sha1collisiondetection JNI bridge

cr-marcstevens/sha1collisiondetection is the library for calculating SHA-1 hash as well as detecting a hash collision. This is a JNI bridge of this library.

This is not an official Google product. This is the author's hobby project. Not for production use.

Build & Test

Use Bazel. I'm not sure how I can create a distributable package with JNI. You would need to change the BUILD files in order to build non-Linux environment.

Note that Sha1DcHasher itself doesn't load the native library. You would need to load sha1dc_jni_bridge.so somewhere else.

Speed comparison

This is not a serious benchmark. It's better to do your own benchmarking if you're looking into this. With bazel test ... -c opt in the author's workstation:

Hashing 2MiB chunked 40MiB file 100 times (== hashing ~ 4GiB)

JGit SHA1: 18152ms
Sha1DcHasher (DirectBuffer): 9812ms
Sha1DcHasher (ByteArray, Copy): 10937ms
Sha1DcHasher (ByteArray, GCLock): 9831ms
Standard SHA-1 Hasher (ByteArray): 12160ms

JGit's SHA1 class and Sha1DcHasher class are collision detection enabled implementations.