deannon

PowerShell-based utility for anonymizing and deanonymizing plain-text files via an INI configuration. The script (deannon.ps1) includes a shebang so you can run it directly on Linux/macOS or via pwsh -File on any platform.

Prerequisites

• PowerShell 7.6 or newer in PATH
• Bash (only needed to run the Smokey test suite)
• Smokey available in PATH
• Optional but recommended: Git and write access to the INI file (the tool appends new full.* sections when hints discover fresh tokens)

How It Works

1. Direction is detected from full.* pairs:
   • If at least one original token exists but no anonymized token, the file is anonymized.
   • If only anonymized tokens appear, the file is deanonymized.
   • Files containing both or none are skipped with a warning.
   • direction_markers act only as a fallback when no full pairs exist.
2. full.* sections define case-insensitive replacements that work in both directions.
3. hint.* sections accept regular expressions (case-insensitive). Every match is anonymized and recorded as a new full.* pair so future runs (including deanonymization) rely solely on the growing full list.

INI Structure Example

[direction_markers]
original=io.metafence,de.micwin

[full.base-domain]
original=io.metafence
anonymized=custA.example

; Example of an auto-generated hint hit
[full.ns-prod-alpha]
original=ns-prod-alpha
anonymized=NSX001

[hint.namespaces]
hint=ns-prod-[a-z0-9]+   ; regex pattern (case-insensitive)
prefix=NSX               ; prefix for generated values
width=3                  ; zero-padding length (default 4)
next_index=1             ; incremented after each new match

[hint.metafence]
hint=metafence(?=\.net) ; only replace "metafence" before ".net"
prefix=CARL
width=3
next_index=1

• direction_markers is optional and only used when no full pairs exist.
• full.<name> defines a static pair.
• hint.<name> needs at least a regex; prefix, width, and next_index are optional.
• Newly discovered matches are appended as full.* sections.

Installation

chmod +x deannon.ps1

Usage

./deannon.ps1 -Config deannon.ini file1.txt file2.txt

If -Config is omitted, the script looks for ./deannon.ini in the current working directory and aborts if the file does not exist.

pwsh -File deannon.ps1 -Config deannon.ini file.txt

During anonymization the script updates the INI; please commit those changes if you track the file in Git.

Tests

Smoke tests run via Smokey (https://github.com/micwin/smokey):

cd /home/micwin/projects/deannon
smokey --tests-dir tests.d

Each run creates a scratch directory under tests.d/.smokey-state/ and executes:

• 000-setup copies fixtures from tests/testdata/ into the temporary workspace.
• 010-anonymize runs ./deannon.ps1 and checks the anonymized output.
• 020-deanonymize runs the tool again and ensures the original content is restored without mutating the config snapshot.

Fixtures live in tests/testdata/, and the suite requires pwsh to be available.