App Signature Tools

Used to extract the signature file from APK or DER file(s)

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Product

EMDK For Android - 8.0

Devices

Supported on all Zebra Android devices

Overview

SigTools is a command-line utility for converting a certificate into a byte array. Supported inputs are Android .apk app files or those formatted according to Distinguished Encoding Rules (DER), which generally contain an X.509 binary certificate used for secure websites. Output is formatted as a Java class, a hexadecimal string, a base64 encoded string or a DER file and also is copied to the host-system clipboard. Optionally, the output can be written to a file.

The HEX or DER output forms of this utility can be used to create a signature file for securing apps using the Zebra Access Manager CSP.

Requirements

  • A Linux, macOS or Windows host computer with Java runtime environment installed
  • DER-formatted or .apk file(s) from which to extract the signature(s)

DISCLAIMER:

Zebra does not recommend using this utility for production environments. This app is an example of how to extract and generate a signature file from an app. No Zebra support or warranty is expressed or implied.

SYNOPSYS

java -jar SigTools.jar COMMAND -INFORM [DER|APK] -OUTFORM [HEX|BASE64|JAVA|DER] [-OUTFILE filename] -IN FILENAME [FILENAME]...[ARGUMENTS]

Commands

GETCERT - Read the certificate

VERSION - Get the version of this JAR (requires no argument)

Arguments

INFORM (required) - Format of the input file:

  • 'APK'
  • 'DER'

OUTFORM (required) - Format of the output:

  • HEX - a string of hexadecimal digits representing the certificate
  • BASE64 - a Base64-encoded string of characters representing the certificate
  • JAVA - a Java class
  • DER - the certificate itself; most important if extracting from an .apk file

IN (required) - A space-separated list of file names (NOTE: If name contains a space, surround name with quotes)

OUTFILE (optional) - The output file name

Notes

  • This sample app illustrates a single use-case for converting and/or extracting an app's signature file from the app for the purpose of developer validation and certification.

Using Sample App

  1. Download the sample app and unzip it onto the host computer.
  2. Move the SigTools.jar file to a working folder with the .apk or DER file(s) it will operate on.
  3. Open a command prompt or terminal window on the host computer and navigate to the working folder.
  4. Execute SigTools app, modifying the sample commands below as needed for files.
  5. Deploy the signature file (called test.java in the .apk example below) to devices as needed or paste the contents of the clipboard as needed.

WARNING: Sample apps are for demonstration purposes only and should not be used in production environments.

SAMPLE COMMANDS


// For APK files: Extract public signing certificate from an APK and create 
// a JAVA class with an initialized byte array:

Java -jar SigTools.jar GetCert -INFORM APK -OUTFORM JAVA -IN test.apk -OUTFILE test.java


// Convert DER file to hexadecimal string:

Java -jar SigTools.jar GetCert -INFORM DER -OUTFORM HEX -IN test.x509.pem -OUTFILE test.hex