A digital signature is an encoded form of a message, which is used to validate digital information such as e-mail messages, PDF documents by the sender or the sign holder and ensure that the letter sent is not altered.
It is the digital equivalent of a stamped or a handwritten signature, but provides far better security, preventing duplication and tampering in communication. A numeric name can ensure the events to its origin, the status of any electronic documents, identity of the sender.
In many countries, digitally signed documents have a legal identity at par with the traditional paper signed documents. In those countries, the public-private law budget is issued in their electronic version.
Generally, digital signatures are based on cryptography systems such as private and public cryptography. Most of them are based on secret keys also known as asymmetric cryptography. Using algorithms such as RSA, two keys are generated that are mathematically enclosed; one as a private key for encryption purpose and another as public for decryption. To create digital signatures, software like e-mail hash function generates a one-way hash of the data to be signed. The private key is used to encrypt the mixture along with the other required information such as a hashing algorithm. The benefit of encryption using hash is that it can convert any length of data in a fixed-length format, so the memory space is saved and the signing process becomes faster.
The value of each hash is unique. The hash value of the same data may possess different hash value; so it is more secure to execute. Any kind of alteration in data; even deletion or change of a single character results in a difference in the hash value. This kind of attribute helps to authenticate the integrity of the data by the use of the public key to decrypt the data when required. The received is genuine only when the decoded information is matched with its hash value; else it signifies that the data has been altered on the way, or the signature assigned the private key does not match with the public key provided by the signature holder.
Irrespective f the encryption of the message, a digital signature can be used with any type of words. If the message arrives incorrect form with a numeric name embedded on it, the receiver can be assured about the validity of the message and the identity of the sender. A digital signature is a unique identification code, so its authenticity cannot be argued. The documents with the numeric name are bonded with a public which can be used by parties who intend to verify the certificate.
The digital signature feature is supported by the majority of e-mailing applications. So digital signature can be used broadly across many platforms. The digital signature also maintains the authenticity of the data integrity and non-refusal of e-transactions is also supported by it over the internet.
