Digital Signatures provide a viable solution for creating legally enforceable
electronic records, closing the gap in going fully paperless by completely
eliminating the need to print documents for signing. Digital signatures enable
the replacement of slow and expensive paper-based approval processes with fast, low-cost, and fully digital ones. The purpose of a digital signature is the same as that of a handwritten signature. Instead of using pen and paper, a digital signature uses digital keys (public-key cryptography). Like the pen and paper method, a digital signature attaches the identity of the signer to the document and records a binding commitment to the document. However, unlike a handwritten signature, it is considered impossible to forge a digital signature the way a written signature might be. In addition, the digital signature assures that any changes made to the data that has been signed cannot go undetected
Digital signatures are easily transportable, cannot be imitated by someone else and can be automatically time-stamped. A digital signature can be used with any kind of message, whether it is encrypted or plaintext. Thus Digital Signatures provide the following three features:-
- Authentication - Digital signatures are used to authenticate the source of messages. The ownership of a digital signature key is bound to a specific user and thus a valid signature shows that the message was sent by that user.
- Integrity - In many scenarios, the sender and receiver of a message need assurance that the message has not been altered during transmission. Digital Signatures provide this feature by using cryptographic message digest functions.
- Non Repudiation – Digital signatures ensure that the sender who has signed the information cannot at a later time deny having signed it. A handwritten signature scanned and digitally attached with a document does not qualify as a Digital Signature. An ink signature can be easily replicated from one document to another by copying the image manually or electronically.
Digital Signatures cryptographically bind an electronic identity to an electronic
document and the digital signature cannot be copied to another document.