From 1591dbfc4d02b33a17345fd63fc2e8d1f6171638 Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Mon, 26 Jan 2015 06:00:20 +0100
Subject: Make default base and identity points accessible

---
 include/libuecc/ecc.h |  3 +++
 src/ec25519.c         | 48 +++++++++++++++++++++++++-----------------------
 2 files changed, 28 insertions(+), 23 deletions(-)

diff --git a/include/libuecc/ecc.h b/include/libuecc/ecc.h
index c9ea7d9..4f6b870 100644
--- a/include/libuecc/ecc.h
+++ b/include/libuecc/ecc.h
@@ -55,6 +55,9 @@ typedef struct _ecc_25519_work {
  * @{
  */
 
+extern const ecc_25519_work_t ecc_25519_work_identity;
+extern const ecc_25519_work_t ecc_25519_work_default_base;
+
 int ecc_25519_load_xy(ecc_25519_work_t *out, const ecc_int256_t *x, const ecc_int256_t *y);
 void ecc_25519_store_xy(ecc_int256_t *x, ecc_int256_t *y, const ecc_25519_work_t *in);
 
diff --git a/src/ec25519.c b/src/ec25519.c
index 53a9910..736b798 100644
--- a/src/ec25519.c
+++ b/src/ec25519.c
@@ -40,6 +40,28 @@
 #include <libuecc/ecc.h>
 
 
+/** The identity element */
+const ecc_25519_work_t ecc_25519_work_identity = {{0}, {1}, {1}, {0}};
+
+
+/** The ec25519 default base */
+const ecc_25519_work_t ecc_25519_work_default_base = {
+	{0xd4, 0x6b, 0xfe, 0x7f, 0x39, 0xfa, 0x8c, 0x22,
+	 0xe1, 0x96, 0x23, 0xeb, 0x26, 0xb7, 0x8e, 0x6a,
+	 0x34, 0x74, 0x8b, 0x66, 0xd6, 0xa3, 0x26, 0xdd,
+	 0x19, 0x5e, 0x9f, 0x21, 0x50, 0x43, 0x7c, 0x54},
+	{0x58, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66,
+	 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66,
+	 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66,
+	 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66},
+	{1},
+	{0x47, 0x56, 0x98, 0x99, 0xc7, 0x61, 0x0a, 0x82,
+	 0x1a, 0xdf, 0x82, 0x22, 0x1f, 0x2c, 0x72, 0x88,
+	 0xc3, 0x29, 0x09, 0x52, 0x78, 0xe9, 0x1e, 0xe4,
+	 0x47, 0x4b, 0x4c, 0x81, 0xa6, 0x02, 0xfd, 0x29}
+};
+
+
 static const unsigned int zero[32] = {0};
 static const unsigned int one[32] = {1};
 
@@ -478,9 +500,6 @@ void ecc_25519_store_packed(ecc_int256_t *out, const ecc_25519_work_t *in) {
 	out->p[31] |= (y.p[0] << 7);
 }
 
-/** The identity element */
-static const ecc_25519_work_t id = {{0}, {1}, {1}, {0}};
-
 /** Checks if a point is the identity element of the Elliptic Curve group */
 int ecc_25519_is_identity(const ecc_25519_work_t *in) {
 	unsigned int Y_Z[32];
@@ -558,7 +577,7 @@ void ecc_25519_add(ecc_25519_work_t *out, const ecc_25519_work_t *in1, const ecc
  **/
 void ecc_25519_scalarmult_bits(ecc_25519_work_t *out, const ecc_int256_t *n, const ecc_25519_work_t *base, unsigned bits) {
 	ecc_25519_work_t Q2, Q2p;
-	ecc_25519_work_t cur = id;
+	ecc_25519_work_t cur = ecc_25519_work_identity;
 	int b, pos;
 
 	if (bits > 256)
@@ -585,23 +604,6 @@ void ecc_25519_scalarmult(ecc_25519_work_t *out, const ecc_int256_t *n, const ec
 	ecc_25519_scalarmult_bits(out, n, base, 256);
 }
 
-/** The ec25519 default base */
-static const ecc_25519_work_t default_base = {
-	{0xd4, 0x6b, 0xfe, 0x7f, 0x39, 0xfa, 0x8c, 0x22,
-	 0xe1, 0x96, 0x23, 0xeb, 0x26, 0xb7, 0x8e, 0x6a,
-	 0x34, 0x74, 0x8b, 0x66, 0xd6, 0xa3, 0x26, 0xdd,
-	 0x19, 0x5e, 0x9f, 0x21, 0x50, 0x43, 0x7c, 0x54},
-	{0x58, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66,
-	 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66,
-	 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66,
-	 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66, 0x66},
-	{1},
-	{0x47, 0x56, 0x98, 0x99, 0xc7, 0x61, 0x0a, 0x82,
-	 0x1a, 0xdf, 0x82, 0x22, 0x1f, 0x2c, 0x72, 0x88,
-	 0xc3, 0x29, 0x09, 0x52, 0x78, 0xe9, 0x1e, 0xe4,
-	 0x47, 0x4b, 0x4c, 0x81, 0xa6, 0x02, 0xfd, 0x29}
-};
-
 /**
  * Does a scalar multiplication of the default base point (generator element) of the Elliptic Curve with an integer of a given bit length
  *
@@ -610,7 +612,7 @@ static const ecc_25519_work_t default_base = {
  * See the notes about \ref ecc_25519_scalarmult_bits before using this function.
  */
 void ecc_25519_scalarmult_base_bits(ecc_25519_work_t *out, const ecc_int256_t *n, unsigned bits) {
-	ecc_25519_scalarmult_bits(out, n, &default_base, bits);
+	ecc_25519_scalarmult_bits(out, n, &ecc_25519_work_default_base, bits);
 }
 
 /**
@@ -619,5 +621,5 @@ void ecc_25519_scalarmult_base_bits(ecc_25519_work_t *out, const ecc_int256_t *n
  * The order of the base point is \f$ 2^{252} + 27742317777372353535851937790883648493 \f$.
  */
 void ecc_25519_scalarmult_base(ecc_25519_work_t *out, const ecc_int256_t *n) {
-	ecc_25519_scalarmult(out, n, &default_base);
+	ecc_25519_scalarmult(out, n, &ecc_25519_work_default_base);
 }
-- 
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