--- pgp/src/random.c	2018/04/24 16:44:31	1.1.1.8
+++ pgp/src/random.c	2018/04/24 16:45:18	1.1.1.9
@@ -1,579 +1,706 @@
-/*
- * True and cryptographic random number generation.
- *
- * (c) Copyright 1990-1994 by Philip Zimmermann.  All rights reserved.
- * The author assumes no liability for damages resulting from the use
- * of this software, even if the damage results from defects in this
- * software.  No warranty is expressed or implied.
- *
- * Note that while most PGP source modules bear Philip Zimmermann's
- * copyright notice, many of them have been revised or entirely written
- * by contributors who frequently failed to put their names in their
- * code.  Code that has been incorporated into PGP from other authors
- * was either originally published in the public domain or is used with
- * permission from the various authors.
- *
- * PGP is available for free to the public under certain restrictions.
- * See the PGP User's Guide (included in the release package) for
- * important information about licensing, patent restrictions on
- * certain algorithms, trademarks, copyrights, and export controls.
- *
- * Written by Colin Plumb.
- */
-
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
-#include <assert.h>
-#include <signal.h>	/* For SIGINT */
-#include <time.h>
-
-#include "system.h"	/* For ttycbreak, getch, etc. */
-#include "idea.h"
-#include "md5.h"
-#include "noise.h"
-#include "language.h"
-#include "random.h"
-#include "fileio.h"	/* For FOPRBIN */
-#include "pgp.h"	/* For globalRandseedName */
-#include "randpool.h"
-
-/*
- * As of PGP 2.6.2, the randseed.bin file has been expanded.  An explanation
- * of how the whole thing works in in order, as people are always suspiscious
- * of the random number generator.  (After the xorbytes bug in 2.6, perhaps
- * you should be.)  There are two random number generators in PGP.  One
- * is the "cryptRand" family, which is based on X9.17, but uses IDEA instead
- * of 2-key EDE triple-DES.  This is the generator with a lot of peer review.
- * The implementation is in idea.c.
- * The second is the "trueRand" family, which attempt to accurately measure
- * the entropy available from keyboard I/O.  It keeps a lot more state.
- * The implementation of this is in randpool.c.
- * Originally, the trueRand generator was only used for generating primes,
- * and the cryptRand for generating IDEA session keys.  But things have
- * become a bit more complex.  In particular, the X9.17 specification
- * wants a source of high-resolution time-of-day information, as a source
- * of some "true" randomness to throw in.  So we use the trueRand pool
- * for that.
- * The cryptRand functions keep a state file around, usually named
- * randseed.bin, for a seed, as the X9.17 generator requires 24 bytes of
- * known initial information.
- * This data in this file is carefully "washed" before and after use to
- * help ensure that if the file is captured or altered, the keys will
- * not be too vulnerable.  A washing consists of an encryption in PGP's
- * usual CFB mode of the material coming from or being written to the
- * randseed.bin file on disk.  Assuming the cipher is strong, the effects
- * of the wash are as difficult to predict as the key that is used is
- * difficult to guess.
- * Beforehand, we use the MD5 of the file being encrypted as an additional
- * source of randomness (on the theory that an attacker trying to break
- * a session key probably doesn't have the plaintext, or he wouldn't need
- * to bother), and use that as an IDEA key (with a fixed IV of zero)
- * to encrypt the randseed.bin data.
- * After generating an IDEA key and IV, some more random bytes are generated
- * to reinitialize randseed.bin, and these are encrypted in the same manner
- * as the PGP message before being written to disk, on the assumption that
- * if an attacker can decrypt that, they can decrypt the message directly
- * and not bother attacking the randseed.bin file.
- * The previous code only saved the 24 bytes needed by the X9.17 algorithm.
- * But in 2.6.2, we decided to make the randseed.bin file substantially
- * larger to hold more information that a would-be attacker must guess.
- * There are two reasons for this:
- * - Every time you run PGP, especially when responding to one of PGP's
- *   prompts, PGP samples the keystrokes for use as random numbers.
- *   It is a shame to throw this entropy (randomness) away just because
- *   there is no need for it in the current invocation of PGP.
- * - A feature was added to 2.6.2 to generate files full of random bytes
- *   for other programs to use as key material.  In this case, we haven't
- *   got a message we're encrypting to take some entropy from, and we may
- *   be asked to generate more than 24 random bytes, so there should be
- *   more than 24 bytes of seed material to work from.
- * The implementation is added on to the previous one, to offer assurance
- * that it is no weaker.
- * When the cryptRand generator is opened, the file is washed (if possible)
- * and the first 24 bytes are fed to the cryptographic RNG, while the
- * remainder is added to the trueRand random number pool.
- * When saving, the randseed.bin file is refilled with newly generated
- * bytes, again washed if possible.  It turns out (if you study the
- * X9.17 RNG) that each of the 2^64 possible timestamp information
- * values used in generating each 8 bytes of output generates a output
- * value, so the entropy in the trueRand pool is put to good use; this
- * is not just generating more data from 24 bytes of seed.
- * The random pool is opened and saved with a washing key when
- * generating a session key (see make_random_ideakey in crypto.c),
- * but it is also opened (harmless if alreasy open) and saved
- * (harmless if already saved) without a washing key in the exitPGP routine,
- * to mix in any entropy collected in this invocation of PGP even if
- * a session key was not generated.
- */
-
-/*
- * The new randseed size, big enough to hold the full context of the cryptRand
- * and trueRand generators.  With the current RANDPOOLBITS of 3072 (384 bytes),
- * that's 408 bytes.  It's useless to make it any larger, although if
- * RANDPOOLBITS is increased, it might be an idea to keep this smaller than
- * one disk block on all systems (512 bytes is a good figure to use)
- * so we don't change the space requirements for randseed.bin.
- */
-#define RANDSEED_BYTES	(RANDPOOLBITS/8 + 24)
-/* Have we read in the randseed.bin file? */
-static boolean randSeedOpen = 0;
-static struct IdeaRandContext randContext;
-
-/*
- * Load the RNG state from the randseed.bin file on disk.
- * Returns 0 on success, <0 on error.
- *
- * If cfb is non-zero, prewashes the data by encrypting with it.
- */
-int
-cryptRandOpen(struct IdeaCfbContext *cfb)
-{
-	byte buf[256];
-	int len;
-	FILE *f;
-
-	if (randSeedOpen)
-		return 0;	/* Already open */
-
-	f = fopen(globalRandseedName, FOPRBIN);
-	if (!f)
-		return -1;
-
-	/* First get the bare minimum 24 bytes we need for the IDEA RNG */
-	len = fread((char *)buf, 1, 24, f);
-	if (cfb)
-		ideaCfbEncrypt(cfb, buf, buf, 24);
-	ideaRandInit(&randContext, buf, buf+16);
-	randSeedOpen = TRUE;
-	if (len != 24) { /* Error */
-		fclose(f);
-		return -1;
-	}
-
-	/* Read any extra into the random pool */
-	for (;;) {
-		len = fread((char *)buf, 1, sizeof(buf), f);
-		if (len <= 0)
-			break;
-		if (cfb)
-			ideaCfbEncrypt(cfb, buf, buf, len);
-		randPoolAddBytes(buf, len);
-	}
-
-	fclose(f);
-	burn(buf);
-	return 0;
-}
-
-/* Create a new state from the output of trueRandByte */
-void
-cryptRandInit(struct IdeaCfbContext *cfb)
-{
-	byte buf[24];
-	int i;
-
-	for (i = 0; i < sizeof(buf); i++)
-		buf[i] = trueRandByte();
-	if (cfb)
-		ideaCfbEncrypt(cfb, buf, buf, sizeof(buf));
-
-	ideaRandInit(&randContext, buf, buf+16);
-	randSeedOpen = TRUE;
-	burn(buf);
-}
-
-byte
-cryptRandByte(void)
-{
-	if (!randSeedOpen)
-		cryptRandOpen((struct IdeaCfbContext *)0);
-	return ideaRandByte(&randContext);
-}
-
-/*
- * Write out a file of random bytes.  If cfb is defined, wash it with the
- * cipher.
- */
-int
-cryptRandWriteFile(char const *name, struct IdeaCfbContext *cfb, unsigned bytes)
-{
-	byte buf[256];
-	FILE *f;
-	int i, len;
-
-	f = fopen(name, FOPWBIN);
-	if (!f)
-		return -1;
-
-	while (bytes) {
-		len = (bytes < sizeof(buf)) ? bytes : sizeof(buf);
-		for (i = 0; i < len; i++)
-			buf[i] = ideaRandByte(&randContext);
-		if (cfb)
-			ideaCfbEncrypt(cfb, buf, buf, len);
-		i = fwrite(buf, 1, len, f);
-		if (i < len)
-			break;
-		bytes -= len;
-	}
-
-	return (fclose(f) != 0 || bytes != 0) ? -1 : 0;
-}
-
-/*
- * Create a new RNG state, encrypt it with the supplied key, and save it
- * out to disk.
- *
- * When we encrypt a file, the saved data is "postwashed" using the
- * same key and initial vector (including the repeated check bytes and
- * everything) that is used to encrypt the user's message.
- * The hope is that this "postwash" renders it is at least as hard to
- * derive old session keys from randseed.bin as it is to crack the the
- * message directly.
- *
- * The purpose of using EXACTLY the same encryption is to make sure that
- * there isn't related, but different data floating around that can be
- * used for cryptanalysis.
- *
- * This function is always called by exitPGP, without a washing encryption,
- * so this function ignores that call if it has previously been called
- * to save washed bytes.
- */
-void
-cryptRandSave(struct IdeaCfbContext *cfb)
-{
-	static boolean savedwashed = FALSE;
-
-	if (!randSeedOpen)
-		return;	/* Do nothing */
-
-	if (cfb)
-		savedwashed = TRUE;
-	else if (savedwashed)
-		return;	/* Don't re-save if it's already been saved washed. */
-
-	(void)cryptRandWriteFile(globalRandseedName, cfb, RANDSEED_BYTES);
-}
-
-/*
- * True random bit handling
- */
-
-/*
- * Because these truly random bytes are so unwieldy to accumulate,
- * they can be regarded as a precious resource.  Unfortunately,
- * cryptographic key generation algorithms may require a great many
- * random bytes while searching about for large random prime numbers.
- * Fortunately, they need not all be truly random.  We only need as
- * many truly random bits as there are bits in the large prime we
- * are searching for.  These random bytes can be recycled and modified
- * via pseudorandom numbers until the key is generated, without losing
- * any of the integrity of randomness of the final key.
- *
- * The technique used is a pool of random numbers, which bytes are
- * taken from successively and, when the end is reached, the pool
- * is stirred using an irreversible hash function.  Some (64 bytes)
- * of the pool is not returned to ensure the sequence is not predictible
- * from the values retriefed from trueRandByte().  To be precise,
- * MD5Transform is used as a block cipher in CBC mode, and then the
- * "key" (i.e. what is usually the material to be hashed) is overwritten
- * with some of the just-generated random bytes.
- *
- * This is implemented in randpool.c; see that file for details.
- *
- * An estimate of the number of bits of true (Shannon) entropy in the
- * pool is kept in trueRandBits.  This is incremented when timed
- * keystrokes are available, and decremented when bits are explicitly
- * consumed for some purpose (such as prime generation) or another.
- *
- * trueRandFlush is called to obliterate traces of old random bits after
- * prime generation is completed.  (Primes are the most carefully-guarded
- * values in PGP.)
- */
-
-static unsigned trueRandBits = 0;	/* Bits of entropy in pool */
-
-/* trueRandPending is bits to add to next accumulation request */
-static unsigned trueRandPending = 0;
-
-/*
- * Destroys already-used random numbers.  Ensures no sensitive data
- * remains in memory that can be recovered later.  This is called
- * after RSA key generation, so speed is not critical, but security is.
- * RSA key generation takes long enough that interrupts and other
- * tasks are likely to have used a measurable and difficult-to-predict
- * amount of real time, so there is some virtue in sampling the clocks
- * with noise().
- */
-void
-trueRandFlush(void)
-{
-	noise();
-	randPoolStir();	/* Destroy evidence of what primes were generated */
-	randPoolStir();
-	randPoolStir();
-	randPoolStir();	/* Make *really* certain */
-}
-
-/*
- * "Consumes" count bits worth of entropy from the true random pool for some
- * purpose, such as prime generation.
- *
- * Note that something like prime generation can end up calling trueRandByte
- * more often than is implied by the count passed to trueRandClaim; this
- * may happen if the random bit consumer is not perfectly efficient in its
- * use of random bits.  For example, if a search for a suitable prime fails,
- * the easiest thing to do is to get another load of random bits and try
- * again.  It is perfectly acceptable if these bits are correlated with the
- * bits used in the failed attempt, since they are discarded.
- */
-void
-trueRandConsume(unsigned count)
-{
-	assert (trueRandBits >= count);
-	trueRandBits -= count;
-}
-
-/*
- * Returns a truly random byte if any are available.  It degenerates to
- * a pseudorandom value if there are none.  It is not an error to call
- * this if none are available.  For example, it is called when generating
- * session keys to add to other sources of cryptographic random numbers.
- *
- * This forces an accumulation if any extra random bytes are pending.
- */
-int
-trueRandByte(void)
-{
-	if (trueRandPending)
-		trueRandAccum(0);
-
-	return randPoolGetByte();
-}
-
-/*
- * Given an event (typically a keystroke) coded by "event"
- * at a random time, add all randomness to the random pool,
- * compute a (conservative) estimate of the amount, add it
- * to the pool, and return the amount of randomness.
- * (The return value is just for informational purposes.)
- *
- * Double events are okay, but three in a row is considered
- * suspiscous and the randomness is counted as 0.
- */
-unsigned
-trueRandEvent(int event)
-{
-	static int event1 = 0, event2 = 0;
-	word32 delta;
-	unsigned cbits;
-
-	delta = noise();
-	randPoolAddBytes((byte *)&event, sizeof(event));
-
-	if (event == event1 && event == event2) {
-		cbits = 0;
-	} else {
-		event2 = event1;
-		event1 = event;
-
-		for (cbits = 0; delta; cbits++)
-			delta >>= 1;
-
-		/* Excessive paranoia? */
-		if (cbits > 8)
-			cbits = 8;
-	}
-
-	trueRandBits += cbits;
-	if (trueRandBits > RANDPOOLBITS)
-		trueRandBits = RANDPOOLBITS;
-
-	return cbits;
-}
-
-
-/*
- * Since getting random bits from the keyboard requires user attention,
- * we buffer up requests for them until we can do one big request.
- */
-void
-trueRandAccumLater(unsigned bitcount)
-{
-	trueRandPending += bitcount;	/* Wow, that was easy! :-) */
-}
-
-static void flush_input(void);
-
-/*
- * Performs an accumulation of random bits.  As long as there are fewer bits
- * in the buffer than are needed (the number passed, plus pending bits),
- * prompt for more.
- */
-void
-trueRandAccum(unsigned count)	/* Get this many random bits ready */
-{
-	int c;
-#if defined(MSDOS) || defined(__MSDOS__)
-	time_t timer;
-#endif
-
-	count += trueRandPending;	/* Do deferred accumulation now */
-	trueRandPending = 0;
-
-	if (count > RANDPOOLBITS)
-		count = RANDPOOLBITS;
-
-	if (trueRandBits >= count)
-		return;
-
-	fprintf(stderr,
-LANG("\nWe need to generate %u random bits.  This is done by measuring the\
-\ntime intervals between your keystrokes.  Please enter some random text\
-\non your keyboard until you hear the beep:\n"), count-trueRandBits);
-
-	ttycbreak();
-
-	do {
-		/* display counter to show progress */
-		fprintf(stderr,"\r%4d ", count-trueRandBits);
-		fflush(stderr);	/* assure screen update */
-
-		flush_input();	/* If there's no delay, we can't use it */
-		c = getch();	/* always wait for input */
-#ifdef MSDOS
-		if (c == 3)
-			breakHandler(SIGINT);
-		if (c == 0)
-			c = getch() + 256;
-#endif
-		/* Print flag indicating acceptance (or not) */
-		putc(trueRandEvent(c) ? '.' : '?' , stderr);
-	} while (trueRandBits < count);
-
-	fputs("\r   0 *", stderr);
-	fputs(LANG("\007 -Enough, thank you.\n"), stderr);
-
-#if defined(MSDOS) || defined(__MSDOS__)
-	/* Wait until one full second has passed without keyboard input */
-	do {
-		flush_input();
-		sleep(1);
-	} while (kbhit());
-#else
-	sleep(1);
-	flush_input();
-#endif
-
-	ttynorm();
-}
-
-#define BS 8
-#define LF 10
-#define CR 13
-#define DEL 127
-
-#ifdef VMS
-int putch(int);
-#else
-#define putch(c) putc(c, stderr)
-#endif
-
-int
-getstring(char *strbuf, unsigned maxlen, int echo)
-/* Gets string from user, with no control characters allowed.
- * Also accumulates random numbers.
- * maxlen is max length allowed for string.
- * echo is TRUE iff we should echo keyboard to screen.
- * Returns null-terminated string in strbuf.
- */
-{
-	unsigned i;
-	char c;
-
-	ttycbreak();
-
-#ifdef AMIGA
-	aecho = (int)echo;
-	echo = FALSE;   /* echo is done in getch */
-#endif  /* AMIGA */
-
-	fflush(stdout);
-	i=0;
-	for (;;) {
-#ifndef VMS
-		fflush(stderr);
-#endif /* VMS */
-		c = getch();
-		trueRandEvent(c);
-#ifdef VMS
-		if (c == 25) {  /*  Control-Y detected */
-		    ttynorm();
-		    breakHandler(SIGINT);
-		}
-#endif /* VMS */
-#if defined(MSDOS) || defined (__MSDOS__)
-		if (c == 3)
-			breakHandler(SIGINT);
-#endif
-		if (c==BS || c==DEL) {
-			if (i) {
-				if (echo) {
-					putch(BS);
-					putch(' ');
-					putch(BS);
-				}
-				i--;
-			} else {
-				putch('\007');
-			}
-			continue;
-		}
-		if (c < ' ' && c != LF && c != CR) {
-			putch('\007');
-#if defined(MSDOS) || defined (__MSDOS__)
-			if (c == 3)
-				breakHandler(SIGINT);	
-			if (c == 0)
-				getch(); /* Skip extended key codes */
-#endif
-			continue;
-		}
-		if (echo)
-			putch(c);
-		if (c==CR) {
-			if (echo)
-				putch(LF);
-			break;
-		}
-		if (c==LF)
-			break;
-		if (c=='\n')
-			break;
-		strbuf[i++] = c;
-		if (i >= maxlen) {
-			fputs("\007*\n", stderr);	/* -Enough! */
-#if 0
-			while (kbhit())
-				getch();	/* clean up any typeahead */
-#endif
-			break;
-		}
-	}
-	strbuf[i] = '\0';	/* null termination of string */
-
-	ttynorm();
-
-	return(i);		/* returns string length */
-} /* getstring */
-
-
-static void
-flush_input(void)
-{	/* on unix ttycbreak() will flush the input queue */
-#if defined(MSDOS) || defined (__MSDOS__)
-	while (kbhit())	/* flush typahead buffer */
-		getch();
-#endif
-}
+/*
+ * True and cryptographic random number generation.
+ *
+ * (c) Copyright 1990-1996 by Philip Zimmermann.  All rights reserved.
+ * The author assumes no liability for damages resulting from the use
+ * of this software, even if the damage results from defects in this
+ * software.  No warranty is expressed or implied.
+ *
+ * Note that while most PGP source modules bear Philip Zimmermann's
+ * copyright notice, many of them have been revised or entirely written
+ * by contributors who frequently failed to put their names in their
+ * code.  Code that has been incorporated into PGP from other authors
+ * was either originally published in the public domain or is used with
+ * permission from the various authors.
+ *
+ * PGP is available for free to the public under certain restrictions.
+ * See the PGP User's Guide (included in the release package) for
+ * important information about licensing, patent restrictions on
+ * certain algorithms, trademarks, copyrights, and export controls.
+ *
+ * Written by Colin Plumb.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+#include <signal.h>	/* For SIGINT */
+#include <time.h>
+
+#ifdef AMIGA      /* Includes for timer -- RKNOP */
+#include <devices/timer.h>
+#include <exec/memory.h>
+#include <exec/libraries.h>
+#include <proto/dos.h>
+#include <proto/timer.h>
+#include <proto/exec.h>
+#endif /* AMIGA */
+
+#ifdef __PUREC__
+#include <ext.h>
+#endif
+
+#include "system.h"	/* For ttycbreak, getch, etc. */
+#include "idea.h"
+#include "md5.h"
+#include "noise.h"
+#include "language.h"
+#include "random.h"
+#include "fileio.h"	/* For FOPRBIN */
+#include "pgp.h"	/* For globalRandseedName */
+#include "randpool.h"
+#ifdef MACTC5
+#include "Macutil2.h"
+#include "Macutil3.h"
+#include "TimeManager.h"
+#include <unix.h>
+#endif
+
+/*
+ * As of PGP 2.6.2, the randseed.bin file has been expanded.  An explanation
+ * of how the whole thing works in in order, as people are always suspiscious
+ * of the random number generator.  (After the xorbytes bug in 2.6, perhaps
+ * you should be.)  There are two random number generators in PGP.  One
+ * is the "cryptRand" family, which is based on X9.17, but uses IDEA instead
+ * of 2-key EDE triple-DES.  This is the generator with a lot of peer review.
+ * The implementation is in idea.c.
+ * The second is the "trueRand" family, which attempt to accurately measure
+ * the entropy available from keyboard I/O.  It keeps a lot more state.
+ * The implementation of this is in randpool.c.
+ * Originally, the trueRand generator was only used for generating primes,
+ * and the cryptRand for generating IDEA session keys.  But things have
+ * become a bit more complex.  In particular, the X9.17 specification
+ * wants a source of high-resolution time-of-day information, as a source
+ * of some "true" randomness to throw in.  So we use the trueRand pool
+ * for that.
+ * The cryptRand functions keep a state file around, usually named
+ * randseed.bin, for a seed, as the X9.17 generator requires 24 bytes of
+ * known initial information.
+ * This data in this file is carefully "washed" before and after use to
+ * help ensure that if the file is captured or altered, the keys will
+ * not be too vulnerable.  A washing consists of an encryption in PGP's
+ * usual CFB mode of the material coming from or being written to the
+ * randseed.bin file on disk.  Assuming the cipher is strong, the effects
+ * of the wash are as difficult to predict as the key that is used is
+ * difficult to guess.
+ * Beforehand, we use the MD5 of the file being encrypted as an additional
+ * source of randomness (on the theory that an attacker trying to break
+ * a session key probably doesn't have the plaintext, or he wouldn't need
+ * to bother), and use that as an IDEA key (with a fixed IV of zero)
+ * to encrypt the randseed.bin data.
+ * After generating an IDEA key and IV, some more random bytes are generated
+ * to reinitialize randseed.bin, and these are encrypted in the same manner
+ * as the PGP message before being written to disk, on the assumption that
+ * if an attacker can decrypt that, they can decrypt the message directly
+ * and not bother attacking the randseed.bin file.
+ * The previous code only saved the 24 bytes needed by the X9.17 algorithm.
+ * But in 2.6.2, we decided to make the randseed.bin file substantially
+ * larger to hold more information that a would-be attacker must guess.
+ * There are two reasons for this:
+ * - Every time you run PGP, especially when responding to one of PGP's
+ *   prompts, PGP samples the keystrokes for use as random numbers.
+ *   It is a shame to throw this entropy (randomness) away just because
+ *   there is no need for it in the current invocation of PGP.
+ * - A feature was added to 2.6.2 to generate files full of random bytes
+ *   for other programs to use as key material.  In this case, we haven't
+ *   got a message we're encrypting to take some entropy from, and we may
+ *   be asked to generate more than 24 random bytes, so there should be
+ *   more than 24 bytes of seed material to work from.
+ * The implementation is added on to the previous one, to offer assurance
+ * that it is no weaker.
+ * When the cryptRand generator is opened, the file is washed (if possible)
+ * and the first 24 bytes are fed to the cryptographic RNG, while the
+ * remainder is added to the trueRand random number pool.
+ * When saving, the randseed.bin file is refilled with newly generated
+ * bytes, again washed if possible.  It turns out (if you study the
+ * X9.17 RNG) that each of the 2^64 possible timestamp information
+ * values used in generating each 8 bytes of output generates a output
+ * value, so the entropy in the trueRand pool is put to good use; this
+ * is not just generating more data from 24 bytes of seed.
+ * The random pool is opened and saved with a washing key when
+ * generating a session key (see make_random_ideakey in crypto.c),
+ * but it is also opened (harmless if alreasy open) and saved
+ * (harmless if already saved) without a washing key in the exitPGP routine,
+ * to mix in any entropy collected in this invocation of PGP even if
+ * a session key was not generated.
+ */
+
+/*
+ * The new randseed size, big enough to hold the full context of the cryptRand
+ * and trueRand generators.  With the current RANDPOOLBITS of 3072 (384 bytes),
+ * that's 408 bytes.  It's useless to make it any larger, although if
+ * RANDPOOLBITS is increased, it might be an idea to keep this smaller than
+ * one disk block on all systems (512 bytes is a good figure to use)
+ * so we don't change the space requirements for randseed.bin.
+ */
+#define RANDSEED_BYTES	(RANDPOOLBITS/8 + 24)
+/* Have we read in the randseed.bin file? */
+static boolean randSeedOpen = 0;
+static struct IdeaRandContext randContext;
+
+/*
+ * Load the RNG state from the randseed.bin file on disk.
+ * Returns 0 on success, <0 on error.
+ *
+ * If cfb is non-zero, prewashes the data by encrypting with it.
+ */
+int
+cryptRandOpen(struct IdeaCfbContext *cfb)
+{
+	byte buf[256];
+	int len;
+	FILE *f;
+
+	if (randSeedOpen)
+		return 0;	/* Already open */
+
+	f = fopen(globalRandseedName, FOPRBIN);
+	if (!f)
+		return -1;
+
+	/* First get the bare minimum 24 bytes we need for the IDEA RNG */
+	len = fread((char *)buf, 1, 24, f);
+	if (cfb)
+		ideaCfbEncrypt(cfb, buf, buf, 24);
+	ideaRandInit(&randContext, buf, buf+16);
+	randSeedOpen = TRUE;
+	if (len != 24) { /* Error */
+		fclose(f);
+		return -1;
+	}
+
+	/* Read any extra into the random pool */
+	for (;;) {
+		len = fread((char *)buf, 1, sizeof(buf), f);
+		if (len <= 0)
+			break;
+		if (cfb)
+			ideaCfbEncrypt(cfb, buf, buf, len);
+		randPoolAddBytes(buf, len);
+	}
+
+	fclose(f);
+	burn(buf);
+#ifdef MACTC5
+	PGPSetFinfo(globalRandseedName,'RSed','MPGP');
+#endif
+	return 0;
+}
+
+/* Create a new state from the output of trueRandByte */
+void
+cryptRandInit(struct IdeaCfbContext *cfb)
+{
+	byte buf[24];
+	int i;
+
+	for (i = 0; i < sizeof(buf); i++)
+		buf[i] = trueRandByte();
+	if (cfb)
+		ideaCfbEncrypt(cfb, buf, buf, sizeof(buf));
+
+	ideaRandInit(&randContext, buf, buf+16);
+	randSeedOpen = TRUE;
+	burn(buf);
+}
+
+byte
+cryptRandByte(void)
+{
+	if (!randSeedOpen)
+		cryptRandOpen((struct IdeaCfbContext *)0);
+	return ideaRandByte(&randContext);
+}
+
+/*
+ * Write out a file of random bytes.  If cfb is defined, wash it with the
+ * cipher.
+ */
+int
+cryptRandWriteFile(char const *name, struct IdeaCfbContext *cfb, unsigned bytes)
+{
+	byte buf[256];
+	FILE *f;
+	int i, len;
+
+	f = fopen(name, FOPWBIN);
+	if (!f)
+		return -1;
+
+	while (bytes) {
+		len = (bytes < sizeof(buf)) ? bytes : sizeof(buf);
+		for (i = 0; i < len; i++)
+			buf[i] = ideaRandByte(&randContext);
+		if (cfb)
+			ideaCfbEncrypt(cfb, buf, buf, len);
+		i = fwrite(buf, 1, len, f);
+		if (i < len)
+			break;
+		bytes -= len;
+	}
+
+#ifdef MACTC5
+	PGPSetFinfo((char *)name,'RSed','MPGP');
+#endif
+
+	return (fclose(f) != 0 || bytes != 0) ? -1 : 0;
+}
+
+/*
+ * Create a new RNG state, encrypt it with the supplied key, and save it
+ * out to disk.
+ *
+ * When we encrypt a file, the saved data is "postwashed" using the
+ * same key and initial vector (including the repeated check bytes and
+ * everything) that is used to encrypt the user's message.
+ * The hope is that this "postwash" renders it is at least as hard to
+ * derive old session keys from randseed.bin as it is to crack the the
+ * message directly.
+ *
+ * The purpose of using EXACTLY the same encryption is to make sure that
+ * there isn't related, but different data floating around that can be
+ * used for cryptanalysis.
+ *
+ * This function is always called by exitPGP, without a washing encryption,
+ * so this function ignores that call if it has previously been called
+ * to save washed bytes.
+ */
+#ifdef MACTC5
+	boolean savedwashed = FALSE;
+#endif
+
+void
+cryptRandSave(struct IdeaCfbContext *cfb)
+{
+#ifndef MACTC5
+	static boolean savedwashed = FALSE;
+#endif
+
+	if (!randSeedOpen)
+		return;	/* Do nothing */
+
+	if (cfb)
+		savedwashed = TRUE;
+	else if (savedwashed)
+		return;	/* Don't re-save if it's already been saved washed. */
+
+	(void)cryptRandWriteFile(globalRandseedName, cfb, RANDSEED_BYTES);
+#ifdef MACTC5
+	PGPSetFinfo(globalRandseedName,'RSed','MPGP');
+#endif
+}
+
+/*
+ * True random bit handling
+ */
+
+/*
+ * Because these truly random bytes are so unwieldy to accumulate,
+ * they can be regarded as a precious resource.  Unfortunately,
+ * cryptographic key generation algorithms may require a great many
+ * random bytes while searching about for large random prime numbers.
+ * Fortunately, they need not all be truly random.  We only need as
+ * many truly random bits as there are bits in the large prime we
+ * are searching for.  These random bytes can be recycled and modified
+ * via pseudorandom numbers until the key is generated, without losing
+ * any of the integrity of randomness of the final key.
+ *
+ * The technique used is a pool of random numbers, which bytes are
+ * taken from successively and, when the end is reached, the pool
+ * is stirred using an irreversible hash function.  Some (64 bytes)
+ * of the pool is not returned to ensure the sequence is not predictible
+ * from the values retriefed from trueRandByte().  To be precise,
+ * MD5Transform is used as a block cipher in CBC mode, and then the
+ * "key" (i.e. what is usually the material to be hashed) is overwritten
+ * with some of the just-generated random bytes.
+ *
+ * This is implemented in randpool.c; see that file for details.
+ *
+ * An estimate of the number of bits of true (Shannon) entropy in the
+ * pool is kept in trueRandBits.  This is incremented when timed
+ * keystrokes are available, and decremented when bits are explicitly
+ * consumed for some purpose (such as prime generation) or another.
+ *
+ * trueRandFlush is called to obliterate traces of old random bits after
+ * prime generation is completed.  (Primes are the most carefully-guarded
+ * values in PGP.)
+ */
+
+static unsigned trueRandBits = 0;	/* Bits of entropy in pool */
+
+#ifdef MACTC5
+#define CBITS 5
+#define TRByt 3
+#define TREvt 1
+
+static void perturb(rbits)
+int rbits;
+{	
+	spinner();
+	randPoolAddBytes((byte *) seedBuffer, 8);
+	trueRandBits +=rbits;
+	if (trueRandBits > RANDPOOLBITS)
+		trueRandBits = RANDPOOLBITS;
+	return;
+}
+#endif
+
+/* trueRandPending is bits to add to next accumulation request */
+static unsigned trueRandPending = 0;
+
+/*
+ * Destroys already-used random numbers.  Ensures no sensitive data
+ * remains in memory that can be recovered later.  This is called
+ * after RSA key generation, so speed is not critical, but security is.
+ * RSA key generation takes long enough that interrupts and other
+ * tasks are likely to have used a measurable and difficult-to-predict
+ * amount of real time, so there is some virtue in sampling the clocks
+ * with noise().
+ */
+void
+trueRandFlush(void)
+{
+	noise();
+	randPoolStir();	/* Destroy evidence of what primes were generated */
+	randPoolStir();
+	randPoolStir();
+	randPoolStir();	/* Make *really* certain */
+}
+
+/*
+ * "Consumes" count bits worth of entropy from the true random pool for some
+ * purpose, such as prime generation.
+ *
+ * Note that something like prime generation can end up calling trueRandByte
+ * more often than is implied by the count passed to trueRandClaim; this
+ * may happen if the random bit consumer is not perfectly efficient in its
+ * use of random bits.  For example, if a search for a suitable prime fails,
+ * the easiest thing to do is to get another load of random bits and try
+ * again.  It is perfectly acceptable if these bits are correlated with the
+ * bits used in the failed attempt, since they are discarded.
+ */
+void
+trueRandConsume(unsigned count)
+{
+#ifdef MACTC5
+	if( trueRandBits >= count )
+		trueRandBits -= count;
+	else
+		trueRandBits = 0;
+#else
+	assert (trueRandBits >= count);
+	trueRandBits -= count;
+#endif
+}
+
+/*
+ * Returns a truly random byte if any are available.  It degenerates to
+ * a pseudorandom value if there are none.  It is not an error to call
+ * this if none are available.  For example, it is called when generating
+ * session keys to add to other sources of cryptographic random numbers.
+ *
+ * This forces an accumulation if any extra random bytes are pending.
+ */
+int
+trueRandByte(void)
+{
+	if (trueRandPending)
+		trueRandAccum(0);
+#ifdef MACTC5
+	while( trueRandBits < 8 ) {
+		perturb(TRByt);
+		spinner();
+		}
+#endif
+
+	return randPoolGetByte();
+}
+
+/*
+ * Given an event (typically a keystroke) coded by "event"
+ * at a random time, add all randomness to the random pool,
+ * compute a (conservative) estimate of the amount, add it
+ * to the pool, and return the amount of randomness.
+ * (The return value is just for informational purposes.)
+ *
+ * Double events are okay, but three in a row is considered
+ * suspiscous and the randomness is counted as 0.
+ */
+unsigned
+trueRandEvent(int event)
+{
+	static int event1 = 0, event2 = 0;
+	word32 delta;
+	unsigned cbits;
+
+	delta = noise();
+	randPoolAddBytes((byte *)&event, sizeof(event));
+
+#ifdef MACTC5
+	perturb(TRByt);
+#endif
+
+	if (event == event1 && event == event2) {
+		cbits = 0;
+	} else {
+		event2 = event1;
+		event1 = event;
+
+		for (cbits = 0; delta; cbits++)
+			delta >>= 1;
+
+		/* Excessive paranoia? */
+#ifdef MACTC5
+		if (cbits > CBITS)
+			cbits = CBITS;
+#else
+		if (cbits > 8)
+			cbits = 8;
+#endif
+	}
+
+	trueRandBits += cbits;
+	if (trueRandBits > RANDPOOLBITS)
+		trueRandBits = RANDPOOLBITS;
+
+	return cbits;
+}
+
+
+/*
+ * Since getting random bits from the keyboard requires user attention,
+ * we buffer up requests for them until we can do one big request.
+ */
+void
+trueRandAccumLater(unsigned bitcount)
+{
+	trueRandPending += bitcount;	/* Wow, that was easy! :-) */
+#ifdef MACTC5
+	spinner();
+#endif
+}
+
+static void flush_input(void);
+
+#ifdef AMIGA  /* Globals used for timing here and in noise.c - RKNOP 940613 */
+struct Library *TimerBase=NULL;
+struct timerequest *TimerIO=NULL;
+union { struct timeval t;
+        struct EClockVal e;
+      } time0,time1;
+unsigned short use_eclock=0;
+#endif /* AMIGA */
+
+/*
+ * Performs an accumulation of random bits.  As long as there are fewer bits
+ * in the buffer than are needed (the number passed, plus pending bits),
+ * prompt for more.
+ */
+void
+trueRandAccum(unsigned count)	/* Get this many random bits ready */
+{
+	int c;
+#if defined(MSDOS) || defined(__MSDOS__)
+	time_t timer;
+#endif
+
+	count += trueRandPending;	/* Do deferred accumulation now */
+	trueRandPending = 0;
+
+	if (count > RANDPOOLBITS)
+		count = RANDPOOLBITS;
+
+	if (trueRandBits >= count)
+		return;
+
+	fprintf(stderr,
+LANG("\nWe need to generate %u random bits.  This is done by measuring the\
+\ntime intervals between your keystrokes.  Please enter some random text\
+\non your keyboard until you hear the beep:\n"), count-trueRandBits);
+
+	ttycbreak();
+
+#ifdef AMIGA  /* RKNOP 940613 */
+        TimerIO=(struct timerequest *)AllocMem(sizeof(struct timerequest),
+                                               MEMF_PUBLIC|MEMF_CLEAR);
+        if (TimerIO)
+        {  if (OpenDevice(TIMERNAME,UNIT_MICROHZ,(struct IORequest *)TimerIO,0))
+              TimerBase=NULL;
+           else
+           {  TimerBase=(struct Library *)TimerIO->tr_node.io_Device;
+              if (TimerBase->lib_Version>=36) /* Use E-clock instead */
+              {  use_eclock=1;
+                 CloseDevice((struct IORequest *)TimerIO);
+                 if (!OpenDevice(TIMERNAME,UNIT_ECLOCK,
+                                 (struct IORequest *)TimerIO,0))
+                    TimerBase=(struct Library *)TimerIO->tr_node.io_Device;
+                 else
+                    TimerBase=NULL;
+              }
+              else use_eclock=0;
+           }
+        }
+        else TimerBase=NULL;
+#endif /* AMIGA */
+
+	do {
+		/* display counter to show progress */
+		fprintf(stderr,"\r%4d ", count-trueRandBits);
+		fflush(stderr);	/* assure screen update */
+
+		flush_input();	/* If there's no delay, we can't use it */
+#ifdef MACTC5
+		StartTMCounter();
+#endif
+		c = getch();	/* always wait for input */
+#ifdef MSDOS
+		if (c == 3)
+			breakHandler(SIGINT);
+		if (c == 0)
+			c = getch() + 256;
+#endif
+		/* Print flag indicating acceptance (or not) */
+                /* putc a macro, not safe to have function as an arg!! */
+                fputc(trueRandEvent(c) ? '.' : '?' , stderr);
+#ifdef MACTC5
+		StopTMCounter();
+#endif
+	} while (trueRandBits < count);
+
+	fputs("\r   0 *", stderr);
+	fputs(LANG("\007 -Enough, thank you.\n"), stderr);
+
+#if defined(MSDOS) || defined(__MSDOS__)
+	/* Wait until one full second has passed without keyboard input */
+	do {
+		flush_input();
+		sleep(1);
+	} while (kbhit());
+#else
+#ifdef AMIGA       /* Added RKNOP 940608 */
+        Delay(50*1);    /* dos.library function, wait 1 second */
+        if (TimerBase) CloseDevice((struct IORequest *)TimerIO);
+        TimerBase=NULL;
+        if (TimerIO) FreeMem(TimerIO,sizeof(struct timerequest));
+        TimerIO=NULL;
+#else
+	sleep(1);
+	flush_input();
+#endif
+#endif
+
+	ttynorm();
+}
+
+#ifndef EBCDIC                   /* already defined in usuals.h */
+#define BS 8
+#define LF 10
+#define CR 13
+#define DEL 127
+#endif
+
+#ifdef VMS
+int putch(int);
+#else
+#define putch(c) putc(c, stderr)
+#endif
+
+int
+getstring(char *strbuf, unsigned maxlen, int echo)
+/* Gets string from user, with no control characters allowed.
+ * Also accumulates random numbers.
+ * maxlen is max length allowed for string.
+ * echo is TRUE iff we should echo keyboard to screen.
+ * Returns null-terminated string in strbuf.
+ */
+{
+	unsigned i;
+	char c;
+
+	ttycbreak();
+
+#ifdef AMIGA     /* In case of -f (use stdio for plaintext input),
+                    use ReqTools for input from the user */
+        if (!IsInteractive(Input()))
+           return AmigaRequestString(strbuf,maxlen,echo);
+#endif
+
+	fflush(stdout);
+	i=0;
+	for (;;) {
+#ifndef VMS
+		fflush(stderr);
+#endif /* VMS */
+		c = getch();
+		trueRandEvent(c);
+#ifdef VMS
+		if (c == 25) {  /*  Control-Y detected */
+		    ttynorm();
+		    breakHandler(SIGINT);
+		}
+#endif /* VMS */
+#if defined(MSDOS) || defined (__MSDOS__)
+		if (c == 3)
+			breakHandler(SIGINT);
+#endif
+		if (c==BS || c==DEL) {
+			if (i) {
+				if (echo) {
+					putch(BS);
+					putch(' ');
+					putch(BS);
+				}
+				i--;
+			} else {
+				putch('\007');
+			}
+			continue;
+		}
+		if (c < ' ' && c != LF && c != CR) {
+			putch('\007');
+#if defined(MSDOS) || defined (__MSDOS__)
+			if (c == 3)
+				breakHandler(SIGINT);	
+			if (c == 0)
+				getch(); /* Skip extended key codes */
+#endif
+			continue;
+		}
+		if (echo)
+			putch(c);
+		if (c==CR) {
+			if (echo)
+				putch(LF);
+			break;
+		}
+		if (c==LF)
+			break;
+		if (c=='\n')
+			break;
+		strbuf[i++] = c;
+		if (i >= maxlen) {
+			fputs("\007*\n", stderr);	/* -Enough! */
+#if 0
+			while (kbhit())
+				getch();	/* clean up any typeahead */
+#endif
+			break;
+		}
+	}
+	strbuf[i] = '\0';	/* null termination of string */
+
+	ttynorm();
+
+	return(i);		/* returns string length */
+} /* getstring */
+
+
+static void
+flush_input(void)
+{	/* on unix ttycbreak() will flush the input queue */
+#if defined(MSDOS) || defined (__MSDOS__) || defined(MACTC5)
+	while (kbhit())	/* flush typahead buffer */
+		getch();
+#endif
+}