commit c1402e768ac98746996b57069362ec89be66d9c0
author Ken MacKay <kmackay@gmail.com> Wed Oct 07 11:50:05 2020 -0700
committer GitHub <noreply@github.com> Wed Oct 07 11:50:05 2020 -0700
tree 60af7f49f121f504299935035fa12742fe1cb664
parent 1b5f5cea5145c96dd8791b9b2c41424fc74c2172
parent 66ef25a3716aaafa7368a65b3f9e0dbf627c2ec1

Merge pull request #143 from westin123/master

Conditionally removed vararg related macros for platforms where they …

README.md

diff --git a/README.md b/README.md
index fd31d1c..111321b 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@
 Usage Notes
 -----------
 ### Point Representation ###
-Compressed points are represented in the standard format as defined in http://www.secg.org/sec1-v2.pdf; uncompressed points are represented in standard format, but without the `0x04` prefix. All functions except `uECC_compress()` only accept uncompressed points; use `uECC_compress()` and `uECC_decompress()` to convert between compressed and uncompressed point representations.
+Compressed points are represented in the standard format as defined in http://www.secg.org/sec1-v2.pdf; uncompressed points are represented in standard format, but without the `0x04` prefix. All functions except `uECC_decompress()` only accept uncompressed points; use `uECC_compress()` and `uECC_decompress()` to convert between compressed and uncompressed point representations.
 
 Private keys are represented in the standard format.
 

uECC.c

diff --git a/uECC.c b/uECC.c
index bb4e232..3cf2b1f 100644
--- a/uECC.c
+++ b/uECC.c
@@ -1120,7 +1120,7 @@
 }
 #endif /* uECC_SUPPORT_COMPRESSED_POINT */
 
-int uECC_valid_point(const uECC_word_t *point, uECC_Curve curve) {
+uECC_VLI_API int uECC_valid_point(const uECC_word_t *point, uECC_Curve curve) {
     uECC_word_t tmp1[uECC_MAX_WORDS];
     uECC_word_t tmp2[uECC_MAX_WORDS];
     wordcount_t num_words = curve->num_words;
@@ -1215,7 +1215,7 @@
     bcopy((uint8_t *) native, bits, bits_size);
 #else
     uECC_vli_bytesToNative(native, bits, bits_size);
-#endif    
+#endif
     if (bits_size * 8 <= (unsigned)curve->num_n_bits) {
         return;
     }
@@ -1244,6 +1244,7 @@
     uECC_word_t tmp[uECC_MAX_WORDS];
     uECC_word_t s[uECC_MAX_WORDS];
     uECC_word_t *k2[2] = {tmp, s};
+    uECC_word_t *initial_Z = 0;
 #if uECC_VLI_NATIVE_LITTLE_ENDIAN
     uECC_word_t *p = (uECC_word_t *)signature;
 #else
@@ -1260,7 +1261,15 @@
     }
 
     carry = regularize_k(k, tmp, s, curve);
-    EccPoint_mult(p, curve->G, k2[!carry], 0, num_n_bits + 1, curve);
+    /* If an RNG function was specified, try to get a random initial Z value to improve
+       protection against side-channel attacks. */
+    if (g_rng_function) {
+        if (!uECC_generate_random_int(k2[carry], curve->p, num_words)) {
+            return 0;
+        }
+        initial_Z = k2[carry];
+    }
+    EccPoint_mult(p, curve->G, k2[!carry], initial_Z, num_n_bits + 1, curve);
     if (uECC_vli_isZero(p, num_words)) {
         return 0;
     }
@@ -1304,7 +1313,7 @@
     bcopy((uint8_t *) signature + curve->num_bytes, (uint8_t *) s, curve->num_bytes);
 #else
     uECC_vli_nativeToBytes(signature + curve->num_bytes, curve->num_bytes, s);
-#endif    
+#endif
     return 1;
 }
 
@@ -1477,7 +1486,7 @@
     uECC_word_t *_public = (uECC_word_t *)public_key;
 #else
     uECC_word_t _public[uECC_MAX_WORDS * 2];
-#endif    
+#endif
     uECC_word_t r[uECC_MAX_WORDS], s[uECC_MAX_WORDS];
     wordcount_t num_words = curve->num_words;
     wordcount_t num_n_words = BITS_TO_WORDS(curve->num_n_bits);