Security Parameter Bundle Discussion for Connecting MAPLE with HEIR

[JianmingTONG]

Issue 1: Security parameter exploration

MAPLE explicitly explores key CKKS parameter choices, including:

the maximum multiplicative depth, and
the number of slots.

Issue 2: Preventing large MLIR from dominating back-end compilation time

MAPLE’s lowering can generate extremely large MLIR. For instance, lowering MNIST produces 279 MB of IR because loops are explicitly unrolled. This substantially increases compilation time in downstream compilers such as OpenFHE.

Keeping loops in the generated MLIR would help, but bootstrapping complicates this design: bootstrap insertion depends on analyzing the remaining level budget, which currently relies on partially unrolled code.

A practical workaround is for MAPLE to manually split loops and insert bootstrap annotations via mgmt.bootstrap:
https://heir.dev/docs/dialects/mgmt/#mgmtbootstrap-heirmgmtbootstrapop

@j2kun @asraa @akashmadhu4
Suggestions are appreciated!

[j2kun]

If MAPLE can output loops and choose the total number of levels and slots, then you would need to set the corresponding slot-number and level-budget options here:

heir/lib/Transforms/SecretInsertMgmt/Passes.td

Lines 113 to 118 in c6d4eee

	Option<"slotNumber", "slot-number", "int",
	/*default=*/"1024", "Default number of slots use for ciphertext space.">,
	Option<"bootstrapWaterline", "bootstrap-waterline", "int",
	/*default=*/"10", "Waterline for insert bootstrap op">,
	Option<"levelBudget", "level-budget", "int", /*default=*/"0",
	"An optional maximum level budget for the pipeline to assume">,

as configuration options to secret-insert-mgmt. This should just work for heuristic partial unrolling and bootstrap placement. However, it is still somewhat experimental.

Also, I think there is a bit of a gap in that secret-insert-mgmt may not be aware of the number of levels that bootstrap requires internally to its implementation. So you may need to subtract from level-budget the number of levels consumed by bootstrap for this pass.