NSP(4) BSD Kernel Interfaces Manual NSP(4)NAMEnsp — NBMK/CyberGuard/NetOctave NSP2000 crypto accelerator
SYNOPSIS
nsp* at pci? dev ? function ?
DESCRIPTION
The nsp driver supports cards using the NSP2000 cryptographic processor,
originally manufactured and sold by NetOctave, then CyberGuard, and
presently (late 2008) by NBMK Encryption Technologies.
The NSP2000 is a cryptographic “packet processor” or “macro processor”
featuring extensive support for protocol handshake acceleration and pro‐
tocol record operations (e.g. single-pass pad-encrypt-and-hash for SSL or
ESP messages). It also provides various cryptographic and mathematical
primitives such as random number generation, encryption/decryption (DES,
3DES, and RC4), hash computation (MD5, SHA1, and HMAC), and an extensive
set of operations for arbitrary precision arithmetic. It contains a tam‐
per-resistant write-only memory region for storage of cryptographic keys.
The nsp driver registers support for the following operations with
opencrypto(9):
CRYPTO_DES_CBC DES in CBC mode.
CRYPTO_3DES_CBC Triple-DES in CBC mode.
CRYPTO_MD5 The MD5 hash algorithm.
CRYPTO_SHA1 The SHA-1 hash algorithm.
CRYPTO_SHA1_HMAC The HMAC message authentication code using
SHA-1 as the hash function.
CRYPTO_MD5_HMAC The HMAC message authentication code using MD5
as the hash function.
CRK_MOD Compute x modulo y.
CRK_MOD_ADD Modular addition.
CRK_MOD_ADDINV Modular additive inversion.
CRK_MOD_SUB Modular subtraction.
CRK_MOD_MULT Modular multiplication.
CRK_MOD_MULTINV Modular multiplicative inversion.
CRK_MOD_EXP Modular exponentiation.
CRK_DSA_SIGN DSA signature creation.
CRK_DSA_VERIFY DSA signature verification.
CRK_DH_COMPUTE_KEY Diffie-Hellman key computation.
PERFORMANCE
The nsp driver can perform several hundred 1024-bit RSA operations per
second, and can encrypt and hash about 200Mbit/sec of data with symmetric
operations. Each figure is approximately 1/3 the rated throughput for
the device.
Several restrictions limit the performance of this driver:
1. The CRK_MOD_EXP_CRT operation (modular exponentiation with operands
in Chinese Remainder Theorem form) is unfortunately not supported
because the opencrypto(9) interface specifies this operation in a
way which may only be compatible with the ubsec(4) accelerator.
2. The handshake operations and record transforms are not supported as
they are a poor fit for the current opencrypto(9) API. Support for
either would require a method of passing record-transform contexts
between layers of the framework, likely in both directions across
the user-kernel boundary. Without record operations, the host CPU
will almost always perform RC4 faster than the NSP2000, so RC4 sup‐
port is disabled in the nsp driver.
3. The on-board key memory is not supported. It would be relatively
easy to add support for this feature to opencrypto(9), but the
interface for supporting this functionality in OpenSSL in OpenSSL is
complex and poorly documented, which makes kernel support useless.
4. The OpenSSL “engine” for crypto(4) does not yet support the HMAC
forms of the hash operations, which roughly halves performance for
many workloads.
On a more positive note, the NSP2000 and nsp driver offer excellent per‐
formance for small modular arithmetic operations, achieving 75,000 or
more such operations per second.
SEE ALSOcrypto(4), fast_ipsec(4), intro(4), rnd(4), opencrypto(9)HISTORY
The nsp device driver is descended from the NetOctave SDK for
FreeBSD 4.11, where it was called “noct”. It is unrelated to the driver
of that name which appeared in OpenBSD 3.2, which does not support the
public-key (or other bignum) functions of the device. The nsp driver was
ported to NetBSD 5.0 by Coyote Point Systems, Inc and generously made
available under a BSD-style license by NBMK Encryption Technologies, Inc,
the corporate successor of NetOctave.
The nsp device driver does not currently support the device node inter‐
face provided by the original NetOctave “noct” driver (which offers hand‐
shake acceleration, record operations, memory-mapped handling of packet
payloads, and several other useful features) but most of the code to do
so is still present, albeit in untested form.
BUGS
Support for limitations of the NSP2000 PCI interface (broken burst-mode
operation, lack of scatter-gather support) is present but tested only on
a fairly small range of host systems.
It appears that most if not all NSP2000 cards ever manufactured were
designed to carry either one or two accelerator chips, which suggests
that cards exist with both chips populated. The nsp driver has never
been tested with more than one instance present at a time.
BSD November 2, 2008 BSD
