--- pgp/src/random.c	2018/04/24 16:37:52	1.1
+++ pgp/src/random.c	2018/04/24 16:40:51	1.1.1.6
@@ -1,383 +1,479 @@
-/**********************************************************************
-	random.c - C source code for random number generation - 19 Nov 86
-	(c) Copyright 1986 by Philip Zimmermann.  All rights reserved.  
-	Revised Jul 88 by PRZ and again Dec 88 by Allan Hoeltje
-		to use IBM PC 8253 timer0 for a faster counter.
-	Revised Apr 89 by PRZ to recycle random bytes.
-	Last revised 15 Dec 90 by PRZ.
-
-	This code generates truly random numbers derived from a counter that is 
-	incremented continuously while the keyboard is scanned for user input.
-	Every time the user touches a key, the least significant bits of the 
-	counter are pushed on a stack.  Later, this supply of random bytes can
-	be popped off the stack by applications requiring stochastic numbers.
-	Cryptographic applications require this kind of randomness.
-
-	The only requirement to make this work is that keypress must be called 
-	frequently, and/or getkey must be called to read the keyboard.  
-
-	Note that you can only get as many random bytes as the number of 
-	bytes accumulated by the user touching the keyboard.
-**********************************************************************/
-
-#include	<stdio.h>	/* for putchar() and printf() */
-#include	<conio.h>	/* for kbhit() and getch() */
-#include	"random.h"
-
-/* #define USEPCTIMER  /* use fast hardware timer on IBM PC or AT or clone */
-/* #define DEBUG */
-
-#ifdef DEBUG
-#define DEBUGprintf1(x) fprintf(stderr,x)
-#define DEBUGprintf2(x,y) fprintf(stderr,x,y)
-#else
-#define DEBUGprintf1(x)
-#define DEBUGprintf2(x,y)
-#endif
+/*
+ * 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"
+
+static struct IdeaRandContext randContext;
+static int randInitFlag = 0;
+
+/*
+ * Load the RNG state from the randseed.bin file on disk.
+ * Returns 0 on success, <0 on error.
+ */
+int
+cryptRandOpen(void)
+{
+	byte buf[24];
+	int len;
+	FILE *f;
+
+	if (randInitFlag)
+		return 0;
+
+	f = fopen(globalRandseedName, FOPRBIN);
+	if (!f)
+		return -1;
+	len = fread((char *)buf, 1, 24, f);
+	fclose(f);
+	ideaRandInit(&randContext, buf, buf+16);
+	randInitFlag = 1;
 
+	return (len == 24) ? 0 : -1;
+}
 
-static int randseed=0; /* used only by pseudorand() function. */
-int pseudorand(void)
-/*	Home-grown 16-bit LCG pseudorandom generator. */
-{	randseed = (randseed*31421 + 6927) & 0xffff;
-	return (randseed);
-}	/* pseudorand */
-
-
-int randcount = 0 ;		/* # of random bytes accumulated in pool */
-static byte randpool[256] = {0} ;	/* pool of truly random bytes */
-static int recyclecount = 0 ;	/* # of recycled random bytes accumulated */
-static byte recyclepool[256] = {0} ; /* pool of recycled random bytes */
-static int recycleptr = 0;	/* points to next byte to grab in recyclepool */
-
-/* fastcounter is a free-running counter incremented in main event loop */
-static byte fastcounter = 0;	/* not needed if we can use the PC timer. */
-
-
-#ifdef USEPCTIMER	/* we will use fast hardware timer on IBM PC */
-/* #include <conio.h>	/* function definitions for inp() and outp() */
-/* outp() and inp() works only for Microsoft C for IBM PC or AT */
-/* timer0 on 8253-5 on IBM PC or AT tics every .84 usec. */
-#define timer0		0x40	/* 8253 timer 0 port */
-#define timercntl	0x43	/* 8253 control register */
-#define timer0rwl	0x00	/* read lo/hi bytes of cntr 2 with latch */
-#define timer0rnl	0x30	/* read lo/hi bytes of cntr 2 w/o latch */
-
-static byte latched_hitimer = 0; /* captured by keyboard ISR */
-static byte latched_lotimer = 0; /* captured by keyboard ISR */
-/* when kbisr captures timer, timer_latched is set. */
-static boolean timer_latched = FALSE;
-
-static void kbisr(void)	/* Keyboard Interrupt Service Routine (ISR) */
-/*
-	kbisr should be called on the way into, or on the way out of,
-	or from within the DOS keyboard ISR, as long as it gets called
-	at the time of a keyboard interrupt.  Assumes that the real
-	DOS keyboard ISR captures the keystroke in the normal way.
-	Only the hardware timer counter is captured by the kbisr routine,
-	leaving the actual keystroke capture to the normal DOS keyboard ISR.
-	We indicate that a timer capture has taken place by setting 
-	timer_latched.
-
-	NOTE: WE STILL NEED TO FIND A WAY to connect this subroutine with the 
-	normal keyboard ISR, so that kbisr gets called when there's a keyboard 
-	interrupt.
-*/
-{	outp(timercntl,timer0rwl);
-	latched_lotimer = inp(timer0);
-	latched_hitimer = inp(timer0);
-	timer_latched = TRUE;
-}	/* kbisr */
-
-static unsigned short pctimer0(void)
-{
-/*	Reads and returns the hardware 8253 timer0 on the PC or AT
-**	or clone, shifted right 1 bit.
-**
-**	DO NOT SET THE HARDWARE COUNTER TO ZERO. It is already initialized
-**	by the system to be used by the clock.  It is set up in mode 3
-**	(square wave rate generator) and counts down by 2 from 0 (0xFFFF+1)
-**	to produce an 18.2 Hz square wave.  We may, however, READ the
-**	lo and hi bytes without causing any problems.  BUT just
-**	remember that the lo byte will always be even (since it is
-**	counting by two).
-**
-**	Note that we can not use counter 1 since it is tied to the
-**	dynamic RAM refresh hardware.  Counter 2 is tied to the 8255
-**	PPI chip to do things like sound.  Though it would be safe to
-**	use counter 2 it is not desirable since we would have to turn
-**	the speaker on in order to make the timer count!  Normally one
-**	sets counter 2 to mode 3 (square wave generator) to sound the
-**	speaker.  You can set mode 2 (pulse generator) and the speaker
-**	hardly makes any sound at all, a click when you turn it on and
-**	a click when you turn it off.  Counter 0 should be safe if
-**	we only read the counter bytes.
-**
-**	WARNING:  To use the hardware timer the way it really should be
-**	used, we ought to capture it via a keyboard interrupt service
-**	routine (ISR).	Otherwise, we may experience weaknesses in randomness
-**	due to harmonic relationships between the hardware counter frequency
-**	and the keyboard software polling frequency.  Unfortunately, this
-**	implementation does not currently use keyboard interrupts to
-**	capture the counter.  This is not a problem if we don't use the
-**	hardware counter, but instead use the software counter fastcounter.
-**	Thus, the hardware counter should not be used at all, unless we
-**	support it with an ISR.
-*/
-	unsigned short t ;
-	/* See if timer has been latched by kbisr(). */
-	if (!timer_latched) /* The timer was not already latched. */
-		kbisr();	/* latch timer */
-	/* return latched timer and clear latch */
-	t = ( 	(((unsigned short) latched_hitimer) << 8) |
-		 ((unsigned short) latched_lotimer)
-		) >> 1 ;
-	timer_latched = FALSE;
-	return (t) ;
-}	/* pctimer0 */
-
-#endif	/* ifdef USEPCTIMER */
-
-
-void capturecounter(void)
-/*	Push a fast counter on the random stack.  Should be called when
-**	the user touches a key or clicks the mouse.
-*/
-{
-	static unsigned int accum = 0;
-	static byte abits = 0;	/* number of accumulated bits in accum */
-
-#ifdef USEPCTIMER	/* we will use fast hardware timer on IBM PC */
-#define cbits 8		/* number of bits of counter to capture each time */
-	fastcounter += pctimer0();
-#else			/* no fast hardware timer available */
-#define cbits 4		/* number of bits of counter to capture each time */
-#endif	/* ifdef USEPCTIMER */
-#define cbitsmask ((1 << cbits)-1)
-
-	accum = (accum << cbits) | (unsigned int) (fastcounter & cbitsmask);
-	abits += cbits;
-	while (abits >= 8) 
-	{	if (randcount < sizeof(randpool))
-			/* take lower byte of accum */
-			randpool[randcount++] = accum;
-		abits -= 8;
-		accum >>= 8;
+void
+cryptRandCreate(void)
+{
+	byte randbuf[24];
+	int i;
+	FILE *f;
+
+	for (i = 0; i < 24; i++)
+		randbuf[i] = trueRandByte();
+
+	ideaRandInit(&randContext, (byte *)randbuf, (byte *)randbuf+16);
+	randInitFlag = 1;
+
+	f = fopen(globalRandseedName, FOPWBIN);
+	if (f) {
+		fwrite(randbuf, 1, 24, f);
+		fclose(f);
 	}
-	fastcounter = 0;
-#undef cbitsmask
-}	/* capturecounter */
-
-
-/* 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 bytes as there are bytes 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.
-*/
-
-
-static void randstir(void)
-/* Stir up the recycled random number bin, via a pseudorandom generator */
-{	int i;
-	i = recyclecount;
-	while (i--)
-		recyclepool[i] ^= (byte) pseudorand();
-	DEBUGprintf2(" Stirring %d recycled bytes. ",recyclecount);
-}	/* randstir */
-
-
-short randload(short bitcount)
-/*	Flushes stale recycled random bits and copies a fresh supply of raw 
-	random bits from randpool to recyclepool.  Returns actual number of 
-	bits transferred.  Formerly named randrecycle. */
-{	int bytecount;
-	bytecount = (bitcount+7)/8;
-	bytecount = min(bytecount,randcount);
-	randflush();	/* reset recyclecount, discarding recyclepool */
-	while (bytecount--)
-		recyclepool[recyclecount++] = randpool[--randcount];
-	DEBUGprintf2("\nAllocating %d recycleable random bytes. ",recyclecount);
-	return(recyclecount*8);
-}	/* randload */
-
-
-void randflush(void)	/* destroys pool of recycled random numbers */
-/* Ensures no sensitive data remains in memory that can be recovered later. */
-{	recyclecount = sizeof (recyclepool);
-	while (recyclecount)
-		recyclepool[--recyclecount]=0;
-	/* recyclecount is left at 0 */
-	recycleptr = 0;
-}	/* randflush */
-
-
-short randombyte(void)
-/*	Returns truly random byte from pool, or a pseudorandom value
-**	if pool is empty.  It is recommended that the caller check
-**	the value of randcount before calling randombyte.
-*/
-{	
-	/* First try to get a cheap recycled random byte, if there are any. */
-	if (recyclecount)	/* nonempty recycled pool */
-	{	if (++recycleptr >= recyclecount)	/* ran out? */
-		{	recycleptr = 0;	/* ran out of recycled random numbers */
-			randstir();	/* stir up recycled bits */
-		}
-		return (recyclepool[recycleptr]);
+	return;
+}
+
+/*
+ * Encrypt the state of the PRNG with the given key.  It is intended
+ * that this key is the md5 of the message to be encrypted, which is
+ * unpredictable to a would-be attacker who does not posess the message.
+ * This is simply a way to get some "random" bytes without a random
+ * number source.  This "prewash" attempts to reduce the value of a
+ * captured randseed.bin file.
+ */
+void
+cryptRandWash(byte const key[16])
+{
+	struct IdeaCfbContext cfb;
+
+	if (!randInitFlag)
+		cryptRandOpen();
+	ideaCfbInit(&cfb, key);
+	ideaRandWash(&randContext, &cfb);
+	ideaCfbDestroy(&cfb);
+}
+
+byte
+cryptRandByte(void)
+{
+	if (!randInitFlag)
+		cryptRandOpen();
+	return ideaRandByte(&randContext);
+}
+
+/*
+ * Create a new RNG state, encrypt it with the session key, and save it
+ * out to disk.  The RNG is re-initialized with the saved parameters.
+ *
+ * This uses 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.
+ */
+void
+cryptRandSave(byte const key[16], byte const iv[8])
+{
+	struct IdeaCfbContext cfb;
+	byte buf[24];
+	FILE *f;
+	int i;
+
+	/* This IV is EXACTLY the same as is used on bulk files. */
+	memcpy(buf, iv, 8);
+	buf[8] = buf[6];	/* "check bytes" */
+	buf[9] = buf[7];
+
+	ideaCfbInit(&cfb, key);
+	ideaCfbEncrypt(&cfb, buf, buf, 10);
+	ideaCfbSync(&cfb);
+	for (i = 0; i < 24; i++)
+		buf[i] = ideaRandByte(&randContext);
+	ideaCfbEncrypt(&cfb, buf, buf, 24);
+	ideaCfbDestroy(&cfb);
+	ideaRandInit(&randContext, buf, buf+16);
+
+	f = fopen(globalRandseedName, FOPWBIN);
+	if (f) {
+		fwrite(buf, 1, 24, f);
+		fclose(f);
 	}
+}
 
-	/* Empty recycled pool.  Try a more expensive fresh random byte. */
-	if (randcount)	/* nonempty random pool--return a very random number */
-		return (randpool[--randcount]);
-
-	/* Alas, fresh random pool is empty.  Get a pseudorandom byte.
-	   Pseudorandom numbers are risky for cryptographic applications.
-	   Although we will return a pseudorandom byte in the low order byte,
-	   indicate error by making the result negative in the high byte.
-	*/
-	/* DEBUGprintf1("\007Warning: random pool empty! "); */
-	return ( (pseudorand() & 0xFF) ^ (-1) );
-}	/* randombyte */
-
-
-static short keybuf = 0;	/* used only by keypress() and getkey()	*/
-
-boolean keypress(void)	/* TRUE iff keyboard input ready */
-{	/* Accumulates random numbers by timing user keystrokes. */
-	static short lastkey = 0; /* used to detect autorepeat key sequences */
-	static short next_to_lastkey = 0; /* allows a single repeated key */
-
-#ifndef USEPCTIMER	/* no fast hardware timer available */
-	fastcounter++;	/* used in lieu of fast hardware timer counter */
-#endif	/* ifndef USEPCTIMER */
-
-	if (keybuf & 0x100)	/* bit 8 means keybuf contains valid data */
-		return( TRUE );	/* key was hit the last time thru */
-
-	if (kbhit() == 0)	/* keyboard was not hit */
-		return( FALSE );
-
-	keybuf = getch() | 0x100; /* set data latch bit */
-
-	/* Keyboard was hit.  Decide whether to call capturecounter... */
-
-	/*  Guard against typahead buffer defeating fastcounter's randomness.
-	**  This could be a problem for multicharacter sequences generated
-	**  by a function key expansion or by the user generating keystrokes
-	**  faster than our event loop can handle them.  Only the last 
-	**  character of a multicharacter sequence will trigger the counter
-	**  capture.  Also, don't let the keyboard's autorepeat feature
-	**  produce nonrandom counter capture.  However, we do allow a 
-	**  single repeated character to trigger counter capture, because
-	**  many english words have double letter combinations, and it's 
-	**  unlikely a typist would exploit the autorepeat feature to
-	**  type a simple double letter sequence.
-	*/
-
-	if (kbhit() == 0)	/* nothing in typahead buffer */
-	{	/* don't capture counter if key repeated */
-		if (keybuf != lastkey)
-			capturecounter(); /* save current random number seed */
-		else if (keybuf != next_to_lastkey) /* allow single repeat */
-			capturecounter();
-		next_to_lastkey = lastkey;
-		lastkey = keybuf;
+/*
+ * 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;
 	}
-	return( TRUE );
-}	/* keypress */
 
+	trueRandBits += cbits;
+	if (trueRandBits > RANDPOOLBITS)
+		trueRandBits = RANDPOOLBITS;
+
+	return cbits;
+}
 
-short getkey(void)	/* Returns data from keyboard (no echo). */
-{	/* Also accumulates random numbers via keypress(). */
-	while(! keypress() );		/* loop until key is pressed. */
-	return( keybuf &= 0xff);	/* clear latch bit 8 */
-}	/* getkey */
-
-
-#define BS 8	/* ASCII backspace */
-#define CR 13	/* ASCII carriage return */
-#define LF 10	/* ASCII linefeed */
-
-
-int getstring(char *strbuf, int maxlen, boolean echo)
-/*	Gets string from user, with no control characters allowed.
-	Also accumulates random numbers by calling getkey().
-	maxlen is max length allowed for string.
-	echo is TRUE iff we should echo keyboard to screen.
-	Returns null-terminated string in strbuf. 
-*/
-{	short i;
+
+/*
+ * 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;
-	while (TRUE)
-	{	c = getkey();
-	 	if (c==BS) 
-		{	if (i) 
-			{	if (echo) 
-				{	fputc(BS,stderr);
-					fputc(' ',stderr);
-					fputc(BS,stderr);
+	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--;
 			}
 			continue;
 		}
-	 	if (echo) fputc(c,stderr);
-		if (c==CR) 
-		{	if (echo) fputc(LF,stderr);
+		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;
-		if (c<' ')	/* any ASCII control character */
-			break;
 		strbuf[i++] = c;
-		if (i>=maxlen) 
-		{	fprintf(stderr,"\007*\n");	/* -Enough! */
-			while (keypress())
-				getkey();	/* clean up any typeahead */
+		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 */
-	return(i);		/* returns string length */
-}	/* getstring */
 
+	ttynorm();
 
-void randaccum(short bitcount)	/* Get this many random bits ready */
-/* We will need a series of truly random bits for key generation.
-   In most implementations, our random number supply is derived from
-   random keyboard delays rather than a hardware random number
-   chip.  So we will have to ensure we have a large enough pool of
-   accumulated random numbers from the keyboard.  Later, randombyte
-   will return bytes one at a time from the accumulated pool of
-   random numbers.  For ergonomic reasons, we may want to prefill
-   this random pool all at once initially.  This routine prefills
-   a pool of random bits. */
-{	short nbytes;
-	char c;
-	nbytes = min((bitcount+7)/8,sizeof(randpool));
+	return(i);		/* returns string length */
+} /* getstring */
 
-	if (randcount < nbytes)	/* if we don't have enough already */
-	{	fprintf(stderr,"\nWe need to generate %d random bytes.  This is done by measuring the",
-			nbytes-randcount);
-		fprintf(stderr,"\ntime intervals between your keystrokes.  Please enter some text on your");
-		fprintf(stderr,"\nkeyboard, at least %d nonrepeating keystrokes, until you hear the bell:\n",
-			(8*(nbytes-randcount)+cbits-1)/cbits);
-		while (randcount < nbytes) 
-		{	c=getkey();
-			fputc(c,stderr);
-			if (c==CR) fputc(LF,stderr);
-		}
-		fprintf(stderr,"\007*\n-Enough, thank you.\n");
-		while (keypress()) getkey();	/* clean up any typeahead */
-	}	/* if (randcount < nbytes) */
-}	/* randaccum */
 
+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
+}