stage iii : february 9 h 2004 gate level design

Team W1Team W1Design Manager: Rebecca MillerDesign Manager: Rebecca Miller

1. Bobby Colyer (W11)1. Bobby Colyer (W11)2. Jeffrey Kuo (W12)2. Jeffrey Kuo (W12)3. Myron Kwai (W13)3. Myron Kwai (W13)4. Shirlene Lim (W14)4. Shirlene Lim (W14)

Stage IIIStage III: : February 9February 9hh 2004 2004

GATE LEVEL DESIGNGATE LEVEL DESIGN

Presentation #4: Rijndael Presentation #4: Rijndael EncryptionEncryption

Overall Project Objective:Implement the new AES Rijndael algorithm on

chip

18-525 Integrated Circuit Design Project

StatusStatus

Design Proposal Architecture Proposal Size Estimates/Floorplan Gate Level Design

Schematic Design (needs to be changed) Layout (10% done)

To be Done Simulations/Optimizations Everything else…

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Design Decisions & Design Decisions & ProblemsProblems

DECISIONS Change Verilog to match new input control logic to SBOX

Previously using MUX, now using ANDs

Implemented clock divider using counters Propagate valid-in signal through dffs to obtain valid-out signal Tried adding 3rd SBOX

o PROBLEMSTransistor Count is TOO big (~45k)

Should we remove 5 rounds of permutations? (Ideal)Should we remove the third SBOX? (More problems: Wiring & Control Logic Change)

Top Level Schematic simulations not done All blocks simulated and working

Except output logic from SBOX (Demux logic)

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FLOORPLAN

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ADDED SBOX #3-Previous design inefficient for small text

- But increased transistor count drastically to ~45k

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ELIMINATION- Eliminate 5 rounds

- Eliminate 1 SBOX & control logic

- Reduce transistor count to 27k

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module logicandsbox (Out, In); output [7:0] Out; input [7:0] In;reg [7:0] Out;

always @(In)case(In) // synopsys

full_case parallel_case 8'h00: Out=8'h63; 8'h01: Out=8'h7c; 8'h02: Out=8'h77; 8'h03: Out=8'h7b; 8'h04: Out=8'hf2; 8'h05: Out=8'h6b; 8'h06: Out=8'h6f; 8'h07: Out=8'hc5; 8'h08: Out=8'h30; 8'h09: Out=8'h01; 8'h0a: Out=8'h67; 8'h0b: Out=8'h2b; 8'h0c: Out=8'hfe; 8'h0d: Out=8'hd7; 8'h0e: Out=8'hab;

FUNCTIONAL MODEL OF ROM

Case Statements

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Schematic Simulation Schematic Simulation ResultsResults

e0 e0 34 34 e7 e7 8b8b

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Metal DirectionalityMetal Directionality

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COMPONENTSCOMPONENTS AREA ESTIMATE (AREA ESTIMATE (umum22))

Key Schedule Registers & XORs 351 um x 70 um = 24,570 um2

ROM SBOX (2) 50 um x 170 um x 2 = 14,000 um2

Control Logic (352 um x 70 um) – 14,000 um2 = 10,640 um2

Transformation Register & XORs 160 um x 352 um = 56,320 um2

Others Buffers & Wiring 10% = 10,553 um2

TOTALTOTAL 116,083 um2 (~350 um x ~350 um)

PREVIOUS AREA PREVIOUS AREA ESTIMATEESTIMATE

Previous Transistor Previous Transistor CountCount

(Assuming(Assuming 32-bit Implementation) 32-bit Implementation)

XORs 14,336 DFFs 6,416 ANDs 120 SBOX 2304 Muxes & Demuxes 1074 Buffers (10%) 2000

Total: 26,250

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Current PROBLEMATIC Current PROBLEMATIC Transistor CountTransistor Count

(Assuming(Assuming 32-bit Implementation) 32-bit Implementation)

Clock Divider ~210 Text In ~362 Valid signals ~304 Input Logic (3) ~7320 Logic & SBOX (3) ~8916 Output Logic (3) ~10,944 Final Text Output ~256 Pipeline DFFs ~4608 Key Expansion (10) ~3840 Round Permutations (9)

~8280

Total: ~45040

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Alternative ImplementationsAlternative ImplementationsTransistor CountTransistor Count

(Assuming(Assuming 32-bit Implementation) 32-bit Implementation)

Current ~45,040

Minus 1 SBOX & Logic

~35,980 Minus 5 rounds & 1 SBOX and logic

~27,156

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Problems:Problems:

- Deciding between the three implementations

- Security problems, transistor counts,

- Pipelining implementation given consideration

Questions?Questions?

Answers???Answers???

18-525 Integrated Circuit Design Project