fix(security): remove private key from log output by beonde · Pull Request #52 · capiscio/capiscio-sdk-python

beonde · 2026-04-17T04:33:23Z

GA-006: Remove private key from logger

Priority: P0 — private key leakage

Problem

_log_agent_key_capture_hint() in connect.py was logging the full private JWK (including the d parameter) via logger.warning(). If logging is configured to write to a file, stdout capture, or any log aggregation service, the agent's private key would be exposed.

Fix

Replaced logger.warning() call that included json.dumps(private_jwk) with a print() to stderr
The hint now shows only the key ID (kid) and directs users to:
- capiscio identity export --format env (CLI)
- ~/.capiscio/identities/<agent>/private.jwk (file path)
No key material appears in any log call

Verification

grep -rn "compact_json\|private.*log\|jwk.*warning" capiscio_sdk/ returns no source code matches (only proto binary/cache files)

GA-006: Replace logger.warning() that included full private JWK with a stderr hint directing users to 'capiscio identity export' or the identity directory. Key material is never logged.

github-actions · 2026-04-17T04:33:58Z

✅ Documentation validation passed!

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github-actions · 2026-04-17T04:36:00Z

✅ All checks passed! Ready for review.

codecov · 2026-04-17T04:36:07Z

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✅ All modified and coverable lines are covered by tests.

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github-actions · 2026-04-17T04:36:47Z

✅ SDK server contract tests passed (test_server_integration.py). Cross-product scenarios are validated in capiscio-e2e-tests.

Copilot

Pull request overview

Removes private key material from CapiscIO.connect()’s user-facing “capture hint” output to prevent leaking private JWKs (including d) via logging sinks.

Changes:

Replaces the previous logger-based hint that included the full private JWK with a stderr hint that only shows kid and guidance for exporting/copying the key.
Adds an explicit SECURITY note in the hint helper to discourage logging key material.

Copilot · 2026-04-17T04:36:46Z

@@ -66,11 +72,18 @@ def _log_agent_key_capture_hint(agent_id: str, private_jwk: dict) -> None:
        "  serverless, CI) the identity will be lost on restart unless\n"
        "  you persist the private key.\n"
        "\n"
-        "  Add to your secrets manager / .env:\n"
+        f"  Key ID: {kid}\n"
+        "\n"
+        "  To export the private key for your secrets manager:\n"
+        "\n"
+        "    capiscio identity export --format env\n"
+        "\n"
+        "  Or copy the key file from:\n"
        "\n"
-        "    CAPISCIO_AGENT_PRIVATE_KEY_JWK='" + compact_json + "'\n"
+        "    ~/.capiscio/identities/<agent>/private.jwk\n"
        "\n"
-        "  The DID will be recovered automatically from the JWK on startup.\n"
+        "  The DID will be recovered automatically from the JWK on startup.\n",
+        file=sys.stderr,
    )


Security regression prevention: there’s no unit test asserting that the capture hint output never includes private key material (e.g., the JWK d value) and doesn’t emit the full JWK. Since this is a P0 leakage fix, consider adding a test that captures stderr/logging and verifies only non-sensitive identifiers (e.g., kid) appear.

Copilot · 2026-04-17T04:36:46Z

+        "  Or copy the key file from:\n"
        "\n"
-        "    CAPISCIO_AGENT_PRIVATE_KEY_JWK='" + compact_json + "'\n"
+        "    ~/.capiscio/identities/<agent>/private.jwk\n"
        "\n"


The hint message points users to ~/.capiscio/identities/<agent>/private.jwk, but this module’s default storage location is DEFAULT_KEYS_DIR / agent_id (i.e., ~/.capiscio/keys/<agent_id>/private.jwk) or a user-provided keys_dir. This will send users to a non-existent/wrong path—consider printing the actual on-disk path (or at least the correct default path) and using the existing agent_id parameter to fill in the directory name.

Copilot · 2026-04-17T04:36:47Z

@@ -66,11 +72,18 @@ def _log_agent_key_capture_hint(agent_id: str, private_jwk: dict) -> None:
        "  serverless, CI) the identity will be lost on restart unless\n"
        "  you persist the private key.\n"
        "\n"
-        "  Add to your secrets manager / .env:\n"
+        f"  Key ID: {kid}\n"
+        "\n"
+        "  To export the private key for your secrets manager:\n"
+        "\n"
+        "    capiscio identity export --format env\n"
+        "\n"
+        "  Or copy the key file from:\n"
        "\n"
-        "    CAPISCIO_AGENT_PRIVATE_KEY_JWK='" + compact_json + "'\n"
+        "    ~/.capiscio/identities/<agent>/private.jwk\n"
        "\n"
-        "  The DID will be recovered automatically from the JWK on startup.\n"
+        "  The DID will be recovered automatically from the JWK on startup.\n",
+        file=sys.stderr,
    )


This helper now prints unconditionally to sys.stderr during CapiscIO.connect() identity initialization. Unlike the rest of this module (which uses logger.*), this output can’t be suppressed/redirected via logging configuration and may pollute stderr in library use (e.g., ASGI apps, tests, serverless logs). Consider switching back to logger.warning/info with sanitized content (no key material) or gating the hint behind an explicit opt-in/verbosity flag.

Copilot · 2026-04-17T04:36:47Z

 def _log_agent_key_capture_hint(agent_id: str, private_jwk: dict) -> None:
-    """Log a one-time hint telling the user how to persist key material."""
-    compact_json = json.dumps(private_jwk, separators=(",", ":"))
-    logger.warning(
+    """Log a one-time hint telling the user how to persist key material.
+
+    SECURITY: Never log private key material. Instead, direct users to
+    export the key using the CLI or check the identity directory.
+    """
+    # Derive the key ID (kid) from the public portion for identification only
+    kid = private_jwk.get("kid", "unknown")
+    print(


Naming/docs mismatch: _log_agent_key_capture_hint (and its docstring) still says it "Log[s]" a hint, but the implementation uses print(). Also the inline comment says "Derive" the kid from the public portion, but the code just reads private_jwk.get("kid"). Consider renaming/updating the docstring/comment to reflect what the function actually does, and/or explicitly label kid as the DID in this SDK (since elsewhere kid is treated as the DID).

Copilot

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

Copilot · 2026-04-17T04:41:57Z

+    # Derive the key ID (kid) from the public portion for identification only
+    kid = private_jwk.get("kid", "unknown")
+    print(


The inline comment says the kid is derived “from the public portion”, but the code reads it directly from private_jwk. This is functionally fine, but the comment is inaccurate; either derive kid from _public_jwk_from_private(private_jwk) or reword the comment to match the implementation.

- Rename _log_agent_key_capture_hint → _print_agent_key_capture_hint to match actual behavior (print to stderr, not logger) - Fix key path in hint: ~/.capiscio/keys/{agent_id}/private.jwk (was incorrectly showing ~/.capiscio/identities/<agent>/...) - Add TestPrintAgentKeyCaptureHint regression tests: - Verify no private key material (d, x) in output - Verify correct key file path in output

github-actions · 2026-04-17T04:48:37Z

✅ Documentation validation passed!

Unified docs will be deployed from capiscio-docs repo.

github-actions · 2026-04-17T04:50:26Z

✅ All checks passed! Ready for review.

github-actions · 2026-04-17T04:51:42Z

✅ SDK server contract tests passed (test_server_integration.py). Cross-product scenarios are validated in capiscio-e2e-tests.

fix(security): remove private key from log output

64f5b13

GA-006: Replace logger.warning() that included full private JWK with a stderr hint directing users to 'capiscio identity export' or the identity directory. Key material is never logged.

Copilot AI review requested due to automatic review settings April 17, 2026 04:33

Copilot started reviewing on behalf of beonde April 17, 2026 04:33 View session

Copilot AI reviewed Apr 17, 2026

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beonde requested a review from Copilot April 17, 2026 04:39

Copilot started reviewing on behalf of beonde April 17, 2026 04:39 View session

Copilot AI reviewed Apr 17, 2026

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beonde merged commit 3a42731 into main Apr 17, 2026
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beonde deleted the fix/ga-key-logging branch April 17, 2026 04:53

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beonde commented Apr 17, 2026

GA-006: Remove private key from logger

Problem

Fix

Verification

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