Extract and view X509 signing certificate information from APK files
Every Android APK file must be digitally signed before installation:
APKs use X.509 certificates to prove the identity of the app developer and ensure file integrity
SHA-256 fingerprints uniquely identify certificates and are used for API key restrictions
Certificates have a validity period. Expired certificates prevent app updates
Android supports v1 (JAR), v2, v3, and v4 signature schemes for different security levels
Encode, decode, measure sizes, and transform common formats.