The APKINDEX.tar.gz format

From apk-tools-2.0_pre15 there was added support for package signing. The caused the index format to chage, as it needs to contain a signature for the repository. This document explains how the new index works and how it is created.

Creating APKINDEX.tar.gz

The APKINDEX.tar.gz is created by concatenating 2 other tar.gz files, signature.tar.gz and APKINDEX.unsigned.tar.gz.

cat signature.tar.gz APKINDEX.unsigned.tar.gz > APKINDEX.tar.gz

Creating signature.tar.gz

First we create a signature file for APKINDEX.unsigned.tar.gz, using our private key.

openssl dgst -sha1 -sign privatekeyfile -out .SIGN.RSA.nameofpublickey APKINDEX.unsigned.tar.gz

Then we put this in a tar file, without the end-of-tar record at the end of the file. This is because we will concatenate this tar archive with the index tar archive.

tar -c .SIGN.RSA.nameofpublickey | abuild-tar --cut | gzip -9 > signature.tar.gz

The name of public key should be the email address of the developer.

Creating APKINDEX.unsigned.tar.gz

The APKINDEX.unsigned.tar.gz is an old 1.9 style index file in a tar archive. This is created with:

apk index -o APKINDEX.unsigned.tar.gz *.apk