psiphon-tunnel-core/openssl

Psiphon OpenSSL README

Overview

Psiphon Tunnel Core may be configured to use OpenSSL, in place of Go's TLS, when it is advantageous to emulate more common TLS implementations. This facility is used as a circumvention measure to ensure Psiphon client TLS ClientHello messages mimic common TLS ClientHellos from, e.g., stock Android app SSLSocket connections vs. the more distinguishable (blockable) Go TLS ClientHello.

This directory contains source and scripts to build OpenSSL libraries that can be statically linked with Psiphon Tunnel Core.

Mimicking stock TLS implementations is done both at compile time (no-heartbeats) and at runtime (specific cipher suites and options).

Android

Ensure ANDROID_NDK_ROOT is set. Run the build-android.sh script to build static libraries for Android.

When running gomobile bind to build the Android library, set CGO environment variables as follows (alternatively, set up pkg-config, which is used by the openssl package).

export CGO_CFLAGS="-I<path>/include"
export CGO_LDFLAGS="-L<path> -lssl -lcrypto"