bear the cost,  in particular the recipients and the ISPs at the receiving end. It wasted a lot of recipients' time and disk space... :(

b. Spam also ties up bandwidth and resources on computers and routers all over the Internet. Every unwanted email message adds to the total cost of operating the networks of computers which form the Internet. Spam can disrupt a network by crashing mail servers and filling up hard drives. Spam also constitutes an invasion of Internet users' online privacy... :(

c. On the other hand, if any servers or organizations / institutes being classified as SPAM sites, others may not be able to receive normal emails from these sites... :(

 

 So what can I do to avoid Spam...?

a. Never ever Sign Up on Un-Known websites and never share your Email Id to Anonymous...

b. Avoid clicking the links that are in the email you receive if the sender is an anonymous...

c. It is common sense that no one today will ask your help by Introducing themselves as XYZ working in ABC with income of several $ as post photos through email and asks your personal details or may call you to meet her/him...!

d. Here is how to take revenge against these bloody mother fuckers, through Report Spam, i.e before you delete your spam, forward your spam to: spam@uce.gov as this is the Spam box for FTC (Federal Trade Commission). Mail sent to this box is investigated. If it is indeed spam, the original sender can be charged $500 per email. The more mail they get from different users but same spammer, the more it's likely to be investigated. 

 Be aware of attractive, erotic, pornographic images that will reach any of your mail boxes and never forget these words before clicking on them...!!!

Do you love experiments so here is my journey in finding a spammer by Backtracking the senders Email, and never forget to stay Anonymous on Web    

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