The composition operation (Originates with [MR91])

• Start with:

• Protocol F that uses ideal calls to a “trusted party” F

• Protocol that “emulates” F

• Construct the composed protocol :

• Each call to F is replaced with an invocation of .

• Each value returned from is treated as coming from F.

• Note: In F parties may call many copies of F.

•  In many copies of run concurrently.

Notes: