diff --git a/README.md b/README.md
index ecd9a056..f29bef6d 100644
--- a/README.md
+++ b/README.md
@@ -113,6 +113,19 @@ export IPINFO_API_KEY="your_token_here"
 export OPENCAGE_API_KEY="your_token_here"
 ```
 
+The extraction heuristic validator encrypts internal IP regex patterns by default. To preserve this security default, set:
+
+```bash
+export S3_LOG_EXTRACTION_PASSWORD="your_encryption_password"
+```
+
+On trusted internal processing servers where you want to skip decryption overhead, you can disable encrypted regex handling and provide the plaintext regex directly:
+
+```bash
+export S3_LOG_EXTRACTION_ENCRYPT_IP_REGEX="false"
+export S3_LOG_EXTRACTION_DROGON_IP_REGEX="<plaintext regex>"
+```
+
 To update the region codes and their coordinates:
 
 ```bash
diff --git a/src/s3_log_extraction/validate/_extraction_heuristic_pre_validator.py b/src/s3_log_extraction/validate/_extraction_heuristic_pre_validator.py
index 14fc6851..ea23c946 100644
--- a/src/s3_log_extraction/validate/_extraction_heuristic_pre_validator.py
+++ b/src/s3_log_extraction/validate/_extraction_heuristic_pre_validator.py
@@ -1,4 +1,5 @@
 import hashlib
+import os
 import pathlib
 import subprocess
 
@@ -29,7 +30,7 @@ def __hash__(self) -> int:
 
     # TODO: parallelize
     def __init__(self):
-        self.DROGON_IP_REGEX = decrypt_bytes(encrypted_data=DROGON_IP_REGEX_ENCRYPTED)
+        self.DROGON_IP_REGEX = _get_drogon_ip_regex()
 
         # TODO: does this hold after bundling?
         self._relative_awk_script_path = (
@@ -58,3 +59,25 @@ def _run_validation(self, file_path: pathlib.Path) -> None:
                 f"stderr: {result.stderr}\n"
             )
             raise RuntimeError(message)
+
+
+def _get_drogon_ip_regex() -> str:
+    encrypt_ip_regex = os.environ.get("S3_LOG_EXTRACTION_ENCRYPT_IP_REGEX", "true").lower() not in {
+        "0",
+        "false",
+        "no",
+        "off",
+    }
+
+    if encrypt_ip_regex:
+        return decrypt_bytes(encrypted_data=DROGON_IP_REGEX_ENCRYPTED).decode("utf-8")
+
+    drogon_ip_regex = os.environ.get("S3_LOG_EXTRACTION_DROGON_IP_REGEX")
+    if drogon_ip_regex is None:
+        message = (
+            "Environment variable `S3_LOG_EXTRACTION_DROGON_IP_REGEX` is required when "
+            "`S3_LOG_EXTRACTION_ENCRYPT_IP_REGEX` is disabled."
+        )
+        raise EnvironmentError(message)
+
+    return drogon_ip_regex
diff --git a/tests/test_extraction_heuristic_pre_validator.py b/tests/test_extraction_heuristic_pre_validator.py
new file mode 100644
index 00000000..8ab3c1ff
--- /dev/null
+++ b/tests/test_extraction_heuristic_pre_validator.py
@@ -0,0 +1,76 @@
+import importlib.util
+import pathlib
+import sys
+import types
+
+import pytest
+
+
+def _load_extraction_heuristic_module():
+    source_root = pathlib.Path(__file__).parent.parent / "src" / "s3_log_extraction"
+
+    for name in (
+        "s3_log_extraction",
+        "s3_log_extraction.validate",
+        "s3_log_extraction.utils",
+        "s3_log_extraction._regex",
+        "s3_log_extraction.utils.encryption",
+        "s3_log_extraction.validate._base_validator",
+        "s3_log_extraction.validate._extraction_heuristic_pre_validator",
+    ):
+        sys.modules.pop(name, None)
+
+    package = types.ModuleType("s3_log_extraction")
+    package.__path__ = [str(source_root)]  # type: ignore[attr-defined]
+    sys.modules["s3_log_extraction"] = package
+
+    validate_package = types.ModuleType("s3_log_extraction.validate")
+    validate_package.__path__ = [str(source_root / "validate")]  # type: ignore[attr-defined]
+    sys.modules["s3_log_extraction.validate"] = validate_package
+
+    utils_package = types.ModuleType("s3_log_extraction.utils")
+    utils_package.__path__ = [str(source_root / "utils")]  # type: ignore[attr-defined]
+    sys.modules["s3_log_extraction.utils"] = utils_package
+
+    for module_name, relative_path in (
+        ("s3_log_extraction._regex", "_regex.py"),
+        ("s3_log_extraction.utils.encryption", "utils/encryption.py"),
+        ("s3_log_extraction.validate._base_validator", "validate/_base_validator.py"),
+        (
+            "s3_log_extraction.validate._extraction_heuristic_pre_validator",
+            "validate/_extraction_heuristic_pre_validator.py",
+        ),
+    ):
+        spec = importlib.util.spec_from_file_location(module_name, source_root / relative_path)
+        module = importlib.util.module_from_spec(spec)
+        assert spec is not None and spec.loader is not None
+        sys.modules[module_name] = module
+        spec.loader.exec_module(module)
+
+    return sys.modules["s3_log_extraction.validate._extraction_heuristic_pre_validator"]
+
+
+def test_drogon_ip_regex_uses_encryption_by_default(monkeypatch: pytest.MonkeyPatch) -> None:
+    module = _load_extraction_heuristic_module()
+    monkeypatch.delenv("S3_LOG_EXTRACTION_ENCRYPT_IP_REGEX", raising=False)
+    monkeypatch.setattr(module, "decrypt_bytes", lambda *, encrypted_data: b"decoded-regex")
+
+    assert module._get_drogon_ip_regex() == "decoded-regex"
+
+
+def test_drogon_ip_regex_uses_plaintext_override_when_disabled(monkeypatch: pytest.MonkeyPatch) -> None:
+    module = _load_extraction_heuristic_module()
+    monkeypatch.setenv("S3_LOG_EXTRACTION_ENCRYPT_IP_REGEX", "false")
+    monkeypatch.setenv("S3_LOG_EXTRACTION_DROGON_IP_REGEX", "plain-regex")
+    monkeypatch.setattr(module, "decrypt_bytes", lambda *, encrypted_data: b"should-not-be-used")
+
+    assert module._get_drogon_ip_regex() == "plain-regex"
+
+
+def test_drogon_ip_regex_requires_plaintext_value_when_encryption_disabled(monkeypatch: pytest.MonkeyPatch) -> None:
+    module = _load_extraction_heuristic_module()
+    monkeypatch.setenv("S3_LOG_EXTRACTION_ENCRYPT_IP_REGEX", "false")
+    monkeypatch.delenv("S3_LOG_EXTRACTION_DROGON_IP_REGEX", raising=False)
+
+    with pytest.raises(EnvironmentError, match="S3_LOG_EXTRACTION_DROGON_IP_REGEX"):
+        module._get_drogon_ip_regex()