MPCL

Multi-Party Computation Language (MPCL)

Multi-Party Computation Language is a high-level programming language that implements secure two-party computation with Garbled Circuit Protocol. The Go programming language highly inspires the MCPL. Therefore, it is easy to use existing Go functions and programs in MPCL with minor modifications. However, the goal is not to make MPCL fully compatible with Go.

Basic Application Invocation

Secure multi-party computation has two parties: garbler and evaluator. Both parties run the garbled application with appropritate arguments:

-e: specifies circuit evaluator mode. If the -e option is not specified, the peer runs in the garbler mode.
-i: defines the peer input values. Multiple input values can be specified by providing the -i option multiple times, or by separating input values with comma.

For example, this is how you can run Yao’s Millionaires’ Problem. The evaluator is started with input 800000:

$ apps/garbled/garbled -e -i 800000 apps/garbled/examples/millionaire.mpcl
 - In1: a{1,0}i64:int64
 + In2: b{1,0}i64:int64
 - Out: %_{0,1}b1:bool1
 -  In: [800000]
Listening for connections at :8080

The garbler is started with input 750000:

$ apps/garbled/garbled -i 750000 apps/garbled/examples/millionaire.mpcl
 + In1: a{1,0}i64:int64
 - In2: b{1,0}i64:int64
 - Out: %_{0,1}b1:bool1
 -  In: [75000]
Result[0]: false

Both garbler and evaluator return the result false since garbler’s input is smaller than evaluator’s input.

Streaming Mode

Command Line Arguments

The garbled application takes the following command line arguments:

-O: optimization level (default 1 enabling all current optimizations).
-circ: compile inputs to circuit format.
-cpuprofile: write cpu profile to the specified file.
-d: enable diagnostics outputs.
-dot: generate Graphviz DOT output.
-e: specifies circuit evaluator / garbler mode. The circuit evaluator creates a TCP listener and waits for garblers to connect with computation.
-format: specifies circuit format for the -circ output file. Possible values are: mpclc (default), bristol.
-i: specifies comma-separated input values for the circuit.
-memprofile: write memory profile to the specified file.
-ssa: compile MPCL input to SSA assembly.
-stream: streaming mode.
-svg: generate SVG output.
-v: enabled verbose output.