Set caffe net parameters via string - encryption

Question

What I want to do is the following:
I encrypted the ".prototxt" and ".caffemodel" file, so the files are not readable and the parameters not visible. During my program I decrypt the file and store the result as a string. But now I need to set the layers in my caffe network.
Is there a method to set the caffe network layers with the parameters from my string? Same for the layers in the trained network? Something comparable with the source code below (I know this source code would not work)?
shared_ptr<Net<float> > net_;
string modelString;
string trainedString;
//Decryption stuff
net_.reset(new Net<float>(modelString, TEST));
net_->CopyTrainedLayersFrom(trainedString);
Thank you a lot.

Answer 1

You could initialize a NetParameter class directly using the Protocol Buffer API of the NetParameter class (you'll need to include caffe/proto/caffe.pb.h):
bool ParseFromString(const string& data);
and then use it to initialize a Net class using the following constructor:
explicit Net(const NetParameter& param, const Net* root_net = NULL);
and for copying the weights:
void CopyTrainedLayersFrom(const NetParameter& param);
It's important to note that the above method requires that the string variable contains binary-formatted protobuffer and not the text-format. While the caffemodel outputted by Caffe is already in binary format, you'll have to convert the prototxt file to binary format as well, but you could do that using the protoc command-line program combined with the --encode flag.
For a more information, I'd suggest you'll look in the Protocol-Buffer's website: https://developers.google.com/protocol-buffers/

Answer 2

Loading net model from text format (without converting with protoc) can be done by following:
#include <google/protobuf/text_format.h>
// [...]
NetParameter net_parameter;
bool success = google::protobuf::TextFormat::ParseFromString(model, &net_parameter);
if (success){
net_parameter.mutable_state()->set_phase(TEST);
net_.reset(new Net<float>(net_parameter));
}