--- pgp/src/random.c	2018/04/24 16:37:52	1.1.1.2
+++ pgp/src/random.c	2018/04/24 16:39:11	1.1.1.4
@@ -1,712 +1,768 @@
-/**********************************************************************
-	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.
-	Revised 29 Jul 91 by PRZ for use in more limited environments.
-	Later revised by several other folks to run in difficult environments
-	such as Unix, VAX/VMS and others.
-	Revised 2 Sep 92 by Peter Gutmann and PRZ to use MD5 to distill 
-	high quality randomness down from low-grade random noise.
-
-	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 	<string.h>
-#include 	<time.h>
-#include	"random.h"
-#include	"language.h"
-
-/*	pseudorand() is used mainly for debugging while porting to a new
-	machine-- it makes reproducible sequences, which makes debugging
-	easier.  To use it as the source of random numbers, define
-	PSEUDORANDOM.  Warning:  Don't do this for actual applications.
-*/
-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 */
-
-
-#ifndef PSEUDORANDOM		/* use truly random numbers */
-
-/* #define USEPCTIMER */ /* use fast hardware timer on IBM PC or AT or clone */
-/* #define DEBUG */
-
-/*	If operating system shields keyboard event timings from user, then 
-	we can't use any hardware or software timer logic to time events.
-	This is a messy situation, so we have special logic to handle
-	it, defining the symbol CRUDE to compile special code. 
-	This may be needed in multiuser Unix systems, for example.
-*/
-#ifdef CRUDE /* No environmental support to capture keyboard event times */
-#undef USEPCTIMER
-#endif	/* CRUDE */
-
-#include	<stdio.h>	/* for putchar() and printf() */
-#include 	<time.h>
-
-/* Prototypes for kbhit() (whether the keyboard has been hit) and getch()
-   (like getchar() but no echo, no buffering).  Not available under some
-   implementations */
-
-int kbhit( void );
-int getch( void );
-
-#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
-
-
-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 unsigned fastcounter = 0;	/* not needed if we can use the PC timer. */
-static unsigned lastcounter = 0;
-static char toofast = 0;
-/* toofast indicates keystroke rejected because it was typed too fast */
-
-#ifdef CRUDE 
-static boolean capturemode = FALSE;
-#endif	/* CRUDE */
-
-#ifdef AMIGA
-int aecho;
-#endif
-
-/* Information needed by the MD5 code for distilling large quantities of
-   semi-random information into a small amount of highly-random information.
-   This works as follows:
-
-   Initially we have no random information.  Whenever we add more slightly
-   random data, we put it in the MD5 data field and run MD5 over the
-   random byte pool.  This propagates the randomness in the data evenly
-   throughout the pool due to the avalanche effect of the MD5 transformation.
-   The randomness transformation is carried out inside capturecounter() when
-   the data is entered, and is transparent to the operation of the rest of
-   the code.
-
-   The use of this randomness-distillation can be turned off by toggling the
-   following define in case the randomness code needs to be run on a
-   washing-machine controller or somesuch.
-*/
-
-#define USE_MD5		/* Turn on MD5 randomization */
-
-#ifdef USE_MD5
-void Transform( unsigned long *seedBuffer, unsigned long *data );
-byte seedBuffer[ 64 ];			/* Buffer for MD5 seed value */
-boolean isInitialised = FALSE;	/* Whether buffer has been inited */
-byte iv[ 16 ];					/* IV for MD5 transformation */
-#endif	/* USE_MD5 */
-
-#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 */
-
-
-/* keybuf is used only by keypress(), getkey(), and capturecounter(). */
-static short keybuf = 0;
-
-
-#ifdef VMS
-
-extern unsigned long	vms_clock_bits[2];	/* VMS Hardware Clock */
-extern const long	vms_ticks_per_update;	/* Clock update int. */
-
-#endif /* VMS */
-
-void capturecounter(void)
-/*	Push a fast counter on the random stack.  Should be called when
-**	the user touches a key or clicks the mouse.
-*/
-{
-	int dt, i, j;
-#ifndef USE_MD5
-	static unsigned int accum = 0;
-#endif /* USE_MD5 */
-	static byte abits = 0;	/* number of accumulated bits in accum */
-	unsigned int accum1;
-
-#define cbitsmask ((1 << cbits)-1)
-
-#ifdef CRUDE /* No environmental support to capture keyboard event times. */
-	if (!capturemode)
-		return;	/* only captures during randaccum function */
-#endif	/* CRUDE */
-
-	/*	fastcounter only contains timing information, in the form of a 
-		free-running timer, either hardware or software.
-		accum1 contains stuff from fastcounter and other sources,
-		like the actual key the user hit.
-	*/
-
-#if defined( USEPCTIMER	) /* we will use fast hardware timer on IBM PC */
-#define cbits 8		/* number of bits of counter to capture each time */
-	fastcounter = pctimer0();	/* capture hardware timer */
-#elif defined( CRUDE )			/* no fast hardware timer available */
-#define cbits 2
-#else	/* not CRUDE */
-#define cbits 4		/* number of bits of counter to capture each time */
-#ifdef VMS
-	/* Capture fast system timer: */
-	SYS$GETTIM(&vms_clock_bits);
-	lib$ediv (&vms_ticks_per_update,
-		&vms_clock_bits,&vms_clock_bits,&vms_clock_bits[1]);
-	fastcounter = vms_clock_bits[1];
-#endif /* VMS */
-#endif	/* not USEPCTIMER */
-
-#ifndef CRUDE	/* keyboard timings are available */
-	dt = fastcounter - lastcounter;
-	if (dt < 0)		/* timer rolled over past zero */
-		dt = -dt;	/* absolute value of time elapsed */
-#ifdef TEST_COUNTER
-	fprintf(stderr,"<dt=%6u>\n", dt);
-#endif
-	if ( ((unsigned) dt) < (unsigned)(1 << (cbits + 2)))
-	{
-		toofast++;	/* indicate a too-fast keystroke */
-		return;	/* only captures if enough time has passed */
-	}
-#endif /* not CRUDE */
-
-	lastcounter = fastcounter;	/* latch timer info */
-
-#ifdef USE_MD5
-	/* Initialise the MD5 info if necessary */
-	if( !isInitialised )
-	{	memset(seedBuffer, 0, 64);
-		memset(iv, 0, 16);
-		isInitialised = TRUE;
-	}
-
-	/*	Add the slightly-random data to the MD5 input buffer.  Currently we
-		just add a few bytes of environmental noise, but we could mix in 
-		up to 512 bits worth.
-	*/
-	seedBuffer[ 0 ] = keybuf;	/* actual character user typed */
-	seedBuffer[ 1 ] = lastcounter & 0xFF;
-	seedBuffer[ 2 ] = lastcounter >> 8;
-	accum1 = ( int ) clock();			/* clock ticks */
-	seedBuffer[ 3 ] = accum1 & 0xFF;
-	seedBuffer[ 4 ] = accum1 >> 8;
-	accum1 = ( int ) time(NULL);		/* seconds */
-	seedBuffer[ 5 ] = accum1 & 0xFF;
-	seedBuffer[ 6 ] = accum1 >> 8;
-	/* The preceding "noise quantum" has only cbits worth of randomness. */
-
-	/* Now use MD5 to diffuse the randomness in these bits over the random
-	   byte pool, raising the salinity of randomness in the pool.  The
-	   transformation is carried out by "encrypting" the data in CFB mode
-	   with MD5 as the block cipher */
-	for(i = 0; i < sizeof(randpool); i += 16)
-	{
-		Transform((unsigned long *) iv, (unsigned long *) seedBuffer);
-		for(j = 0; j < 16; j++)
-			randpool[i+j] ^= iv[j];
-		memcpy(iv, randpool+i, 16);
-	}
-
-	/*
-		Now the somewhat dubious bit:  In order to make this fit in with
-		the existing code, we use the existing mechanism of keeping track
-		of a high-water mark in the buffer.  This is actually reasonably
-		realistic, since it keeps a count of what percentage of the full
-		buffer is random enough-- measuring the "molarity" of solution. 
-		However when it comes time to re-randomize the buffer in
-		randombyte(), it would probably be better to use the above
-		transformation than the existing randombyte() code.  I've left it 
-		as is to keep it as compatible as possible.
-	*/
-
-	abits += cbits;		/* Update count of bits of randomness */
-	while (abits >= 8)
-	{	/* We've got another byte's worth, increment the buffer pointer */
-		if (randcount < sizeof(randpool))
-			randcount++; /* not a byte counter-- now a molarity of randomness */
-		abits -= 8;
-	}
-#else	/* not USE_MD5 */
-	/* combine several sources to attempt maximum randomness... */
-	accum1 = keybuf;		/* actual keystroke */
-	accum1 += lastcounter;	/* add latched timer info */
-	accum1 += clock();		/* clock ticks */
-	accum1 += time(NULL);	/* seconds */
-
-	accum1 ^= (accum1 >> cbits);	/* Fold upper and lower bits */
-
-	/* slide some new bits into the bit accumulator: */
-	accum = (accum << cbits) | (unsigned int) (accum1 & cbitsmask);
-	abits += cbits;
-	while (abits >= 8)	/* another byte's worth of bits accumulated */
-	{	if (randcount < sizeof(randpool))
-			/* take lower byte of accum */
-			randpool[randcount++] = accum;
-		abits -= 8;
-		accum >>= 8;
-	}
-#endif /* not USE_MD5 */
-#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;
-	memset(seedBuffer, 0, 64);
-	memset(iv, 0, 16);
-}	/* 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]);
-	}
-
-	/* 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 bad 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 */
-
-
-boolean keypress(void)	/* TRUE iff keyboard input ready */
-{	/* Accumulates random numbers by timing user keystrokes. */
-#ifndef CRUDE
-	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.
-	**  We have some separate checks in capturecounter() to guard
-	**  against other reasons for characters coming in too fast.
-	*/
-
-	if (kbhit() == 0)	/* nothing in typahead buffer */
-	{	/* don't capture counter if key repeated */
-		if (keybuf != lastkey)
-			capturecounter(); /* read random noise from environment */
-		else if (keybuf != next_to_lastkey) /* allow single repeat */
-			capturecounter();
-		next_to_lastkey = lastkey;
-		lastkey = keybuf;
-	}
-	return( TRUE );
-#else	/* CRUDE */
-	return(FALSE);
-#endif
-}	/* keypress */
-
-
-short getkey(void)	/* Returns data from keyboard (no echo). */
-{	/* Also accumulates random numbers via keypress(). */
-#ifndef CRUDE
-	while(! keypress() );		/* loop until key is pressed. */
-	return( keybuf &= 0xff);	/* clear latch bit 8 */
-#else
-	return(keybuf = getch() & 0xff);
-#endif
-}	/* getkey */
-
-
-#define BS	8		/* ASCII backspace */
-#define CR	13		/* ASCII carriage return */
-#define LF	10		/* ASCII linefeed */
-#define DEL 0177    /* ASCII delete */
-
-/* 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.  The randaccum function
-   prefills a pool of random bits.
-*/
-
-#if defined(UNIX) || defined(AMIGA) || defined(VMS)
-#define NEEDBREAK
-void ttycbreak();
-void ttynorm();
-#endif
-
-#ifndef CRUDE	/* We can measure keyboard event times accurately. */
-
-void randaccum(short bitcount)	/* Get this many random bits ready */
-{	short nbytes;
-	char c;
-	int col = 0;
-	unsigned long timer;
-	int fasts_rejected = 0;			/* number of too-fast keystrokes */
-
-	nbytes = min((bitcount+7)/8,sizeof(randpool));
-	fasts_rejected = 0;	/* number of too-fast keystrokes */
-	toofast = 0;	/* clear too-fast latch */
-
-	if (randcount < nbytes)	/* if we don't have enough already */
-	{	fprintf(stderr,PSTR("\nWe need to generate %d random bytes.  This is done by measuring the\
-\ntime intervals between your keystrokes.  Please enter some text on your\
-\nkeyboard, at least %d nonrepeating keystrokes, until you hear the beep:\n"),
-			nbytes-randcount, (8*(nbytes-randcount)+cbits-1)/cbits);
-#ifdef NEEDBREAK
-		ttycbreak();
-#endif
-		while (randcount < nbytes)
-		{	c=getkey();
-			if (toofast)
-			{	fasts_rejected++;	/* keep score */
-				toofast = 0;		/* reset latch */
-				putc('?', stderr);	/* indicate trouble */
-			}
-			else if ((nbytes - randcount) < 2)
-				putc('O', stderr);
-			else if ((nbytes - randcount) < 4)
-				putc('o', stderr);
-			else 
-				putc('.', stderr);
-			/**
-			putc(c,stderr);
-			if (c==CR) fputc(LF,stderr);
-			**/
-			if (++col == 64)
-			{	putc('\n', stderr);
-				col = 0;
-			}
-			fflush(stderr);
-		}
-		fprintf(stderr,PSTR("\007*\n-Enough, thank you.\n"));
-
-		if (fasts_rejected > 2)	/* Did user type too fast? */
-			fprintf(stderr,PSTR("(Ignored %d keystrokes that were typed too fast.)\n"), 
-				fasts_rejected);
-
-		/* Clean up typeahead for at least 1 full second... */
-		timer = time(NULL) + 1;	/* need at least 1 second of quiet */
-		while ((unsigned long) time(NULL) <= timer)
-		{	if (keypress())	/* user touched a key, reset timer */
-			{	getkey();
-				timer = time(NULL) + 1;
-			}
-		}
-
-#ifdef NEEDBREAK
-		ttynorm();
-#endif /* !NEEDBREAK */
-	}
-}	/* randaccum */
-
-#endif	/* not CRUDE */
-
-
-#ifdef CRUDE	/* We cannot measure keyboard event times accurately. */
-
-/*	This is a really lousy way to make random numbers.  We will only use
-	this method as a last resort, only if this machine does not allow
-	keyboard events to be timed accurately.  It's better than nothing.
-	The other randaccum function listed above is much better, if the
-	CRUDE symbol is undefined and the environment will support it.
-
-	We could improve this scheme somewhat by using a good hashing
-	function such as MD4 or MD5 on the user input before capturing it 
-	in the random pool.
-*/
-
-void randaccum(short bitcount)	/* Get this many random bits ready */
-{	short nbytes;
-	char c, flushbuf[80];
-	nbytes = min((bitcount+7)/8,sizeof(randpool));
-
-	randcount = 0;	/* start with nothing in pool. */
-	capturemode = TRUE;	/* enable capture of random keys */
-	fastcounter += time(0);	/* start with time of day, if available */
-
-	fprintf(stderr,PSTR("\nWe need to generate %d random bytes.\
-\nPlease enter at least %d random keystrokes, as random\
-\nas you can possibly make them.\n"),
-		nbytes-randcount, (8*(nbytes-randcount)+cbits-1)/cbits);
-	while (randcount < nbytes)
-	{	c=getkey();
-		capturecounter();
-	}
-	/*
-	 * CRUDE mode must work in normal tty mode, so we can't
-	 * use keypress() to flush input.
-	 */
-#ifdef AMIGA
-    while(keypress()) getch();
-#else
-	fgets(flushbuf, sizeof(flushbuf), stdin);
-#endif
-	fprintf(stderr,PSTR("\007 -Enough, thank you.\n"));
-
-	capturemode = FALSE;	/* don't capture any more keys */
-
-#ifdef NEEDBREAK
-	ttynorm();
-#endif
-}	/* randaccum */
-
-#endif	/* CRUDE */
-
-
-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;
-	char c;
-#ifdef NEEDBREAK
-	ttycbreak();
-#endif
-#ifdef AMIGA
-    aecho = (int)echo;
-    echo = FALSE;   /* echo is done in getch */
-#endif  /* AMIGA */
-	fflush(stdout);
-	i=0;
-	while (TRUE)
-	{	fflush(stderr);
-		c = getkey();
-		if (c==BS || c==DEL)
-		{	if (i)
-			{	if (echo)
-				{	fputc(BS,stderr);
-					fputc(' ',stderr);
-					fputc(BS,stderr);
-				}
-				i--;
-			}
-			continue;
-		}
-		if (c < ' ' && c != LF && c != CR)
-		{	putc('\007', stderr);
-			continue;
-		}
-		if (echo) fputc(c,stderr);
-		if (c==CR)
-		{	if (echo) fputc(LF,stderr);
-			break;
-		}
-		if (c==LF)
-			break;
-		if (c=='\n')
-			break;
-		strbuf[i++] = c;
-		if (i>=maxlen)
-		{	fprintf(stderr,"\007*\n");	/* -Enough! */
-			while (keypress())
-				getkey();	/* clean up any typeahead */
-			break;
-		}
-	}
-	strbuf[i] = '\0';	/* null termination of string */
-#ifdef NEEDBREAK
-	ttynorm();
-#endif
-	return(i);		/* returns string length */
-}	/* getstring */
-
-
-#endif			/* ifndef PSEUDORANDOM */
-
-void flush_input()
-{
-#ifdef NEEDBREAK
-	ttycbreak();
-#endif
-	while (keypress())	/* flush typahead buffer */
-		getkey();
-#ifdef NEEDBREAK
-	ttynorm();
-#endif
-}
-
+/**********************************************************************
+	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.
+	Revised 29 Jul 91 by PRZ for use in more limited environments.
+	Later revised by several other folks to run in difficult environments
+	such as Unix, VAX/VMS and others.
+	Revised 2 Sep 92 by Peter Gutmann and PRZ to use MD5 to distill 
+	high quality randomness down from low-grade random noise.
+	Revised 25 Feb 93 by Colin Plumb to use MD5 much more for
+	more secure random numbers.  (randstir hacked)
+	Revised 4 Mar 93 by Colin Plumb to remove the CRUDE and non-USE_MD5
+	options, as no platform currently uses them, they make the code
+	hard to read, and they were suffering bit rot.  Also added
+	NO_ITIMER for the isc port and randaccum_later.
+
+	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.
+**********************************************************************/
+
+#ifdef UNIX
+#include <sys/types.h>
+#include <sys/time.h>
+
+#ifdef NO_ITIMER	/* Some systems lie about itimer */
+#undef ITIMER_REAL
+#endif
+
+#ifndef ITIMER_REAL
+#include <sys/times.h>
+#endif
+#endif /* UNIX */
+
+#if defined(UNIX) || defined(VMS)
+#include <signal.h>
+#endif
+
+#include	<stdio.h>	/* for putchar() and printf() */
+#include 	<string.h>
+#ifndef _BSD
+#include 	<time.h>
+#endif
+#include	"system.h"
+#include	"random.h"
+#include	"language.h"
+
+static long pseudorand(void);	/* 31-bit LCG pseudorandom generator */
+
+#ifdef  M_XENIX
+long time();
+#endif
+#ifdef UNIX
+#define	clock	Clock
+#endif
+
+/*	pseudorand() is used mainly for debugging while porting to a new
+	machine-- it makes reproducible sequences, which makes debugging
+	easier.  To use it as the source of random numbers, define
+	PSEUDORANDOM.  Warning:  Don't do this for actual applications.
+*/
+/**
+ ** Minimal Standard Pseudo-Random Number Generator
+ **
+ ** Author: Fuat C. Baran, Columbia University, 1988
+ **
+ ** Based on code in "Random Number Generators: Good Ones are Hard to Find",
+ ** by Stephen K. Park and Keith W. Miller in Communications of the ACM,
+ ** 31, 10 (Oct. 1988) pp. 1192-1201.
+ **
+ **/
+
+/* some constants we need */
+#define A 16807L
+#define M 2147483647L		/* Mersenne prime 2^31 -1 */
+#define Q 127773L			/* M div A (M / A) */
+#define R 2836L				/* M mod A (M % A) */
+
+static long pseudorand(void)
+{
+	long hi, lo;
+#ifdef DEBUG
+	static long seed = 1;
+#else
+	static long seed = 0;
+#endif
+	if (!seed || seed == M)
+#ifdef UNIX
+		seed = ((long) getpid() << 16) ^ time(NULL);
+#else
+		seed = ((long) clock() << 16) ^ time(NULL);
+#endif
+	hi = seed / Q;
+	lo = seed % Q;
+	if ((seed = A * lo - R * hi) <= 0)
+		seed += M;
+	return seed;
+}
+
+
+#ifndef PSEUDORANDOM		/* use truly random numbers */
+
+/* #define USEPCTIMER */ /* use fast hardware timer on IBM PC or AT or clone */
+/* #define DEBUG */
+
+/* Prototypes for kbhit() (whether the keyboard has been hit) and getch()
+   (like getchar() but no echo, no buffering).  Not available under some
+   implementations */
+#ifdef MSDOS
+#include <conio.h>
+typedef word16 fastcnt_t;
+#else
+typedef word32 fastcnt_t;
+#ifdef VMS
+int putch(int);
+#else
+#define	putch(c)	putc(c, stderr)
+#endif
+#endif /* !MSDOS */
+
+#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
+
+#define POOLSIZE 256
+static int randcount = 0;		/* # of random bytes accumulated in pool */
+static byte randpool[POOLSIZE] = {0} ;	/* pool of truly random bytes */
+static int recyclecount = 0 ;	/* # of recycled random bytes accumulated */
+static byte recyclepool[POOLSIZE] = {0} ; /* pool of recycled random bytes */
+
+static int accumpending = 0;	/* # of random bits to add to next request */
+
+static void randstir(byte *pool);
+
+/* fastcounter is a free-running counter incremented in main event loop. */
+static fastcnt_t fastcounter = 0;	/* not needed if we can use the PC timer. */
+static fastcnt_t lastcounter = 0;
+static int cbits;
+static char toofast = 0;
+/* toofast indicates keystroke rejected because it was typed too fast */
+
+#ifdef AMIGA
+int aecho;
+#endif
+
+/* Information needed by the MD5 code for distilling large quantities of
+   semi-random information into a small amount of highly-random information.
+   This works as follows:
+
+   Initially we have no random information.  Whenever we add more slightly
+   random data, we put it in the MD5 data field and run MD5 over the
+   random byte pool.  This propagates the randomness in the data evenly
+   throughout the pool due to the avalanche effect of the MD5 transformation.
+   The randomness transformation is carried out inside capturecounter() when
+   the data is entered, and is transparent to the operation of the rest of
+   the code.
+*/
+
+#include "md5.h"
+static byte seedBuffer[ 64 ];			/* Buffer for MD5 seed value */
+static boolean isInitialised = FALSE;	/* Whether buffer has been inited */
+static byte iv[ 16 ];					/* IV for MD5 transformation */
+
+#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 */
+
+
+/* keybuf is used only by keypress(), getkey(), and capturecounter(). */
+static short keybuf = 0;
+
+
+#ifdef VMS
+
+extern unsigned long	vms_clock_bits[2];	/* VMS Hardware Clock */
+extern const long	vms_ticks_per_update;	/* Clock update int. */
+
+#endif /* VMS */
+
+static void capturecounter(void)
+/*	Push a fast counter on the random stack.  Should be called when
+**	the user touches a key or clicks the mouse.
+*/
+{
+	fastcnt_t dt;
+#ifndef MSDOS
+	byte *random_xtra;	/* extra timer info */
+#endif
+	static byte abits = 0;	/* number of accumulated bits in accum */
+	unsigned int accum1;
+
+#define cbitsmask ((1 << cbits)-1)
+
+	/*	fastcounter only contains timing information, in the form of a 
+		free-running timer, either hardware or software.
+		accum1 contains stuff from fastcounter and other sources,
+		like the actual key the user hit.
+	*/
+
+#if defined(USEPCTIMER) /* we will use fast hardware timer on IBM PC */
+	fastcounter = pctimer0();	/* capture hardware timer */
+#endif	/* not USEPCTIMER */
+
+#ifdef VMS
+#define	HW_TIMER	1		/* using hardware timer */
+	/* Capture fast system timer: */
+	SYS$GETTIM(vms_clock_bits);
+#ifdef TEST_COUNTER
+	fprintf(stderr," time %10ol %10ol\n",vms_clock_bits[0],vms_clock_bits[1]);
+#endif
+	/* vms_clock_bits[0] and vms_ticks_per_update are 32-bits each. */
+	fastcounter = vms_clock_bits[0] / vms_ticks_per_update;
+#endif /* VMS */
+
+#ifdef UNIX
+#define	HW_TIMER	1		/* using hardware timer */
+#ifdef ITIMER_REAL
+	{	static struct itimerval it;
+		getitimer(ITIMER_REAL, &it);
+		if (it.it_value.tv_sec == 0 && it.it_value.tv_usec == 0)
+		{	/* start the timer */
+			it.it_value.tv_sec = 100000;
+			it.it_value.tv_usec = 0;
+			it.it_interval.tv_sec = 100000;
+			it.it_interval.tv_usec = 0;
+			signal(SIGALRM, SIG_IGN);	/* just in case.. */
+			setitimer(ITIMER_REAL, &it, NULL);
+			return;
+		}
+		/* divide by 64 (we can at least expect a 60Hz clock) */
+		fastcounter = 6400000-(it.it_value.tv_usec / (1000000/64)
+				+ it.it_value.tv_sec * 64);
+		random_xtra = (byte *) &it.it_value;
+#define	XTRA_BYTES	(sizeof(struct timeval))
+	}
+#else /* !ITIMER_REAL */
+	{	static struct tms tms;
+		fastcounter = times(&tms);
+		random_xtra = (byte *) &tms;
+#define	XTRA_BYTES	(sizeof(struct tms))
+	}
+#endif /* !ITIMER_REAL */
+#endif /* UNIX */
+
+	dt = fastcounter - lastcounter;
+#ifdef TEST_COUNTER
+	fprintf(stderr,"%6lu", dt);
+#endif
+#ifndef NO_CBIT_STRIP
+	dt /= 6;	/* use 2.5 bits less than the actual count */
+#endif
+	for (cbits = 0; dt; ++cbits)
+		dt >>= 1;
+#if 0	/* I don't think this is necessary - CP */
+	if (cbits > 8)
+		cbits = 8;
+#endif
+
+#ifdef TEST_COUNTER
+	fprintf(stderr,"%6u\n", cbits);
+#endif
+	if (cbits <= 0)
+	{
+		toofast++;	/* indicate a too-fast keystroke */
+		return;	/* only captures if enough time has passed */
+	}
+
+	lastcounter = fastcounter;	/* latch timer info */
+
+	/* Initialise the MD5 info if necessary */
+	if( !isInitialised )	/* we probably shouldn't bother */
+	{	memset(seedBuffer, 0, 64);
+		memset(iv, 0, 16);
+		isInitialised = TRUE;
+	}
+
+	/*	Add the slightly-random data to the MD5 input buffer.  Currently we
+		just add a few bytes of environmental noise, but we could mix in 
+		up to 512 bits worth.  This should be extended in a system-specific
+		manner.
+	*/
+	seedBuffer[ 0 ] = keybuf;	/* actual character user typed */
+	seedBuffer[ 1 ] = lastcounter & 0xFF;
+	seedBuffer[ 2 ] = lastcounter >> 8;
+#ifdef MSDOS
+	accum1 = ( int ) clock();			/* clock ticks */
+	seedBuffer[ 3 ] = accum1 & 0xFF;
+	seedBuffer[ 4 ] = accum1 >> 8;
+#endif
+	accum1 = ( int ) time(NULL);		/* seconds */
+	seedBuffer[ 5 ] = accum1 & 0xFF;
+	seedBuffer[ 6 ] = accum1 >> 8;
+#ifdef XTRA_BYTES	/* add some extra "random" stuff */
+	memcpy(seedBuffer+16, random_xtra, XTRA_BYTES);
+#endif
+	/* The preceding "noise quantum" has only cbits worth of randomness. */
+	/* Spread it uniformly across the entire pool */
+
+	randstir(randpool);
+
+	/*
+		Now the somewhat dubious bit:  In order to make this fit in with
+		the existing code, we use the existing mechanism of keeping track
+		of a high-water mark in the buffer.  This is actually reasonably
+		realistic, since it keeps a count of what percentage of the full
+		buffer is random enough-- measuring the "molarity" of solution. 
+	*/
+
+	abits += cbits;		/* Update count of bits of randomness */
+	while (abits >= 8)
+	{	/* We've got another byte's worth, increment the buffer pointer */
+		if (randcount < sizeof(randpool))
+			randcount++; /* not a byte counter-- now a molarity of randomness */
+		abits -= 8;
+	}
+}	/* 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(byte *pool)
+/* Stir up the recycled random number bin, via a pseudorandom generator
+   Any truly random bytes stored into the seedBuffer are hashed into the
+   pool, and then destroyed for security reasons. */
+{	int i;
+	int j;
+	/* Now use MD5 to diffuse the randomness in these bits over the random
+	   byte pool, raising the salinity of randomness in the pool.  The
+	   transformation is carried out by "encrypting" the data in CFB mode
+	   with MD5 as the block cipher */
+	for(i = 0; i < POOLSIZE; i += 16)
+	{
+		Transform((unsigned long *) iv, (unsigned long *) seedBuffer);
+		for(j = 0; j < 16; j++)
+			pool[i+j] ^= iv[j];
+		memcpy(iv, pool+i, 16);
+	}
+/* CFB encryption is reversible; if we want the stirring operation to
+   be strictly one-way, we must destroy the key.  The operation
+   accomplishes that, and increases the end-to-beginning feedback
+   in randstir(), in an attempt to make all bytes depend on all
+   other bytes. */
+	memcpy(seedBuffer, pool+POOLSIZE-sizeof(seedBuffer),
+	       sizeof(seedBuffer));
+}	/* 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. */
+{	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);
+	randstir(recyclepool);
+	recyclecount = sizeof(recyclepool);
+	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. */
+{	
+/* We do not actually destroy the random bytes (which would be somewhat
+   wasteful); we just stir them so that they are irretrievable.  This
+   assumes that MD5 is truly one-way. */
+	randstir(recyclepool);
+	recyclecount = 0;
+}	/* randflush */
+
+short try_randombyte(void)
+/* Returns a truly random byte if any are available, or -1 if none.
+ * it is not an error to call this if none are available.  For example,
+ * make_random_ideakey calls it to add to its other sources of pseudo-random
+ * noise.
+ */
+{
+	/* First try to get a cheap recycled random byte, if there are any. */
+	if (recyclecount)	/* nonempty recycled pool */
+	{
+		byte b;
+		b = recyclepool[--recyclecount];
+		if (!recyclecount)	/* Used them all up? */
+			randstir(recyclepool);	/* Refresh recycled pool */
+		return b;
+	}
+
+	/* Empty recycled pool.  Try a more expensive fresh random byte. */
+
+	if (randcount)	/* nonempty random pool--return a very random number */
+		return (randpool[--randcount]);
+
+	/* No, all is for naught.  Return -1. */
+	return -1;
+}
+
+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.
+*/
+{	
+	short r;
+
+	r = try_randombyte();
+	if (r >= 0)
+		return r;
+
+	/* Oops!  Random pool empty.  Were there some unsatisifed deferred
+	   accumulation requests? */
+	randaccum(0);
+	r = try_randombyte();
+	if (r >= 0)
+		return r;
+	
+	/* Alas, fresh random pool is truly empty.  Complain, and return
+	   a pseudorandom byte.  Pseudorandom numbers are bad 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.
+	*/
+	fprintf(stderr, " \007WARNING: Random pool empty! ");
+	return ( (pseudorand() & 0xFF) ^ (-1) );
+}	/* randombyte */
+
+
+static 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 HW_TIMER	/* no fast hardware timer available */
+	fastcounter++;	/* used in lieu of fast hardware timer counter */
+#endif	/* ifndef HW_TIMER */
+
+	if (keybuf & 0x100)	/* bit 8 means keybuf contains valid data */
+		return( TRUE );	/* key was hit the last time thru */
+
+	/*
+	 * If HW_TIMER is defined we don't need a busy loop, so keypress
+	 * waits for a key and will always return TRUE.
+	 */
+#ifndef HW_TIMER
+	if (kbhit() == 0)	/* keyboard was not hit */
+		return( FALSE );
+#endif
+
+	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.
+	**  We have some separate checks in capturecounter() to guard
+	**  against other reasons for characters coming in too fast.
+	*/
+
+#ifndef HW_TIMER
+	if (kbhit() == 0)	/* nothing in typahead buffer */
+#endif
+	{	/* don't capture counter if key repeated */
+		if (keybuf != lastkey)
+			capturecounter(); /* read random noise from environment */
+		else if (keybuf != next_to_lastkey) /* allow single repeat */
+			capturecounter();
+		next_to_lastkey = lastkey;
+		lastkey = keybuf;
+	}
+	return( TRUE );
+}	/* keypress */
+
+
+static 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 */
+#define DEL 0177    /* ASCII delete */
+
+/* Since getting random bits from the keyboard requires user attention,
+   we buffer up requests for them until we can do one big request. */
+
+void randaccum_later(short bitcount)
+{
+	accumpending += bitcount;	/* Wow, that was easy! :-) */
+}
+
+/* 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.  The randaccum function
+   prefills a pool of random bits.
+*/
+
+void randaccum(short bitcount)	/* Get this many random bits ready */
+{	short nbytes;
+#ifndef HW_TIMER
+	unsigned long timer;
+#endif
+	int fasts_rejected = 0;			/* number of too-fast keystrokes */
+
+	bitcount += accumpending;	/* Do deferred accumulation now */
+	accumpending = 0;
+	nbytes = min((bitcount+7)/8,sizeof(randpool));
+	fasts_rejected = 0;	/* number of too-fast keystrokes */
+	toofast = 0;	/* clear too-fast latch */
+
+	if (randcount < nbytes)	/* if we don't have enough already */
+	{	fprintf(stderr,
+PSTR("\nWe need to generate %d random bytes.  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"), nbytes-randcount);
+#ifdef NEEDBREAK
+		ttycbreak();
+#endif
+		/* display counter to show progress */
+
+		while (randcount < nbytes)
+		{
+#ifndef TEST_COUNTER
+			fprintf(stderr,"\r%3d ",nbytes-randcount);
+#endif
+			fflush(stderr);
+			getkey();
+			if (toofast)
+			{	fasts_rejected++;	/* keep score */
+				toofast = 0;		/* reset latch */
+				putc('?', stderr);	/* indicate trouble */
+			}
+			else 
+				putc('.', stderr);
+		}
+
+		fprintf(stderr,PSTR("\007*\n-Enough, thank you.\n"));
+
+		if (fasts_rejected > 2)	/* Did user type too fast? */
+			fprintf(stderr,PSTR("(Ignored %d keystrokes that were typed too fast.)\n"), 
+				fasts_rejected);
+
+#ifdef HW_TIMER	/* keypress() would block if using hardware timer */
+		sleep(1);
+#else
+		/* Clean up typeahead for at least 1 full second... */
+		timer = time(NULL) + 1;	/* need at least 1 second of quiet */
+		while ((unsigned long) time(NULL) <= timer)
+		{	if (keypress())	/* user touched a key, reset timer */
+			{	getkey();
+				timer = time(NULL) + 1;
+			}
+		}
+#endif
+
+#ifdef NEEDBREAK
+		ttynorm();
+#endif /* !NEEDBREAK */
+	}
+}	/* randaccum */
+
+
+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;
+	char c;
+#ifdef NEEDBREAK
+	ttycbreak();
+#endif
+#ifdef AMIGA
+    aecho = (int)echo;
+    echo = FALSE;   /* echo is done in getch */
+#endif  /* AMIGA */
+	fflush(stdout);
+	i=0;
+	while (TRUE)
+	{	
+#ifndef VMS
+		fflush(stderr);
+#endif /* VMS */
+		c = getkey();
+#ifdef VMS
+		if (c == 25) {  /*  Control-Y detected */
+		    ttynorm();
+		    breakHandler(SIGINT);
+		}
+#endif /* VMS */
+		if (c==BS || c==DEL)
+		{	if (i)
+			{	if (echo)
+				{	putch(BS);
+					putch(' ');
+					putch(BS);
+				}
+				i--;
+			}
+			continue;
+		}
+		if (c < ' ' && c != LF && c != CR)
+		{	putch('\007');
+			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)
+		{	fprintf(stderr,"\007*\n");	/* -Enough! */
+			while (keypress())
+				getkey();	/* clean up any typeahead */
+			break;
+		}
+	}
+	strbuf[i] = '\0';	/* null termination of string */
+#ifdef NEEDBREAK
+	ttynorm();
+#endif
+	return(i);		/* returns string length */
+}	/* getstring */
+
+
+#endif			/* ifndef PSEUDORANDOM */
+
+void flush_input(void)
+{	/* on unix ttycbreak() will flush the input queue */
+#ifndef HW_TIMER
+	while (keypress())	/* flush typahead buffer */
+		getkey();
+#endif
+}
+