diff --git a/contrib/lax_der_parsing.h b/contrib/lax_der_parsing.h
index 6d27871a7c..7eaf63bf6a 100644
--- a/contrib/lax_der_parsing.h
+++ b/contrib/lax_der_parsing.h
@@ -48,14 +48,14 @@
  *   8.3.1.
  */
 
-#ifndef _SECP256K1_CONTRIB_LAX_DER_PARSING_H_
-#define _SECP256K1_CONTRIB_LAX_DER_PARSING_H_
+#ifndef SECP256K1_CONTRIB_LAX_DER_PARSING_H
+#define SECP256K1_CONTRIB_LAX_DER_PARSING_H
 
 #include <secp256k1.h>
 
-# ifdef __cplusplus
+#ifdef __cplusplus
 extern "C" {
-# endif
+#endif
 
 /** Parse a signature in "lax DER" format
  *
@@ -88,4 +88,4 @@ int ecdsa_signature_parse_der_lax(
 }
 #endif
 
-#endif
+#endif /* SECP256K1_CONTRIB_LAX_DER_PARSING_H */
diff --git a/contrib/lax_der_privatekey_parsing.h b/contrib/lax_der_privatekey_parsing.h
index 2fd088f8ab..fece261fb9 100644
--- a/contrib/lax_der_privatekey_parsing.h
+++ b/contrib/lax_der_privatekey_parsing.h
@@ -25,14 +25,14 @@
  * library are sufficient.
  */
 
-#ifndef _SECP256K1_CONTRIB_BER_PRIVATEKEY_H_
-#define _SECP256K1_CONTRIB_BER_PRIVATEKEY_H_
+#ifndef SECP256K1_CONTRIB_BER_PRIVATEKEY_H
+#define SECP256K1_CONTRIB_BER_PRIVATEKEY_H
 
 #include <secp256k1.h>
 
-# ifdef __cplusplus
+#ifdef __cplusplus
 extern "C" {
-# endif
+#endif
 
 /** Export a private key in DER format.
  *
@@ -87,4 +87,4 @@ SECP256K1_WARN_UNUSED_RESULT int ec_privkey_import_der(
 }
 #endif
 
-#endif
+#endif /* SECP256K1_CONTRIB_BER_PRIVATEKEY_H */
diff --git a/include/secp256k1.h b/include/secp256k1.h
index fc4c5cefbb..3e9c098d19 100644
--- a/include/secp256k1.h
+++ b/include/secp256k1.h
@@ -1,9 +1,9 @@
-#ifndef _SECP256K1_
-# define _SECP256K1_
+#ifndef SECP256K1_H
+#define SECP256K1_H
 
-# ifdef __cplusplus
+#ifdef __cplusplus
 extern "C" {
-# endif
+#endif
 
 #include <stddef.h>
 
@@ -61,7 +61,7 @@ typedef struct {
  *  however guaranteed to be 64 bytes in size, and can be safely copied/moved.
  *  If you need to convert to a format suitable for storage, transmission, or
  *  comparison, use the secp256k1_ecdsa_signature_serialize_* and
- *  secp256k1_ecdsa_signature_serialize_* functions.
+ *  secp256k1_ecdsa_signature_parse_* functions.
  */
 typedef struct {
     unsigned char data[64];
@@ -159,6 +159,13 @@ typedef int (*secp256k1_nonce_function)(
 #define SECP256K1_EC_COMPRESSED (SECP256K1_FLAGS_TYPE_COMPRESSION | SECP256K1_FLAGS_BIT_COMPRESSION)
 #define SECP256K1_EC_UNCOMPRESSED (SECP256K1_FLAGS_TYPE_COMPRESSION)
 
+/** Prefix byte used to tag various encoded curvepoints for specific purposes */
+#define SECP256K1_TAG_PUBKEY_EVEN 0x02
+#define SECP256K1_TAG_PUBKEY_ODD 0x03
+#define SECP256K1_TAG_PUBKEY_UNCOMPRESSED 0x04
+#define SECP256K1_TAG_PUBKEY_HYBRID_EVEN 0x06
+#define SECP256K1_TAG_PUBKEY_HYBRID_ODD 0x07
+
 /** Create a secp256k1 context object.
  *
  *  Returns: a newly created context object.
@@ -607,8 +614,8 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ec_pubkey_combine(
     size_t n
 ) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3);
 
-# ifdef __cplusplus
+#ifdef __cplusplus
 }
-# endif
-
 #endif
+
+#endif /* SECP256K1_H */
diff --git a/include/secp256k1_ecdh.h b/include/secp256k1_ecdh.h
index 4b84d7a963..88492dc1a4 100644
--- a/include/secp256k1_ecdh.h
+++ b/include/secp256k1_ecdh.h
@@ -1,11 +1,11 @@
-#ifndef _SECP256K1_ECDH_
-# define _SECP256K1_ECDH_
+#ifndef SECP256K1_ECDH_H
+#define SECP256K1_ECDH_H
 
-# include "secp256k1.h"
+#include "secp256k1.h"
 
-# ifdef __cplusplus
+#ifdef __cplusplus
 extern "C" {
-# endif
+#endif
 
 /** Compute an EC Diffie-Hellman secret in constant time
  *  Returns: 1: exponentiation was successful
@@ -24,8 +24,8 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdh(
   const unsigned char *privkey
 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
 
-# ifdef __cplusplus
+#ifdef __cplusplus
 }
-# endif
-
 #endif
+
+#endif /* SECP256K1_ECDH_H */
diff --git a/include/secp256k1_recovery.h b/include/secp256k1_recovery.h
index 0553797253..cf6c5ed7f5 100644
--- a/include/secp256k1_recovery.h
+++ b/include/secp256k1_recovery.h
@@ -1,11 +1,11 @@
-#ifndef _SECP256K1_RECOVERY_
-# define _SECP256K1_RECOVERY_
+#ifndef SECP256K1_RECOVERY_H
+#define SECP256K1_RECOVERY_H
 
-# include "secp256k1.h"
+#include "secp256k1.h"
 
-# ifdef __cplusplus
+#ifdef __cplusplus
 extern "C" {
-# endif
+#endif
 
 /** Opaque data structured that holds a parsed ECDSA signature,
  *  supporting pubkey recovery.
@@ -103,8 +103,8 @@ SECP256K1_API SECP256K1_WARN_UNUSED_RESULT int secp256k1_ecdsa_recover(
     const unsigned char *msg32
 ) SECP256K1_ARG_NONNULL(1) SECP256K1_ARG_NONNULL(2) SECP256K1_ARG_NONNULL(3) SECP256K1_ARG_NONNULL(4);
 
-# ifdef __cplusplus
+#ifdef __cplusplus
 }
-# endif
-
 #endif
+
+#endif /* SECP256K1_RECOVERY_H */
diff --git a/sage/group_prover.sage b/sage/group_prover.sage
index ab580c5b23..8521f07999 100644
--- a/sage/group_prover.sage
+++ b/sage/group_prover.sage
@@ -3,7 +3,7 @@
 # to independently set assumptions on input or intermediary variables.
 #
 # The general approach is:
-# * A constraint is a tuple of two sets of of symbolic expressions:
+# * A constraint is a tuple of two sets of symbolic expressions:
 #   the first of which are required to evaluate to zero, the second of which
 #   are required to evaluate to nonzero.
 #   - A constraint is said to be conflicting if any of its nonzero expressions
@@ -17,7 +17,7 @@
 #   - A constraint describing the requirements of the law, called "require"
 # * Implementations are transliterated into functions that operate as well on
 #   algebraic input points, and are called once per combination of branches
-#   exectured. Each execution returns:
+#   executed. Each execution returns:
 #   - A constraint describing the assumptions this implementation requires
 #     (such as Z1=1), called "assumeFormula"
 #   - A constraint describing the assumptions this specific branch requires,
diff --git a/src/asm/field_10x26_arm.s b/src/asm/field_10x26_arm.s
index 5df561f2fc..5a9cc3ffcf 100644
--- a/src/asm/field_10x26_arm.s
+++ b/src/asm/field_10x26_arm.s
@@ -11,7 +11,7 @@ Note:
 
 - To avoid unnecessary loads and make use of available registers, two
   'passes' have every time been interleaved, with the odd passes accumulating c' and d' 
-  which will be added to c and d respectively in the the even passes
+  which will be added to c and d respectively in the even passes
 
 */
 
@@ -23,7 +23,7 @@ Note:
 	.eabi_attribute 10, 0 @ Tag_FP_arch = none
 	.eabi_attribute 24, 1 @ Tag_ABI_align_needed = 8-byte
 	.eabi_attribute 25, 1 @ Tag_ABI_align_preserved = 8-byte, except leaf SP
-	.eabi_attribute 30, 2 @ Tag_ABI_optimization_goals = Agressive Speed
+	.eabi_attribute 30, 2 @ Tag_ABI_optimization_goals = Aggressive Speed
 	.eabi_attribute 34, 1 @ Tag_CPU_unaligned_access = v6
 	.text
 
diff --git a/src/basic-config.h b/src/basic-config.h
index c4c16eb7ca..fc588061ca 100644
--- a/src/basic-config.h
+++ b/src/basic-config.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_BASIC_CONFIG_
-#define _SECP256K1_BASIC_CONFIG_
+#ifndef SECP256K1_BASIC_CONFIG_H
+#define SECP256K1_BASIC_CONFIG_H
 
 #ifdef USE_BASIC_CONFIG
 
@@ -28,5 +28,6 @@
 #define USE_FIELD_10X26 1
 #define USE_SCALAR_8X32 1
 
-#endif // USE_BASIC_CONFIG
-#endif // _SECP256K1_BASIC_CONFIG_
+#endif /* USE_BASIC_CONFIG */
+
+#endif /* SECP256K1_BASIC_CONFIG_H */
diff --git a/src/bench.h b/src/bench.h
index d67f08a426..d5ebe01301 100644
--- a/src/bench.h
+++ b/src/bench.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_BENCH_H_
-#define _SECP256K1_BENCH_H_
+#ifndef SECP256K1_BENCH_H
+#define SECP256K1_BENCH_H
 
 #include <stdio.h>
 #include <math.h>
@@ -63,4 +63,4 @@ void run_benchmark(char *name, void (*benchmark)(void*), void (*setup)(void*), v
     printf("us\n");
 }
 
-#endif
+#endif /* SECP256K1_BENCH_H */
diff --git a/src/ecdsa.h b/src/ecdsa.h
index 54ae101b92..80590c7cc8 100644
--- a/src/ecdsa.h
+++ b/src/ecdsa.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_ECDSA_
-#define _SECP256K1_ECDSA_
+#ifndef SECP256K1_ECDSA_H
+#define SECP256K1_ECDSA_H
 
 #include <stddef.h>
 
@@ -18,4 +18,4 @@ static int secp256k1_ecdsa_sig_serialize(unsigned char *sig, size_t *size, const
 static int secp256k1_ecdsa_sig_verify(const secp256k1_ecmult_context *ctx, const secp256k1_scalar* r, const secp256k1_scalar* s, const secp256k1_ge *pubkey, const secp256k1_scalar *message);
 static int secp256k1_ecdsa_sig_sign(const secp256k1_ecmult_gen_context *ctx, secp256k1_scalar* r, secp256k1_scalar* s, const secp256k1_scalar *seckey, const secp256k1_scalar *message, const secp256k1_scalar *nonce, int *recid);
 
-#endif
+#endif /* SECP256K1_ECDSA_H */
diff --git a/src/ecdsa_impl.h b/src/ecdsa_impl.h
index 453bb11880..c3400042d8 100644
--- a/src/ecdsa_impl.h
+++ b/src/ecdsa_impl.h
@@ -5,8 +5,8 @@
  **********************************************************************/
 
 
-#ifndef _SECP256K1_ECDSA_IMPL_H_
-#define _SECP256K1_ECDSA_IMPL_H_
+#ifndef SECP256K1_ECDSA_IMPL_H
+#define SECP256K1_ECDSA_IMPL_H
 
 #include "scalar.h"
 #include "field.h"
@@ -81,8 +81,6 @@ static int secp256k1_der_read_len(const unsigned char **sigp, const unsigned cha
         return -1;
     }
     while (lenleft > 0) {
-        if ((ret >> ((sizeof(size_t) - 1) * 8)) != 0) {
-        }
         ret = (ret << 8) | **sigp;
         if (ret + lenleft > (size_t)(sigend - *sigp)) {
             /* Result exceeds the length of the passed array. */
@@ -312,4 +310,4 @@ static int secp256k1_ecdsa_sig_sign(const secp256k1_ecmult_gen_context *ctx, sec
     return 1;
 }
 
-#endif
+#endif /* SECP256K1_ECDSA_IMPL_H */
diff --git a/src/eckey.h b/src/eckey.h
index 42739a3bea..b621f1e6c3 100644
--- a/src/eckey.h
+++ b/src/eckey.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_ECKEY_
-#define _SECP256K1_ECKEY_
+#ifndef SECP256K1_ECKEY_H
+#define SECP256K1_ECKEY_H
 
 #include <stddef.h>
 
@@ -22,4 +22,4 @@ static int secp256k1_eckey_pubkey_tweak_add(const secp256k1_ecmult_context *ctx,
 static int secp256k1_eckey_privkey_tweak_mul(secp256k1_scalar *key, const secp256k1_scalar *tweak);
 static int secp256k1_eckey_pubkey_tweak_mul(const secp256k1_ecmult_context *ctx, secp256k1_ge *key, const secp256k1_scalar *tweak);
 
-#endif
+#endif /* SECP256K1_ECKEY_H */
diff --git a/src/eckey_impl.h b/src/eckey_impl.h
index ce38071ac2..1ab9a68ec0 100644
--- a/src/eckey_impl.h
+++ b/src/eckey_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_ECKEY_IMPL_H_
-#define _SECP256K1_ECKEY_IMPL_H_
+#ifndef SECP256K1_ECKEY_IMPL_H
+#define SECP256K1_ECKEY_IMPL_H
 
 #include "eckey.h"
 
@@ -15,16 +15,17 @@
 #include "ecmult_gen.h"
 
 static int secp256k1_eckey_pubkey_parse(secp256k1_ge *elem, const unsigned char *pub, size_t size) {
-    if (size == 33 && (pub[0] == 0x02 || pub[0] == 0x03)) {
+    if (size == 33 && (pub[0] == SECP256K1_TAG_PUBKEY_EVEN || pub[0] == SECP256K1_TAG_PUBKEY_ODD)) {
         secp256k1_fe x;
-        return secp256k1_fe_set_b32(&x, pub+1) && secp256k1_ge_set_xo_var(elem, &x, pub[0] == 0x03);
+        return secp256k1_fe_set_b32(&x, pub+1) && secp256k1_ge_set_xo_var(elem, &x, pub[0] == SECP256K1_TAG_PUBKEY_ODD);
     } else if (size == 65 && (pub[0] == 0x04 || pub[0] == 0x06 || pub[0] == 0x07)) {
         secp256k1_fe x, y;
         if (!secp256k1_fe_set_b32(&x, pub+1) || !secp256k1_fe_set_b32(&y, pub+33)) {
             return 0;
         }
         secp256k1_ge_set_xy(elem, &x, &y);
-        if ((pub[0] == 0x06 || pub[0] == 0x07) && secp256k1_fe_is_odd(&y) != (pub[0] == 0x07)) {
+        if ((pub[0] == SECP256K1_TAG_PUBKEY_HYBRID_EVEN || pub[0] == SECP256K1_TAG_PUBKEY_HYBRID_ODD) &&
+            secp256k1_fe_is_odd(&y) != (pub[0] == SECP256K1_TAG_PUBKEY_HYBRID_ODD)) {
             return 0;
         }
         return secp256k1_ge_is_valid_var(elem);
@@ -42,10 +43,10 @@ static int secp256k1_eckey_pubkey_serialize(secp256k1_ge *elem, unsigned char *p
     secp256k1_fe_get_b32(&pub[1], &elem->x);
     if (compressed) {
         *size = 33;
-        pub[0] = 0x02 | (secp256k1_fe_is_odd(&elem->y) ? 0x01 : 0x00);
+        pub[0] = secp256k1_fe_is_odd(&elem->y) ? SECP256K1_TAG_PUBKEY_ODD : SECP256K1_TAG_PUBKEY_EVEN;
     } else {
         *size = 65;
-        pub[0] = 0x04;
+        pub[0] = SECP256K1_TAG_PUBKEY_UNCOMPRESSED;
         secp256k1_fe_get_b32(&pub[33], &elem->y);
     }
     return 1;
@@ -96,4 +97,4 @@ static int secp256k1_eckey_pubkey_tweak_mul(const secp256k1_ecmult_context *ctx,
     return 1;
 }
 
-#endif
+#endif /* SECP256K1_ECKEY_IMPL_H */
diff --git a/src/ecmult.h b/src/ecmult.h
index 20484134f5..6d44aba60b 100644
--- a/src/ecmult.h
+++ b/src/ecmult.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_ECMULT_
-#define _SECP256K1_ECMULT_
+#ifndef SECP256K1_ECMULT_H
+#define SECP256K1_ECMULT_H
 
 #include "num.h"
 #include "group.h"
@@ -28,4 +28,4 @@ static int secp256k1_ecmult_context_is_built(const secp256k1_ecmult_context *ctx
 /** Double multiply: R = na*A + ng*G */
 static void secp256k1_ecmult(const secp256k1_ecmult_context *ctx, secp256k1_gej *r, const secp256k1_gej *a, const secp256k1_scalar *na, const secp256k1_scalar *ng);
 
-#endif
+#endif /* SECP256K1_ECMULT_H */
diff --git a/src/ecmult_const.h b/src/ecmult_const.h
index 2b0097655c..72bf7d7582 100644
--- a/src/ecmult_const.h
+++ b/src/ecmult_const.h
@@ -4,12 +4,12 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_ECMULT_CONST_
-#define _SECP256K1_ECMULT_CONST_
+#ifndef SECP256K1_ECMULT_CONST_H
+#define SECP256K1_ECMULT_CONST_H
 
 #include "scalar.h"
 #include "group.h"
 
 static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, const secp256k1_scalar *q);
 
-#endif
+#endif /* SECP256K1_ECMULT_CONST_H */
diff --git a/src/ecmult_const_impl.h b/src/ecmult_const_impl.h
index 0db314c48e..7d7a172b7b 100644
--- a/src/ecmult_const_impl.h
+++ b/src/ecmult_const_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_ECMULT_CONST_IMPL_
-#define _SECP256K1_ECMULT_CONST_IMPL_
+#ifndef SECP256K1_ECMULT_CONST_IMPL_H
+#define SECP256K1_ECMULT_CONST_IMPL_H
 
 #include "scalar.h"
 #include "group.h"
@@ -42,11 +42,12 @@
 } while(0)
 
 
-/** Convert a number to WNAF notation. The number becomes represented by sum(2^{wi} * wnaf[i], i=0..return_val)
- *  with the following guarantees:
+/** Convert a number to WNAF notation.
+ *  The number becomes represented by sum(2^{wi} * wnaf[i], i=0..WNAF_SIZE(w)+1) - return_val.
+ *  It has the following guarantees:
  *  - each wnaf[i] an odd integer between -(1 << w) and (1 << w)
  *  - each wnaf[i] is nonzero
- *  - the number of words set is returned; this is always (WNAF_BITS + w - 1) / w
+ *  - the number of words set is always WNAF_SIZE(w) + 1
  *
  *  Adapted from `The Width-w NAF Method Provides Small Memory and Fast Elliptic Scalar
  *  Multiplications Secure against Side Channel Attacks`, Okeya and Tagaki. M. Joye (Ed.)
@@ -236,4 +237,4 @@ static void secp256k1_ecmult_const(secp256k1_gej *r, const secp256k1_ge *a, cons
     }
 }
 
-#endif
+#endif /* SECP256K1_ECMULT_CONST_IMPL_H */
diff --git a/src/ecmult_gen.h b/src/ecmult_gen.h
index eb2cc9ead6..7564b7015f 100644
--- a/src/ecmult_gen.h
+++ b/src/ecmult_gen.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_ECMULT_GEN_
-#define _SECP256K1_ECMULT_GEN_
+#ifndef SECP256K1_ECMULT_GEN_H
+#define SECP256K1_ECMULT_GEN_H
 
 #include "scalar.h"
 #include "group.h"
@@ -40,4 +40,4 @@ static void secp256k1_ecmult_gen(const secp256k1_ecmult_gen_context* ctx, secp25
 
 static void secp256k1_ecmult_gen_blind(secp256k1_ecmult_gen_context *ctx, const unsigned char *seed32);
 
-#endif
+#endif /* SECP256K1_ECMULT_GEN_H */
diff --git a/src/ecmult_gen_impl.h b/src/ecmult_gen_impl.h
index 35f2546077..9615b932dd 100644
--- a/src/ecmult_gen_impl.h
+++ b/src/ecmult_gen_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_ECMULT_GEN_IMPL_H_
-#define _SECP256K1_ECMULT_GEN_IMPL_H_
+#ifndef SECP256K1_ECMULT_GEN_IMPL_H
+#define SECP256K1_ECMULT_GEN_IMPL_H
 
 #include "scalar.h"
 #include "group.h"
@@ -207,4 +207,4 @@ static void secp256k1_ecmult_gen_blind(secp256k1_ecmult_gen_context *ctx, const
     secp256k1_gej_clear(&gb);
 }
 
-#endif
+#endif /* SECP256K1_ECMULT_GEN_IMPL_H */
diff --git a/src/ecmult_impl.h b/src/ecmult_impl.h
index 4e40104ad4..93d3794cb4 100644
--- a/src/ecmult_impl.h
+++ b/src/ecmult_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_ECMULT_IMPL_H_
-#define _SECP256K1_ECMULT_IMPL_H_
+#ifndef SECP256K1_ECMULT_IMPL_H
+#define SECP256K1_ECMULT_IMPL_H
 
 #include <string.h>
 
@@ -403,4 +403,4 @@ static void secp256k1_ecmult(const secp256k1_ecmult_context *ctx, secp256k1_gej
     }
 }
 
-#endif
+#endif /* SECP256K1_ECMULT_IMPL_H */
diff --git a/src/field.h b/src/field.h
index bbb1ee866c..bb6692ad57 100644
--- a/src/field.h
+++ b/src/field.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_FIELD_
-#define _SECP256K1_FIELD_
+#ifndef SECP256K1_FIELD_H
+#define SECP256K1_FIELD_H
 
 /** Field element module.
  *
@@ -129,4 +129,4 @@ static void secp256k1_fe_storage_cmov(secp256k1_fe_storage *r, const secp256k1_f
 /** If flag is true, set *r equal to *a; otherwise leave it. Constant-time. */
 static void secp256k1_fe_cmov(secp256k1_fe *r, const secp256k1_fe *a, int flag);
 
-#endif
+#endif /* SECP256K1_FIELD_H */
diff --git a/src/field_10x26.h b/src/field_10x26.h
index 61ee1e0965..727c5267fb 100644
--- a/src/field_10x26.h
+++ b/src/field_10x26.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_FIELD_REPR_
-#define _SECP256K1_FIELD_REPR_
+#ifndef SECP256K1_FIELD_REPR_H
+#define SECP256K1_FIELD_REPR_H
 
 #include <stdint.h>
 
@@ -44,4 +44,5 @@ typedef struct {
 
 #define SECP256K1_FE_STORAGE_CONST(d7, d6, d5, d4, d3, d2, d1, d0) {{ (d0), (d1), (d2), (d3), (d4), (d5), (d6), (d7) }}
 #define SECP256K1_FE_STORAGE_CONST_GET(d) d.n[7], d.n[6], d.n[5], d.n[4],d.n[3], d.n[2], d.n[1], d.n[0]
-#endif
+
+#endif /* SECP256K1_FIELD_REPR_H */
diff --git a/src/field_10x26_impl.h b/src/field_10x26_impl.h
index 234c13a644..94f8132fc8 100644
--- a/src/field_10x26_impl.h
+++ b/src/field_10x26_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_FIELD_REPR_IMPL_H_
-#define _SECP256K1_FIELD_REPR_IMPL_H_
+#ifndef SECP256K1_FIELD_REPR_IMPL_H
+#define SECP256K1_FIELD_REPR_IMPL_H
 
 #include "util.h"
 #include "num.h"
@@ -1158,4 +1158,4 @@ static SECP256K1_INLINE void secp256k1_fe_from_storage(secp256k1_fe *r, const se
 #endif
 }
 
-#endif
+#endif /* SECP256K1_FIELD_REPR_IMPL_H */
diff --git a/src/field_5x52.h b/src/field_5x52.h
index 8e69a560dc..bccd8feb4d 100644
--- a/src/field_5x52.h
+++ b/src/field_5x52.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_FIELD_REPR_
-#define _SECP256K1_FIELD_REPR_
+#ifndef SECP256K1_FIELD_REPR_H
+#define SECP256K1_FIELD_REPR_H
 
 #include <stdint.h>
 
@@ -44,4 +44,4 @@ typedef struct {
     (d6) | (((uint64_t)(d7)) << 32) \
 }}
 
-#endif
+#endif /* SECP256K1_FIELD_REPR_H */
diff --git a/src/field_5x52_asm_impl.h b/src/field_5x52_asm_impl.h
index 98cc004bf0..1fc3171f6b 100644
--- a/src/field_5x52_asm_impl.h
+++ b/src/field_5x52_asm_impl.h
@@ -11,8 +11,8 @@
  * - December 2014, Pieter Wuille: converted from YASM to GCC inline assembly
  */
 
-#ifndef _SECP256K1_FIELD_INNER5X52_IMPL_H_
-#define _SECP256K1_FIELD_INNER5X52_IMPL_H_
+#ifndef SECP256K1_FIELD_INNER5X52_IMPL_H
+#define SECP256K1_FIELD_INNER5X52_IMPL_H
 
 SECP256K1_INLINE static void secp256k1_fe_mul_inner(uint64_t *r, const uint64_t *a, const uint64_t * SECP256K1_RESTRICT b) {
 /**
@@ -499,4 +499,4 @@ __asm__ __volatile__(
 );
 }
 
-#endif
+#endif /* SECP256K1_FIELD_INNER5X52_IMPL_H */
diff --git a/src/field_5x52_impl.h b/src/field_5x52_impl.h
index 8e8b286baf..957c61b014 100644
--- a/src/field_5x52_impl.h
+++ b/src/field_5x52_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_FIELD_REPR_IMPL_H_
-#define _SECP256K1_FIELD_REPR_IMPL_H_
+#ifndef SECP256K1_FIELD_REPR_IMPL_H
+#define SECP256K1_FIELD_REPR_IMPL_H
 
 #if defined HAVE_CONFIG_H
 #include "libsecp256k1-config.h"
@@ -493,4 +493,4 @@ static SECP256K1_INLINE void secp256k1_fe_from_storage(secp256k1_fe *r, const se
 #endif
 }
 
-#endif
+#endif /* SECP256K1_FIELD_REPR_IMPL_H */
diff --git a/src/field_5x52_int128_impl.h b/src/field_5x52_int128_impl.h
index 0bf22bdd3e..95a0d1791c 100644
--- a/src/field_5x52_int128_impl.h
+++ b/src/field_5x52_int128_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_FIELD_INNER5X52_IMPL_H_
-#define _SECP256K1_FIELD_INNER5X52_IMPL_H_
+#ifndef SECP256K1_FIELD_INNER5X52_IMPL_H
+#define SECP256K1_FIELD_INNER5X52_IMPL_H
 
 #include <stdint.h>
 
@@ -274,4 +274,4 @@ SECP256K1_INLINE static void secp256k1_fe_sqr_inner(uint64_t *r, const uint64_t
     /* [r4 r3 r2 r1 r0] = [p8 p7 p6 p5 p4 p3 p2 p1 p0] */
 }
 
-#endif
+#endif /* SECP256K1_FIELD_INNER5X52_IMPL_H */
diff --git a/src/field_impl.h b/src/field_impl.h
index 5127b279bc..20428648af 100644
--- a/src/field_impl.h
+++ b/src/field_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_FIELD_IMPL_H_
-#define _SECP256K1_FIELD_IMPL_H_
+#ifndef SECP256K1_FIELD_IMPL_H
+#define SECP256K1_FIELD_IMPL_H
 
 #if defined HAVE_CONFIG_H
 #include "libsecp256k1-config.h"
@@ -312,4 +312,4 @@ static int secp256k1_fe_is_quad_var(const secp256k1_fe *a) {
 #endif
 }
 
-#endif
+#endif /* SECP256K1_FIELD_IMPL_H */
diff --git a/src/group.h b/src/group.h
index 4957b248fe..ea1302deb8 100644
--- a/src/group.h
+++ b/src/group.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_GROUP_
-#define _SECP256K1_GROUP_
+#ifndef SECP256K1_GROUP_H
+#define SECP256K1_GROUP_H
 
 #include "num.h"
 #include "field.h"
@@ -141,4 +141,4 @@ static void secp256k1_ge_storage_cmov(secp256k1_ge_storage *r, const secp256k1_g
 /** Rescale a jacobian point by b which must be non-zero. Constant-time. */
 static void secp256k1_gej_rescale(secp256k1_gej *r, const secp256k1_fe *b);
 
-#endif
+#endif /* SECP256K1_GROUP_H */
diff --git a/src/group_impl.h b/src/group_impl.h
index 7d723532ff..b31b6c12ef 100644
--- a/src/group_impl.h
+++ b/src/group_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_GROUP_IMPL_H_
-#define _SECP256K1_GROUP_IMPL_H_
+#ifndef SECP256K1_GROUP_IMPL_H
+#define SECP256K1_GROUP_IMPL_H
 
 #include "num.h"
 #include "field.h"
@@ -697,4 +697,4 @@ static int secp256k1_gej_has_quad_y_var(const secp256k1_gej *a) {
     return secp256k1_fe_is_quad_var(&yz);
 }
 
-#endif
+#endif /* SECP256K1_GROUP_IMPL_H */
diff --git a/src/hash.h b/src/hash.h
index fca98cab9f..e08d25d225 100644
--- a/src/hash.h
+++ b/src/hash.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_HASH_
-#define _SECP256K1_HASH_
+#ifndef SECP256K1_HASH_H
+#define SECP256K1_HASH_H
 
 #include <stdlib.h>
 #include <stdint.h>
@@ -38,4 +38,4 @@ static void secp256k1_rfc6979_hmac_sha256_initialize(secp256k1_rfc6979_hmac_sha2
 static void secp256k1_rfc6979_hmac_sha256_generate(secp256k1_rfc6979_hmac_sha256_t *rng, unsigned char *out, size_t outlen);
 static void secp256k1_rfc6979_hmac_sha256_finalize(secp256k1_rfc6979_hmac_sha256_t *rng);
 
-#endif
+#endif /* SECP256K1_HASH_H */
diff --git a/src/hash_impl.h b/src/hash_impl.h
index b47e65f830..4c9964ee06 100644
--- a/src/hash_impl.h
+++ b/src/hash_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_HASH_IMPL_H_
-#define _SECP256K1_HASH_IMPL_H_
+#ifndef SECP256K1_HASH_IMPL_H
+#define SECP256K1_HASH_IMPL_H
 
 #include "hash.h"
 
@@ -278,4 +278,4 @@ static void secp256k1_rfc6979_hmac_sha256_finalize(secp256k1_rfc6979_hmac_sha256
 #undef Maj
 #undef Ch
 
-#endif
+#endif /* SECP256K1_HASH_IMPL_H */
diff --git a/src/modules/ecdh/main_impl.h b/src/modules/ecdh/main_impl.h
index 9e30fb73dd..01ecba4d53 100644
--- a/src/modules/ecdh/main_impl.h
+++ b/src/modules/ecdh/main_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_MODULE_ECDH_MAIN_
-#define _SECP256K1_MODULE_ECDH_MAIN_
+#ifndef SECP256K1_MODULE_ECDH_MAIN_H
+#define SECP256K1_MODULE_ECDH_MAIN_H
 
 #include "include/secp256k1_ecdh.h"
 #include "ecmult_const_impl.h"
@@ -51,4 +51,4 @@ int secp256k1_ecdh(const secp256k1_context* ctx, unsigned char *result, const se
     return ret;
 }
 
-#endif
+#endif /* SECP256K1_MODULE_ECDH_MAIN_H */
diff --git a/src/modules/ecdh/tests_impl.h b/src/modules/ecdh/tests_impl.h
index 85a5d0a9a6..cec30b67c6 100644
--- a/src/modules/ecdh/tests_impl.h
+++ b/src/modules/ecdh/tests_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_MODULE_ECDH_TESTS_
-#define _SECP256K1_MODULE_ECDH_TESTS_
+#ifndef SECP256K1_MODULE_ECDH_TESTS_H
+#define SECP256K1_MODULE_ECDH_TESTS_H
 
 void test_ecdh_api(void) {
     /* Setup context that just counts errors */
@@ -102,4 +102,4 @@ void run_ecdh_tests(void) {
     test_bad_scalar();
 }
 
-#endif
+#endif /* SECP256K1_MODULE_ECDH_TESTS_H */
diff --git a/src/modules/recovery/main_impl.h b/src/modules/recovery/main_impl.h
index c6fbe23981..2f6691c5a1 100755
--- a/src/modules/recovery/main_impl.h
+++ b/src/modules/recovery/main_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_MODULE_RECOVERY_MAIN_
-#define _SECP256K1_MODULE_RECOVERY_MAIN_
+#ifndef SECP256K1_MODULE_RECOVERY_MAIN_H
+#define SECP256K1_MODULE_RECOVERY_MAIN_H
 
 #include "include/secp256k1_recovery.h"
 
@@ -190,4 +190,4 @@ int secp256k1_ecdsa_recover(const secp256k1_context* ctx, secp256k1_pubkey *pubk
     }
 }
 
-#endif
+#endif /* SECP256K1_MODULE_RECOVERY_MAIN_H */
diff --git a/src/modules/recovery/tests_impl.h b/src/modules/recovery/tests_impl.h
index 765c7dd81e..5c9bbe8610 100644
--- a/src/modules/recovery/tests_impl.h
+++ b/src/modules/recovery/tests_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_MODULE_RECOVERY_TESTS_
-#define _SECP256K1_MODULE_RECOVERY_TESTS_
+#ifndef SECP256K1_MODULE_RECOVERY_TESTS_H
+#define SECP256K1_MODULE_RECOVERY_TESTS_H
 
 static int recovery_test_nonce_function(unsigned char *nonce32, const unsigned char *msg32, const unsigned char *key32, const unsigned char *algo16, void *data, unsigned int counter) {
     (void) msg32;
@@ -390,4 +390,4 @@ void run_recovery_tests(void) {
     test_ecdsa_recovery_edge_cases();
 }
 
-#endif
+#endif /* SECP256K1_MODULE_RECOVERY_TESTS_H */
diff --git a/src/num.h b/src/num.h
index 7bb9c5be8c..49f2dd791d 100644
--- a/src/num.h
+++ b/src/num.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_NUM_
-#define _SECP256K1_NUM_
+#ifndef SECP256K1_NUM_H
+#define SECP256K1_NUM_H
 
 #ifndef USE_NUM_NONE
 
@@ -71,4 +71,4 @@ static void secp256k1_num_negate(secp256k1_num *r);
 
 #endif
 
-#endif
+#endif /* SECP256K1_NUM_H */
diff --git a/src/num_gmp.h b/src/num_gmp.h
index 7dd813088a..3619844bd5 100644
--- a/src/num_gmp.h
+++ b/src/num_gmp.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_NUM_REPR_
-#define _SECP256K1_NUM_REPR_
+#ifndef SECP256K1_NUM_REPR_H
+#define SECP256K1_NUM_REPR_H
 
 #include <gmp.h>
 
@@ -17,4 +17,4 @@ typedef struct {
     int limbs;
 } secp256k1_num;
 
-#endif
+#endif /* SECP256K1_NUM_REPR_H */
diff --git a/src/num_gmp_impl.h b/src/num_gmp_impl.h
index 3a46495eea..0ae2a8ba0e 100644
--- a/src/num_gmp_impl.h
+++ b/src/num_gmp_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_NUM_REPR_IMPL_H_
-#define _SECP256K1_NUM_REPR_IMPL_H_
+#ifndef SECP256K1_NUM_REPR_IMPL_H
+#define SECP256K1_NUM_REPR_IMPL_H
 
 #include <string.h>
 #include <stdlib.h>
@@ -285,4 +285,4 @@ static void secp256k1_num_negate(secp256k1_num *r) {
     r->neg ^= 1;
 }
 
-#endif
+#endif /* SECP256K1_NUM_REPR_IMPL_H */
diff --git a/src/num_impl.h b/src/num_impl.h
index 0b0e3a072a..c45193b033 100644
--- a/src/num_impl.h
+++ b/src/num_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_NUM_IMPL_H_
-#define _SECP256K1_NUM_IMPL_H_
+#ifndef SECP256K1_NUM_IMPL_H
+#define SECP256K1_NUM_IMPL_H
 
 #if defined HAVE_CONFIG_H
 #include "libsecp256k1-config.h"
@@ -21,4 +21,4 @@
 #error "Please select num implementation"
 #endif
 
-#endif
+#endif /* SECP256K1_NUM_IMPL_H */
diff --git a/src/scalar.h b/src/scalar.h
index 27e9d8375e..59304cb66e 100644
--- a/src/scalar.h
+++ b/src/scalar.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_SCALAR_
-#define _SECP256K1_SCALAR_
+#ifndef SECP256K1_SCALAR_H
+#define SECP256K1_SCALAR_H
 
 #include "num.h"
 
@@ -103,4 +103,4 @@ static void secp256k1_scalar_split_lambda(secp256k1_scalar *r1, secp256k1_scalar
 /** Multiply a and b (without taking the modulus!), divide by 2**shift, and round to the nearest integer. Shift must be at least 256. */
 static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b, unsigned int shift);
 
-#endif
+#endif /* SECP256K1_SCALAR_H */
diff --git a/src/scalar_4x64.h b/src/scalar_4x64.h
index cff406038f..19c7495d1c 100644
--- a/src/scalar_4x64.h
+++ b/src/scalar_4x64.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_SCALAR_REPR_
-#define _SECP256K1_SCALAR_REPR_
+#ifndef SECP256K1_SCALAR_REPR_H
+#define SECP256K1_SCALAR_REPR_H
 
 #include <stdint.h>
 
@@ -16,4 +16,4 @@ typedef struct {
 
 #define SECP256K1_SCALAR_CONST(d7, d6, d5, d4, d3, d2, d1, d0) {{((uint64_t)(d1)) << 32 | (d0), ((uint64_t)(d3)) << 32 | (d2), ((uint64_t)(d5)) << 32 | (d4), ((uint64_t)(d7)) << 32 | (d6)}}
 
-#endif
+#endif /* SECP256K1_SCALAR_REPR_H */
diff --git a/src/scalar_4x64_impl.h b/src/scalar_4x64_impl.h
index 56e7bd82af..db1ebf94be 100644
--- a/src/scalar_4x64_impl.h
+++ b/src/scalar_4x64_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_SCALAR_REPR_IMPL_H_
-#define _SECP256K1_SCALAR_REPR_IMPL_H_
+#ifndef SECP256K1_SCALAR_REPR_IMPL_H
+#define SECP256K1_SCALAR_REPR_IMPL_H
 
 /* Limbs of the secp256k1 order. */
 #define SECP256K1_N_0 ((uint64_t)0xBFD25E8CD0364141ULL)
@@ -946,4 +946,4 @@ SECP256K1_INLINE static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r,
     secp256k1_scalar_cadd_bit(r, 0, (l[(shift - 1) >> 6] >> ((shift - 1) & 0x3f)) & 1);
 }
 
-#endif
+#endif /* SECP256K1_SCALAR_REPR_IMPL_H */
diff --git a/src/scalar_8x32.h b/src/scalar_8x32.h
index 1319664f65..2c9a348e24 100644
--- a/src/scalar_8x32.h
+++ b/src/scalar_8x32.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_SCALAR_REPR_
-#define _SECP256K1_SCALAR_REPR_
+#ifndef SECP256K1_SCALAR_REPR_H
+#define SECP256K1_SCALAR_REPR_H
 
 #include <stdint.h>
 
@@ -16,4 +16,4 @@ typedef struct {
 
 #define SECP256K1_SCALAR_CONST(d7, d6, d5, d4, d3, d2, d1, d0) {{(d0), (d1), (d2), (d3), (d4), (d5), (d6), (d7)}}
 
-#endif
+#endif /* SECP256K1_SCALAR_REPR_H */
diff --git a/src/scalar_8x32_impl.h b/src/scalar_8x32_impl.h
index aae4f35c08..4f9ed61fea 100644
--- a/src/scalar_8x32_impl.h
+++ b/src/scalar_8x32_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_SCALAR_REPR_IMPL_H_
-#define _SECP256K1_SCALAR_REPR_IMPL_H_
+#ifndef SECP256K1_SCALAR_REPR_IMPL_H
+#define SECP256K1_SCALAR_REPR_IMPL_H
 
 /* Limbs of the secp256k1 order. */
 #define SECP256K1_N_0 ((uint32_t)0xD0364141UL)
@@ -718,4 +718,4 @@ SECP256K1_INLINE static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r,
     secp256k1_scalar_cadd_bit(r, 0, (l[(shift - 1) >> 5] >> ((shift - 1) & 0x1f)) & 1);
 }
 
-#endif
+#endif /* SECP256K1_SCALAR_REPR_IMPL_H */
diff --git a/src/scalar_impl.h b/src/scalar_impl.h
index 2690d86558..fa790570ff 100644
--- a/src/scalar_impl.h
+++ b/src/scalar_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_SCALAR_IMPL_H_
-#define _SECP256K1_SCALAR_IMPL_H_
+#ifndef SECP256K1_SCALAR_IMPL_H
+#define SECP256K1_SCALAR_IMPL_H
 
 #include "group.h"
 #include "scalar.h"
@@ -330,4 +330,4 @@ static void secp256k1_scalar_split_lambda(secp256k1_scalar *r1, secp256k1_scalar
 #endif
 #endif
 
-#endif
+#endif /* SECP256K1_SCALAR_IMPL_H */
diff --git a/src/scalar_low.h b/src/scalar_low.h
index 5574c44c7a..5836febc5b 100644
--- a/src/scalar_low.h
+++ b/src/scalar_low.h
@@ -4,12 +4,12 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_SCALAR_REPR_
-#define _SECP256K1_SCALAR_REPR_
+#ifndef SECP256K1_SCALAR_REPR_H
+#define SECP256K1_SCALAR_REPR_H
 
 #include <stdint.h>
 
 /** A scalar modulo the group order of the secp256k1 curve. */
 typedef uint32_t secp256k1_scalar;
 
-#endif
+#endif /* SECP256K1_SCALAR_REPR_H */
diff --git a/src/scalar_low_impl.h b/src/scalar_low_impl.h
index 4f94441f49..c80e70c5a2 100644
--- a/src/scalar_low_impl.h
+++ b/src/scalar_low_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_SCALAR_REPR_IMPL_H_
-#define _SECP256K1_SCALAR_REPR_IMPL_H_
+#ifndef SECP256K1_SCALAR_REPR_IMPL_H
+#define SECP256K1_SCALAR_REPR_IMPL_H
 
 #include "scalar.h"
 
@@ -111,4 +111,4 @@ SECP256K1_INLINE static int secp256k1_scalar_eq(const secp256k1_scalar *a, const
     return *a == *b;
 }
 
-#endif
+#endif /* SECP256K1_SCALAR_REPR_IMPL_H */
diff --git a/src/testrand.h b/src/testrand.h
index f8efa93c7c..f1f9be077e 100644
--- a/src/testrand.h
+++ b/src/testrand.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_TESTRAND_H_
-#define _SECP256K1_TESTRAND_H_
+#ifndef SECP256K1_TESTRAND_H
+#define SECP256K1_TESTRAND_H
 
 #if defined HAVE_CONFIG_H
 #include "libsecp256k1-config.h"
@@ -35,4 +35,4 @@ static void secp256k1_rand256_test(unsigned char *b32);
 /** Generate pseudorandom bytes with long sequences of zero and one bits. */
 static void secp256k1_rand_bytes_test(unsigned char *bytes, size_t len);
 
-#endif
+#endif /* SECP256K1_TESTRAND_H */
diff --git a/src/testrand_impl.h b/src/testrand_impl.h
index 15c7b9f12d..1255574209 100644
--- a/src/testrand_impl.h
+++ b/src/testrand_impl.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_TESTRAND_IMPL_H_
-#define _SECP256K1_TESTRAND_IMPL_H_
+#ifndef SECP256K1_TESTRAND_IMPL_H
+#define SECP256K1_TESTRAND_IMPL_H
 
 #include <stdint.h>
 #include <string.h>
@@ -107,4 +107,4 @@ static void secp256k1_rand256_test(unsigned char *b32) {
     secp256k1_rand_bytes_test(b32, 32);
 }
 
-#endif
+#endif /* SECP256K1_TESTRAND_IMPL_H */
diff --git a/src/util.h b/src/util.h
index 4092a86c91..b0441d8e30 100644
--- a/src/util.h
+++ b/src/util.h
@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_UTIL_H_
-#define _SECP256K1_UTIL_H_
+#ifndef SECP256K1_UTIL_H
+#define SECP256K1_UTIL_H
 
 #if defined HAVE_CONFIG_H
 #include "libsecp256k1-config.h"
@@ -110,4 +110,4 @@ static SECP256K1_INLINE void *checked_malloc(const secp256k1_callback* cb, size_
 SECP256K1_GNUC_EXT typedef unsigned __int128 uint128_t;
 #endif
 
-#endif
+#endif /* SECP256K1_UTIL_H */