ObfusKit

ObfusKit is a ruby script that generates obfuscated secrets for Swift and Kotlin.

Installation and usage

Install the latest version of the gem using:

gem install obfuskit

Call obfuskit -h for help.

Usage: obfuskit [options]

Specific options:
    -l, --language [LANGUAGE]        Output language (swift, kotlin). Kotlin requires a package parameter.
    -k SECRET_1,SECRET_2,SECRET_3,   List of environment variable keys
        --keys
    -p, --package [PACKAGE]          Package name for Kotlin
    -t, --type [TYPE]                Output type name. Defaults to `ObfusKit`
    -e, --env [PATH]                 Path to an alternative .env file

Common options:
    -h, --help                       Show this message
    -v, --version                    Show version

Swift

To generate Swift code, run the following command:

obfuskit -l swift -k SECRET_1,SECRET_2 > generated.swift

It will create the file generated.swift containing an obfuscated version of the environment variables SECRET_1 and SECRET_2. This file should be excluded from the git repository and generated at build time. The obfuscation salt is regenerated for each run.

import Foundation

enum ObfusKit {
	static let SECRET_1: String = _o.r([30, 113, 37, 119, 32, 37, 36])
	static let SECRET_2: String = _o.r([24, 117, 35, 119, 38, 33, 34])

	private class _3f3eccd2e5ea46b39738e5502bda6bef { }
	private static let _o = O(String(describing: _3f3eccd2e5ea46b39738e5502bda6bef.self))
}
// ...

Kotlin

The same concept applies to the Kotlin language using:

obfuskit -l kotlin -p com.myapp.configuration.environment -k SECRET_1,SECRET_2 > generated.kt

It will create the Kotlin version generated.kt.

package com.myapp.configuration.environment

object ObfusKit {
        private val _o = O(_6572131328ef462d9d4a05cf4b2a2516::class.java.simpleName)
        private class _6572131328ef462d9d4a05cf4b2a2516

        val SECRET_1: String = _o.r(byteArrayOf(30, 116, 118, 115, 119, 119, 116))
        val SECRET_2: String = _o.r(byteArrayOf(24, 112, 112, 115, 113, 115, 114))
}
// ...

Android Code shrinking and Obfuscation

Proguard/R8 changes class names and method names. This will break revealing secrets at run time. To prevent this, add the according rules to your proguard-rules.pro file or use the --keep-annotation parameter to inject a custom annotation like @androidx.annotation.Keep into the generated code.

For example:

obfuskit -l kotlin -p com.myapp.configuration.environment -k SECRET_1,SECRET_2 --keep-annotation @androidx.annotation.Keep > generated.kt

Use a custom .env file location

Use the -e option to define the path to a different .env file, e.g., if you want to reuse the fastlane/.env file.

obfuskit -l swift -k SECRET_3,SECRET_4 -e fastlane/.env > generated.swift

Features

• Generate Swift
• Generate Kotlin
• Read Secrets from the Environment
• Add dynamic salt for obfuscation
• Support for .env files
• Use template engine for code generation
• Read secrets from 1Password CLI