This is a bugfix release.
Bug fixes:
* Fixed a bug in the new ECC code. The ecc_j_to_a function
called GMP:s mpn_mul_n (via ecc_modp_mul) with overlapping
input and output arguments, which is not supported.
* The assembly files for SHA1, SHA256 and AES depend on ARMv6
instructions, breaking nettle-2.7 for pre-v6 ARM processors.
The configure script now enables those assembly files only
when building for ARMv6 or later.
* Use a more portable C expression for rotations. The
previous version used the following "standard" expression
for 32-bit rotation:
(x << n) | (x >> (32 - n))
But this gives undefined behavior (according to the C
specification) for n = 0. The rotate expression is replaced
by the more portable:
(x << n) | (x >> ((-n)&31))
This change affects only CAST128, which uses non-constant
rotation counts. Unfortunately, the new expression is poorly
optimized by released versions of gcc, making CAST128 a bit
slower. This is being fixed by the gcc hackers, see
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57157.
The following problems have been reported, but are *not* fixed
in this release:
* ARM assembly files use instruction syntax which is not
supported by all assemblers. Workaround: Use a current
version of GNU as, or configure with --disable-assembler.
* Configuring with --disable-static doesn't work on windows.
The libraries are intended to be binary compatible with
nettle-2.2 and later. The shared library names are
libnettle.so.4.7 and libhogweed.so.2.5, with sonames still
libnettle.so.4 and libhogweed.so.2.
This release includes an implementation of elliptic curve
cryptography (ECC) and optimizations for the ARM architecture.
This work was done at the offices of South Pole AB, and
generously funded by the .SE Internet Fund.
Bug fixes:
* Fixed a bug in the buffer handling for incremental SHA3
hashing, with a possible buffer overflow. Patch by Edgar
E. Iglesias.
New features:
* Support for ECDSA signatures. Elliptic curve operations over
the following curves: secp192r1, secp224r1, secp256r1,
secp384r1 and secp521r1, including x86_64 and ARM assembly
for the most important primitives.
* Support for UMAC, including x86_64 and ARM assembly.
* Support for 12-round salsa20, "salsa20r12", as specified by
eSTREAM. Contributed by Nikos Mavrogiannopoulos.
Optimizations:
* ARM assembly code for several additional algorithms,
including AES, Salsa20, and the SHA family of hash
functions.
* x86_64 assembly for SHA256, SHA512, and SHA3. (SHA3 assembly
was included in the 2.6 release, but disabled due to poor
performance on some AMD processors. Hopefully, that
performance problem is fixed now).
The ARM code was tested and benchmarked on Cortex-A9. Some of
the functions use "neon" instructions. The configure script
decides if neon instructions can be used, and the command line
options --enable-arm-neon and --disable-arm-neon can be used
to override its choice. Feedback appreciated.
The libraries are intended to be binary compatible with
nettle-2.2 and later. The shared library names are
libnettle.so.4.6 and libhogweed.so.2.4, with sonames still
libnettle.so.4 and libhogweed.so.2.
NEWS for the 2.4 release
This is a bugfix release only. It turned out ripemd160 in the
2.3 release was broken on all big-endian systems, due to a
missing include of config.h. nettle-2.4 fixes this.
The library is intended to be binary compatible with
nettle-2.2 and nettle-2.3. The shared library names are
libnettle.so.4.3 and libhogweed.so.2.1, with sonames still
libnettle.so.4 and libhogweed.so.2.
NEWS for the 2.3 release
* Support for the ripemd-160 hash function.
* Generates and installs nettle.pc and hogweed.pc files, for
use with pkg-config. Feedback appreciated. For projects
using autoconf, the traditional non-pkg-config ways of
detecting libraries, and setting LIBS and LDFLAGS, is still
recommended.
* Fixed a bug which made the testsuite fail in the GCM test on
certain platforms. Should not affect any documented features
of the library.
* Reorganization of the code for the various Merkle-Damg
hash functions. Some fields in the context structs for md4,
md5 and sha1 have been renamed, for consistency.
Applications should not peek inside these structs, and the
ABI is unchanged.
* In the manual, fixed mis-placed const in certain function
prototypes.
The library is intended to be binary compatible with
nettle-2.2. The shared library names are libnettle.so.4.2 and
libhogweed.so.2.1, with sonames still libnettle.so.4 and
libhogweed.so.2.
NEWS for the 2.2 release
Licensing change:
* Relicensed as LGPL v2.1 or later (user's option).
* Replaced blowfish and serpent implementation. New code is
based on the LGPLed code in libgcrypt.
New features:
* Support for Galois/Counter Mode (GCM).
* New interface for enumerating (most) available algorithms,
contributed by Daniel Kahn Gillmor.
* New tool nettle-hash. Can generate hash digests using any
supported hash function, with output compatible with md5sum
and friends from GNU coreutils. Checking (like md5sum -c)
not yet implemented.
Bug fixes:
* The old serpent code had a byte order bug (introduced by
yours truly about ten years ago). New serpent implementation
does not interoperate with earlier versions of nettle.
* Fixed ABI-dependent libdir default for Linux-based systems
which do not follow the Linux File Hierarchy Standard, e.g.,
Debian GNU/Linux.
Optimizations:
* x86_64 implemention of serpent.
* x86_64 implemention of camellia.
* Optimized memxor using word rather than byte operations.
Both generic C and x86_64 assembler.
* Eliminated a memcpy for in-place CBC decrypt.
Miscellaneous:
* In command line tools, no longer support -? for requesting
help, since using it without shell quoting is a dangerous
habit. Use long option --help instead.
The shared library names are libnettle.so.4.1 and
libhogweed.so.2.1, with sonames libnettle.so.4 and
libhogweed.so.2.
or less any context: In crypto toolkits for object-oriented languages
(C++, Python, Pike, ...), in applications like LSH or GNUPG, or even in
kernel space. In most contexts, you need more than the basic
cryptographic algorithms, you also need some way to keep track of available
algorithms, their properties and variants. You often have some algorithm
selection process, often dictated by a protocol you want to implement.
And as the requirements of applications differ in subtle and not so
subtle ways, an API that fits one application well can be a pain to use
in a different context. And that is why there are so many different
cryptographic libraries around.
Nettle tries to avoid this problem by doing one thing, the low-level
crypto stuff, and providing a simple but general interface to it.
In particular, Nettle doesn't do algorithm selection. It doesn't do
memory allocation. It doesn't do any I/O.
The idea is that one can build several application and context specific
interfaces on top of Nettle, and share the code, test cases, benchmarks,
documentation, etc. Examples are the Nettle module for the Pike
language, and LSH, which both use an object-oriented abstraction on top
of the library.
