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Fix key reuse vuln. in arc4

This commit is contained in:
Neale Pickett 2011-03-17 13:04:13 -06:00
parent e4c252ef4e
commit 40e7560b38
11 changed files with 171 additions and 620 deletions
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114
include/arc4.c
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@ -1,114 +0,0 @@
#include <stdint.h>
#include <stdlib.h>
#include "arc4.h"
#define swap(a, b) do {int _swap=a; a=b, b=_swap;} while (0)
void
arc4_init(struct arc4_ctx *ctx, uint8_t const *key, size_t keylen)
{
int i;
int j = 0;
for (i = 0; i < 256; i += 1) {
ctx->S[i] = i;
}
for (i = 0; i < 256; i += 1) {
j = (j + ctx->S[i] + key[i % keylen]) % 256;
swap(ctx->S[i], ctx->S[j]);
}
ctx->i = 0;
ctx->j = 0;
}
uint8_t
arc4_out(struct arc4_ctx *ctx)
{
ctx->i = (ctx->i + 1) % 256;
ctx->j = (ctx->j + ctx->S[ctx->i]) % 256;
swap(ctx->S[ctx->i], ctx->S[ctx->j]);
return ctx->S[(ctx->S[ctx->i] + ctx->S[ctx->j]) % 256];
}
void
arc4_crypt(struct arc4_ctx *ctx,
uint8_t *obuf, const uint8_t *ibuf, size_t buflen)
{
size_t k;
for (k = 0; k < buflen; k += 1) {
obuf[k] = ibuf[k] ^ arc4_out(ctx);
}
}
void
arc4_crypt_buffer(const uint8_t *key, size_t keylen,
uint8_t *buf, size_t buflen)
{
struct arc4_ctx ctx;
arc4_init(&ctx, key, keylen);
arc4_crypt(&ctx, buf, buf, buflen);
}
#ifdef ARC4_MAIN
#include <stdio.h>
#include <sysexits.h>
#include <string.h>
int
main(int argc, char *argv[])
{
struct arc4_ctx ctx;
/* Read key and initialize context */
{
uint8_t key[256];
size_t keylen = 0;
char *ekey = getenv("KEY");
FILE *f;
if (argc == 2) {
if (! (f = fopen(argv[1], "r"))) {
perror(argv[0]);
}
} else {
f = fdopen(3, "r");
}
if (f) {
keylen = fread(key, 1, sizeof(key), f);
fclose(f);
} else if (ekey) {
keylen = strlen(ekey);
if (keylen > sizeof(key)) {
keylen = sizeof(key);
}
memcpy(key, ekey, keylen);
}
if (0 == keylen) {
fprintf(stderr, "Usage: %s [KEYFILE] <PLAINTEXT\n", argv[0]);
fprintf(stderr, "\n");
fprintf(stderr, "You can also pass in the key on fd 3 or in\n");
fprintf(stderr, "$KEY; omit KEYFILE in this case.\n");
return EX_IOERR;
}
arc4_init(&ctx, key, (size_t)keylen);
}
/* Encrypt */
while (1) {
int c = getchar();
if (EOF == c) break;
putchar(c ^ arc4_out(&ctx));
}
return 0;
}
#endif /* ARC4_MAIN */

280
include/md5.c
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/*
* This code implements the MD5 message-digest algorithm.
* The algorithm is due to Ron Rivest. This code was
* written by Colin Plumb in 1993, no copyright is claimed.
* This code is in the public domain; do with it what you wish.
*
* Equivalent code is available from RSA Data Security, Inc.
* This code has been tested against that, and is equivalent,
* except that you don't need to include two pages of legalese
* with every copy.
*
* To compute the message digest of a chunk of bytes, declare an
* MD5Context structure, pass it to MD5Init, call MD5Update as
* needed on buffers full of bytes, and then call MD5Final, which
* will fill a supplied 16-byte array with the digest.
*/
/* Brutally hacked by John Walker back from ANSI C to K&R (no
prototypes) to maintain the tradition that Netfone will compile
with Sun's original "cc". */
#include <memory.h> /* for memcpy() */
#include <stdint.h>
#include <stdio.h>
#include "md5.h"
void md5_transform(uint32_t buf[4], uint32_t in[16]);
#ifndef HIGHFIRST
#define byteReverse(buf, len) /* Nothing */
#else
/*
* Note: this code is harmless on little-endian machines.
*/
static void byteReverse(uint8_t *buf, size_t words)
{
uint32_t t;
do {
t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
((unsigned) buf[1] << 8 | buf[0]);
*(uint32_t *) buf = t;
buf += 4;
} while (--words);
}
#endif
/*
* Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
* initialization constants.
*/
void md5_init(struct md5_context *ctx)
{
ctx->buf[0] = 0x67452301;
ctx->buf[1] = 0xefcdab89;
ctx->buf[2] = 0x98badcfe;
ctx->buf[3] = 0x10325476;
ctx->bits[0] = 0;
ctx->bits[1] = 0;
}
/*
* Update context to reflect the concatenation of another buffer full
* of bytes.
*/
void md5_update(struct md5_context *ctx,
const uint8_t *buf,
size_t len)
{
uint32_t t;
/* Update bitcount */
t = ctx->bits[0];
if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
ctx->bits[1]++; /* Carry from low to high */
ctx->bits[1] += len >> 29;
t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */
/* Handle any leading odd-sized chunks */
if (t) {
unsigned char *p = (unsigned char *) ctx->in + t;
t = 64 - t;
if (len < t) {
memcpy(p, buf, len);
return;
}
memcpy(p, buf, t);
byteReverse(ctx->in, 16);
md5_transform(ctx->buf, (uint32_t *) ctx->in);
buf += t;
len -= t;
}
/* Process data in 64-byte chunks */
while (len >= 64) {
memcpy(ctx->in, buf, 64);
byteReverse(ctx->in, 16);
md5_transform(ctx->buf, (uint32_t *) ctx->in);
buf += 64;
len -= 64;
}
/* Handle any remaining bytes of data. */
memcpy(ctx->in, buf, len);
}
/*
* Final wrapup - pad to 64-byte boundary with the bit pattern
* 1 0* (64-bit count of bits processed, MSB-first)
*/
void md5_final(struct md5_context *ctx, uint8_t *digest)
{
unsigned int count;
uint8_t *p;
/* Compute number of bytes mod 64 */
count = (ctx->bits[0] >> 3) & 0x3F;
/* Set the first char of padding to 0x80. This is safe since there is
always at least one byte free */
p = ctx->in + count;
*p++ = 0x80;
/* Bytes of padding needed to make 64 bytes */
count = 64 - 1 - count;
/* Pad out to 56 mod 64 */
if (count < 8) {
/* Two lots of padding: Pad the first block to 64 bytes */
memset(p, 0, count);
byteReverse(ctx->in, 16);
md5_transform(ctx->buf, (uint32_t *) ctx->in);
/* Now fill the next block with 56 bytes */
memset(ctx->in, 0, 56);
} else {
/* Pad block to 56 bytes */
memset(p, 0, count - 8);
}
byteReverse(ctx->in, 14);
/* Append length in bits and transform */
((uint32_t *) ctx->in)[14] = ctx->bits[0];
((uint32_t *) ctx->in)[15] = ctx->bits[1];
md5_transform(ctx->buf, (uint32_t *) ctx->in);
byteReverse((unsigned char *) ctx->buf, 4);
memcpy(digest, ctx->buf, 16);
memset(ctx, 0, sizeof(ctx)); /* In case it's sensitive */
}
/* The four core functions - F1 is optimized somewhat */
/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))
/* This is the central step in the MD5 algorithm. */
#define md5_step(f, w, x, y, z, data, s) \
( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
/*
* The core of the MD5 algorithm, this alters an existing MD5 hash to
* reflect the addition of 16 longwords of new data. MD5Update blocks
* the data and converts bytes into longwords for this routine.
*/
void md5_transform(uint32_t buf[4], uint32_t in[16])
{
register uint32_t a, b, c, d;
a = buf[0];
b = buf[1];
c = buf[2];
d = buf[3];
md5_step(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
md5_step(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
md5_step(F1, c, d, a, b, in[2] + 0x242070db, 17);
md5_step(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
md5_step(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
md5_step(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
md5_step(F1, c, d, a, b, in[6] + 0xa8304613, 17);
md5_step(F1, b, c, d, a, in[7] + 0xfd469501, 22);
md5_step(F1, a, b, c, d, in[8] + 0x698098d8, 7);
md5_step(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
md5_step(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
md5_step(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
md5_step(F1, a, b, c, d, in[12] + 0x6b901122, 7);
md5_step(F1, d, a, b, c, in[13] + 0xfd987193, 12);
md5_step(F1, c, d, a, b, in[14] + 0xa679438e, 17);
md5_step(F1, b, c, d, a, in[15] + 0x49b40821, 22);
md5_step(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
md5_step(F2, d, a, b, c, in[6] + 0xc040b340, 9);
md5_step(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
md5_step(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
md5_step(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
md5_step(F2, d, a, b, c, in[10] + 0x02441453, 9);
md5_step(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
md5_step(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
md5_step(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
md5_step(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
md5_step(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
md5_step(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
md5_step(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
md5_step(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
md5_step(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
md5_step(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
md5_step(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
md5_step(F3, d, a, b, c, in[8] + 0x8771f681, 11);
md5_step(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
md5_step(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
md5_step(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
md5_step(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
md5_step(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
md5_step(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
md5_step(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
md5_step(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
md5_step(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
md5_step(F3, b, c, d, a, in[6] + 0x04881d05, 23);
md5_step(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
md5_step(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
md5_step(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
md5_step(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
md5_step(F4, a, b, c, d, in[0] + 0xf4292244, 6);
md5_step(F4, d, a, b, c, in[7] + 0x432aff97, 10);
md5_step(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
md5_step(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
md5_step(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
md5_step(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
md5_step(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
md5_step(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
md5_step(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
md5_step(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
md5_step(F4, c, d, a, b, in[6] + 0xa3014314, 15);
md5_step(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
md5_step(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
md5_step(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
md5_step(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
md5_step(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
buf[0] += a;
buf[1] += b;
buf[2] += c;
buf[3] += d;
}
void
md5_digest(const uint8_t *buf, size_t buflen, uint8_t *digest)
{
struct md5_context ctx;
md5_init(&ctx);
md5_update(&ctx, buf, buflen);
md5_final(&ctx, digest);
}
void
md5_hexdigest(const uint8_t *buf, size_t buflen, char *hexdigest)
{
uint8_t digest[MD5_DIGEST_LEN];
int i;
md5_digest(buf, buflen, digest);
for (i = 0; i < MD5_DIGEST_LEN; i += 1) {
sprintf(hexdigest + (i*2), "%02x", digest[i]);
}
}

42
include/md5.h
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@ -1,42 +0,0 @@
#ifndef MD5_H
#define MD5_H
#include <stdint.h>
/* The following tests optimise behaviour on little-endian
machines, where there is no need to reverse the byte order
of 32 bit words in the MD5 computation. By default,
HIGHFIRST is defined, which indicates we're running on a
big-endian (most significant byte first) machine, on which
the byteReverse function in md5.c must be invoked. However,
byteReverse is coded in such a way that it is an identity
function when run on a little-endian machine, so calling it
on such a platform causes no harm apart from wasting time.
If the platform is known to be little-endian, we speed
things up by undefining HIGHFIRST, which defines
byteReverse as a null macro. Doing things in this manner
insures we work on new platforms regardless of their byte
order. */
#define HIGHFIRST
#ifdef __i386__
#undef HIGHFIRST
#endif
#define MD5_DIGEST_LEN 16
#define MD5_HEXDIGEST_LEN (MD5_DIGEST_LEN * 2)
struct md5_context {
uint32_t buf[4];
uint32_t bits[2];
uint8_t in[64];
};
void md5_init(struct md5_context *ctx);
void md5_update(struct md5_context *ctx, const uint8_t *buf, size_t len);
void md5_final(struct md5_context *ctx, uint8_t *digest);
void md5_digest(const uint8_t *buf, size_t buflen, uint8_t *digest);
void md5_hexdigest(const uint8_t *buf, size_t buflen, char *hexdigest);
#endif /* !MD5_H */

46
include/test.c
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#include <stdio.h>
#include <stdint.h>
#include "rand.h"
#include "md5.h"
#include "token.h"
int
main()
{
int i;
uint8_t zeroes[64] = {0};
uint8_t digest[MD5_DIGEST_LEN];
for (i = 0; i < 10; i += 1) {
printf("%d ", randu32() % 10);
}
printf("\n4ae71336e44bf9bf79d2752e234818a5\n");
md5_digest(zeroes, 16, digest);
for (i = 0; i < sizeof(digest); i += 1) {
printf("%02x", digest[i]);
}
printf("\n");
{
char hd[MD5_HEXDIGEST_LEN + 1] = {0};
md5_hexdigest(zeroes, 16, hd);
printf("%s\n", hd);
}
{
ssize_t len;
char token[TOKEN_MAX];
len = read_token("foo", 0, 4, token, sizeof(token));
if (-1 != len) {
printf("rut roh\n");
} else {
printf("Good.\n");
}
}
return 0;
}

117
include/token.c
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@ -1,117 +0,0 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <unistd.h>
#include <values.h>
#ifndef CTF_BASE
#define CTF_BASE "/var/lib/ctf"
#endif
/*
*
* ARC-4 stuff
*
*/
struct arc4_ctx {
uint8_t S[256];
uint8_t i;
uint8_t j;
};
#define swap(a, b) do {int _swap=a; a=b, b=_swap;} while (0)
void
arc4_init(struct arc4_ctx *ctx, uint8_t const *key, size_t keylen)
{
int i;
int j = 0;
for (i = 0; i < 256; i += 1) {
ctx->S[i] = i;
}
for (i = 0; i < 256; i += 1) {
j = (j + ctx->S[i] + key[i % keylen]) % 256;
swap(ctx->S[i], ctx->S[j]);
}
ctx->i = 0;
ctx->j = 0;
}
uint8_t
arc4_out(struct arc4_ctx *ctx)
{
ctx->i = (ctx->i + 1) % 256;
ctx->j = (ctx->j + ctx->S[ctx->i]) % 256;
swap(ctx->S[ctx->i], ctx->S[ctx->j]);
return ctx->S[(ctx->S[ctx->i] + ctx->S[ctx->j]) % 256];
}
void
arc4_crypt(struct arc4_ctx *ctx,
uint8_t *obuf, const uint8_t *ibuf, size_t buflen)
{
size_t k;
for (k = 0; k < buflen; k += 1) {
obuf[k] = ibuf[k] ^ arc4_out(ctx);
}
}
void
arc4_crypt_buffer(const uint8_t *key, size_t keylen,
uint8_t *buf, size_t buflen)
{
struct arc4_ctx ctx;
arc4_init(&ctx, key, keylen);
arc4_crypt(&ctx, buf, buf, buflen);
}
/*
*
*/
ssize_t
read_token_fd(int fd,
uint8_t const *key, size_t keylen,
char *buf, size_t buflen)
{
ssize_t ret;
ret = read(fd, buf, buflen);
if (-1 != ret) {
arc4_crypt_buffer(key, keylen, (uint8_t *)buf, (size_t)ret);
}
return ret;
}
ssize_t
read_token(char const *name,
uint8_t const *key, size_t keylen,
char *buf, size_t buflen)
{
char path[PATH_MAX];
int pathlen;
int fd;
ssize_t ret;
pathlen = snprintf(path, sizeof(path) - 1,
CTF_BASE "/tokens/%s", name);
path[pathlen] = '\0';
fd = open(path, O_RDONLY);
if (-1 == fd) return -1;
ret = read_token_fd(fd, key, keylen, buf, buflen);
close(fd);
return ret;
}

20
include/token.h
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@ -1,20 +0,0 @@
#ifndef __TOKEN_H__
#define __TOKEN_H__
#include <unistd.h>
#include <stdlib.h>
#include <stdint.h>
#define TOKEN_MAX 80
/* ARC4 functions, in case anybody wants 'em */
ssize_t read_token_fd(int fd,
uint8_t const *key, size_t keylen,
char *buf, size_t buflen);
ssize_t read_token(char const *name,
uint8_t const *key, size_t keylen,
char *buf, size_t buflen);
#endif

8
src/Makefile
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@ -1,2 +1,8 @@
all: bubblebabble
TARGETS = bubblebabble arc4
all: $(TARGETS)
arc4: CFLAGS=-DARC4_MAIN
clean:
rm -f *.o $(TARGETS)

161
src/arc4.c Normal file
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@ -0,0 +1,161 @@
#include <stdint.h>
#include <stdlib.h>
#include "arc4.h"
#define DUMPf(fmt, args...) fprintf(stderr, "%s:%s:%d " fmt "\n", __FILE__, __FUNCTION__, __LINE__, ##args)
#define DUMP() DUMPf("")
#define DUMP_d(v) DUMPf("%s = %d", #v, v)
#define DUMP_x(v) DUMPf("%s = 0x%x", #v, v)
#define DUMP_s(v) DUMPf("%s = %s", #v, v)
#define DUMP_c(v) DUMPf("%s = '%c' (0x%02x)", #v, v, v)
#define DUMP_p(v) DUMPf("%s = %p", #v, v)
#define swap(a, b) do {uint8_t _swap=a; a=b, b=_swap;} while (0)
void
arc4_init(struct arc4_ctx *ctx, uint8_t const *key, size_t keylen)
{
int i;
int j = 0;
for (i = 0; i < 256; i += 1) {
ctx->S[i] = i;
}
for (i = 0; i < 256; i += 1) {
j = (j + ctx->S[i] + key[i % keylen]) % 256;
swap(ctx->S[i], ctx->S[j]);
}
ctx->i = 0;
ctx->j = 0;
}
uint8_t
arc4_out(struct arc4_ctx *ctx)
{
ctx->i = (ctx->i + 1) % 256;
ctx->j = (ctx->j + ctx->S[ctx->i]) % 256;
swap(ctx->S[ctx->i], ctx->S[ctx->j]);
return ctx->S[(ctx->S[ctx->i] + ctx->S[ctx->j]) % 256];
}
void
arc4_crypt(struct arc4_ctx *ctx,
uint8_t *obuf, const uint8_t *ibuf, size_t buflen)
{
size_t k;
for (k = 0; k < buflen; k += 1) {
obuf[k] = ibuf[k] ^ arc4_out(ctx);
}
}
void
arc4_crypt_buffer(const uint8_t *key, size_t keylen,
uint8_t *buf, size_t buflen)
{
struct arc4_ctx ctx;
arc4_init(&ctx, key, keylen);
arc4_crypt(&ctx, buf, buf, buflen);
}
/* Create a nonce as an arc4 stream with key=seed */
void
arc4_nonce(uint8_t *nonce, size_t noncelen,
void *seed, size_t seedlen)
{
struct arc4_ctx ctx;
int i;
arc4_init(&ctx, seed, seedlen);
for (i = 0; i < noncelen; i += 1) {
nonce[i] = arc4_out(&ctx);
}
}
#ifdef ARC4_MAIN
#include <stdio.h>
#include <sysexits.h>
#include <time.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
int
usage(const char *prog)
{
fprintf(stderr, "Usage: %s [-e] <PLAINTEXT\n", prog);
fprintf(stderr, "\n");
fprintf(stderr, "You must pass in a key on fd 3 or in the environment variable KEY.\n");
return EX_USAGE;
}
int
main(int argc, char *argv[])
{
struct arc4_ctx ctx;
uint8_t key[ARC4_KEYLEN] = {0};
size_t keylen;
uint8_t nonce[ARC4_KEYLEN];
time_t seed;
int i;
/* Read key and initialize context */
{
char *ekey = getenv("KEY");
if (ekey) {
keylen = strlen(ekey);
memcpy(key, ekey, keylen);
} else {
FILE *f = fdopen(3, "r");
if (NULL == f) {
return usage(argv[0]);
}
keylen = fread(key, 1, ARC4_KEYLEN, f);
fclose(f);
}
}
if (argv[1] && (0 == strcmp(argv[1], "-e"))) {
seed = time(NULL) * getpid();
fwrite("arc4", 1, 4, stdout);
fwrite(&seed, sizeof(seed), 1, stdout);
} else if (argv[1]) {
return usage(argv[0]);
} else {
char sig[4];
fread(&sig, sizeof(sig), 1, stdin);
if (memcmp(sig, "arc4", 4)) {
fprintf(stderr, "%s: error: Input is not arc4-encrypted.", argv[0]);
return 1;
}
fread(&seed, sizeof(seed), 1, stdin);
}
arc4_nonce(nonce, sizeof(nonce), &seed, sizeof(seed));
/* Xor key with nonce */
for (i = 0; i < sizeof(key); i += 1) {
key[i] ^= nonce[i];
}
arc4_init(&ctx, key, sizeof(key));
while (1) {
int c = getchar();
if (EOF == c) break;
putchar(c ^ arc4_out(&ctx));
}
return 0;
}
#endif /* ARC4_MAIN */

3
include/arc4.h → src/arc4.h
View File

@ -4,6 +4,8 @@
#include <stdint.h>
#include <stdlib.h>
#define ARC4_KEYLEN 256
struct arc4_ctx {
uint8_t S[256];
uint8_t i;
@ -16,4 +18,5 @@ void arc4_crypt(struct arc4_ctx *ctx,
uint8_t *obuf, const uint8_t *ibuf, size_t buflen);
void arc4_crypt_buffer(const uint8_t *key, size_t keylen,
uint8_t *buf, size_t buflen);
void arc4_nonce(uint8_t *nonce, size_t noncelen, void *seed, size_t seedlen);
#endif

0
include/rand.c → src/rand.c
View File

0
include/rand.h → src/rand.h
View File