How to safely mask and share COBOL code

When this guide is useful

Users looking for ways to mask, anonymize, or replace sensitive information in their COBOL code can learn how to safely share it to reviewers or generating AI while preserving its structure.

• Paste the COBOL code to the generation AI and consult the cause of the error
• Share defect reproduction code with external vendors or other teams
• Replace unique information before posting to question sites or external reviews

Confidential information that tends to remain in COBOL code

• PROGRAM-ID, section name, paragraph name, data item name, file name
• Customer code, account item, COPY clause, file name, business message
• Comments and log messages including customer name, product name, and environment name
• String containing internal URL, IP address, file path, and authentication information

Steps to mask while preserving structure

1. Enter only what you need to share and decide on a policy for leaving comments and values.
2. Select the target from PROGRAM-ID, section name, paragraph name, data item name, file name, character string, numerical value, and comment.
3. After masking, confirm that the division/section/paragraph, level number, and PERFORM correspondence can be read.
4. Right-click on the result side, remove only the parts necessary for the explanation, and do a final check.

공유하기 전에 확인할 포인트

Even if only the identifier is replaced, it may be possible to infer the system or customer from the customer code, account item, COPY clause, file name, or business message. Please also check that the same original value has the same kana.

Check for the same information in any logs, configuration files, or screenshots you share with your code.

Masking results do not guarantee that COBOL will compile or run. Visually check syntax and dependencies before sharing.

Concrete example: sharing a COBOL program that processes customer data for research

COBOL programs that process customer data may contain multiple types of information at the same time, such as identifiers, connection destinations, log statements, and fixed values. First, remove peripheral code that is unnecessary for explanation.

Additional information: PERFORM 々

1. Copy
2. Select
3. Execute masking and check whether the original information remains and the structure collapses.
4. Remove only the parts necessary for the explanation and paste it to the shared destination.

Just before sending to the shared destination, please search for any part of the company name, domain, path, or email address to check if it is still valid.

Frequently asked questions

Is the COBOL code sent to the server?

Input

Can I just run the code after masking?

Although maintaining the structure is a priority, complete parsing and build success are not guaranteed, so please check in another environment if necessary.