view libtommath/changes.txt @ 350:01e4180895ba

merge of '9a4e042fd565f46141e81e0c1ab90260303348fe' and 'bea3887a5875cf3ab8a1331e15e698b37b61fe37'
author Matt Johnston <>
date Mon, 07 Aug 2006 13:41:23 +0000
parents eed26cff980b
children 5ff8218bcee9
line wrap: on
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March 12th, 2005
v0.35  -- Stupid XOR function missing line again... oops.
       -- Fixed bug in invmod not handling negative inputs correctly [Wolfgang Ehrhardt]
       -- Made exteuclid always give positive u3 output...[ Wolfgang Ehrhardt ]
       -- [Wolfgang Ehrhardt] Suggested a fix for mp_reduce() which avoided underruns.  ;-)
       -- mp_rand() would emit one too many digits and it was possible to get a 0 out of it ... oops
       -- Added montgomery to the testing to make sure it handles 1..10 digit moduli correctly
       -- Fixed bug in comba that would lead to possible erroneous outputs when "pa < digs" 
       -- Fixed bug in mp_toradix_size for "0" [Kevin Kenny]
       -- Updated chapters 1-5 of the textbook ;-) It now talks about the new comba code!

February 12th, 2005
v0.34  -- Fixed two more small errors in mp_prime_random_ex()
       -- Fixed overflow in mp_mul_d() [Kevin Kenny]
       -- Added mp_to_(un)signed_bin_n() functions which do bounds checking for ya [and report the size]
       -- Added "large" diminished radix support.  Speeds up things like DSA where the moduli is of the form 2^k - P for some P < 2^(k/2) or so
          Actually is faster than Montgomery on my AMD64 (and probably much faster on a P4)
       -- Updated the manual a bit
       -- Ok so I haven't done the textbook work yet... My current freelance gig has landed me in France till the 
          end of Feb/05.  Once I get back I'll have tons of free time and I plan to go to town on the book.
          As of this release the API will freeze.  At least until the book catches up with all the changes.  I welcome
          bug reports but new algorithms will have to wait.

December 23rd, 2004
v0.33  -- Fixed "small" variant for mp_div() which would munge with negative dividends...
       -- Fixed bug in mp_prime_random_ex() which would set the most significant byte to zero when
          no special flags were set
       -- Fixed overflow [minor] bug in fast_s_mp_sqr()
       -- Made the makefiles easier to configure the group/user that ltm will install as
       -- Fixed "final carry" bug in comba multipliers. (Volkan Ceylan)
       -- Matt Johnston pointed out a missing semi-colon in mp_exptmod

October 29th, 2004
v0.32  -- Added "makefile.shared" for shared object support
       -- Added more to the build options/configs in the manual
       -- Started the Depends framework, wrote to scan deps and 
          produce "callgraph.txt" ;-)
       -- Wrote SC_RSA_1 which will enable close to the minimum required to perform
          RSA on 32-bit [or 64-bit] platforms with LibTomCrypt
       -- Merged in the small/slower mp_div replacement.  You can now toggle which
          you want to use as your mp_div() at build time.  Saves roughly 8KB or so.
       -- Renamed a few files and changed some comments to make depends system work better.
          (No changes to function names)
       -- Merged in new Combas that perform 2 reads per inner loop instead of the older 
          3reads/2writes per inner loop of the old code.  Really though if you want speed
          learn to use TomsFastMath ;-)

August 9th, 2004
v0.31  -- "profiled" builds now :-) new timings for Intel Northwoods
       -- Added "pretty" build target
       -- Update mp_init() to actually assign 0's instead of relying on calloc()
       -- "Wolfgang Ehrhardt" <[email protected]> found a bug in mp_mul() where if
          you multiply a negative by zero you get negative zero as the result.  Oops.
       -- J Harper from PeerSec let me toy with his AMD64 and I got 60-bit digits working properly
          [this also means that I fixed a bug where if sizeof(int) < sizeof(mp_digit) it would bug]

April 11th, 2004
v0.30  -- Added "mp_toradix_n" which stores upto "n-1" least significant digits of an mp_int
       -- Johan Lindh sent a patch so MSVC wouldn't whine about redefining malloc [in weird dll modes]
       -- Henrik Goldman spotted a missing OPT_CAST in mp_fwrite()
       -- Tuned tommath.h so that when MP_LOW_MEM is defined MP_PREC shall be reduced.
          [I also allow MP_PREC to be externally defined now]
       -- Sped up mp_cnt_lsb() by using a 4x4 table [e.g. 4x speedup]
       -- Added mp_prime_random_ex() which is a more versatile prime generator accurate to
          exact bit lengths (unlike the deprecated but still available mp_prime_random() which
          is only accurate to byte lengths).  See the new LTM_PRIME_* flags ;-)
       -- Alex Polushin contributed an optimized mp_sqrt() as well as mp_get_int() and mp_is_square().
          I've cleaned them all up to be a little more consistent [along with one bug fix] for this release.
       -- Added mp_init_set and mp_init_set_int to initialize and set small constants with one function
       -- Removed /etclib directory [um LibTomPoly deprecates this].
       -- Fixed mp_mod() so the sign of the result agrees with the sign of the modulus.
       ++ N.B.  My semester is almost up so expect updates to the textbook to be posted to the 

Jan 25th, 2004
v0.29  ++ Note: "Henrik" from the v0.28 changelog refers to Henrik Goldman ;-)
       -- Added fix to mp_shrink to prevent a realloc when used == 0 [e.g. realloc zero bytes???]
       -- Made the mp_prime_rabin_miller_trials() function internal table smaller and also
          set the minimum number of tests to two (sounds a bit safer).
       -- Added a mp_exteuclid() which computes the extended euclidean algorithm.
       -- Fixed a memory leak in s_mp_exptmod() [called when Barrett reduction is to be used] which would arise
          if a multiplication or subsequent reduction failed [would not free the temp result].
       -- Made an API change to mp_radix_size().  It now returns an error code and stores the required size
          through an "int star" passed to it.

Dec 24th, 2003
v0.28  -- Henrik Goldman suggested I add casts to the montomgery code [stores into mu...] so compilers wouldn't
          spew [erroneous] diagnostics... fixed.
       -- Henrik Goldman also spotted two typos.  One in mp_radix_size() and another in mp_toradix().
       -- Added fix to mp_shrink() to avoid a memory leak.
       -- Added mp_prime_random() which requires a callback to make truly random primes of a given nature
          (idea from chat with Niels Ferguson at Crypto'03)
       -- Picked up a second wind.  I'm filled with Gooo.  Mission Gooo!
       -- Removed divisions from mp_reduce_is_2k()
       -- Sped up mp_div_d() [general case] to use only one division per digit instead of two.
       -- Added the heap macros from LTC to LTM.  Now you can easily [by editing four lines of tommath.h]
          change the name of the heap functions used in LTM [also compatible with LTC via MPI mode]
       -- Added bn_prime_rabin_miller_trials() which gives the number of Rabin-Miller trials to achieve
          a failure rate of less than 2^-96
       -- fixed bug in fast_mp_invmod().  The initial testing logic was wrong.  An invalid input is not when
          "a" and "b" are even it's when "b" is even [the algo is for odd moduli only].
       -- Started a new manual [finally].  It is incomplete and will be finished as time goes on.  I had to stop
          adding full demos around half way in chapter three so I could at least get a good portion of the
          manual done.   If you really need help using the library you can always email me!
       -- My Textbook is now included as part of the package [all Public Domain]

Sept 19th, 2003
v0.27  -- Removed changes.txt~ which was made by accident since "kate" decided it was
          a good time to re-enable backups... [kde is fun!]
       -- In mp_grow() "a->dp" is not overwritten by realloc call [re: memory leak]
          Now if mp_grow() fails the mp_int is still valid and can be cleared via
          mp_clear() to reclaim the memory.
       -- Henrik Goldman found a buffer overflow bug in mp_add_d().  Fixed.
       -- Cleaned up mp_mul_d() to be much easier to read and follow.

Aug 29th, 2003
v0.26  -- Fixed typo that caused warning with GCC 3.2
       -- Martin Marcel noticed a bug in mp_neg() that allowed negative zeroes.
          Also, Martin is the fellow who noted the bugs in mp_gcd() of 0.24/0.25.
       -- Martin Marcel noticed an optimization [and slight bug] in mp_lcm().
       -- Added fix to mp_read_unsigned_bin to prevent a buffer overflow.
       -- Beefed up the comments in the baseline multipliers [and montgomery]
       -- Added "mont" demo to the makefile.msvc in etc/
       -- Optimized sign compares in mp_cmp from 4 to 2 cases.

Aug 4th, 2003
v0.25  -- Fix to mp_gcd again... oops (0,-a) == (-a, 0) == a
       -- Fix to mp_clear which didn't reset the sign  [Greg Rose]
       -- Added mp_error_to_string() to convert return codes to strings.  [Greg Rose]
       -- Optimized fast_mp_invmod() to do the test for invalid inputs [both even]
          first so temps don't have to be initialized if it's going to fail.
       -- Optimized mp_gcd() by removing mp_div_2d calls for when one of the inputs
          is odd.
       -- Tons of new comments, some indentation fixups, etc.
       -- mp_jacobi() returns MP_VAL if the modulus is less than or equal to zero.
       -- fixed two typos in the header of each file :-)
       -- LibTomMath is officially Public Domain [see LICENSE]

July 15th, 2003
v0.24  -- Optimized mp_add_d and mp_sub_d to not allocate temporary variables
       -- Fixed mp_gcd() so the gcd of 0,0 is 0.  Allows the gcd operation to be chained
          e.g. (0,0,a) == a [instead of 1]
       -- Should be one of the last release for a while.  Working on LibTomMath book now.
       -- optimized the pprime demo [/etc/pprime.c] to first make a huge table of single
          digit primes then it reads them randomly instead of randomly choosing/testing single
          digit primes.

July 12th, 2003
v0.23  -- Optimized mp_prime_next_prime() to not use mp_mod [via is_divisible()] in each
          iteration.  Instead now a smaller table is kept of the residues which can be updated
          without division.
       -- Fixed a bug in next_prime() where an input of zero would be treated as odd and
          have two added to it [to move to the next odd].
       -- fixed a bug in prime_fermat() and prime_miller_rabin() which allowed the base
          to be negative, zero or one.  Normally the test is only valid if the base is
          greater than one.
       -- changed the next_prime() prototype to accept a new parameter "bbs_style" which
          will find the next prime congruent to 3 mod 4.  The default [bbs_style==0] will
          make primes which are either congruent to 1 or 3 mod 4.
       -- fixed mp_read_unsigned_bin() so that it doesn't include both code for
          the case DIGIT_BIT < 8 and >= 8
       -- optimized div_d() to easy out on division by 1 [or if a == 0] and use
          logical shifts if the divisor is a power of two.
       -- the default DIGIT_BIT type was not int for non-default builds.  Fixed.

July 2nd, 2003
v0.22  -- Fixed up mp_invmod so the result is properly in range now [was always congruent to the inverse...]
       -- Fixed up s_mp_exptmod and mp_exptmod_fast so the lower half of the pre-computed table isn't allocated
          which makes the algorithm use half as much ram.
       -- Fixed the install script not to make the book :-) [which isn't included anyways]
       -- added mp_cnt_lsb() which counts how many of the lsbs are zero
       -- optimized mp_gcd() to use the new mp_cnt_lsb() to replace multiple divisions by two by a single division.
       -- applied similar optimization to mp_prime_miller_rabin().
       -- Fixed a bug in both mp_invmod() and fast_mp_invmod() which tested for odd
          via "mp_iseven() == 0" which is not valid [since zero is not even either].

June 19th, 2003
v0.21  -- Fixed bug in mp_mul_d which would not handle sign correctly [would not always forward it]
       -- Removed the #line lines from [was in violation of ISO C]

June 8th, 2003
v0.20  -- Removed the book from the package.  Added the TDCAL license document.
       -- This release is officially pure-bred TDCAL again [last officially TDCAL based release was v0.16]

June 6th, 2003
v0.19  -- Fixed a bug in mp_montgomery_reduce() which was introduced when I tweaked mp_rshd() in the previous release.
          Essentially the digits were not trimmed before the compare which cause a subtraction to occur all the time.
       -- Fixed up etc/tune.c a bit to stop testing new cutoffs after 16 failures [to find more optimal points].
          Brute force ho!

May 29th, 2003
v0.18  -- Fixed a bug in s_mp_sqr which would handle carries properly just not very elegantly.
          (e.g. correct result, just bad looking code)
       -- Fixed bug in mp_sqr which still had a 512 constant instead of MP_WARRAY
       -- Added Toom-Cook multipliers [needs tuning!]
       -- Added efficient divide by 3 algorithm mp_div_3
       -- Re-wrote mp_div_d to be faster than calling mp_div
       -- Added in a donated BCC makefile and a single page LTM poster ([email protected])
       -- Added mp_reduce_2k which reduces an input modulo n = 2**p - k for any single digit k
       -- Made the exptmod system be aware of the 2k reduction algorithms.
       -- Rewrote mp_dr_reduce to be smaller, simpler and easier to understand.

May 17th, 2003
v0.17  -- Benjamin Goldberg submitted optimized mp_add and mp_sub routines.  A new as well
          as several smaller suggestions.  Thanks!
       -- removed call to mp_cmp in inner loop of mp_div and put mp_cmp_mag in its place :-)
       -- Fixed bug in mp_exptmod that would cause it to fail for odd moduli when DIGIT_BIT != 28
       -- mp_exptmod now also returns errors if the modulus is negative and will handle negative exponents
       -- mp_prime_is_prime will now return true if the input is one of the primes in the prime table
       -- Damian M Gryski ([email protected]) found a index out of bounds error in the
          mp_fast_s_mp_mul_high_digs function which didn't come up before.  (fixed)
       -- Refactored the DR reduction code so there is only one function per file.
       -- Fixed bug in the mp_mul() which would erroneously avoid the faster multiplier [comba] when it was
          allowed.  The bug would not cause the incorrect value to be produced just less efficient (fixed)
       -- Fixed similar bug in the Montgomery reduction code.
       -- Added tons of (mp_digit) casts so the 7/15/28/31 bit digit code will work flawlessly out of the box.
          Also added limited support for 64-bit machines with a 60-bit digit.  Both thanks to Tom Wu ([email protected])
       -- Added new comments here and there, cleaned up some code [style stuff]
       -- Fixed a lingering typo in mp_exptmod* that would set bitcnt to zero then one.  Very silly stuff :-)
       -- Fixed up mp_exptmod_fast so it would set "redux" to the comba Montgomery reduction if allowed.  This
          saves quite a few calls and if statements.
       -- Added etc/mont.c a test of the Montgomery reduction [assuming all else works :-| ]
       -- Fixed up etc/tune.c to use a wider test range [more appropriate] also added a x86 based addition which
          uses RDTSC for high precision timing.
       -- Updated demo/demo.c to remove MPI stuff [won't work anyways], made the tests run for 2 seconds each so its
          not so insanely slow.  Also made the output space delimited [and fixed up various errors]
       -- Added logs directory, logs/graph.dem which will use gnuplot to make a series of PNG files
          that go with the pre-made index.html.  You have to build [via make timing] and run ltmtest first in the
          root of the package.
       -- Fixed a bug in mp_sub and mp_add where "-a - -a" or "-a + a" would produce -0 as the result [obviously invalid].
       -- Fixed a bug in mp_rshd.  If the count == a.used it should zero/return [instead of shifting]
       -- Fixed a "off-by-one" bug in mp_mul2d.  The initial size check on alloc would be off by one if the residue
          shifting caused a carry.
       -- Fixed a bug where s_mp_mul_digs() would not call the Comba based routine if allowed.  This made Barrett reduction
          slower than it had to be.

Mar 29th, 2003
v0.16  -- Sped up mp_div by making normalization one shift call
       -- Sped up mp_mul_2d/mp_div_2d by aliasing pointers :-)
       -- Cleaned up mp_gcd to use the macros for odd/even detection
       -- Added comments here and there, mostly there but occasionally here too.

Mar 22nd, 2003
v0.15  -- Added series of prime testing routines to lib
       -- Fixed up etc/tune.c
       -- Added DR reduction algorithm
       -- Beefed up the manual more.
       -- Fixed up demo/demo.c so it doesn't have so many warnings and it does the full series of
       -- Added "pre-gen" directory which will hold a ""'ed copy of the entire lib [done at
          zipup time so its always the latest]
       -- Added conditional casts for C++ users [boo!]

Mar 15th, 2003
v0.14  -- Tons of manual updates
       -- cleaned up the directory
       -- added MSVC makefiles
       -- source changes [that I don't recall]
       -- Fixed up the lshd/rshd code to use pointer aliasing
       -- Fixed up the mul_2d and div_2d to not call rshd/lshd unless needed
       -- Fixed up etc/tune.c a tad
       -- fixed up demo/demo.c to output comma-delimited results of timing
          also fixed up timing demo to use a finer granularity for various functions
       -- fixed up demo/demo.c testing to pause during testing so my Duron won't catch on fire
          [stays around 31-35C during testing :-)]

Feb 13th, 2003
v0.13  -- tons of minor speed-ups in low level add, sub, mul_2 and div_2 which propagate
          to other functions like mp_invmod, mp_div, etc...
       -- Sped up mp_exptmod_fast by using new code to find R mod m [e.g. B^n mod m]
       -- minor fixes

Jan 17th, 2003
v0.12  -- re-wrote the majority of the makefile so its more portable and will
          install via "make install" on most *nix platforms
       -- Re-packaged all the source as seperate files.  Means the library a single
          file packagage any more.  Instead of just adding "bn.c" you have to add
       -- Renamed "bn.h" to "tommath.h"
       -- Changes to the manual to reflect all of this
       -- Used GNU Indent to clean up the source

Jan 15th, 2003
v0.11  -- More subtle fixes
       -- Moved to gentoo linux [hurrah!] so made *nix specific fixes to the make process
       -- Sped up the montgomery reduction code quite a bit
       -- fixed up demo so when building timing for the x86 it assumes ELF format now

Jan 9th, 2003
v0.10  -- Pekka Riikonen suggested fixes to the radix conversion code.
       -- Added baseline montgomery and comba montgomery reductions, sped up exptmods
          [to a point, see bn.h for MONTGOMERY_EXPT_CUTOFF]

Jan 6th, 2003
v0.09  -- Updated the manual to reflect recent changes.  :-)
       -- Added Jacobi function (mp_jacobi) to supplement the number theory side of the lib
       -- Added a Mersenne prime finder demo in ./etc/mersenne.c

Jan 2nd, 2003
v0.08  -- Sped up the multipliers by moving the inner loop variables into a smaller scope
       -- Corrected a bunch of small "warnings"
       -- Added more comments
       -- Made "mtest" be able to use /dev/random, /dev/urandom or stdin for RNG data
       -- Corrected some bugs where error messages were potentially ignored
       -- add etc/pprime.c program which makes numbers which are provably prime.

Jan 1st, 2003
v0.07  -- Removed alot of heap operations from core functions to speed them up
       -- Added a root finding function [and mp_sqrt macro like from MPI]
       -- Added more to manual

Dec 31st, 2002
v0.06  -- Sped up the s_mp_add, s_mp_sub which inturn sped up mp_invmod, mp_exptmod, etc...
       -- Cleaned up the header a bit more

Dec 30th, 2002
v0.05  -- Builds with MSVC out of the box
       -- Fixed a bug in mp_invmod w.r.t. even moduli
       -- Made mp_toradix and mp_read_radix use char instead of unsigned char arrays
       -- Fixed up exptmod to use fewer multiplications
       -- Fixed up mp_init_size to use only one heap operation
          -- Note there is a slight "off-by-one" bug in the library somewhere
             without the padding (see the source for comment) the library
             crashes in libtomcrypt.  Anyways a reasonable workaround is to pad the
             numbers which will always correct it since as the numbers grow the padding
             will still be beyond the end of the number
       -- Added more to the manual

Dec 29th, 2002
v0.04  -- Fixed a memory leak in mp_to_unsigned_bin
       -- optimized invmod code
       -- Fixed bug in mp_div
       -- use exchange instead of copy for results
       -- added a bit more to the manual

Dec 27th, 2002
v0.03  -- Sped up s_mp_mul_high_digs by not computing the carries of the lower digits
       -- Fixed a bug where mp_set_int wouldn't zero the value first and set the used member.
       -- fixed a bug in s_mp_mul_high_digs where the limit placed on the result digits was not calculated properly
       -- fixed bugs in add/sub/mul/sqr_mod functions where if the modulus and dest were the same it wouldn't work
       -- fixed a bug in mp_mod and mp_mod_d concerning negative inputs
       -- mp_mul_d didn't preserve sign
       -- Many many many many fixes
       -- Works in LibTomCrypt now :-)
       -- Added iterations to the timing demos... more accurate.
       -- Tom needs a job.

Dec 26th, 2002
v0.02  -- Fixed a few "slips" in the manual.  This is "LibTomMath" afterall :-)
       -- Added mp_cmp_mag, mp_neg, mp_abs and mp_radix_size that were missing.
       -- Sped up the fast [comba] multipliers more [yahoo!]

Dec 25th,2002
v0.01  -- Initial release.  Gimme a break.
       -- Todo list,
           add details to manual [e.g. algorithms]
           more comments in code
           example programs