1 files changed, 67 insertions, 0 deletions
diff --git a/src/model/c/src/montgomery_array.c b/src/model/c/src/montgomery_array.c
index c3579a9..259dcff 100644
--- a/src/model/c/src/montgomery_array.c
+++ b/src/model/c/src/montgomery_array.c
@@ -102,6 +102,53 @@ void mont_exp_array(uint32_t length, uint32_t *X, uint32_t *E, uint32_t *M,
 
 }
 
+// Experimental version where we add explicit lengths.
+void mont_exp_array2(uint32_t explength, uint32_t modlength, uint32_t *X, uint32_t *E, uint32_t *M,
+		uint32_t *Nr, uint32_t *P, uint32_t *ONE, uint32_t *temp,
+		uint32_t *temp2, uint32_t *Z) {
+	//debugArray("X ", length, X);
+	//debugArray("E ", length, E);
+	//debugArray("M ", length, M);
+
+	// 1. Nr := 2 ** 2N mod M
+	const uint32_t N = 32 * modlength;
+	m_residue_2_2N_array(modlength, N, M, temp, Nr);
+	//debugArray("Nr", length, Nr);
+
+	// 2. Z0 := MontProd( 1, Nr, M )
+	zero_array(modlength, ONE);
+	ONE[modlength - 1] = 1;
+	mont_prod_array(modlength, ONE, Nr, M, Z);
+	//debugArray("Z0", length, Z);
+
+	// 3. P0 := MontProd( X, Nr, M );
+	mont_prod_array(modlength, X, Nr, M, P);
+	//debugArray("P0", length, P);
+
+	// 4. for i = 0 to explength - 1 loop
+	for (uint32_t i = 0; i < (explength * 32); i++) {
+		uint32_t ei_ = E[explength - 1 - (i / 32)];
+		uint32_t ei = (ei_ >> (i % 32)) & 1;
+		// 6. if (ei = 1) then Zi+1 := MontProd ( Zi, Pi, M) else Zi+1 := Zi
+		if (ei == 1) {
+			mont_prod_array(modlength, Z, P, M, temp2);
+			copy_array(modlength, temp2, Z);
+			//debugArray("Z ", length, Z);
+		}
+		// 5. Pi+1 := MontProd( Pi, Pi, M );
+		mont_prod_array(modlength, P, P, M, temp2);
+		copy_array(modlength, temp2, P);
+		//debugArray("P ", length, P);
+		// 7. end for
+	}
+	// 8. Zn := MontProd( 1, Zn, M );
+	mont_prod_array(modlength, ONE, Z, M, temp2);
+	copy_array(modlength, temp2, Z);
+	//debugArray("Z ", length, Z);
+	// 9. RETURN Zn
+
+}
+
 void die(const char *c) {
 	printf("Fatal error: %s\n", c);
 	exit(1);
@@ -125,3 +172,23 @@ void mod_exp_array(uint32_t length, uint32_t *X, uint32_t *E, uint32_t *M, uint3
 	free(temp);
 	free(temp2);
 }
+
+// Experimental version with explicit explength separate from modlength.
+void mod_exp_array2(uint32_t explength, uint32_t modlength, uint32_t *X, uint32_t *E, uint32_t *M, uint32_t *Z) {
+	uint32_t *Nr = calloc(modlength, sizeof(uint32_t));
+	uint32_t *P = calloc(modlength, sizeof(uint32_t));
+	uint32_t *ONE = calloc(modlength, sizeof(uint32_t));
+	uint32_t *temp = calloc(modlength, sizeof(uint32_t));
+	uint32_t *temp2 = calloc(modlength, sizeof(uint32_t));
+	if (Nr == NULL) die("calloc");
+	if (P == NULL) die("calloc");
+	if (ONE == NULL) die("calloc");
+	if (temp == NULL) die("calloc");
+	if (temp2 == NULL) die("calloc");
+	mont_exp_array2(explength, modlength, X, E, M, Nr, P, ONE, temp, temp2, Z);
+	free(Nr);
+	free(P);
+	free(ONE);
+	free(temp);
+	free(temp2);
+}