- Test program: mini-totp.c
- Language: C
- LoC: 465
- Functions: 13
- Compiler cmdline: clang -Os
Mini-TOTP is a self-contained OATH-TOTP implementation with a hardcoded seed. Normalized compression distance and absolute increase in Kolmogorov complexity were calculated for various combinations of obfuscating transformations.
| Transformation | Cmdline | ΔK | NCD |
|---|---|---|---|
| 2 opaque predicates per function | tigress --Transform=InitOpaque --Functions=* --Transform=UpdateOpaque --Functions=* --Transform=AddOpaque --Functions=* --AddOpaqueCount=2 --AddOpaqueKinds=call,bug,true --Transform=CleanUp --Functions=* --out=test-01.c mini-totp.c | 1,939 | 0.7866 |
| 10 opaque predicates per function | tigress --Transform=InitOpaque --Functions=* --Transform=UpdateOpaque --Functions=* --Transform=AddOpaque --Functions=* --AddOpaqueCount=10 --AddOpaqueKinds=call,bug,true --Transform=CleanUp --Functions=* --out=test-01.c mini-totp.c | 5,079 | 0.8690 |
| Virtualize 8 functions | tigress --Transform=Virtualize --Functions=/oath/,sha1_read_ctx,sha1_finish_ctx,hmac_sha1,sha1_stream,sha1_buffer,sha1_init_ctx --Transform=CleanUp --CleanUpKinds=annotations --out=test-03.c mini-totp.c | 6,286 | 0.8750 |
| Virtualize 8 functions, use linear dispatch, merge instructions into "superoperators" | tigress --Transform=Virtualize --Functions=/oath/,sha1_read_ctx,sha1_finish_ctx,hmac_sha1,sha1_stream,sha1_buffer,sha1_init_ctx --VirtualizeDispatch=linear --VirtualizeMaxDuplicateOps=2 --VirtualizeOperands=* --VirtualizeSuperOpsRatio=2.0 --VirtualizeMaxMergeLength=10 --VirtualizeOptimizeBody=true --Transform=CleanUp --CleanUpKinds=annotations --out=test-04.c mini-totp.c | 14,318 | 0.9275 |