A Useful Guide To Understand What Is A Digital Signature

By Author: Mark Taylor
Total Articles: 42
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Many people including those who belong to the technical field are not clear about the concept of what is a digital signature. A digital signature is said to be an electronic mark which is added to the documents for the security purpose. It validates that the sender of some file is reliable one and that there has not been done any single modification since the time it was signed. The absence of the signature signifies that the source from where certain information has been sent is known or belongs to who can claim to sign it. Moreover even if the sign are valid one cannot be always sure that content in the file would be harmless.

Next is how digital signatures are used for verification. It can be explained with the help of an example. If a person is about to send a signed message to other, the sender would create the message digest with hash function. As the digest function is a like a fingerprint any single modification would return some different outcome. The message is then encrypted by the first person with the private key and this form of message is digital signature. Then sender will send the information and esign ...
... to second person. The recipient will decrypt the information by using public key.

The receiver can verify the information with the use of hash function that has been used by sender and compare the results with message. If both would be similar then the receiver will get confident that information has been sent by some known otherwise it is insecure. It is worth noting that sender can ensure for security of information by encryption with public key of receiver. Receiver can decrypt by private key.

It is not possible to find two messages hashing to same value or one hashing the given value. It is only possible when hacker appends the fake message with sender digital signatures. There can be one or more than one digital certificate with one signature. Next for how long the key will remain valid. Generally the key expires after one year. In that case a file or message signed with the expired key will not be accepted. Still a vast number of circumstances are there when it becomes integral that the document signed would be regarded to be valid file long after the expiry which is more than two years. The examples included are contracts and long term lease.

It is possible by registering contract under the digital time stamping at the time it is signed. Then the esign can be verified long after the key is expired. All the parties should keep a copy of the stamp which will be an evidence to show that the agreement was signed by the valid keys. It is possible to time-stamp digital signature containing document which will confirm the integrity of sign after the expiration of the key. What is a digital signature and how it is useful is a very broad topic. In conclusion, it can be said that the digital signature is useful in transaction, legal cases, corruption and tampering.

About: - In the current scenario when there is high risk of insecurity of data it has become necessary for the reputation of every organization that they should send reliable data only. It can only be done by use of digital signatures which is equivalent to a stamp of reliable sender.