Ultra-Compact Advanced Encryption Standard (AES, FIPS-197) Core

General Description

	The AES core implements Rijndael cipher encoding and decoding in compliance with the NIST Advanced Encryption Standard. It processes 128-bit data blocks with 128-bit key (a 256-bit key version is available).
	Basic core is designed only for encryption and is the smallest available on the market (less than 3,000 gates). Enhanced versions are available that support encryption and decryption for various NIST cipher modes (ECB,CBC, OFB, CFB, CTR), as well as different datapath widths for size/performance tradeoff. The core includes the key expansion logic.
	The design is fully synchronous and available in both source and netlist form.
	Optional data integrity and differential power attack resistance features.

Base Core Features

	Encrypts using the AES Rijndael Block Cipher Algorithm.
	Satisfies Federal Information Processing Standard (FIPS) Publication 197 from the US National Institute of Standards and Technology (NIST). FIPS-197 validated (AESAVS).
	Processes 128-bit data blocks with 8, 16 or 32-bit data interface
	Employs key sizes of 128 bits (AES128), 192, or 256 bits (AES256)
	Includes the key expansion function
	Optional parity check feature for data integrity
	Optional additive data masking throughout the core (including the Sbox additive masking) for strong differential power attack (DPA) resistance
	Optional cycle hiding for DPA resistance
	Simple, fully synchronous, reusable design
	Completely self-contained: does not require external memory
	Available as fully functional and synthesizable Verilog or VHDL, or as a netlist for popular programmable devices and ASIC libraries
	Deliverables include self-checking test benches

Symbol

Applications

	Cipher for wireless communications, including IEEE 802.11i (Wi-Fi), IEEE 802.15.3, IEEE 802.15.4 (Zigbee), MBOA (WiMedia), 802.16e, Wibree, sensor networks ("smart dust"), motes
	Electronic financial transactions
	Power line networks
	Digital Rights Management (DRM) including Digital Cinema System Specification (DCSS) and High-bandwidth Digital Content Protection (HDCP 2.0)
	Secure video surveillance systems
	Encrypted data storage
	Secure RFID, immobilizers
	Secure Smart Cards
	ITU H.235
	Secure RTP (SRTP, RFC 3711)

Pin Description

Name	Type	Description
CLK	Input	Core clock signal
EN	Input	Synchronous enable signal. When LOW the core ignores all its inputs and all its outputs must be ignored.
Start	Input	When goes HIGH, a cryptographic operation is started
Load	Output	Input data request signal
Ready	Output	Output data ready and valid

8-bit Data Interface

KEY[7:0]	Input	Encryption Key
PT[7:0]	Input	Input Plain Text Data
CT[7:0]	Output	Output Cipher Text Data

16-bit Data Interface

KEY[15:0]	Input	Encryption Key
PT[15:0]	Input	Input Plain Text Data
CT[15:0]	Output	Output Cipher Text Data

32-bit Data Interface

KEY[31:0]	Input	Encryption Key
PT[31:0]	Input	Input Plain Text Data
CT[31:0]	Output	Output Cipher Text Data

Function Description

An AES encryption operation transforms a 128-bit block into a block of the same size. The encryption key size is 128 bit. The key is expanded during cryptographic operations. The block performs AES encryption as defined in the FIPS-197
http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf and SP 800-38A http://csrc.nist.gov/publications/nistpubs/800-38a/sp800-38a.pdf

Operation

A rising input on the START port triggers the beginning of a cryptographic operation on the data PT, using the KEY as key. The core then raises the LOAD signal requesting the data block. It then starts to process the state according to the AES algorithm. The timing diagram below shows how the data is fed to the core at the start.

Key and data input at the start of encryption

Both the data and the key are input serially, 8, 16 or 32 bits at the time. The diagram above shows the case where the input data is 8 bit

When all the rounds are completed, the READY signal is raised and the encrypted data starts to flow out. This is shown in the timing diagram below.

Cipher text output

It is possible to start a new cryptographic operation as soon as the data from the previous one is output. A cryptographic operation can be aborted at any time by lowering the START signal for at least one clock cycle.
The core is fully pipelined. Keeping the START signal HIGH causes the new cryptographic operation to start simultaneously with ending of previous one; in this case LOAD and READY signals are generated by the core simultaneously. Loading of the new plain text data and key is combined with outputting cipher text data from

the previous operation. This is shown in the timing diagram below.

Cipher text from a previous operation is being output while new plaintext is input

New key can be used for each cryptographic operation. The absence of gaps allows sustaining the throughput listed in the table below.

Core	AES1-8	AES1-16	AES1-32	AES1-64	AES1-128
Cycles for 128-bit key	160	80	40	20	10
Bit per clock cycle	0.8	1.6	3.2	6.4	12.8

Synthesis Details

The core size starts at less than 3K ASIC gates. The 128-bit wide core has been synthesized in the TSMC 90 nm LV process to run at above 800 MHz, delivering 10 Gbps of throughput. Representative area/resources figures are shown below.

Core	Technology	Area / Resources	Throughput bits / clock
AES1-8E	TSMC 0.18 u	2948 gates	0.8
AES1-8E	Altera FPGA	639 ALUT	0.8
AES1-8E	Actel ProAsic-3	864 tiles	0.8
AES1-32E/256	Xilinx FPGA	284 slices 7 BRAM	3.2
AES1-32CBCE	Actel A3P400	18%	3.2
AES1-32CBC	Altera FPGA	718 ALUT 24576 bits	3.2

Please feel free to contact us for additional synthesis data.

Available Versions

The AES core is available in AES-ECB, AES-CFB, AES-CBC, AES-OFB, AES-OMAC and AES-CTR modes, for different data path widths, and for key sizes of 128, 192, and 256 bits. Encryption- and decryption-only options are also available (identified by E/D).

The core is name is formed in the following way: AES1-<internal width> [/<external data bus width>][mode][E/D][/key size]. By default the data bus width is equal to the internal core width, mode is ECB, core is E+D, and the key size is 128 bits. For example, AES1-32E/256 is an ECB encryption-only 32-bit wide core supporting 256-bit keys, AES1-32CBC is an AES core implementing the AES-CBC mode.

Export Permits

US Bureau of Industry and Security has assigned the export control classification number 5E002 to the core. The core is eligible for the license exception ENC under section 740.17(A) and (B)(1) of the export administration regulations. See the licensing basics page, for links to US government sites and more details.

Deliverables

HDL Source Licenses

	Synthesizable Verilog RTL source code (VHDL option available)
	Testbench (self-checking, in Verilog 2008)
	Test vectors
	Expected results
	Simulation script
	Synthesis script
	User Documentation

Netlist Licenses

	Post-synthesis EDIF
	Testbench (self-checking)
	Test vectors
	Expected results
	Place & Route script
	Simulation script

NIST FIPS-197 validation (AESAVS) test bench is available as an option

Contact Information

IP Cores, Inc.
3731 Middlefield Rd.
Palo Alto, CA 94303, USA
Phone: +1 (650) 815-7996

E-mail: [email protected]
www.ipcores.com

IP Cores, Inc., 3731 Middlefield Rd., Palo Alto, CA 94303, USA

Phone: +1 (650) 815-7996 | E-mail: [email protected] | www.ipcores.com

.	NIST Encryption Modes