Entity: keccak_round

• File: keccak_round.sv

Diagram

Description

Generics

Generic name	Type	Value	Description
Width	int	1600	b= {25, 50, 100, 200, 400, 800, 1600}
W	int	Width/25	Derived
L	int	$clog2(W)
MaxRound	int	12 + 2*L	Keccak-f only
RndW	int	$clog2(MaxRound+1)	Representing up to MaxRound-1
DInWidth	int	64	currently only 64bit supported
DInEntry	int	Width / DInWidth
DInAddr	int	$clog2(DInEntry)
EnMasking	bit	1'b0	Enable secure hardening
Share	int	EnMasking ? 2 : 1
ReuseShare	bit	1'b0	Re-use adjacent share for entropy

Ports

Port name	Direction	Type	Description
clk_i	input
rst_ni	input
valid_i	input		Message Feed
addr_i	input	[DInAddr-1:0]
data_i	input	[DInWidth-1:0]
ready_o	output
run_i	input		Pulse signal to initiates Keccak full round
rand_valid_i	input
rand_data_i	input	[Width-1:0]
rand_consumed_o	output
complete_o	output		Indicates full round is done
state_o	output	[Width-1:0]	State out. This can be used as Digest
clear_i	input		Clear internal state to '0

Signals

Name	Type	Description
update_storage	logic	/////////////////// Control signals // /////////////////// Update storage register
rst_storage	logic	Reset the storage to 0 to initiate new Hash operation
xor_message	logic	XOR message into storage register It only does based on the given DInWidth. If DInWidth < Width, it takes multiple cycles to XOR all message
sel_mux	logic	Select Keccak_p datapath 0: Select Phase1 (Theta -> Rho -> Pi) 1: Select Phase2 (Chi -> Iota) sel_mux need to be asserted until the Chi stage is consumed, It means sel_mux should be 1 until one cycle after rand_valid_i is asserted.
inc_rnd_num	logic	Increase/ Reset Round number
rst_rnd_num	logic
rnd_eq_end	logic	Round reaches end This signal indicates the round reaches desired number, which is MaxRound -1. MaxRound is dependant on the Width. In case of SHA3/SHAKE, MaxRound is 24.
complete_d	logic	Complete of Keccak_f State machine asserts complete_d when it reaches at the end of round and operation (Phase3 if Masked). The the stage, the storage still doesn't have the valid states. So precisely it is not completed yet. State generated complete_d is latched with the clock and creates a pulse signal one cycle later. The signal is the indication of completion. Intentionally removed any intermediate step (so called StComplete) in order to save a clock to proceeds next round.
keccak_out	logic [Width-1:0]	//////////////////// Datapath Signals // //////////////////// Single round keccak output data
round	logic [RndW-1:0]	Keccak Round indicator: range from 0 .. MaxRound
keccak_rand_valid	logic	Random value and valid signal used in Keccak_p There's plan to make random value generation configurable. 1. Tied to 0 in case of random value is not needed. It means the Keccak doesn't need to be masked and throughput is the most important thing. 2. Receive random value from entropy source. This requires to fill 1600b of entropy. It takes long time so generally it will have smaller bits from tru entropy source and expands to 1600b (Width). 3. Reuse Share. This option is to reuse the other part of share. Chi stage uses 3 sheets to create a sheet. (newX = X ^ (~(X+1) & (X+2))). So the other two shares (X-1, X-2) can be assumed as random values, and may be used as entropy source. It is weaker than the use of true entropy, but much faster.
keccak_rand_consumed	logic	Random value and valid signal used in Keccak_p There's plan to make random value generation configurable. 1. Tied to 0 in case of random value is not needed. It means the Keccak doesn't need to be masked and throughput is the most important thing. 2. Receive random value from entropy source. This requires to fill 1600b of entropy. It takes long time so generally it will have smaller bits from tru entropy source and expands to 1600b (Width). 3. Reuse Share. This option is to reuse the other part of share. Chi stage uses 3 sheets to create a sheet. (newX = X ^ (~(X+1) & (X+2))). So the other two shares (X-1, X-2) can be assumed as random values, and may be used as entropy source. It is weaker than the use of true entropy, but much faster.
keccak_rand_data	logic [Width-1:0]
keccak_st	keccak_st_e
keccak_st_d	keccak_st_e
storage_d	begin
end	end

Constants

Name	Type	Value	Description
W	int	Width/25	Derived
L	int	$clog2(W)
MaxRound	int	12 + 2*L	Keccak-f only
RndW	int	$clog2(MaxRound+1)	Representing up to MaxRound-1
DInEntry	int	Width / DInWidth
DInAddr	int	$clog2(DInEntry)
Share	int	EnMasking ? 2 : 1

Types

Name	Type	Description
keccak_st_e	enum logic [2:0] { StIdle, StActive, StPhase1, StPhase2, StPhase3, StError }

Processes

• unnamed: ( @(posedge clk_i or negedge rst_ni) )

• unnamed: ( )

• unnamed: ( )

• unnamed: ( @(posedge clk_i or negedge rst_ni) )

• unnamed: ( @(posedge clk_i or negedge rst_ni) )

Instantiations

• u_keccak_p: keccak_2share