nhyatt/putty-source
1
0
Fork 0
mirror of https://git.tartarus.org/simon/putty.git synced 2025-01-09 17:38:00 +00:00
Code Issues Projects Releases Wiki Activity
d36a4c3685
putty-source/sshdes.c
Simon Tatham d36a4c3685 Introduced wrapper macros snew(), snewn() and sresize() for the 
malloc functions, which automatically cast to the same type they're
allocating the size of. Should prevent any future errors involving
mallocing the size of the wrong structure type, and will also make
life easier if we ever need to turn the PuTTY core code from real C
into C++-friendly C. I haven't touched the Mac frontend in this
checkin because I couldn't compile or test it.

[originally from svn r3014]
2003-03-29 16:14:26 +00:00

1004 lines
34 KiB
C
Raw Blame History

#include <assert.h>
#include "ssh.h"
/* des.c - implementation of DES
*/
/*
* Description of DES
* ------------------
*
* Unlike the description in FIPS 46, I'm going to use _sensible_ indices:
* bits in an n-bit word are numbered from 0 at the LSB to n-1 at the MSB.
* And S-boxes are indexed by six consecutive bits, not by the outer two
* followed by the middle four.
*
* The DES encryption routine requires a 64-bit input, and a key schedule K
* containing 16 48-bit elements.
*
* First the input is permuted by the initial permutation IP.
* Then the input is split into 32-bit words L and R. (L is the MSW.)
* Next, 16 rounds. In each round:
* (L, R) <- (R, L xor f(R, K[i]))
* Then the pre-output words L and R are swapped.
* Then L and R are glued back together into a 64-bit word. (L is the MSW,
* again, but since we just swapped them, the MSW is the R that came out
* of the last round.)
* The 64-bit output block is permuted by the inverse of IP and returned.
*
* Decryption is identical except that the elements of K are used in the
* opposite order. (This wouldn't work if that word swap didn't happen.)
*
* The function f, used in each round, accepts a 32-bit word R and a
* 48-bit key block K. It produces a 32-bit output.
*
* First R is expanded to 48 bits using the bit-selection function E.
* The resulting 48-bit block is XORed with the key block K to produce
* a 48-bit block X.
* This block X is split into eight groups of 6 bits. Each group of 6
* bits is then looked up in one of the eight S-boxes to convert
* it to 4 bits. These eight groups of 4 bits are glued back
* together to produce a 32-bit preoutput block.
* The preoutput block is permuted using the permutation P and returned.
*
* Key setup maps a 64-bit key word into a 16x48-bit key schedule. Although
* the approved input format for the key is a 64-bit word, eight of the
* bits are discarded, so the actual quantity of key used is 56 bits.
*
* First the input key is converted to two 28-bit words C and D using
* the bit-selection function PC1.
* Then 16 rounds of key setup occur. In each round, C and D are each
* rotated left by either 1 or 2 bits (depending on which round), and
* then converted into a key schedule element using the bit-selection
* function PC2.
*
* That's the actual algorithm. Now for the tedious details: all those
* painful permutations and lookup tables.
*
* IP is a 64-to-64 bit permutation. Its output contains the following
* bits of its input (listed in order MSB to LSB of output).
*
* 6 14 22 30 38 46 54 62 4 12 20 28 36 44 52 60
* 2 10 18 26 34 42 50 58 0 8 16 24 32 40 48 56
* 7 15 23 31 39 47 55 63 5 13 21 29 37 45 53 61
* 3 11 19 27 35 43 51 59 1 9 17 25 33 41 49 57
*
* E is a 32-to-48 bit selection function. Its output contains the following
* bits of its input (listed in order MSB to LSB of output).
*
* 0 31 30 29 28 27 28 27 26 25 24 23 24 23 22 21 20 19 20 19 18 17 16 15
* 16 15 14 13 12 11 12 11 10 9 8 7 8 7 6 5 4 3 4 3 2 1 0 31
*
* The S-boxes are arbitrary table-lookups each mapping a 6-bit input to a
* 4-bit output. In other words, each S-box is an array[64] of 4-bit numbers.
* The S-boxes are listed below. The first S-box listed is applied to the
* most significant six bits of the block X; the last one is applied to the
* least significant.
*
* 14 0 4 15 13 7 1 4 2 14 15 2 11 13 8 1
* 3 10 10 6 6 12 12 11 5 9 9 5 0 3 7 8
* 4 15 1 12 14 8 8 2 13 4 6 9 2 1 11 7
* 15 5 12 11 9 3 7 14 3 10 10 0 5 6 0 13
*
* 15 3 1 13 8 4 14 7 6 15 11 2 3 8 4 14
* 9 12 7 0 2 1 13 10 12 6 0 9 5 11 10 5
* 0 13 14 8 7 10 11 1 10 3 4 15 13 4 1 2
* 5 11 8 6 12 7 6 12 9 0 3 5 2 14 15 9
*
* 10 13 0 7 9 0 14 9 6 3 3 4 15 6 5 10
* 1 2 13 8 12 5 7 14 11 12 4 11 2 15 8 1
* 13 1 6 10 4 13 9 0 8 6 15 9 3 8 0 7
* 11 4 1 15 2 14 12 3 5 11 10 5 14 2 7 12
*
* 7 13 13 8 14 11 3 5 0 6 6 15 9 0 10 3
* 1 4 2 7 8 2 5 12 11 1 12 10 4 14 15 9
* 10 3 6 15 9 0 0 6 12 10 11 1 7 13 13 8
* 15 9 1 4 3 5 14 11 5 12 2 7 8 2 4 14
*
* 2 14 12 11 4 2 1 12 7 4 10 7 11 13 6 1
* 8 5 5 0 3 15 15 10 13 3 0 9 14 8 9 6
* 4 11 2 8 1 12 11 7 10 1 13 14 7 2 8 13
* 15 6 9 15 12 0 5 9 6 10 3 4 0 5 14 3
*
* 12 10 1 15 10 4 15 2 9 7 2 12 6 9 8 5
* 0 6 13 1 3 13 4 14 14 0 7 11 5 3 11 8
* 9 4 14 3 15 2 5 12 2 9 8 5 12 15 3 10
* 7 11 0 14 4 1 10 7 1 6 13 0 11 8 6 13
*
* 4 13 11 0 2 11 14 7 15 4 0 9 8 1 13 10
* 3 14 12 3 9 5 7 12 5 2 10 15 6 8 1 6
* 1 6 4 11 11 13 13 8 12 1 3 4 7 10 14 7
* 10 9 15 5 6 0 8 15 0 14 5 2 9 3 2 12
*
* 13 1 2 15 8 13 4 8 6 10 15 3 11 7 1 4
* 10 12 9 5 3 6 14 11 5 0 0 14 12 9 7 2
* 7 2 11 1 4 14 1 7 9 4 12 10 14 8 2 13
* 0 15 6 12 10 9 13 0 15 3 3 5 5 6 8 11
*
* P is a 32-to-32 bit permutation. Its output contains the following
* bits of its input (listed in order MSB to LSB of output).
*
* 16 25 12 11 3 20 4 15 31 17 9 6 27 14 1 22
* 30 24 8 18 0 5 29 23 13 19 2 26 10 21 28 7
*
* PC1 is a 64-to-56 bit selection function. Its output is in two words,
* C and D. The word C contains the following bits of its input (listed
* in order MSB to LSB of output).
*
* 7 15 23 31 39 47 55 63 6 14 22 30 38 46
* 54 62 5 13 21 29 37 45 53 61 4 12 20 28
*
* And the word D contains these bits.
*
* 1 9 17 25 33 41 49 57 2 10 18 26 34 42
* 50 58 3 11 19 27 35 43 51 59 36 44 52 60
*
* PC2 is a 56-to-48 bit selection function. Its input is in two words,
* C and D. These are treated as one 56-bit word (with C more significant,
* so that bits 55 to 28 of the word are bits 27 to 0 of C, and bits 27 to
* 0 of the word are bits 27 to 0 of D). The output contains the following
* bits of this 56-bit input word (listed in order MSB to LSB of output).
*
* 42 39 45 32 55 51 53 28 41 50 35 46 33 37 44 52 30 48 40 49 29 36 43 54
* 15 4 25 19 9 1 26 16 5 11 23 8 12 7 17 0 22 3 10 14 6 20 27 24
*/
/*
* Implementation details
* ----------------------
*
* If you look at the code in this module, you'll find it looks
* nothing _like_ the above algorithm. Here I explain the
* differences...
*
* Key setup has not been heavily optimised here. We are not
* concerned with key agility: we aren't codebreakers. We don't
* mind a little delay (and it really is a little one; it may be a
* factor of five or so slower than it could be but it's still not
* an appreciable length of time) while setting up. The only tweaks
* in the key setup are ones which change the format of the key
* schedule to speed up the actual encryption. I'll describe those
* below.
*
* The first and most obvious optimisation is the S-boxes. Since
* each S-box always targets the same four bits in the final 32-bit
* word, so the output from (for example) S-box 0 must always be
* shifted left 28 bits, we can store the already-shifted outputs
* in the lookup tables. This reduces lookup-and-shift to lookup,
* so the S-box step is now just a question of ORing together eight
* table lookups.
*
* The permutation P is just a bit order change; it's invariant
* with respect to OR, in that P(x)|P(y) = P(x|y). Therefore, we
* can apply P to every entry of the S-box tables and then we don't
* have to do it in the code of f(). This yields a set of tables
* which might be called SP-boxes.
*
* The bit-selection function E is our next target. Note that E is
* immediately followed by the operation of splitting into 6-bit
* chunks. Examining the 6-bit chunks coming out of E we notice
* they're all contiguous within the word (speaking cyclically -
* the end two wrap round); so we can extract those bit strings
* individually rather than explicitly running E. This would yield
* code such as
*
* y |= SPboxes[0][ (rotl(R, 5) ^ top6bitsofK) & 0x3F ];
* t |= SPboxes[1][ (rotl(R,11) ^ next6bitsofK) & 0x3F ];
*
* and so on; and the key schedule preparation would have to
* provide each 6-bit chunk separately.
*
* Really we'd like to XOR in the key schedule element before
* looking up bit strings in R. This we can't do, naively, because
* the 6-bit strings we want overlap. But look at the strings:
*
* 3322222222221111111111
* bit 10987654321098765432109876543210
*
* box0 XXXXX X
* box1 XXXXXX
* box2 XXXXXX
* box3 XXXXXX
* box4 XXXXXX
* box5 XXXXXX
* box6 XXXXXX
* box7 X XXXXX
*
* The bit strings we need to XOR in for boxes 0, 2, 4 and 6 don't
* overlap with each other. Neither do the ones for boxes 1, 3, 5
* and 7. So we could provide the key schedule in the form of two
* words that we can separately XOR into R, and then every S-box
* index is available as a (cyclically) contiguous 6-bit substring
* of one or the other of the results.
*
* The comments in Eric Young's libdes implementation point out
* that two of these bit strings require a rotation (rather than a
* simple shift) to extract. It's unavoidable that at least _one_
* must do; but we can actually run the whole inner algorithm (all
* 16 rounds) rotated one bit to the left, so that what the `real'
* DES description sees as L=0x80000001 we see as L=0x00000003.
* This requires rotating all our SP-box entries one bit to the
* left, and rotating each word of the key schedule elements one to
* the left, and rotating L and R one bit left just after IP and
* one bit right again just before FP. And in each round we convert
* a rotate into a shift, so we've saved a few per cent.
*
* That's about it for the inner loop; the SP-box tables as listed
* below are what I've described here (the original S value,
* shifted to its final place in the input to P, run through P, and
* then rotated one bit left). All that remains is to optimise the
* initial permutation IP.
*
* IP is not an arbitrary permutation. It has the nice property
* that if you take any bit number, write it in binary (6 bits),
* permute those 6 bits and invert some of them, you get the final
* position of that bit. Specifically, the bit whose initial
* position is given (in binary) as fedcba ends up in position
* AcbFED (where a capital letter denotes the inverse of a bit).
*
* We have the 64-bit data in two 32-bit words L and R, where bits
* in L are those with f=1 and bits in R are those with f=0. We
* note that we can do a simple transformation: suppose we exchange
* the bits with f=1,c=0 and the bits with f=0,c=1. This will cause
* the bit fedcba to be in position cedfba - we've `swapped' bits c
* and f in the position of each bit!
*
* Better still, this transformation is easy. In the example above,
* bits in L with c=0 are bits 0x0F0F0F0F, and those in R with c=1
* are 0xF0F0F0F0. So we can do
*
* difference = ((R >> 4) ^ L) & 0x0F0F0F0F
* R ^= (difference << 4)
* L ^= difference
*
* to perform the swap. Let's denote this by bitswap(4,0x0F0F0F0F).
* Also, we can invert the bit at the top just by exchanging L and
* R. So in a few swaps and a few of these bit operations we can
* do:
*
* Initially the position of bit fedcba is fedcba
* Swap L with R to make it Fedcba
* Perform bitswap( 4,0x0F0F0F0F) to make it cedFba
* Perform bitswap(16,0x0000FFFF) to make it ecdFba
* Swap L with R to make it EcdFba
* Perform bitswap( 2,0x33333333) to make it bcdFEa
* Perform bitswap( 8,0x00FF00FF) to make it dcbFEa
* Swap L with R to make it DcbFEa
* Perform bitswap( 1,0x55555555) to make it acbFED
* Swap L with R to make it AcbFED
*
* (In the actual code the four swaps are implicit: R and L are
* simply used the other way round in the first, second and last
* bitswap operations.)
*
* The final permutation is just the inverse of IP, so it can be
* performed by a similar set of operations.
*/
typedef struct {
word32 k0246[16], k1357[16];
word32 iv0, iv1;
} DESContext;
#define rotl(x, c) ( (x << c) | (x >> (32-c)) )
#define rotl28(x, c) ( ( (x << c) | (x >> (28-c)) ) & 0x0FFFFFFF)
static word32 bitsel(word32 * input, const int *bitnums, int size)
{
word32 ret = 0;
while (size--) {
int bitpos = *bitnums++;
ret <<= 1;
if (bitpos >= 0)
ret |= 1 & (input[bitpos / 32] >> (bitpos % 32));
}
return ret;
}
static void des_key_setup(word32 key_msw, word32 key_lsw, DESContext * sched)
{
static const int PC1_Cbits[] = {
7, 15, 23, 31, 39, 47, 55, 63, 6, 14, 22, 30, 38, 46,
54, 62, 5, 13, 21, 29, 37, 45, 53, 61, 4, 12, 20, 28
};
static const int PC1_Dbits[] = {
1, 9, 17, 25, 33, 41, 49, 57, 2, 10, 18, 26, 34, 42,
50, 58, 3, 11, 19, 27, 35, 43, 51, 59, 36, 44, 52, 60
};
/*
* The bit numbers in the two lists below don't correspond to
* the ones in the above description of PC2, because in the
* above description C and D are concatenated so `bit 28' means
* bit 0 of C. In this implementation we're using the standard
* `bitsel' function above and C is in the second word, so bit
* 0 of C is addressed by writing `32' here.
*/
static const int PC2_0246[] = {
49, 36, 59, 55, -1, -1, 37, 41, 48, 56, 34, 52, -1, -1, 15, 4,
25, 19, 9, 1, -1, -1, 12, 7, 17, 0, 22, 3, -1, -1, 46, 43
};
static const int PC2_1357[] = {
-1, -1, 57, 32, 45, 54, 39, 50, -1, -1, 44, 53, 33, 40, 47, 58,
-1, -1, 26, 16, 5, 11, 23, 8, -1, -1, 10, 14, 6, 20, 27, 24
};
static const int leftshifts[] =
{ 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 };
word32 C, D;
word32 buf[2];
int i;
buf[0] = key_lsw;
buf[1] = key_msw;
C = bitsel(buf, PC1_Cbits, 28);
D = bitsel(buf, PC1_Dbits, 28);
for (i = 0; i < 16; i++) {
C = rotl28(C, leftshifts[i]);
D = rotl28(D, leftshifts[i]);
buf[0] = D;
buf[1] = C;
sched->k0246[i] = bitsel(buf, PC2_0246, 32);
sched->k1357[i] = bitsel(buf, PC2_1357, 32);
}
sched->iv0 = sched->iv1 = 0;
}
static const word32 SPboxes[8][64] = {
{0x01010400, 0x00000000, 0x00010000, 0x01010404,
0x01010004, 0x00010404, 0x00000004, 0x00010000,
0x00000400, 0x01010400, 0x01010404, 0x00000400,
0x01000404, 0x01010004, 0x01000000, 0x00000004,
0x00000404, 0x01000400, 0x01000400, 0x00010400,
0x00010400, 0x01010000, 0x01010000, 0x01000404,
0x00010004, 0x01000004, 0x01000004, 0x00010004,
0x00000000, 0x00000404, 0x00010404, 0x01000000,
0x00010000, 0x01010404, 0x00000004, 0x01010000,
0x01010400, 0x01000000, 0x01000000, 0x00000400,
0x01010004, 0x00010000, 0x00010400, 0x01000004,
0x00000400, 0x00000004, 0x01000404, 0x00010404,
0x01010404, 0x00010004, 0x01010000, 0x01000404,
0x01000004, 0x00000404, 0x00010404, 0x01010400,
0x00000404, 0x01000400, 0x01000400, 0x00000000,
0x00010004, 0x00010400, 0x00000000, 0x01010004L},
{0x80108020, 0x80008000, 0x00008000, 0x00108020,
0x00100000, 0x00000020, 0x80100020, 0x80008020,
0x80000020, 0x80108020, 0x80108000, 0x80000000,
0x80008000, 0x00100000, 0x00000020, 0x80100020,
0x00108000, 0x00100020, 0x80008020, 0x00000000,
0x80000000, 0x00008000, 0x00108020, 0x80100000,
0x00100020, 0x80000020, 0x00000000, 0x00108000,
0x00008020, 0x80108000, 0x80100000, 0x00008020,
0x00000000, 0x00108020, 0x80100020, 0x00100000,
0x80008020, 0x80100000, 0x80108000, 0x00008000,
0x80100000, 0x80008000, 0x00000020, 0x80108020,
0x00108020, 0x00000020, 0x00008000, 0x80000000,
0x00008020, 0x80108000, 0x00100000, 0x80000020,
0x00100020, 0x80008020, 0x80000020, 0x00100020,
0x00108000, 0x00000000, 0x80008000, 0x00008020,
0x80000000, 0x80100020, 0x80108020, 0x00108000L},
{0x00000208, 0x08020200, 0x00000000, 0x08020008,
0x08000200, 0x00000000, 0x00020208, 0x08000200,
0x00020008, 0x08000008, 0x08000008, 0x00020000,
0x08020208, 0x00020008, 0x08020000, 0x00000208,
0x08000000, 0x00000008, 0x08020200, 0x00000200,
0x00020200, 0x08020000, 0x08020008, 0x00020208,
0x08000208, 0x00020200, 0x00020000, 0x08000208,
0x00000008, 0x08020208, 0x00000200, 0x08000000,
0x08020200, 0x08000000, 0x00020008, 0x00000208,
0x00020000, 0x08020200, 0x08000200, 0x00000000,
0x00000200, 0x00020008, 0x08020208, 0x08000200,
0x08000008, 0x00000200, 0x00000000, 0x08020008,
0x08000208, 0x00020000, 0x08000000, 0x08020208,
0x00000008, 0x00020208, 0x00020200, 0x08000008,
0x08020000, 0x08000208, 0x00000208, 0x08020000,
0x00020208, 0x00000008, 0x08020008, 0x00020200L},
{0x00802001, 0x00002081, 0x00002081, 0x00000080,
0x00802080, 0x00800081, 0x00800001, 0x00002001,
0x00000000, 0x00802000, 0x00802000, 0x00802081,
0x00000081, 0x00000000, 0x00800080, 0x00800001,
0x00000001, 0x00002000, 0x00800000, 0x00802001,
0x00000080, 0x00800000, 0x00002001, 0x00002080,
0x00800081, 0x00000001, 0x00002080, 0x00800080,
0x00002000, 0x00802080, 0x00802081, 0x00000081,
0x00800080, 0x00800001, 0x00802000, 0x00802081,
0x00000081, 0x00000000, 0x00000000, 0x00802000,
0x00002080, 0x00800080, 0x00800081, 0x00000001,
0x00802001, 0x00002081, 0x00002081, 0x00000080,
0x00802081, 0x00000081, 0x00000001, 0x00002000,
0x00800001, 0x00002001, 0x00802080, 0x00800081,
0x00002001, 0x00002080, 0x00800000, 0x00802001,
0x00000080, 0x00800000, 0x00002000, 0x00802080L},
{0x00000100, 0x02080100, 0x02080000, 0x42000100,
0x00080000, 0x00000100, 0x40000000, 0x02080000,
0x40080100, 0x00080000, 0x02000100, 0x40080100,
0x42000100, 0x42080000, 0x00080100, 0x40000000,
0x02000000, 0x40080000, 0x40080000, 0x00000000,
0x40000100, 0x42080100, 0x42080100, 0x02000100,
0x42080000, 0x40000100, 0x00000000, 0x42000000,
0x02080100, 0x02000000, 0x42000000, 0x00080100,
0x00080000, 0x42000100, 0x00000100, 0x02000000,
0x40000000, 0x02080000, 0x42000100, 0x40080100,
0x02000100, 0x40000000, 0x42080000, 0x02080100,
0x40080100, 0x00000100, 0x02000000, 0x42080000,
0x42080100, 0x00080100, 0x42000000, 0x42080100,
0x02080000, 0x00000000, 0x40080000, 0x42000000,
0x00080100, 0x02000100, 0x40000100, 0x00080000,
0x00000000, 0x40080000, 0x02080100, 0x40000100L},
{0x20000010, 0x20400000, 0x00004000, 0x20404010,
0x20400000, 0x00000010, 0x20404010, 0x00400000,
0x20004000, 0x00404010, 0x00400000, 0x20000010,
0x00400010, 0x20004000, 0x20000000, 0x00004010,
0x00000000, 0x00400010, 0x20004010, 0x00004000,
0x00404000, 0x20004010, 0x00000010, 0x20400010,
0x20400010, 0x00000000, 0x00404010, 0x20404000,
0x00004010, 0x00404000, 0x20404000, 0x20000000,
0x20004000, 0x00000010, 0x20400010, 0x00404000,
0x20404010, 0x00400000, 0x00004010, 0x20000010,
0x00400000, 0x20004000, 0x20000000, 0x00004010,
0x20000010, 0x20404010, 0x00404000, 0x20400000,
0x00404010, 0x20404000, 0x00000000, 0x20400010,
0x00000010, 0x00004000, 0x20400000, 0x00404010,
0x00004000, 0x00400010, 0x20004010, 0x00000000,
0x20404000, 0x20000000, 0x00400010, 0x20004010L},
{0x00200000, 0x04200002, 0x04000802, 0x00000000,
0x00000800, 0x04000802, 0x00200802, 0x04200800,
0x04200802, 0x00200000, 0x00000000, 0x04000002,
0x00000002, 0x04000000, 0x04200002, 0x00000802,
0x04000800, 0x00200802, 0x00200002, 0x04000800,
0x04000002, 0x04200000, 0x04200800, 0x00200002,
0x04200000, 0x00000800, 0x00000802, 0x04200802,
0x00200800, 0x00000002, 0x04000000, 0x00200800,
0x04000000, 0x00200800, 0x00200000, 0x04000802,
0x04000802, 0x04200002, 0x04200002, 0x00000002,
0x00200002, 0x04000000, 0x04000800, 0x00200000,
0x04200800, 0x00000802, 0x00200802, 0x04200800,
0x00000802, 0x04000002, 0x04200802, 0x04200000,
0x00200800, 0x00000000, 0x00000002, 0x04200802,
0x00000000, 0x00200802, 0x04200000, 0x00000800,
0x04000002, 0x04000800, 0x00000800, 0x00200002L},
{0x10001040, 0x00001000, 0x00040000, 0x10041040,
0x10000000, 0x10001040, 0x00000040, 0x10000000,
0x00040040, 0x10040000, 0x10041040, 0x00041000,
0x10041000, 0x00041040, 0x00001000, 0x00000040,
0x10040000, 0x10000040, 0x10001000, 0x00001040,
0x00041000, 0x00040040, 0x10040040, 0x10041000,
0x00001040, 0x00000000, 0x00000000, 0x10040040,
0x10000040, 0x10001000, 0x00041040, 0x00040000,
0x00041040, 0x00040000, 0x10041000, 0x00001000,
0x00000040, 0x10040040, 0x00001000, 0x00041040,
0x10001000, 0x00000040, 0x10000040, 0x10040000,
0x10040040, 0x10000000, 0x00040000, 0x10001040,
0x00000000, 0x10041040, 0x00040040, 0x10000040,
0x10040000, 0x10001000, 0x10001040, 0x00000000,
0x10041040, 0x00041000, 0x00041000, 0x00001040,
0x00001040, 0x00040040, 0x10000000, 0x10041000L}
};
#define f(R, K0246, K1357) (\
s0246 = R ^ K0246, \
s1357 = R ^ K1357, \
s0246 = rotl(s0246, 28), \
SPboxes[0] [(s0246 >> 24) & 0x3F] | \
SPboxes[1] [(s1357 >> 24) & 0x3F] | \
SPboxes[2] [(s0246 >> 16) & 0x3F] | \
SPboxes[3] [(s1357 >> 16) & 0x3F] | \
SPboxes[4] [(s0246 >> 8) & 0x3F] | \
SPboxes[5] [(s1357 >> 8) & 0x3F] | \
SPboxes[6] [(s0246 ) & 0x3F] | \
SPboxes[7] [(s1357 ) & 0x3F])
#define bitswap(L, R, n, mask) (\
swap = mask & ( (R >> n) ^ L ), \
R ^= swap << n, \
L ^= swap)
/* Initial permutation */
#define IP(L, R) (\
bitswap(R, L, 4, 0x0F0F0F0F), \
bitswap(R, L, 16, 0x0000FFFF), \
bitswap(L, R, 2, 0x33333333), \
bitswap(L, R, 8, 0x00FF00FF), \
bitswap(R, L, 1, 0x55555555))
/* Final permutation */
#define FP(L, R) (\
bitswap(R, L, 1, 0x55555555), \
bitswap(L, R, 8, 0x00FF00FF), \
bitswap(L, R, 2, 0x33333333), \
bitswap(R, L, 16, 0x0000FFFF), \
bitswap(R, L, 4, 0x0F0F0F0F))
static void des_encipher(word32 * output, word32 L, word32 R,
DESContext * sched)
{
word32 swap, s0246, s1357;
IP(L, R);
L = rotl(L, 1);
R = rotl(R, 1);
L ^= f(R, sched->k0246[0], sched->k1357[0]);
R ^= f(L, sched->k0246[1], sched->k1357[1]);
L ^= f(R, sched->k0246[2], sched->k1357[2]);
R ^= f(L, sched->k0246[3], sched->k1357[3]);
L ^= f(R, sched->k0246[4], sched->k1357[4]);
R ^= f(L, sched->k0246[5], sched->k1357[5]);
L ^= f(R, sched->k0246[6], sched->k1357[6]);
R ^= f(L, sched->k0246[7], sched->k1357[7]);
L ^= f(R, sched->k0246[8], sched->k1357[8]);
R ^= f(L, sched->k0246[9], sched->k1357[9]);
L ^= f(R, sched->k0246[10], sched->k1357[10]);
R ^= f(L, sched->k0246[11], sched->k1357[11]);
L ^= f(R, sched->k0246[12], sched->k1357[12]);
R ^= f(L, sched->k0246[13], sched->k1357[13]);
L ^= f(R, sched->k0246[14], sched->k1357[14]);
R ^= f(L, sched->k0246[15], sched->k1357[15]);
L = rotl(L, 31);
R = rotl(R, 31);
swap = L;
L = R;
R = swap;
FP(L, R);
output[0] = L;
output[1] = R;
}
static void des_decipher(word32 * output, word32 L, word32 R,
DESContext * sched)
{
word32 swap, s0246, s1357;
IP(L, R);
L = rotl(L, 1);
R = rotl(R, 1);
L ^= f(R, sched->k0246[15], sched->k1357[15]);
R ^= f(L, sched->k0246[14], sched->k1357[14]);
L ^= f(R, sched->k0246[13], sched->k1357[13]);
R ^= f(L, sched->k0246[12], sched->k1357[12]);
L ^= f(R, sched->k0246[11], sched->k1357[11]);
R ^= f(L, sched->k0246[10], sched->k1357[10]);
L ^= f(R, sched->k0246[9], sched->k1357[9]);
R ^= f(L, sched->k0246[8], sched->k1357[8]);
L ^= f(R, sched->k0246[7], sched->k1357[7]);
R ^= f(L, sched->k0246[6], sched->k1357[6]);
L ^= f(R, sched->k0246[5], sched->k1357[5]);
R ^= f(L, sched->k0246[4], sched->k1357[4]);
L ^= f(R, sched->k0246[3], sched->k1357[3]);
R ^= f(L, sched->k0246[2], sched->k1357[2]);
L ^= f(R, sched->k0246[1], sched->k1357[1]);
R ^= f(L, sched->k0246[0], sched->k1357[0]);
L = rotl(L, 31);
R = rotl(R, 31);
swap = L;
L = R;
R = swap;
FP(L, R);
output[0] = L;
output[1] = R;
}
#define GET_32BIT_MSB_FIRST(cp) \
(((unsigned long)(unsigned char)(cp)[3]) | \
((unsigned long)(unsigned char)(cp)[2] << 8) | \
((unsigned long)(unsigned char)(cp)[1] << 16) | \
((unsigned long)(unsigned char)(cp)[0] << 24))
#define PUT_32BIT_MSB_FIRST(cp, value) do { \
(cp)[3] = (value); \
(cp)[2] = (value) >> 8; \
(cp)[1] = (value) >> 16; \
(cp)[0] = (value) >> 24; } while (0)
static void des_cbc_encrypt(unsigned char *dest, const unsigned char *src,
unsigned int len, DESContext * sched)
{
word32 out[2], iv0, iv1;
unsigned int i;
assert((len & 7) == 0);
iv0 = sched->iv0;
iv1 = sched->iv1;
for (i = 0; i < len; i += 8) {
iv0 ^= GET_32BIT_MSB_FIRST(src);
src += 4;
iv1 ^= GET_32BIT_MSB_FIRST(src);
src += 4;
des_encipher(out, iv0, iv1, sched);
iv0 = out[0];
iv1 = out[1];
PUT_32BIT_MSB_FIRST(dest, iv0);
dest += 4;
PUT_32BIT_MSB_FIRST(dest, iv1);
dest += 4;
}
sched->iv0 = iv0;
sched->iv1 = iv1;
}
static void des_cbc_decrypt(unsigned char *dest, const unsigned char *src,
unsigned int len, DESContext * sched)
{
word32 out[2], iv0, iv1, xL, xR;
unsigned int i;
assert((len & 7) == 0);
iv0 = sched->iv0;
iv1 = sched->iv1;
for (i = 0; i < len; i += 8) {
xL = GET_32BIT_MSB_FIRST(src);
src += 4;
xR = GET_32BIT_MSB_FIRST(src);
src += 4;
des_decipher(out, xL, xR, sched);
iv0 ^= out[0];
iv1 ^= out[1];
PUT_32BIT_MSB_FIRST(dest, iv0);
dest += 4;
PUT_32BIT_MSB_FIRST(dest, iv1);
dest += 4;
iv0 = xL;
iv1 = xR;
}
sched->iv0 = iv0;
sched->iv1 = iv1;
}
static void des_3cbc_encrypt(unsigned char *dest, const unsigned char *src,
unsigned int len, DESContext * scheds)
{
des_cbc_encrypt(dest, src, len, &scheds[0]);
des_cbc_decrypt(dest, src, len, &scheds[1]);
des_cbc_encrypt(dest, src, len, &scheds[2]);
}
static void des_cbc3_encrypt(unsigned char *dest, const unsigned char *src,
unsigned int len, DESContext * scheds)
{
word32 out[2], iv0, iv1;
unsigned int i;
assert((len & 7) == 0);
iv0 = scheds->iv0;
iv1 = scheds->iv1;
for (i = 0; i < len; i += 8) {
iv0 ^= GET_32BIT_MSB_FIRST(src);
src += 4;
iv1 ^= GET_32BIT_MSB_FIRST(src);
src += 4;
des_encipher(out, iv0, iv1, &scheds[0]);
des_decipher(out, out[0], out[1], &scheds[1]);
des_encipher(out, out[0], out[1], &scheds[2]);
iv0 = out[0];
iv1 = out[1];
PUT_32BIT_MSB_FIRST(dest, iv0);
dest += 4;
PUT_32BIT_MSB_FIRST(dest, iv1);
dest += 4;
}
scheds->iv0 = iv0;
scheds->iv1 = iv1;
}
static void des_3cbc_decrypt(unsigned char *dest, const unsigned char *src,
unsigned int len, DESContext * scheds)
{
des_cbc_decrypt(dest, src, len, &scheds[2]);
des_cbc_encrypt(dest, src, len, &scheds[1]);
des_cbc_decrypt(dest, src, len, &scheds[0]);
}
static void des_cbc3_decrypt(unsigned char *dest, const unsigned char *src,
unsigned int len, DESContext * scheds)
{
word32 out[2], iv0, iv1, xL, xR;
unsigned int i;
assert((len & 7) == 0);
iv0 = scheds->iv0;
iv1 = scheds->iv1;
for (i = 0; i < len; i += 8) {
xL = GET_32BIT_MSB_FIRST(src);
src += 4;
xR = GET_32BIT_MSB_FIRST(src);
src += 4;
des_decipher(out, xL, xR, &scheds[2]);
des_encipher(out, out[0], out[1], &scheds[1]);
des_decipher(out, out[0], out[1], &scheds[0]);
iv0 ^= out[0];
iv1 ^= out[1];
PUT_32BIT_MSB_FIRST(dest, iv0);
dest += 4;
PUT_32BIT_MSB_FIRST(dest, iv1);
dest += 4;
iv0 = xL;
iv1 = xR;
}
scheds->iv0 = iv0;
scheds->iv1 = iv1;
}
static void *des3_make_context(void)
{
return snewn(3, DESContext);
}
static void *des3_ssh1_make_context(void)
{
/* Need 3 keys for each direction, in SSH1 */
return snewn(6, DESContext);
}
static void *des_make_context(void)
{
return snew(DESContext);
}
static void *des_ssh1_make_context(void)
{
/* Need one key for each direction, in SSH1 */
return snewn(2, DESContext);
}
static void des3_free_context(void *handle) /* used for both 3DES and DES */
{
sfree(handle);
}
static void des3_key(void *handle, unsigned char *key)
{
DESContext *keys = (DESContext *) handle;
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &keys[0]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
GET_32BIT_MSB_FIRST(key + 12), &keys[1]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 16),
GET_32BIT_MSB_FIRST(key + 20), &keys[2]);
}
static void des3_iv(void *handle, unsigned char *key)
{
DESContext *keys = (DESContext *) handle;
keys[0].iv0 = GET_32BIT_MSB_FIRST(key);
keys[0].iv1 = GET_32BIT_MSB_FIRST(key + 4);
}
static void des_key(void *handle, unsigned char *key)
{
DESContext *keys = (DESContext *) handle;
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &keys[0]);
}
static void des3_sesskey(void *handle, unsigned char *key)
{
DESContext *keys = (DESContext *) handle;
des3_key(keys, key);
des3_key(keys+3, key);
}
static void des3_encrypt_blk(void *handle, unsigned char *blk, int len)
{
DESContext *keys = (DESContext *) handle;
des_3cbc_encrypt(blk, blk, len, keys);
}
static void des3_decrypt_blk(void *handle, unsigned char *blk, int len)
{
DESContext *keys = (DESContext *) handle;
des_3cbc_decrypt(blk, blk, len, keys+3);
}
static void des3_ssh2_encrypt_blk(void *handle, unsigned char *blk, int len)
{
DESContext *keys = (DESContext *) handle;
des_cbc3_encrypt(blk, blk, len, keys);
}
static void des3_ssh2_decrypt_blk(void *handle, unsigned char *blk, int len)
{
DESContext *keys = (DESContext *) handle;
des_cbc3_decrypt(blk, blk, len, keys);
}
static void des_ssh2_encrypt_blk(void *handle, unsigned char *blk, int len)
{
DESContext *keys = (DESContext *) handle;
des_cbc_encrypt(blk, blk, len, keys);
}
static void des_ssh2_decrypt_blk(void *handle, unsigned char *blk, int len)
{
DESContext *keys = (DESContext *) handle;
des_cbc_decrypt(blk, blk, len, keys);
}
void des3_decrypt_pubkey(unsigned char *key, unsigned char *blk, int len)
{
DESContext ourkeys[3];
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[2]);
des_3cbc_decrypt(blk, blk, len, ourkeys);
memset(ourkeys, 0, sizeof(ourkeys));
}
void des3_encrypt_pubkey(unsigned char *key, unsigned char *blk, int len)
{
DESContext ourkeys[3];
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[2]);
des_3cbc_encrypt(blk, blk, len, ourkeys);
memset(ourkeys, 0, sizeof(ourkeys));
}
void des3_decrypt_pubkey_ossh(unsigned char *key, unsigned char *iv,
unsigned char *blk, int len)
{
DESContext ourkeys[3];
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 16),
GET_32BIT_MSB_FIRST(key + 20), &ourkeys[2]);
ourkeys[0].iv0 = GET_32BIT_MSB_FIRST(iv);
ourkeys[0].iv1 = GET_32BIT_MSB_FIRST(iv+4);
des_cbc3_decrypt(blk, blk, len, ourkeys);
memset(ourkeys, 0, sizeof(ourkeys));
}
void des3_encrypt_pubkey_ossh(unsigned char *key, unsigned char *iv,
unsigned char *blk, int len)
{
DESContext ourkeys[3];
des_key_setup(GET_32BIT_MSB_FIRST(key),
GET_32BIT_MSB_FIRST(key + 4), &ourkeys[0]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 8),
GET_32BIT_MSB_FIRST(key + 12), &ourkeys[1]);
des_key_setup(GET_32BIT_MSB_FIRST(key + 16),
GET_32BIT_MSB_FIRST(key + 20), &ourkeys[2]);
ourkeys[0].iv0 = GET_32BIT_MSB_FIRST(iv);
ourkeys[0].iv1 = GET_32BIT_MSB_FIRST(iv+4);
des_cbc3_encrypt(blk, blk, len, ourkeys);
memset(ourkeys, 0, sizeof(ourkeys));
}
static void des_keysetup_xdmauth(unsigned char *keydata, DESContext *dc)
{
unsigned char key[8];
int i, nbits, j;
unsigned int bits;
bits = 0;
nbits = 0;
j = 0;
for (i = 0; i < 8; i++) {
if (nbits < 7) {
bits = (bits << 8) | keydata[j];
nbits += 8;
j++;
}
key[i] = (bits >> (nbits - 7)) << 1;
bits &= ~(0x7F << (nbits - 7));
nbits -= 7;
}
des_key_setup(GET_32BIT_MSB_FIRST(key), GET_32BIT_MSB_FIRST(key + 4), dc);
}
void des_encrypt_xdmauth(unsigned char *keydata, unsigned char *blk, int len)
{
DESContext dc;
des_keysetup_xdmauth(keydata, &dc);
des_cbc_encrypt(blk, blk, 24, &dc);
}
void des_decrypt_xdmauth(unsigned char *keydata, unsigned char *blk, int len)
{
DESContext dc;
des_keysetup_xdmauth(keydata, &dc);
des_cbc_decrypt(blk, blk, 24, &dc);
}
static const struct ssh2_cipher ssh_3des_ssh2 = {
des3_make_context, des3_free_context, des3_iv, des3_key,
des3_ssh2_encrypt_blk, des3_ssh2_decrypt_blk,
"3des-cbc",
8, 168, "triple-DES"
};
/*
* Single DES in ssh2. It isn't clear that "des-cbc" is an official
* cipher name, but ssh.com support it and apparently aren't the
* only people to do so, so we sigh and implement it anyway.
*/
static const struct ssh2_cipher ssh_des_ssh2 = {
des_make_context, des3_free_context, des3_iv, des_key,
des_ssh2_encrypt_blk, des_ssh2_decrypt_blk,
"des-cbc",
8, 56, "single-DES"
};
static const struct ssh2_cipher *const des3_list[] = {
&ssh_3des_ssh2
};
const struct ssh2_ciphers ssh2_3des = {
sizeof(des3_list) / sizeof(*des3_list),
des3_list
};
static const struct ssh2_cipher *const des_list[] = {
&ssh_des_ssh2
};
const struct ssh2_ciphers ssh2_des = {
sizeof(des3_list) / sizeof(*des_list),
des_list
};
const struct ssh_cipher ssh_3des = {
des3_ssh1_make_context, des3_free_context, des3_sesskey,
des3_encrypt_blk, des3_decrypt_blk,
8, "triple-DES"
};
static void des_sesskey(void *handle, unsigned char *key)
{
DESContext *keys = (DESContext *) handle;
des_key(keys, key);
des_key(keys+1, key);
}
static void des_encrypt_blk(void *handle, unsigned char *blk, int len)
{
DESContext *keys = (DESContext *) handle;
des_cbc_encrypt(blk, blk, len, keys);
}
static void des_decrypt_blk(void *handle, unsigned char *blk, int len)
{
DESContext *keys = (DESContext *) handle;
des_cbc_decrypt(blk, blk, len, keys+1);
}
const struct ssh_cipher ssh_des = {
des_ssh1_make_context, des3_free_context, des_sesskey,
des_encrypt_blk, des_decrypt_blk,
8, "single-DES"
};
Reference in New Issue View Git Blame Copy Permalink