Manual browser: hifn(4)

HIFN(4) Kernel Interfaces Manual HIFN(4)


hifnHifn 7751/7951/7811/7955/7956 crypto accelerator


hifn* at pci? dev ? function ?


The hifn driver supports various cards containing the Hifn 7751, 7951, 7811, 7955, and 7956 chipsets, such as
Invertex AEON
No longer being made. Came as 128KB SRAM model, or 2MB DRAM model.
Hifn 7751
Reference board with 512KB SRAM.
Comes with 512KB SRAM.
Only board based on 7811 (which is faster than 7751 and has a random number generator).
NetSec 7751
Supports the most IPsec sessions, with 1MB SRAM.
Soekris Engineering vpn1201 and vpn1211
Contains a 7951 and supports symmetric and random number operations.
Soekris Engineering vpn1401 and vpn1411
Contains a 7955 and supports symmetric and random number operations.

The hifn driver registers itself to accelerate DES, Triple-DES, AES (7955 and 7956 only), ARC4, MD5, MD5-HMAC, SHA1, and SHA1-HMAC operations for opencrypto(9), and thus for fast_ipsec(4) and crypto(4).

The Hifn 7951, 7811, 7955, and 7956 may also supply data to the kernel rnd(4) subsystem.


The hifn device driver appeared in OpenBSD 2.7. The hifn device driver was imported to FreeBSD 5.0, back-ported to FreeBSD 4.8, and subsequently imported into NetBSD 2.0.


The Hifn 9751 shares the same PCI ID. This chip is basically a 7751, but with the cryptographic functions missing. Instead, the 9751 is only capable of doing compression. Since we do not currently attempt to use any of these chips to do compression, the 9751-based cards are not useful.

Support for the 7955 and 7956 is incomplete; the asymmetric crypto facilities are to be added and the performance is suboptimal.

Supplying data to the kernel rnd(4) subsystem has been disabled, pending verification that the on-chip RNG is statistically adequate.


The 7751 chip starts out at initialization by only supporting compression. A proprietary algorithm, which has been reverse engineered, is required to unlock the cryptographic functionality of the chip. It is possible for vendors to make boards which have a lock ID not known to the driver, but all vendors currently just use the obvious ID which is 13 bytes of 0.
October 8, 2003 NetBSD 7.0