add public function wc_curve25519() "compute the public key from an existing private key, using bare vectors."; rename existing _LOCAL functions wc_curve25519_GetBasePoint() and wc_curve25519() to nxp_ltc_curve25519_GetBasePoint() and nxp_ltc_curve25519() respectively; add const qualifiers opportunistically to existing _LOCAL function curve25519()

wolfcrypt/src/curve25519.c

@@ -51,12 +51,45 @@ const curve25519_set_type curve25519_sets[] = {
     }
 };
 
+/* compute the public key from an existing private key, using bare vectors. */
+int wc_curve25519(int public_size, byte* public, int private_size, const byte* private) {
+    int ret;
+
+    if ((public_size != CURVE25519_KEYSIZE) ||
+        (private_size != CURVE25519_KEYSIZE))
+        return ECC_BAD_ARG_E;
+    if ((public == NULL) || (private == NULL))
+        return ECC_BAD_ARG_E;
+
+    /* check clamping */
+    if ((private[0] & ~248) ||
+        (private[CURVE25519_KEYSIZE-1] & 128))
+        return ECC_BAD_ARG_E;
+
+#ifdef FREESCALE_LTC_ECC
+    {
+        const ECPoint* basepoint = nxp_ltc_curve25519_GetBasePoint();
+        ECPoint wc_pub;
+        ret = nxp_ltc_curve25519(&wc_pub, private, basepoint, kLTC_Weierstrass); /* input basepoint on Weierstrass curve */
+        if (ret == 0)
+            XMEMCPY(public, wc_pub.point, CURVE25519_KEY_SIZE);
+    }
+#else
+    {
+        static const unsigned char basepoint[CURVE25519_KEYSIZE] = {9};
+        ret = curve25519(public, private, basepoint);
+    }
+#endif
+
+    return ret;
+}
+
 int wc_curve25519_make_key(WC_RNG* rng, int keysize, curve25519_key* key)
 {
 #ifdef FREESCALE_LTC_ECC
-    const ECPoint* basepoint = wc_curve25519_GetBasePoint();
+    const ECPoint* basepoint = nxp_ltc_curve25519_GetBasePoint();
 #else
-    unsigned char basepoint[CURVE25519_KEYSIZE] = {9};
+    static const unsigned char basepoint[CURVE25519_KEYSIZE] = {9};
 #endif
     int  ret;
 
@@ -83,7 +116,7 @@ int wc_curve25519_make_key(WC_RNG* rng, int keysize, curve25519_key* key)
 
     /* compute public key */
     #ifdef FREESCALE_LTC_ECC
-        ret = wc_curve25519(&key->p, key->k.point, basepoint, kLTC_Weierstrass); /* input basepoint on Weierstrass curve */
+        ret = nxp_ltc_curve25519(&key->p, key->k.point, basepoint, kLTC_Weierstrass); /* input basepoint on Weierstrass curve */
     #else
         ret = curve25519(key->p.point, key->k.point, basepoint);
     #endif
@@ -127,7 +160,7 @@ int wc_curve25519_shared_secret_ex(curve25519_key* private_key,
         return ECC_BAD_ARG_E;
 
     #ifdef FREESCALE_LTC_ECC
-        ret = wc_curve25519(&o, private_key->k.point, &public_key->p, kLTC_Curve25519 /* input point P on Curve25519 */);
+        ret = nxp_ltc_curve25519(&o, private_key->k.point, &public_key->p, kLTC_Curve25519 /* input point P on Curve25519 */);
     #else
         ret = curve25519(o, private_key->k.point, public_key->p.point);
     #endif

wolfcrypt/src/fe_operations.c

@@ -129,7 +129,7 @@ void fe_init(void)
 
 #if defined(HAVE_CURVE25519) && !defined(CURVE25519_SMALL) && \
     !defined(FREESCALE_LTC_ECC)
-int curve25519(byte* q, byte* n, byte* p)
+int curve25519(byte* q, const byte* n, const byte* p)
 {
 #if 0
   unsigned char e[32];

wolfcrypt/src/port/nxp/ksdk_port.c

@@ -974,7 +974,7 @@ static const ECPoint ecBasePoint = {
     0x1e, 0xe0, 0xb4, 0x86, 0xa0, 0xb8, 0xa1, 0x19, 0xae, 0x20},
 };
 
-const ECPoint *wc_curve25519_GetBasePoint(void)
+const ECPoint *nxp_ltc_curve25519_GetBasePoint(void)
 {
     return &ecBasePoint;
 }
@@ -1122,7 +1122,7 @@ status_t LTC_PKHA_Curve25519ComputeY(ltc_pkha_ecc_point_t *ltcPoint)
 /* if type is set, the input point p is in Montgomery curve coordinates,
     so there is a map to Weierstrass curve */
 /* q output point is always in Montgomery curve coordinates */
-int wc_curve25519(ECPoint *q, byte *n, const ECPoint *p, fsl_ltc_ecc_coordinate_system_t type)
+int nxp_ltc_curve25519(ECPoint *q, byte *n, const ECPoint *p, fsl_ltc_ecc_coordinate_system_t type)
 {
     status_t status;
     ltc_pkha_ecc_point_t ltcPoint;

wolfssl/wolfcrypt/curve25519.h

@@ -86,6 +86,9 @@ enum {
     EC25519_BIG_ENDIAN=1
 };
 
+WOLFSSL_API
+int wc_curve25519(int public_size, byte* public, int private_size, const byte* private);
+
 WOLFSSL_API
 int wc_curve25519_make_key(WC_RNG* rng, int keysize, curve25519_key* key);
 

wolfssl/wolfcrypt/fe_operations.h

@@ -79,7 +79,7 @@ Bounds on each t[i] vary depending on context.
 #if !defined(FREESCALE_LTC_ECC)
 WOLFSSL_LOCAL void fe_init(void);
 
-WOLFSSL_LOCAL int  curve25519(byte * q, byte * n, byte * p);
+WOLFSSL_LOCAL int  curve25519(byte * q, const byte * n, const byte * p);
 #endif
 
 /* default to be faster but take more memory */

wolfssl/wolfcrypt/port/nxp/ksdk_port.h

@@ -65,8 +65,8 @@ int ksdk_port_init(void);
 	int wc_ecc_point_add(ecc_point *mG, ecc_point *mQ, ecc_point *mR, mp_int *m);
 
 	#ifdef HAVE_CURVE25519
-		int wc_curve25519(ECPoint *q, byte *n, const ECPoint *p, fsl_ltc_ecc_coordinate_system_t type);
+		int nxp_ltc_curve25519(ECPoint *q, byte *n, const ECPoint *p, fsl_ltc_ecc_coordinate_system_t type);
-		const ECPoint *wc_curve25519_GetBasePoint(void);
+		const ECPoint *nxp_ltc_curve25519_GetBasePoint(void);
 		status_t LTC_PKHA_Curve25519ToWeierstrass(const ltc_pkha_ecc_point_t *ltcPointIn, ltc_pkha_ecc_point_t *ltcPointOut);
 		status_t LTC_PKHA_WeierstrassToCurve25519(const ltc_pkha_ecc_point_t *ltcPointIn, ltc_pkha_ecc_point_t *ltcPointOut);
 		status_t LTC_PKHA_Curve25519ComputeY(ltc_pkha_ecc_point_t *ltcPoint);