Module scalar

Expand description

Scalar arithmetic modulo the Ed25519 group order.

ScalarEngine accepts wide and 256-bit reductions, modular multiply-add, and canonicality commands through one fixed-latency state machine.

Structs§

Scalar29: Nine-limb radix-2^29 scalar representation used by Dalek-style reduction.
ScalarEngine: Area-oriented scalar reduction, multiply-add, and canonicality engine.
ScalarEngineIn: Command for ScalarEngine.
ScalarEngineOut: Response from ScalarEngine.
ScalarModEngine: Four-word modular add-and-conditional-subtract engine.
ScalarModIn: One modular add/subtract request for ScalarModEngine.
ScalarModOut: Response from ScalarModEngine.
ScalarModRegs: Registered datapath state for ScalarModEngine.
ScalarRadix16: Balanced radix-16 scalar digits used by point multiplication.
ScalarRegs: Registered datapath state for ScalarEngine.
ScalarWords: Canonical-or-loose scalar stored as four little-endian 64-bit words.

SCALAR_OP_CANONICAL: Report whether a 256-bit scalar is strictly less than l.
SCALAR_OP_MUL_ADD: Compute c + a*b mod l.
SCALAR_OP_REDUCE_256: Reduce a 256-bit value modulo l.
SCALAR_OP_REDUCE_WIDE: Reduce a 512-bit SHA-512 digest modulo l.

scalar_add_kernel: Add four-word scalars with propagated carry.
scalar_add_mod_l_kernel: Add two inputs known to require at most one subtraction of l.
scalar_engine_kernel: Next-state/output kernel for ScalarEngine.
scalar_from_bytes_kernel: Parse 32 little-endian bytes into four scalar words without reduction.
scalar_ge_kernel: Unsigned comparison a >= b over four little-endian words.
scalar_l: Return the Ed25519 group order l.
scalar_l_kernel: Synthesizable group-order constructor.
scalar_mod_engine_kernel: Next-state/output kernel for ScalarModEngine.
scalar_radix16_kernel: Recode a 256-bit little-endian scalar into 64 balanced radix-16 digits.
scalar_shift_in_kernel: Shift a scalar left and insert one low bit.
scalar_sub_kernel: Subtract four-word scalars with propagated borrow.
scalar_to_bytes_kernel: Serialize four scalar words as 32 little-endian bytes.
scalar_zero: Return scalar zero.
scalar_zero_kernel: Synthesizable scalar-zero constructor.