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Digital Signature Using SHA-256 with RSA Encryption.
A Comprehensive Explanation
Digital signatures are essential in cryptography for secure communication and data integrity.
But how exactly do they work?
A digital signature, implemented using SHA-256 with RSA encryption, is a secure method for verifying the authenticity and integrity of data.
Here’s a detailed breakdown of how it works:
Step1. Process Overview:
Hashing with SHA-256: The sender takes the original message or data and applies the SHA-256 hash function, which produces a unique fixed-size string (hash) based on the input data.
RSA Encryption: The resulting hash is then encrypted using RSA, where it’s signed with the sender’s private key. Only the recipient with the corresponding public key can decrypt the signature.
Step2. Verification Process:
Upon receiving the message and signature, the recipient decrypts the signature using the sender’s public key to obtain the original hash.
The recipient then hashes the original data (message) again using SHA-256. If this hash matches the decrypted signature hash, the data is confirmed authentic and unaltered.
Step3. Security and Efficiency:
SHA-256: Known for its security and efficiency, SHA-256 produces a 256-bit hash, reducing collision probability and ensuring integrity.
RSA: Utilizes public-key cryptography, where only the private key holder can create a valid signature, ensuring secure authentication.
Step4. Practical Implementation:
The sender’s system hashes the data and encrypts it with their private key.
The recipient verifies by decrypting the signature with the public key and comparing hashes.
Step5. Key Management:
Secure storage and transmission of public and private keys are crucial to prevent unauthorized use and forging of signatures.
