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APK Signing

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Sia edited this page May 31, 2026 · 2 revisions

APK Signature Inspection

Every build detail page runs apksigner verify --verbose --print-certs on the produced APK and shows the result inline.

Why inline

  • Before uploading to Play Console (especially production) you want to confirm the APK is signed with the correct release keystore.
  • A SHA-256 fingerprint mismatch in an upload is one of the most painful troubleshooting paths in Android — Play returns a generic "wrong signature" error long after the upload completes.
  • Inline display lets you check at a glance instead of: apksigner verify --verbose --print-certs <path> from a shell + finding the path.

What's shown

For each generated APK:

Field Meaning
verified badge Did apksigner verify exit 0 + find at least one active scheme + not contain "DOES NOT VERIFY"?
Active schemes v1 (JAR signing) / v2 (APK Signature Scheme v2) / v3 / v4
Signer #N — DN Subject distinguished name (e.g. CN=Jangwook Lee, OU=Mobile, O=Sia Makerlab, …)
Signer #N — SHA-256 Certificate fingerprint, 4-character grouped

Implementation notes

  • ApkSignerInspector.locateApksigner() walks $ANDROID_HOME/build-tools/<version>/apksigner and picks the newest semver directory.
  • Output is parsed by regex (Regex("Verified using (v\\d) scheme.*: (true|false)"), Regex("Signer #(\\d+) certificate SHA-256 digest: ([0-9a-fA-F:]+)"), …) — best-effort. Future apksigner releases that change wording will fall through to "could not extract".
  • 30 s timeout on the verify call.
  • If SDK or build-tools are missing, the card shows a graceful warning ("ANDROID_HOME 미설정" / "apksigner 를 찾을 수 없습니다") — the rest of the build detail page is unaffected.

When to expect mismatches

  • Debug builds use the default Android debug keystore — SHA-256 fingerprint will match whatever debug keystore the SDK ships with on the build host.
  • Release builds need a configured signing config (see Architecture §Keystore generation for the optional REST API). The fingerprint here is what Play / TestFlight will pin to your app forever — verify it matches your reference fingerprint.

Related

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