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Remove sha256crypt ($5$) and sha512crypt ($6$) from strong set. #35

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Remove sha256crypt ($5$) and sha512crypt ($6$) from strong set. #35

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4 changes: 4 additions & 0 deletions NEWS
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Expand Up @@ -11,6 +11,10 @@ Version 4.2.0
* --enable-hashes now supports additional groups of hashing methods:
'altlinux', 'owl', and 'suse', which select the methods historically
supported on those operating systems.
* --enable-hashes=strong now excludes the SHA-2-based hashes
($5$ and $6$). These are still cryptographically sound, but not
hardened against massively parallel brute-force attacks (e.g. using
GPUs to compute SHA-2) as the newer bcrypt, scrypt, and yescrypt are.

Version 4.1.2
* Add optional 'check-valgrind' target to the Makefile.
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2 changes: 1 addition & 1 deletion README.md
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Expand Up @@ -132,7 +132,7 @@ supported hashes. Disabling the traditional ‘des’ hash algorithm
implies `--disable-obsolete-api`. Security-conscious environments
without backward compatibility constraints are encouraged to use
`--enable-hashes=strong`, which enables only the hash functions that
are strong enough to be safe for newly hashed passwords.
are definitely strong enough to be safe for newly hashed passwords.

The original implementation of the SUNMD5 hashing algorithm has a bug,
which is mimicked by libxcrypt to be fully compatible with hashes
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6 changes: 4 additions & 2 deletions crypt.5
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Expand Up @@ -166,6 +166,7 @@ originally for the Tarsnap online backup service.
The algorithm was specifically designed to make it costly to perform
large-scale custom hardware attacks by requiring large amounts of memory.
In 2016, the scrypt algorithm was published by IETF as RFC 7914.
Not as strong as yescrypt, but still acceptable for new hashes.
.hash "$7$" "\e$7\e$[./A-Za-z0-9]{11,97}\e$[./A-Za-z0-9]{43}" unlimited 8 256 256 "up to 512" "6 to 11 (logarithmic)"
.PP
.ti -4
Expand All @@ -176,6 +177,7 @@ modified to have an extra-expensive key schedule.
Originally developed by Niels Provos and David Mazieres for OpenBSD
and also supported on recent versions of FreeBSD and NetBSD,
on Solaris 10 and newer, and on several GNU/*/Linux distributions.
Not as strong as yescrypt, but still acceptable for new hashes.
.hash "$2b$" "\e$2[abxy]\e$[0-9]{2}\e$[./A-Za-z0-9]{53}" 72 8 184 184 128 "4 to 31 (logarithmic)"
.PP
The alternative prefix "$2y$" is equivalent to "$2b$".
Expand All @@ -190,7 +192,7 @@ which incorrectly processed characters with the 8th bit set.
A hash based on SHA-2 with 512-bit output,
originally developed by Ulrich Drepper for GNU libc.
Supported on Linux but not common elsewhere.
Acceptable for new hashes.
Not recommended for new hashes, but not catastrophically weak.
The default CPU time cost parameter is 5000,
which is too low for modern hardware.
.br
Expand All @@ -202,7 +204,7 @@ which is too low for modern hardware.
A hash based on SHA-2 with 256-bit output,
originally developed by Ulrich Drepper for GNU libc.
Supported on Linux but not common elsewhere.
Acceptable for new hashes.
Not recommended for new hashes, but not catastrophically weak.
The default CPU time cost parameter is 5000,
which is too low for modern hardware.
.br
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4 changes: 2 additions & 2 deletions hashes.lst
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Expand Up @@ -34,8 +34,8 @@ bcrypt _a $2a$ 16 STRONG,ALTLINUX,FREEBSD,NETBSD,OPENBSD,OW
bcrypt _b $2b$ 16 STRONG,ALTLINUX,FREEBSD,NETBSD,OPENBSD,OWL,SOLARIS,SUSE
bcrypt _x $2x$ 16 STRONG,ALTLINUX,FREEBSD,NETBSD,OPENBSD,OWL,SOLARIS,SUSE
bcrypt _y $2y$ 16 STRONG,ALTLINUX,FREEBSD,NETBSD,OPENBSD,OWL,SOLARIS,SUSE
sha512 : $6$ 15 STRONG,GLIBC,FREEBSD,SOLARIS
sha256 : $5$ 15 STRONG,GLIBC,FREEBSD,SOLARIS
sha512 : $6$ 15 GLIBC,FREEBSD,SOLARIS
sha256 : $5$ 15 GLIBC,FREEBSD,SOLARIS
md5 : $1$ 9 GLIBC,FREEBSD,NETBSD,OPENBSD,SOLARIS
sunmd5 : $md5 8 SOLARIS
sha1 : $sha1 20 NETBSD
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