The "Application info" settings within PC Guard are foundational for defining a protected application's identity, licensing behavior, and update strategy. The most critical element is the Application Signature, a unique 6-10 character string that serves as the cornerstone for license management. It enables multiple applications to share a single license and allows for seamless, reactivation-free updates. However, its power is matched by a critical operational requirement: all applications sharing the same Application Signature must also share the same Program ID (encryption key). A mismatch will result in a fatal "File damaged!" decryption error for one of the applications.

Beyond the signature, the Update ID provides granular control over the state of an application upon receiving an update, with options to reset demo modes, erase previous licenses, and reset usage counters. Standard file handling settings for defining input/output paths and managing backups round out this configuration section, providing the necessary operational framework for the protection process. Correctly configuring these settings is paramount to ensuring proper license enforcement, successful update deployment, and a stable end-user experience.

1. Core Application Identification

This section details the primary settings used to define the application being protected, including its public-facing name and its location on the file system.

• Application Name: A descriptive string with a maximum length of 40 characters (e.g., "Text editor PRO V4.0"). This name is used by the protected application as the window title when displaying dialogs and interacting with the end-user.
• Application Filename: The full file path to the application executable that is to be protected. This can be selected via a file browser or set directly from the command line using the -FILE option.

2. The Application Signature: The Cornerstone of Licensing and Updates

The Application Signature is a unique string that critically defines how an application and its license are identified on a remote computer. It is described as "highly important" and dictates licensing, updates, and compatibility between related applications.

2.1. Definition and Constraints

• Uniqueness: Uniquely identifies the project files and, consequently, the protected application.
• Format: Any string value with a minimum length of 6 and a maximum length of 10 characters. For an application named "Text editor PRO V4.0", a suggested signature is "TEEDPROV40".

2.2. Key Functions and Capabilities

The Application Signature is central to three primary functions:

1. Shared Licensing: Applications protected with the identical Application Signature will share the same license information on a user's computer. This enables a suite or group of applications to be activated with a single activation code.
2. Seamless Updates: By maintaining the same Application Signature between an original application and its update, the update will automatically use the existing license without requiring the user to re-enter an activation code.
3. Machine ID Generation: The Machine ID (MID) code, which is used for generating activation codes, is based on the Application Signature. This ensures that activation codes can only be generated for applications protected with the appropriate project settings. An attempt to load a project with the wrong signature will result in a MID code decryption error.

2.3. Critical Dependencies and Warnings

The source documentation highlights a critical relationship between the Application Signature and the Program ID that must be strictly managed to avoid runtime errors.

• Signature and Program ID Consistency: It is imperative that applications sharing the same Application Signature also use the same Program ID. The Program ID functions as the encryption key, and if two applications with the same signature have different Program IDs, one will fail to decrypt correctly.
• Error Condition: This mismatch leads to a "File damaged!" error message. The reason is that both applications share the same license data on the target machine, which includes the Program ID. The application that does not match the stored Program ID will fail its decryption routine.
• Update Scenarios:
  • Free Updates: For free updates, the developer must use the same project settings as the original application, including the Application Signature and Program ID.
  • Non-Free Updates: For paid updates requiring a new license, the developer should change the Application Signature. This will cause the update to generate a different Site/MID code, effectively treating it as a new application. Changing the Program ID is also an option in this scenario.

2.4. Best Practices for Testing

To avoid conflicts during development and testing, it is recommended to use unique Application Signatures for each distinct test build or protection scenario. This prevents license data from one test from interfering with another. The documentation suggests using a sequential naming convention, such as TEST0001, TEST0002, TEST0003, and so on.

3. Managing Application Updates with Update ID

The Application Update ID is a numerical identifier used to differentiate between versions of an application.

• Value Range: Can be set to any number from 0 to 999,999.
• Default: The default value is 0.
• Usage: The value should be increased with each subsequent update, as a higher value signifies a newer version.

This ID directly controls and enables a variety of powerful update-related features that can alter the application's state on the end-user's machine.

4. File Handling and Output Configuration

These settings control the physical files involved in the protection process, including backup management and the final output destination.

• Backup Original Application:
  • When enabled, PC Guard creates a backup copy of the original application before applying protection.
  • This option is ON by default.
  • If the backup filename field is left empty, a backup is created using the original filename with an _OLD extension appended.
• Output Filename:
  • Specifies the full path for the protected application file.
  • If this field is left empty, the protection is applied directly to the original application file, overwriting it.
  • This path can be set via the command line using the -OUTPUT option.
• Interface Controls: Three utility buttons are provided in the interface for the output filename field:
  • / button: Opens the target output directory in Windows Explorer.
  • I button: Copies the necessary interface DLL to the output directory.
  • > button: Runs the newly protected application.