All types of information, including confidential information and information with a legal value, such as a contract, are shared using PDF documents. Digital signatures are required to make sure that a document hasn’t been altered by anyone other than its creator and to confirm that the author is who we expect them to be and not someone else.
Overview
The equivalent of an ink signature on a paper document, but considerably more secure, is a digital signature in a PDF. This information is contained within a document, and can use to check two crucial things:
● That nobody other than the author has altered the document.
● That the author of the document is actually the person who claims to be the author.
You can use the right API or tool for free PDF signing.
How to Check a PDF Document’s Integrity?
Imagine someone snooping on a PDF document containing a crucial contractual agreement and attempting to change the terms. Hashing is a technique used by digital signatures in PDF documents to avoid such a situation. A hash is a mathematical operation that turns any block of data into a string of a specific length. If the data block has not been altered, the hash function’s output is always the same.
This hash function is applied to nearly all of the contents of a PDF document when it is signed, and the result is then saved inside the document. This does not, however, entirely resolve the issue of document integrity. What if someone intentionally alters the PDF file, changes the hash that was used, and then stores the modified hash there? We require asymmetric encryption to address this second issue.
Asymmetric Cryptography
You could use an algorithm to encrypt a message and instruct the recipient to use the same technique to decode it if you want to send it to someone but don’t want it to end up in the wrong hands. However, for this to work, both parties must be able to securely and covertly exchange the encryption key in advance.
Asymmetric encryption, on the other hand, uses distinct keys for the sender and the recipient. The sender uses a key that is intended to be kept private (the “private key”) to encrypt the message and gives the recipient access to the other key (the “public key”).
Then, two events must take place. The recipient must initially be able to use that public key to decrypt the communication. Second, only the sender should have access to the private key. Both parties can be confident that the message was written by the sender and not another person if these things are real.
An electronic signature supported by a digital certificate is referred to as a digital signature. The highest level of identity assurance while working with digital documents is provided by digital signatures, which abide by international laws. Similarly, you can make use of such process to sign with USB Token.
