diff -urN popa3d-0.6.2/params.h popa3d-0.6.2-spool-hashing/params.h
--- popa3d-0.6.2/params.h	Sun Sep  8 15:49:24 2002
+++ popa3d-0.6.2-spool-hashing/params.h	Wed Apr  2 15:38:48 2003
@@ -209,6 +209,13 @@
 #define SYSLOG_PRI_HI			LOG_NOTICE
 #define SYSLOG_PRI_ERROR		LOG_CRIT
 
+ /*
+ * Do we need mail spool hashing? Define hash depth here, i.e. value
+ * of 2 means two-level hashing, so user "foo"'s mailbox would be
+ * "SPOOL_PATH/f/o/foo". Value of 0 stands for "no hashing".
+ */
+#define MAIL_SPOOL_HASH			0
+
 /*
  * There's probably no reason to touch anything below this comment.
  */
diff -urN popa3d-0.6.2/pop_root.c popa3d-0.6.2-spool-hashing/pop_root.c
--- popa3d-0.6.2/pop_root.c	Fri Mar 22 01:15:19 2002
+++ popa3d-0.6.2-spool-hashing/pop_root.c	Wed Apr  2 15:38:48 2003
@@ -97,6 +97,60 @@
 	return offset;
 }
 
+#if MAIL_SPOOL_HASH
+/*
+ * This routine returns string like "/var/mail/u/s" based on value
+ * of variable 'user' and 'MAIL_SPOOL_HASH' macro, i.e. if MAIL_SPOOL_HASH
+ * is 3 and user == "user" then returned string will be smth like that:
+ * "/var/mail/u/s/e"
+ */
+
+char * hashed_spool(char * spool, char * user)
+{
+	char * hashed_spool_str = NULL;	/* Return value */
+	char * p = NULL;	/* Temporary pointer */
+	char * u = NULL;	/* Temporary pointer */
+	char c = 0;		/* Temporary char */
+	int i = 0;		/* Counter */
+
+	/* Sanity checks */
+	if (!spool || !*spool) return NULL;
+	if (!user || !*user) return NULL;
+
+	/*
+	 * Memory allocation. Don't bother freeing it, as it will be freed
+	 * at the end of forked process lifetime.
+	 */
+
+	if (!(hashed_spool_str =
+		(char *) malloc(strlen(spool) + 2*MAIL_SPOOL_HASH + 1)))
+			return NULL;
+
+	/*
+	 * We've allocated enough memory, so strcpy() usage is safe
+	 */
+
+	strcpy(hashed_spool_str, spool);
+
+	/*
+	 * This part was stolen from procmail's source and seems safe enough
+	 */
+
+	for (p = hashed_spool_str + strlen(spool),
+		i = MAIL_SPOOL_HASH,
+		u = user;
+		i--;) {
+			*p++ = '/';
+			if (*u) c = *u++;
+			*p++ = c;
+	}
+
+	*p = 0;	/* end of string */
+
+	return hashed_spool_str;
+}
+#endif /* MAIL_SPOOL_HASH */
+
 /*
  * The root-privileged part of the AUTHORIZATION state handling: reads
  * the authentication data obtained over POP from its end of the pipe,
@@ -160,7 +214,13 @@
 
 #if POP_VIRTUAL
 	if (virtual_domain) {
+
+#if MAIL_SPOOL_HASH
+		spool = hashed_spool(virtual_spool, user);
+#else
 		spool = virtual_spool;
+#endif /* MAIL_SPOOL_HASH */
+
 		mailbox = user;
 
 		return AUTH_OK;
@@ -172,7 +232,13 @@
 	return AUTH_FAILED;
 #else
 #ifdef MAIL_SPOOL_PATH
+
+#if MAIL_SPOOL_HASH
+	spool = hashed_spool(MAIL_SPOOL_PATH, user);
+#else
 	spool = MAIL_SPOOL_PATH;
+#endif /* MAIL_SPOOL_HASH */
+
 	mailbox = user;
 #else
 	spool = pw->pw_dir;