diff --git a/src/evmctl.c b/src/evmctl.c
index 04955e0..c3048af 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -108,7 +108,7 @@ enum digest_algo {
 
 struct pubkey_hdr {
 	uint8_t version;	/* key format version */
-	time_t timestamp;	/* key made, always 0 for now */
+	uint32_t timestamp;	/* key made, always 0 for now */
 	uint8_t algo;
 	uint8_t nmpi;
 	char mpi[0];
@@ -116,7 +116,7 @@ struct pubkey_hdr {
 
 struct signature_hdr {
 	uint8_t version;	/* signature format version */
-	time_t timestamp;	/* signature made */
+	uint32_t timestamp;	/* signature made */
 	uint8_t algo;
 	uint8_t hash;
 	uint8_t keyid[8];
@@ -336,7 +336,7 @@ static int sign_hash(const unsigned char *hash, int size, const char *keyfile, u
 
 	/* now create a new hash */
 	hdr->version = 1;
-	time(&hdr->timestamp);
+	hdr->timestamp = time(NULL);
 	hdr->algo = PUBKEY_ALGO_RSA;
 	hdr->hash = DIGEST_ALGO_SHA1;