diff --git a/CHANGES b/CHANGES
index c400ba14a7034a2786d48c0322c9c41069a80c2c..265fa8b20c3c0dd698d01815fa3ec7883f6a0a85 100644
--- a/CHANGES
+++ b/CHANGES
@@ -16,6 +16,9 @@
         RC2_SHORT, RC2_LONG, RC4_LONG, RC4_CHUNK, RC4_INDEX
      [Rich Salz, with advice from Andy Polyakov]
 
+  *) Many BN internals have been moved to an internal header file.
+     [Rich Salz with help from Andy Polyakov]
+
   *) Configuration and writing out the results from it has changed.
      Files such as Makefile include/openssl/opensslconf.h and are now
      produced through general templates, such as Makefile.in and
diff --git a/Configure b/Configure
index 395de481363f7bbf6d870f936b47299d4231931e..9a9b92a7739fb18ceffac9182b2ffd493290305e 100755
--- a/Configure
+++ b/Configure
@@ -1116,17 +1116,21 @@ my $def_int="unsigned int";
 $config{rc4_int}		=$def_int;
 ($config{b64l},$config{b64},$config{b32})=(0,0,1);
 
+my $count = 0;
 foreach (sort split(/\s+/,$target{bn_ops})) {
-    $config{bn_ll}=1				if /BN_LLONG/;
-    $config{rc4_int}="unsigned char"		if /RC4_CHAR/;
-    ($config{b64l},$config{b64},$config{b32},$config{b16},$config{b8})
-	=(0,1,0,0,0)				if /SIXTY_FOUR_BIT/;
-    ($config{b64l},$config{b64},$config{b32},$config{b16},$config{b8})
-	=(1,0,0,0,0)				if /SIXTY_FOUR_BIT_LONG/;
-    ($config{b64l},$config{b64},$config{b32},$config{b16},$config{b8})
-	=(0,0,1,0,0)				if /THIRTY_TWO_BIT/;
-    $config{export_var_as_fn}=1			if /EXPORT_VAR_AS_FN/;
+    $count++ if /SIXTY_FOUR_BIT|SIXTY_FOUR_BIT_LONG|THIRTY_TWO_BIT/;
+    $config{export_var_as_fn}=1                 if $_ eq 'EXPORT_VAR_AS_FN';
+    $config{bn_ll}=1				if $_ eq 'BN_LLONG';
+    $config{rc4_int}="unsigned char"		if $_ eq 'RC4_CHAR';
+    ($config{b64l},$config{b64},$config{b32})
+	=(0,1,0)				if $_ eq 'SIXTY_FOUR_BIT';
+    ($config{b64l},$config{b64},$config{b32})
+	=(1,0,0)				if $_ eq 'SIXTY_FOUR_BIT_LONG';
+    ($config{b64l},$config{b64},$config{b32})
+	=(0,0,1)				if $_ eq 'THIRTY_TWO_BIT';
 }
+die "Exactly one of SIXTY_FOUR_BIT|SIXTY_FOUR_BIT_LONG|THIRTY_TWO_BIT can be set in bn_ops\n"
+    if $count > 1;
 
 
 # Hack cflags for better warnings (dev option) #######################
diff --git a/crypto/bn/bn_div.c b/crypto/bn/bn_div.c
index 2bb9c8c8a1880c56a532e0162981e505c9d70da3..486a31d79a88a4c0a05422ffc3744c7d4a75bd45 100644
--- a/crypto/bn/bn_div.c
+++ b/crypto/bn/bn_div.c
@@ -360,10 +360,6 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
             q = (BN_ULONG)(((((BN_ULLONG) n0) << BN_BITS2) | n1) / d0);
 #   else
             q = bn_div_words(n0, n1, d0);
-#    ifdef BN_DEBUG_LEVITTE
-            fprintf(stderr, "DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\
-X) -> 0x%08X\n", n0, n1, d0, q);
-#    endif
 #   endif
 
 #   ifndef REMAINDER_IS_ALREADY_CALCULATED
@@ -388,10 +384,6 @@ X) -> 0x%08X\n", n0, n1, d0, q);
             BN_ULONG t2l, t2h;
 
             q = bn_div_words(n0, n1, d0);
-#   ifdef BN_DEBUG_LEVITTE
-            fprintf(stderr, "DEBUG: bn_div_words(0x%08X,0x%08X,0x%08\
-X) -> 0x%08X\n", n0, n1, d0, q);
-#   endif
 #   ifndef REMAINDER_IS_ALREADY_CALCULATED
             rem = (n1 - q * d0) & BN_MASK2;
 #   endif
diff --git a/crypto/bn/bn_gcd.c b/crypto/bn/bn_gcd.c
index a3e56c85f68a84778ccafc4687a79ee060b7cad0..b6dd09e5819b18f180f9fbbc01b1c65fe2eef326 100644
--- a/crypto/bn/bn_gcd.c
+++ b/crypto/bn/bn_gcd.c
@@ -290,7 +290,7 @@ BIGNUM *int_bn_mod_inverse(BIGNUM *in,
      *      sign*Y*a  ==  A   (mod |n|).
      */
 
-    if (BN_is_odd(n) && (BN_num_bits(n) <= (BN_BITS <= 32 ? 450 : 2048))) {
+    if (BN_is_odd(n) && (BN_num_bits(n) <= 2048)) {
         /*
          * Binary inversion algorithm; requires odd modulus. This is faster
          * than the general algorithm if the modulus is sufficiently small
diff --git a/crypto/bn/bn_lcl.h b/crypto/bn/bn_lcl.h
index 013c0b3f865abf9f5cdeb5b4b350f1e1e9ead34f..0f3205c0ca77d4298e877e22f6f70c0a6470558c 100644
--- a/crypto/bn/bn_lcl.h
+++ b/crypto/bn/bn_lcl.h
@@ -118,6 +118,94 @@
 extern "C" {
 #endif
 
+/*
+ * These preprocessor symbols control various aspects of the bignum headers
+ * and library code. They're not defined by any "normal" configuration, as
+ * they are intended for development and testing purposes. NB: defining all
+ * three can be useful for debugging application code as well as openssl
+ * itself. BN_DEBUG - turn on various debugging alterations to the bignum
+ * code BN_DEBUG_RAND - uses random poisoning of unused words to trip up
+ * mismanagement of bignum internals. You must also define BN_DEBUG.
+ */
+/* #define BN_DEBUG */
+/* #define BN_DEBUG_RAND */
+
+# ifndef OPENSSL_SMALL_FOOTPRINT
+#  define BN_MUL_COMBA
+#  define BN_SQR_COMBA
+#  define BN_RECURSION
+# endif
+
+/*
+ * This next option uses the C libraries (2 word)/(1 word) function. If it is
+ * not defined, I use my C version (which is slower). The reason for this
+ * flag is that when the particular C compiler library routine is used, and
+ * the library is linked with a different compiler, the library is missing.
+ * This mostly happens when the library is built with gcc and then linked
+ * using normal cc.  This would be a common occurrence because gcc normally
+ * produces code that is 2 times faster than system compilers for the big
+ * number stuff. For machines with only one compiler (or shared libraries),
+ * this should be on.  Again this in only really a problem on machines using
+ * "long long's", are 32bit, and are not using my assembler code.
+ */
+# if defined(OPENSSL_SYS_MSDOS) || defined(OPENSSL_SYS_WINDOWS) || \
+    defined(OPENSSL_SYS_WIN32) || defined(linux)
+#  define BN_DIV2W
+# endif
+
+/*
+ * 64-bit processor with LP64 ABI
+ */
+# ifdef SIXTY_FOUR_BIT_LONG
+#  define BN_ULLONG       unsigned long long
+#  define BN_BITS4        32
+#  define BN_MASK2        (0xffffffffffffffffL)
+#  define BN_MASK2l       (0xffffffffL)
+#  define BN_MASK2h       (0xffffffff00000000L)
+#  define BN_MASK2h1      (0xffffffff80000000L)
+#  define BN_DEC_CONV     (10000000000000000000UL)
+#  define BN_DEC_NUM      19
+#  define BN_DEC_FMT1     "%lu"
+#  define BN_DEC_FMT2     "%019lu"
+# endif
+
+/*
+ * 64-bit processor other than LP64 ABI
+ */
+# ifdef SIXTY_FOUR_BIT
+#  undef BN_LLONG
+#  undef BN_ULLONG
+#  define BN_BITS4        32
+#  define BN_MASK2        (0xffffffffffffffffLL)
+#  define BN_MASK2l       (0xffffffffL)
+#  define BN_MASK2h       (0xffffffff00000000LL)
+#  define BN_MASK2h1      (0xffffffff80000000LL)
+#  define BN_DEC_CONV     (10000000000000000000ULL)
+#  define BN_DEC_NUM      19
+#  define BN_DEC_FMT1     "%llu"
+#  define BN_DEC_FMT2     "%019llu"
+# endif
+
+# ifdef THIRTY_TWO_BIT
+#  ifdef BN_LLONG
+#   if defined(_WIN32) && !defined(__GNUC__)
+#    define BN_ULLONG     unsigned __int64
+#   else
+#    define BN_ULLONG     unsigned long long
+#   endif
+#  endif
+#  define BN_BITS4        16
+#  define BN_MASK2        (0xffffffffL)
+#  define BN_MASK2l       (0xffff)
+#  define BN_MASK2h1      (0xffff8000L)
+#  define BN_MASK2h       (0xffff0000L)
+#  define BN_DEC_CONV     (1000000000L)
+#  define BN_DEC_NUM      9
+#  define BN_DEC_FMT1     "%u"
+#  define BN_DEC_FMT2     "%09u"
+# endif
+
+
 /*-
  * Bignum consistency macros
  * There is one "API" macro, bn_fix_top(), for stripping leading zeroes from
diff --git a/crypto/ec/ecp_nistz256.c b/crypto/ec/ecp_nistz256.c
index 579a3ad622b7efd1cf1dc82f68ff3ef552156ab7..7d953a306d6fa34e836dde4235cbf7e94e3e02e1 100644
--- a/crypto/ec/ecp_nistz256.c
+++ b/crypto/ec/ecp_nistz256.c
@@ -179,7 +179,6 @@ static BN_ULONG is_zero(BN_ULONG in)
 {
     in |= (0 - in);
     in = ~in;
-    in &= BN_MASK2;
     in >>= BN_BITS2 - 1;
     return in;
 }
diff --git a/include/openssl/bio.h b/include/openssl/bio.h
index beacf191838cbc92f7bd00b37dbf422abcf122c2..8b00ffdda792f7fdab293dd2bc1f01c5ffc199ae 100644
--- a/include/openssl/bio.h
+++ b/include/openssl/bio.h
@@ -221,8 +221,6 @@ extern "C" {
  */
 # define BIO_FLAGS_MEM_RDONLY    0x200
 
-typedef struct bio_st BIO;
-
 void BIO_set_flags(BIO *b, int flags);
 int BIO_test_flags(const BIO *b, int flags);
 void BIO_clear_flags(BIO *b, int flags);
diff --git a/include/openssl/bn.h b/include/openssl/bn.h
index 08cdf79018f45ec7e00e30a0f635069ee33a4e69..37baef347fcc4076c7e0fa1daa73e889b2d6ce4b 100644
--- a/include/openssl/bn.h
+++ b/include/openssl/bn.h
@@ -137,126 +137,29 @@ extern "C" {
 #endif
 
 /*
- * These preprocessor symbols control various aspects of the bignum headers
- * and library code. They're not defined by any "normal" configuration, as
- * they are intended for development and testing purposes. NB: defining all
- * three can be useful for debugging application code as well as openssl
- * itself. BN_DEBUG - turn on various debugging alterations to the bignum
- * code BN_DEBUG_RAND - uses random poisoning of unused words to trip up
- * mismanagement of bignum internals. You must also define BN_DEBUG.
- */
-/* #define BN_DEBUG */
-/* #define BN_DEBUG_RAND */
-
-# ifndef OPENSSL_SMALL_FOOTPRINT
-#  define BN_MUL_COMBA
-#  define BN_SQR_COMBA
-#  define BN_RECURSION
-# endif
-
-/*
- * This next option uses the C libraries (2 word)/(1 word) function. If it is
- * not defined, I use my C version (which is slower). The reason for this
- * flag is that when the particular C compiler library routine is used, and
- * the library is linked with a different compiler, the library is missing.
- * This mostly happens when the library is built with gcc and then linked
- * using normal cc.  This would be a common occurrence because gcc normally
- * produces code that is 2 times faster than system compilers for the big
- * number stuff. For machines with only one compiler (or shared libraries),
- * this should be on.  Again this in only really a problem on machines using
- * "long long's", are 32bit, and are not using my assembler code.
- */
-# if defined(OPENSSL_SYS_MSDOS) || defined(OPENSSL_SYS_WINDOWS) || \
-    defined(OPENSSL_SYS_WIN32) || defined(linux)
-#  ifndef BN_DIV2W
-#   define BN_DIV2W
-#  endif
-# endif
-
-/*
- * assuming long is 64bit - this is the DEC Alpha unsigned long long is only
- * 64 bits :-(, don't define BN_LLONG for the DEC Alpha
+ * 64-bit processor with LP64 ABI
  */
 # ifdef SIXTY_FOUR_BIT_LONG
-#  define BN_ULLONG       unsigned long long
 #  define BN_ULONG        unsigned long
-#  define BN_LONG         long
-#  define BN_BITS         128
 #  define BN_BYTES        8
-#  define BN_BITS2        64
-#  define BN_BITS4        32
-#  define BN_MASK         (0xffffffffffffffffffffffffffffffffLL)
-#  define BN_MASK2        (0xffffffffffffffffL)
-#  define BN_MASK2l       (0xffffffffL)
-#  define BN_MASK2h       (0xffffffff00000000L)
-#  define BN_MASK2h1      (0xffffffff80000000L)
-#  define BN_TBIT         (0x8000000000000000L)
-#  define BN_DEC_CONV     (10000000000000000000UL)
-#  define BN_DEC_FMT1     "%lu"
-#  define BN_DEC_FMT2     "%019lu"
-#  define BN_DEC_NUM      19
-#  define BN_HEX_FMT1     "%lX"
-#  define BN_HEX_FMT2     "%016lX"
 # endif
 
 /*
- * This is where the long long data type is 64 bits, but long is 32. For
- * machines where there are 64bit registers, this is the mode to use. IRIX,
- * on R4000 and above should use this mode, along with the relevant assembler
- * code :-).  Do NOT define BN_LLONG.
+ * 64-bit processor other than LP64 ABI
  */
 # ifdef SIXTY_FOUR_BIT
-#  undef BN_LLONG
-#  undef BN_ULLONG
 #  define BN_ULONG        unsigned long long
-#  define BN_LONG         long long
-#  define BN_BITS         128
 #  define BN_BYTES        8
-#  define BN_BITS2        64
-#  define BN_BITS4        32
-#  define BN_MASK2        (0xffffffffffffffffLL)
-#  define BN_MASK2l       (0xffffffffL)
-#  define BN_MASK2h       (0xffffffff00000000LL)
-#  define BN_MASK2h1      (0xffffffff80000000LL)
-#  define BN_TBIT         (0x8000000000000000LL)
-#  define BN_DEC_CONV     (10000000000000000000ULL)
-#  define BN_DEC_FMT1     "%llu"
-#  define BN_DEC_FMT2     "%019llu"
-#  define BN_DEC_NUM      19
-#  define BN_HEX_FMT1     "%llX"
-#  define BN_HEX_FMT2     "%016llX"
 # endif
 
 # ifdef THIRTY_TWO_BIT
-#  ifdef BN_LLONG
-#   if defined(_WIN32) && !defined(__GNUC__)
-#    define BN_ULLONG     unsigned __int64
-#    define BN_MASK       (0xffffffffffffffffI64)
-#   else
-#    define BN_ULLONG     unsigned long long
-#    define BN_MASK       (0xffffffffffffffffLL)
-#   endif
-#  endif
 #  define BN_ULONG        unsigned int
-#  define BN_LONG         int
-#  define BN_BITS         64
 #  define BN_BYTES        4
-#  define BN_BITS2        32
-#  define BN_BITS4        16
-#  define BN_MASK2        (0xffffffffL)
-#  define BN_MASK2l       (0xffff)
-#  define BN_MASK2h1      (0xffff8000L)
-#  define BN_MASK2h       (0xffff0000L)
-#  define BN_TBIT         (0x80000000L)
-#  define BN_DEC_CONV     (1000000000L)
-#  define BN_DEC_FMT1     "%u"
-#  define BN_DEC_FMT2     "%09u"
-#  define BN_DEC_NUM      9
-#  define BN_HEX_FMT1     "%X"
-#  define BN_HEX_FMT2     "%08X"
 # endif
 
-# define BN_DEFAULT_BITS 1280
+# define BN_BITS2       (BN_BYTES * 8)
+# define BN_BITS        (BN_BITS2 * 2)
+# define BN_TBIT        ((BN_ULONG)1 << (BN_BITS2 - 1))
 
 # define BN_FLG_MALLOCED         0x01
 # define BN_FLG_STATIC_DATA      0x02
@@ -441,11 +344,7 @@ int BN_mask_bits(BIGNUM *a, int n);
 # ifndef OPENSSL_NO_STDIO
 int BN_print_fp(FILE *fp, const BIGNUM *a);
 # endif
-# ifdef HEADER_BIO_H
-int BN_print(BIO *fp, const BIGNUM *a);
-# else
-int BN_print(void *fp, const BIGNUM *a);
-# endif
+int BN_print(BIO *bio, const BIGNUM *a);
 int BN_reciprocal(BIGNUM *r, const BIGNUM *m, int len, BN_CTX *ctx);
 int BN_rshift(BIGNUM *r, const BIGNUM *a, int n);
 int BN_rshift1(BIGNUM *r, const BIGNUM *a);
diff --git a/include/openssl/ossl_typ.h b/include/openssl/ossl_typ.h
index faa631931a9f79a09d613101b02185536778bc06..199b14104addfb8e05251ed25d3c0b43523861a1 100644
--- a/include/openssl/ossl_typ.h
+++ b/include/openssl/ossl_typ.h
@@ -119,6 +119,7 @@ typedef struct asn1_sctx_st ASN1_SCTX;
 # ifdef BIGNUM
 #  undef BIGNUM
 # endif
+typedef struct bio_st BIO;
 typedef struct bignum_st BIGNUM;
 typedef struct bignum_ctx BN_CTX;
 typedef struct bn_blinding_st BN_BLINDING;
diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 864e21a18e30f074b11666c2902e48f36edb15dc..1f8b0ea88c976d682c1e0b0224d26b00e0942b6d 100644
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -229,13 +229,6 @@
                          *((c)++)=(unsigned char)(((l)>> 8)&0xff), \
                          *((c)++)=(unsigned char)(((l)    )&0xff))
 
-# define n2l6(c,l)       (l =((BN_ULLONG)(*((c)++)))<<40, \
-                         l|=((BN_ULLONG)(*((c)++)))<<32, \
-                         l|=((BN_ULLONG)(*((c)++)))<<24, \
-                         l|=((BN_ULLONG)(*((c)++)))<<16, \
-                         l|=((BN_ULLONG)(*((c)++)))<< 8, \
-                         l|=((BN_ULLONG)(*((c)++))))
-
 /* NOTE - c is not incremented as per l2c */
 # define l2cn(l1,l2,c,n) { \
                         c+=n; \
diff --git a/test/bntest.c b/test/bntest.c
index 6b62c05050085b0f15676557b2b80b29be4b241d..d315ad843212d58af3abd7c33527d9f378301132 100644
--- a/test/bntest.c
+++ b/test/bntest.c
@@ -502,18 +502,25 @@ int test_div(BIO *bp, BN_CTX *ctx)
 
 static void print_word(BIO *bp, BN_ULONG w)
 {
-#ifdef SIXTY_FOUR_BIT
-    if (sizeof(w) > sizeof(unsigned long)) {
-        unsigned long h = (unsigned long)(w >> 32), l = (unsigned long)(w);
-
-        if (h)
-            BIO_printf(bp, "%lX%08lX", h, l);
+    int i = sizeof(w) * 8;
+    char *fmt = NULL;
+    unsigned char byte;
+
+    do {
+        i -= 8;
+        byte = (unsigned char)(w >> i);
+        if (fmt == NULL)
+            fmt = byte ? "%X" : NULL;
         else
-            BIO_printf(bp, "%lX", l);
-        return;
-    }
-#endif
-    BIO_printf(bp, BN_HEX_FMT1, w);
+            fmt = "%02X";
+
+        if (fmt != NULL)
+            BIO_printf(bp, fmt, byte);
+    } while (i);
+
+    /* If we haven't printed anything, at least print a zero! */
+    if (fmt == NULL)
+        BIO_printf(bp, "0");
 }
 
 int test_div_word(BIO *bp)
diff --git a/test/exptest.c b/test/exptest.c
index 7a155f957db5b9c4724950a746e99d38a7821909..0acdacced73caab727f8a8580360f21aacf0f6a2 100644
--- a/test/exptest.c
+++ b/test/exptest.c
@@ -66,7 +66,7 @@
 #include <openssl/rand.h>
 #include <openssl/err.h>
 
-#define NUM_BITS        (BN_BITS*2)
+#define NUM_BITS        (BN_BITS2 * 4)
 
 static const char rnd_seed[] =
     "string to make the random number generator think it has entropy";