pii-shield-wasi
PII redaction scanner powered by the core Go engine compiled to WebAssembly (WASI). It runs in-process — no network hop — using hybrid heuristic and entropy-based detection.
Installation
pip install pii-shield-wasi
Requires Python 3.9+ and wasmtime 45.0.0+ (pulled in by pip). On macOS this
includes Apple's /usr/bin/python3: the SDK turns off wasmtime's Mach-port trap
handler there, which Apple-signed interpreters do not allow and which used to get
the process killed (Killed: 9) on the first call.
Usage
from pii_shield import PiiShield, PiiShieldConfig
# Initialize the scanner with optional configuration overrides
shield = PiiShield(PiiShieldConfig(
entropy_threshold=4.0,
confidence_score=0.8
))
text = "Connecting to DB with password: MySuperSecretPassword123!"
redacted_text = shield.redact(text)
print(redacted_text)
# Output might redact the high entropy secret based on context
redact() accepts multi-line text. Each line is scanned independently and \n / \r\n endings are preserved, so the output has exactly as many lines as the input (the same contract the CLI gives stdin).
Configuration
PiiShieldConfig accepts these overrides. Any field left unset keeps the core
scanner default, so redaction matches the CLI for the same config.
| Option | Type | Description |
|---|---|---|
entropy_threshold |
float | Shannon entropy cut-off for candidate tokens. |
confidence_score |
float | Hybrid-validation confidence threshold. |
salt |
str | HMAC salt for the [HIDDEN:xxxxxx] tags. Treat it as a secret: anyone who has it can compute the tag of a guessed value. If unset, each instance draws a random salt, so tags match only within that instance; set the same salt in every process that must produce matching tags. |
min_secret_length |
int | Minimum candidate token length before entropy checks apply. |
sensitive_keys |
list[str] | Key names whose values are always redacted (case-insensitive). Replaces the defaults. |
disable_bigram_check |
bool | Disable English bigram analysis (useful for non-English logs). |
adaptive_threshold |
bool | Enable the experimental statistical adaptive-threshold mode. |
entity_type_labels |
bool | Emit [HIDDEN:<type>:<hash>] markers, where <type> names the detector that fired: card, key, context, url, regex, entropy, or one of the issuer-format detectors aws-key, gcp-key, github-token, slack-token, stripe-key, jwt, telegram-bot-token, and private-key (a PEM private-key framing line). A named custom rule uses its own name. Off by default; the hash is unchanged. |
sensitive_key_patterns |
list[str] | Regex patterns matched against key names (equivalent to PII_SENSITIVE_KEY_PATTERNS). |
custom_regexes |
list[dict] | Rules forcing redaction: [{"pattern": ..., "name": ...}] (equivalent to PII_CUSTOM_REGEX_LIST). |
safe_regexes |
list[dict] | Whitelist rules exempting matching tokens (equivalent to PII_SAFE_REGEX_LIST). |
fail_policy |
"open" | "closed" |
On an internal error, open returns the input unchanged; closed returns a drop marker. Handled in this wrapper. |
Invalid regex handling
A bad pattern can never terminate your Python process. An invalid
custom_regexes or safe_regexes entry is skipped and the rest of the list is
applied; each skipped rule is reported with a WARNING on stderr. (Before
version 2.2.4 one invalid entry silently dropped the whole list, so a single
stray bracket switched off every rule in it.) An invalid sensitive_key_patterns
entry disables that pattern list with a warning. The CLI behaves the same way
for its environment-variable lists. Validate patterns before rollout if you need
strictness — a skipped custom rule means its matches are no longer force-redacted.
Features
- In-process: runs the Go WASM binary inside Python via Wasmtime — no network hop by construction.
- Low-allocation hot path: the scan loop is optimized to reduce garbage-collection overhead during large log streaming.
- Hybrid scoring: combines static whitelists, regex heuristics, and Shannon entropy, which helps avoid false positives on structured values like UUIDs and IPv6 addresses.
1 maintainer
Metadata
1 maintainer
Release files for pii-shield-wasi 2.2.5
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| pii_shield_wasi-2.2.5-py3-none-any.whl | Python 3 | none | any | Details |
Total release size: 2.5 MB
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