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GXC3 Core P1619 / 802.1ae (MACSec) GCM/XTS/CBC-AES Core

General Description

LAN security standard IEEE 802.1ae (MACSec) uses AES cipher in the GCM mode, while the disk/tape encryption standard IEEE P1619 uses the XTS mode. Since GCM and XTS share some of their basic components, a combo GCM/XTS/CBC core is not much larger than a dedicated core for either of the modes.
The GXC3 core is tuned for mid-performance P1619 and 802.1ae applications at the data rates up to 10 Gbps. The core contains the base AES core AES1 and is available for immediate licensing.
The design is fully synchronous and available in both source and netlist form.

Base Core Features

Small size: From 70K ASIC gates (at throughput of 18.2 bits per clock)
500 MHz frequency in 90 nm process
Easily parallelizable to achieve higher throughputs
Completely self-contained: does not require external memory. Includes encryption, decryption, key expansion and data interface
Support for Galois Counter Mode Encryption and authentication (GCM) , XEX-based Tweaked CodeBook mode (TCB) with Cipher Text Stealing (CTS) (abbreviated as XTS) mode per IEEE P1619, and Cipher Block Chaining (CBC) mode with 128 and 256-bit AES keys
Flow-through design
Test bench provided
IEEE 802.1ae
LAN switches, routers, NICs
IEEE P1619
Hard drive and tape encryption, SAN, NAS
Pin Description
CLK Input   Core clock signal
Reset Input   Core reset signal (active HIGH)
CEN Input   Synchronous enable signal. When LOW the core ignores all      its inputs and all its outputs must be ignored.
MODE[1:0] Input   Encryption mode. GCM mode if 01, XTS mode if 00, CBC   mode if 10
Encrypt Input   When HIGH, core is encrypting, when LOW core is decrypting
Key256 Input   When HIGH, 256 bit AES key is used, when LOW – 128 bit   AES key
EndC Input   (GCM mode only) Marks last data block
ZeroC Input   (GCM mode only) Marks the block with zero length of   (plaintext/ciphertext field
NewIV Input   (XTS mode only) Marks the last block of the data unit if   followed immediately by the first block of the next data unit with   different IV.
Cts Input   (XTS mode only) Marks the last full 128-bit block of the data   unit in case that the next block of this data unit is less than   128 bit (CTS mode)
Start Input   HIGH level starts the input data processing
Read Output   Read request for the input data byte
Write Output   Write signal for the output interface
D[127:0] Input   Input Data (other data bus widths are also available)
  • For GCM, additional authenticated data (AAD, A), followed by   the plain or cipher text
  • For XTS and CBC, plain or cipher text
K1[255:0] Input 256 bit or 128 bit AES key (128-bit key uses K1[255:128] pins)
K2[255:0] Input  (XTS mode only) Tweak key (K2) (128-bit key uses K2[255:128] pins)
IV[127:0] Input  In GCM mode: initial counter value (Y0, IV || 0311) In CBC mode: initial value (IV) In XTS mode: location (IV)
LenA[63:0] Input  (GCM mode only) Length of additional authenticated data in  bits
Be[3:0] Input  Byte length of the last data block (GCM and XTS modes only) in  bytes minus 1 0 – corresponds to 1 byte 1 – corresponds to 2  bytes … 15 – corresponds to 16 bytes
FK[255:0] Output  256 bit or 128 bit final round key (128-bit key uses FK[255:128]  pins)
FKvalid Output  HIGH when FK is valid
Q[127:0] Output  Output plain or cipher text
T[127:0] Output  (GCM mode only) Computed MAC (tag, T)
Done Output  HIGH when data processing is completed
AES-GCMFunction Description

The Advanced Encryption Standard (AES) algorithm is a new NIST data encryption standard as defined in the http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf

The GXC3 implementation fully supports the AES algorithm for 128 and 256 bit keys in Galois Counter Mode (AES-GCM) as required by the 802.1ae IEEE standard, in AES-XTS mode as required by the IEEE P1619 (SISWG) standard, a the CBC-AES mode per NIST specification SP800-38A.

The core is designed for flow-through operation, with input and output interfaces of flexible width. GCM additional authentication data precede the plaintext in the flow of data. GXC3 supports both encryption and decryption modes.

Export Permits
The core can be a subject of the US export control. See the IP Cores, Inc. licensing basics page, for links to US government sites and more details.

HDL Source Licenses

Synthesizable Verilog RTL source code
Testbench (self-checking)
Vectors for testbenches
User Documentation

Netlist Licenses

Post-synthesis EDIF
Testbench (self-checking)
Vectors for testbenches
Place & Route script
Contact Information
IP Cores, Inc.
3731 Middlefield Rd.
Palo Alto, CA 94303, USA
Phone: +1 (650) 815-7996
E-mail: [email protected]