Yes, digital Signatures helps or prove as you are you in digital world. A person who wants to be sure information she exchange over the Internet is not read by others and is not a forgery uses encryption software to create two keys.

The software typically multiplies two prime numbers-numbers that can be evenly divided only by itself and the number 1. The software uses up to 128 bits to record those numbers. With that many bits, there are a possible 3, 402, 823, 669, 209, 384, 634, 633, 746, 074, 300, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000 different combination's. If, say, both of those numbers have 75digits, their product will consist of 150 digits. Those tow prime number become a private key. The person who creates them is the only one who possesses the private key.

Another person who wants to send the first person a confidential document encrypts the file using the public key as a variable in the logarithm uses by the software. An algorithm is a fixed set of operations that change data in a way that make the original document incomprehensible. A simple example of an algorithm is “shift one letter to the right,” so that HAL becomes IBM. The key to decrypting it would be “shift one letter to left.”

Anyone who wants to reverse the algorithm to restore the original message mist figure out which two prime numbers out of the 3, 402, 823, 669, 209, 384, 634, 633, 746, 074, 300, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000, 000 possibilities are the factors that created the public key. Because there is no known formula for factoring large numbers larger than 80 digits, the only way to find out the private key is through brute-force computations-trying out every possible combination until the right two stumbled upon. Using the most powerful computers available would take decades, if not centuries.

Public key encryption also is used to create digital signatures. A digital signature is typically created by computing a message digests or hash value. These are numbers created when the contents of the documents are run through a hashing algorithm. The resulting value is a mathematical summary of the document. The hash value is encrypted using the private key.

The recipient of the message uses the sender’s public key to decrypt the hash value. The recipient runs the document through the same algorithm the sender did and , if the document is from whom it claims to be from, the two sets of hash values will match. Of as little as a comma has been changed, or of the sender is impersonating someone else, the hash values won’t match.