1. Generate the Keystore using Keytool

Run the following command in your terminal. This creates a PKCS12 keystore, which is the industry standard for modern Spring Boot applications.

keytool -genkeypair \
    -alias signature-key \
    -keyalg RSA \
    -keysize 2048 \
    -sigalg SHA256withRSA \
    -storetype PKCS12 \
    -keystore keystore.p12 \
    -validity 365 \
    -dname "CN=Your Name, OU=Dev, O=Company, L=City, S=State, C=US"

Break down of the parameters:

• -genkeypair: Generates a key pair (public and private key).
• -alias: The identifier used in your Kotlin code (app.security.key-alias).
• -keyalg RSA: The encryption algorithm (RSA is the standard for PDF signatures).
• -keysize 2048: Security strength. 2048 is standard; 4096 is even more secure but slower.
• -storetype PKCS12: The format required for .p12 files.
• -validity 365: Number of days the certificate is valid.
• -dname: Distinguished Name. CN (Common Name) should ideally be the name of the signer or the server.

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2. File Placement

Once generated, place the keystore.p12 file in your project structure: src/main/resources/keystore.p12

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3. Verification

To ensure the keystore was created correctly and see its contents, run:

keytool -list -v -keystore keystore.p12 -storetype PKCS12

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