The ‘sn’ command is a Mono StrongName utility that is used for signing and verifying IL assemblies. It allows you to generate StrongNaming keys, re-sign assemblies with specific private keys, show the public key of a signed assembly, and extract the public key to a file.

Use case 1: Generate a new StrongNaming key

Code:

sn -k path/to/key.snk

Motivation: Generating a new StrongNaming key is useful when you want to sign an assembly with a unique key. This helps ensure the integrity and authenticity of the assembly.

Explanation:

• ‘sn’: The command itself.
• ‘-k’: The option to specify that a new StrongNaming key should be generated.
• ‘path/to/key.snk’: The path where the generated key file should be saved. The “.snk” extension is commonly used for StrongNaming key files.

Example OUTPUT:

Successfully generated StrongNaming key at path/to/key.snk.

Use case 2: Re-sign an assembly with the specified private key

Code:

sn -R path/to/assembly.dll path/to/key_pair.snk

Motivation: Re-signing an assembly with a specific private key is useful when you want to ensure that the assembly was signed by a trusted entity or to replace the current signature with a new one.

Explanation:

• ‘sn’: The command itself.
• ‘-R’: The option to specify re-signing an assembly.
• ‘path/to/assembly.dll’: The path to the assembly that needs to be re-signed.
• ‘path/to/key_pair.snk’: The path to the private key file that will be used to sign the assembly. The file should have the “.snk” extension.

Example OUTPUT:

Successfully re-signed the assembly at path/to/assembly.dll with the provided key at path/to/key_pair.snk.

Use case 3: Show the public key of the private key that was used to sign an assembly

Code:

sn -T path/to/assembly.exe

Motivation: Showing the public key of the private key used to sign an assembly can help you verify the integrity of the assembly and check its authenticity.

Explanation:

• ‘sn’: The command itself.
• ‘-T’: The option to display the public key of a signed assembly.
• ‘path/to/assembly.exe’: The path to the assembly for which you want to view the public key. The “.exe” extension is commonly used for executable assemblies.

Example OUTPUT:

Public Key of Assembly:
1234567890abcdef...

Use case 4: Extract the public key to a file

Code:

sn -e path/to/assembly.dll path/to/output.pub

Motivation: Extracting the public key of an assembly to a separate file can be useful when you want to share the public key with other developers or systems for verification purposes.

Explanation:

• ‘sn’: The command itself.
• ‘-e’: The option to extract the public key of an assembly.
• ‘path/to/assembly.dll’: The path to the assembly for which you want to extract the public key.
• ‘path/to/output.pub’: The path where the extracted public key file should be saved. The “.pub” extension is commonly used for public key files.

Example OUTPUT:

Successfully extracted the public key of the assembly at path/to/assembly.dll to path/to/output.pub.

Conclusion:

The ‘sn’ command provides a range of functionalities related to signing and verifying IL assemblies. It allows you to generate new StrongNaming keys, re-sign assemblies with specific private keys, show the public key of signed assemblies, and extract the public key to separate files. Understanding and utilizing these features can help ensure the integrity and authenticity of your assemblies.