Where Hashing Functions Fit in The Process of Securing Digital Signatures

Digital Signature and Hash Function

For decades, enterprises have been dependent on systems and processes that did not ensure the integrity of their data. Today, enterprises operate in a highly competitive landscape and are more prone to security threats than ever. 


New zero-day threats and digital security exploits that affect the integrity of digital data are emerging around us. Enterprise systems and processes are prone to these threats and need a secure way to store, access, and track documents without compromising integrity.


At an enterprise level, how do you ensure the integrity of the sensitive documents that need to be exchanged, reviewed and signed by multiple stakeholders?

Understanding the Foundation of Digital Signature Security

Digital Signatures are based on the Public Key Cryptography framework and are built on a system comprising different technologies and processes and the system is called a Public Key Infrastructure (PKI). It is a system that enables the Public Key Cryptography (PKC) to ensure the integrity of documents. 


The “Key” in Public Key Cryptography (PKC) refers to using two asymmetric keys, Public Key and Private Key, to secure data. The Public Key, as the name suggests, is freely shared with trusted entities to decrypt information contained in a document. The Private Key is the other piece of the puzzle that encrypts the information in a document and must not be shared. Information encrypted using cryptographic keys can only be decrypted using the same. 


This approach may seem straightforward to ensure the integrity of the documents in a workflow. Cryptographic Keys ensure the confidentiality of a document. But what if the Private Key falls into the wrong hands, leaving enterprise information vulnerable to external threats?


Anyone with access to the Cryptographic Keys can unsuspectingly not only access the documents but also manipulate them and send them across the document workflow.

To safeguard workflow integrity, adding an extra layer of protection is necessary. 


This extra layer of protection comes in the form of Hashing Functions. This blog will help you understand the significance of integration of digital signature and hash functions to ensure the integrity of documents.

What is a Hashing Functions?

Before understanding the role of Hashing Functions in ensuring document integrity, it is vital to know what they are. In simple terms, Hashing is converting a key or string of inputs into a fixed-length output called the Hash or Message Digest using a Hash Function or a Hashing Algorithm


The Hash acts as the digital fingerprint unique to the key or string of inputs provided and ensures data integrity. For example, let us assume a Hashing Function converts a given text input into an output value, the sum of the numerical value of the position of individual letters of the input text in the English alphabet. Now A is one, B is two and so on. When the word “hello” is passed through this Hash Function, it will return the sum of 8, 5, 12, and 15, which is 52.


However, Hashing involves using complex mathematical functions and processes to prevent the reversal of Hashing to reveal the original input. Statistically, a good Hash cannot be reversed to its initial input, making hashing a one-way function.

Message Digest 5(MD5) and Secure Hashing Algorithm (SHA) 256 are the most widely used Hashing Functions. 


These Hash functions are so complex even the most negligible changes made to the input key or string will result in a completely different Hash value. Hash value will help identify any changes made to the data in transit by comparing the Hash value generated at the origin and the destination of the data. 


The Hash values must be the same to ensure the integrity of the data. Hashing Functions have many use cases, and they are most commonly used in verifying the integrity of documents, digital signatures, data retrievals, password storing and blockchains. For instance, Hashing is critical in maintaining a blockchain’s integrity and preventing the tampering of the blocks in a blockchain.

Importance of Digital Signature and Hash Function Integration for Data Security

Hashing Function play a vital role in securing digital signatures. When the signing of a document is initiated, a message digest or hash value, a fixed-length output of the Hash Function, is also generated. This message digest or hash value acts as a digital fingerprint unique to that document. The Hash is further encrypted using the Private Key of the signer. The encrypted Hash and the Public Key together form a Digital Signature.


However, in a Public Key Infrastructure (PKI), a Certificate Authority (CA) verifies the signer’s identity. It issues a signed Public Key Certificate, which includes authentication information of the signer, the Certificate Authority’s Information and the signer’s Public Key. The Certificate


Authority verifies the signer’s identity by giving a signed certificate. The signed Public Key Certificate goes through the Hashing Functions, and the resulting Hash is encrypted using the Private Key of the Certificate Authority.


Digital Signature and Hash Function

The Hash is decrypted at the destination using the Public Key of the Certificate Authority, and the Signed Public Key Certificate undergoes Hashing. Both the decrypted Hash and the newly generated Hash are matched to ensure the document’s integrity. If the Hashes match, it means the document integrity is secure. If they do not match, the document integrity is compromised.

Why It Matters to Enterprises?

Encryption is a two-way process; a document can be encrypted and decrypted. But when combined with Hashing, the result is a complex layer of security that ensures the integrity of a document workflow, from the origin of a document to the destination of a document.


As the adoption of Digital Signatures increases among Enterprises to ensure the integrity of documents, it is equally essential to ensure compliance with globally accepted digital signature security standards. 


Digital Signatures compliant to the cryptographic modules and algorithm standards laid down by entities like the National Institute of Standards and Technology(NIST) in the Federal Information Processing Standards (FIPS) Publication are recommended for signing of documents at Enterprises.


Certinal eSign is the trusted choice of Enterprises for their Digital Signature needs. Certinal eSign offers the most exhaustive coverage of security compliance, including NIST FIPS standards, which dictate the use of cryptographic modules and functions standards in digital signatures.


Certinal eSign has garnered the trust of Global Enterprises. with an exhaustive coverage of security compliance. Certinal eSign maintains document integrity and ensures security compliance at an algorithmic level.


By choosing a trusted Digital Signature provider such as Certinal, enterprises can leverage the expertise of Certinal eSign in document workflow security and focus on staying ahead of their competitors. Take a peek into what happens behind the scenes of Certinal eSign.


Book a demo with us, to have a closer look at the Certinal eSign’s security capabilities designed for Enterprises.

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author avatar
Lokjith is a marketing content writer, and he writes about eSignature technology to raise awareness and help enterprises make informed decisions. Before discovering the SaaS industry, he organized Offline Marketing campaigns campaigns. He has a master’s degree from the Institute of Management Technology, specializing in Marketing.
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