Signing and Verifying

“https://pagefault.blog/2019/04/22/how-to-sign-and-verify-using-openssl/”

Steps to Create a Signature

1. Generate a Private Key:

   Bash

   # Generate 4096-bit RSA private key and extract public key
   openssl genrsa -out key.pem 4096
   
   

   This creates a 2048-bit RSA private key and stores it in the file private.key.

2. Generate a Public Key:

   Bash

   openssl rsa -in key.pem -pubout > key.pub
   

   This extracts the corresponding public key from your private key and stores it in public.key.

3. Create signature:

   Bash

   openssl dgst -sign key.pem -keyform PEM -sha256 -out data.zip.sign -binary data.zip
   

   This generates a hash and then signs it using the private key

4. verify signature:

   Bash

   openssl dgst -verify key.pub -keyform PEM -sha256 -signature data.zip.sign -binary data.zip
   Verified OK