{"id":18959,"date":"2025-12-26T17:24:44","date_gmt":"2025-12-26T22:24:44","guid":{"rendered":"https:\/\/www.iri.com\/blog\/?p=18959"},"modified":"2026-10-02T15:37:22","modified_gmt":"2026-10-02T19:37:22","slug":"masking-pii-in-ach-files","status":"publish","type":"post","link":"https:\/\/www.iri.com\/blog\/data-protection\/masking-pii-in-ach-files\/","title":{"rendered":"Masking PII in ACH Files"},"content":{"rendered":"

Abstract<\/b>: <\/span>This article discusses the content and obfuscation of sensitive sender or receiver information in ACH (NACHA) files, which are regularly used by banks and businesses to transmit payroll and payment data. The solution uses the data definition and manipulation 4GL of the CoSort <\/span><\/i>SortCL<\/span><\/i><\/a> program behind the <\/span><\/i>IRI FieldShield<\/span><\/i><\/a> structured <\/span><\/i>data masking<\/span><\/i><\/a> tool.<\/span><\/i><\/p>\n

What Is an ACH File?<\/h2>\n

\"ACH<\/p>\n

In general, an ACH file, also known as a NACHA file, contains instructions for processing electronic fund transfers through the Automated Clearing House (ACH) Network. More specifically, organizations use ACH files to bundle and send transaction information for direct deposit payroll, customer payments, and bill payments. <\/span>ACH files can also be used to send refunds, expense reimbursements, and to validate bank account information.<\/span><\/p>\n

ACH File Structure and Record Types<\/h2>\n

Each ACH file contains multiple batches of transactions, with each transaction detailing the sender, recipient, and payment amount in 94-character-long lines, and having these features:<\/span><\/p>\n

1.\u00a0 Format<\/b>: An ACH file is a fixed-width, ASCII text file.
\n<\/span>2.\u00a0 Structure<\/b>: In turn, it is organized into records, which are the individual lines of text. Accordingly, NACHA rules define the order and structure of these records.\u00a0<\/span>
\n<\/span>3.\u00a0 Content<\/b>: A file includes a series of records with specific functions, such as:
\n<\/span><\/i><\/p>\n