diff --git a/crypto/sm3/sm3.c b/crypto/sm3/sm3.c
index 41ec80e6..17994f94 100644
--- a/crypto/sm3/sm3.c
+++ b/crypto/sm3/sm3.c
@@ -177,7 +177,7 @@ void sm3_compress(uint32_t digest[8], const unsigned char block[64])
 	for(j =16; j < 64; j++) {
 
 		T[j] = 0x7A879D8A;
-		SS1 = ROTATELEFT((ROTATELEFT(A,12) + E + ROTATELEFT(T[j],j)), 7);
+		SS1 = ROTATELEFT((ROTATELEFT(A,12) + E + ROTATELEFT(T[j],j%32)), 7);
 		SS2 = SS1 ^ ROTATELEFT(A,12);
 		TT1 = FF1(A,B,C) + D + SS2 + W1[j];
 		TT2 = GG1(E,F,G) + H + SS1 + W[j];