crypto: add a ge_p3_identity constant

src/crypto/crypto-ops-data.c

@@ -870,3 +870,4 @@ const fe fe_fffb1 = {-31702527, -2466483, -26106795, -12203692, -12169197, -3210
 const fe fe_fffb2 = {8166131, -6741800, -17040804, 3154616, 21461005, 1466302, -30876704, -6368709, 10503587, -13363080}; /* sqrt(2 * A * (A + 2)) */
 const fe fe_fffb3 = {-13620103, 14639558, 4532995, 7679154, 16815101, -15883539, -22863840, -14813421, 13716513, -6477756}; /* sqrt(-sqrt(-1) * A * (A + 2)) */
 const fe fe_fffb4 = {-21786234, -12173074, 21573800, 4524538, -4645904, 16204591, 8012863, -8444712, 3212926, 6885324}; /* sqrt(sqrt(-1) * A * (A + 2)) */
+const ge_p3 ge_p3_identity = { {0}, {1, 0}, {1, 0}, {0} };

src/crypto/crypto-ops.h

@@ -139,6 +139,7 @@ extern const fe fe_fffb1;
 extern const fe fe_fffb2;
 extern const fe fe_fffb3;
 extern const fe fe_fffb4;
+extern const ge_p3 ge_p3_identity;
 void ge_fromfe_frombytes_vartime(ge_p2 *, const unsigned char *);
 void sc_0(unsigned char *);
 void sc_reduce32(unsigned char *);