Introduction to Digital Signature Algorithm
When a person sends data through a document, it becomes essential to identify his/her authenticity for security and safety reasons. Digital signatures are used for this identification. Authentication of the documents means being aware of who created them and that they did not interfere during their transmission. These signatures are created using certain algorithms. The Digital Signature Algorithm (DSA) is one of these. DSA is a type of public-key encryption algorithm, and it is used to generate an electronic signature.
As we’ve already observed, we use DSA, among many algorithms, to create digital signatures for data transmission. In DSA, a pair of numbers is made and used as a digital signature. We generate these using some specific algorithms. They allow the receiver to authenticate the origin of the message. The digital signature, created using DSA, is private at the data transmission’s starting point while it ends in public. This means that only the data transmitter can create the signature to add to the message, while anyone can authenticate the signature at the receiving end.
Understanding
Several algorithms are used to create digital signatures. Most of these follow a simple method of using the private keys of a sender to sign the message digests. We form the digital thumbprint this way for the data we send. Please note we sign the message digest, not the data. Therefore, the size of the signature is small. However, this is not the case with the digital signature algorithm. The procedure followed when using DSA is not as simple as using a private and public key at the start and end of the transmission. On the other hand, it generates two digital signatures by applying complex and unique mathematical functions, which we will know in detail later in this article.
So, as you can understand, we use DSA only to create the signatures. They cannot be used for the encryption of data. Because of this, it doesn’t face the import and export restrictions usually imposed on RSA.
The Working of Digital Signature Algorithm (DSA)
The DSA algorithm is standard for digital signature, which is based on the algebraic properties of discrete logarithm problems and modular exponentiations and is based on the public-key cryptosystems principle.
Digital signatures work on the principle of two mutually authenticating cryptographic keys. Signatures are based on public/private key pairs. One can create mathematically linked private and public keys with a public-key algorithm like RSA. One can sign a digital message with his private key. A person can encrypt signature-related data with the use of a private key. The private key should always be with a person who wants to create a digital signature. Both the public and the private key can always be derived from one another as they are related mathematically. Signer’s public key is the only way to decrypt this data.
One can give the public key to anyone who needs verification of the signer’s signature. It is vital to keep a private key secret as one can generate your signature on a document with the help of this. In this manner, we complete the authentication of the digital signature. In a digital signature, only public and private keys assure validity.
On the other hand, the digital signature algorithm does not use a private key to encrypt data. Also, a digital signature algorithm does use a public key to decrypt this data. To create a digital signature with two 160-bit numbers, DSA works on the principle of a unique mathematical function. We create these two numbers using the private key and the message digest.
The complexity of the verification process arises because we don’t use the public key to authenticate the signature. Both keys secure data in a special digital signature algorithm for further security assurance.
Now, we use a hash function to create a message digest. The generated message digest and the DSA algorithm give the digital signature. Then, we send this signature along with the message. The receiver uses the same hash function to authenticate the source and the data.
To summarise-
- Keys are generated with the help of the key generation algorithm. We use the created keys to sign a document.
- We use a digital signature algorithm to generate a signature.
- To produce a message digest, we employ a hash function.
- Message digest with DSA gives the digital signature.
- Then, the digital signature transmits along with the sent data.
- The authentication of the signature is done using verification algorithms. We use the same hash function for verification.
Advantages of the Digital Signature Algorithm
- Along with strong strength levels, the signature’s length is smaller than other digital signature standards.
- The signature computation speed is less.
- DSA requires less storage to work as compared to other digital standards.
- The use of the DSA does not require the payment of any patent fees, as it is a patent-free algorithm.
Disadvantages of Digital Signature Algorithm
- It requires much time to authenticate, as the process includes complicated remainder operators. It requires a lot of time for computation.
- The DSA does not encrypt data. We can only authenticate data in this.
- The digital signature algorithm first computes with SHA1 hash and signs it. Any drawbacks in the cryptographic security of SHA1 are reflected in DSA because, implicitly of DSA is dependent on it.
- DSA is of the US National Standard with secret and non-secret communications applications.
Conclusion
We have developed an essential point regarding the digital signature algorithm in the above script. This article explains the digital signature algorithm, its way of working, and its advantages & disadvantages.
The digital signature is one of the best authentication tools for electronic records. Because of their cost, security, time, and speed, digital signatures are popular nowadays. In today’s interconnected and digital world, the digital signature algorithm is vital for creating a safer and more secure environment.
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