diff --git a/t/Makefile.am b/t/Makefile.am
index d9622b3..3300c7e 100644
--- a/t/Makefile.am
+++ b/t/Makefile.am
@@ -6,7 +6,7 @@ noinst_HEADERS = t.h
 
 # Common support code
 check_LTLIBRARIES = libt.la
-libt_la_SOURCES = t_main.c t_file.c
+libt_la_SOURCES = t_main.c t_file.c t_const.c
 
 # Link in the test driver and the full cryb library
 LDADD = $(builddir)/libt.la \
diff --git a/t/t.h b/t/t.h
index 9cb6a72..df77a69 100644
--- a/t/t.h
+++ b/t/t.h
@@ -79,4 +79,10 @@ void t_frewind(struct t_file *);
 void t_fclose(struct t_file *);
 void t_fcloseall(void);
 
+/*
+ * Useful constants
+ */
+extern const uint8_t t_zero[256];
+extern const uint8_t t_seq8[256];
+
 #endif
diff --git a/t/t_hmac_sha1.c b/t/t_hmac_sha1.c
index 0be58df..affe4fa 100644
--- a/t/t_hmac_sha1.c
+++ b/t/t_hmac_sha1.c
@@ -79,14 +79,14 @@ t_hmac_sha1_complete(const void *key, size_t keylen,
  */
 static struct t_vector {
 	const char *desc;
-	uint8_t key[100];
+	const uint8_t *key;
 	size_t keylen;
 	const char *msg;
 	const uint8_t mac[HMAC_SHA1_MAC_LEN];
 } t_hmac_sha1_vectors[] = {
 	{
 		"zero-length key, zero-length message",
-		{ },
+		t_zero,
 		0,
 		"",
 		{
@@ -97,16 +97,7 @@ static struct t_vector {
 	},
 	{
 		"NIST CSRC example 1 (64-byte key)",
-		{
-			0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
-			0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
-			0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
-			0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
-			0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
-			0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
-			0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
-			0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
-		},
+		t_seq8,
 		64,
 		"Sample message for keylen=blocklen",
 		{
@@ -117,11 +108,7 @@ static struct t_vector {
 	},
 	{
 		"NIST CSRC example 2 (20-byte key)",
-		{
-			0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
-			0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
-			0x10, 0x11, 0x12, 0x13,
-		},
+		t_seq8,
 		20,
 		"Sample message for keylen<blocklen",
 		{
@@ -132,21 +119,7 @@ static struct t_vector {
 	},
 	{
 		"NIST CSRC example 3 (100-byte key)",
-		{
-			0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
-			0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
-			0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
-			0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
-			0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
-			0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
-			0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
-			0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
-			0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
-			0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
-			0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
-			0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
-			0x60, 0x61, 0x62, 0x63,
-		},
+		t_seq8,
 		100,
 		/* yes, the text should say keylen>blocklen */
 		"Sample message for keylen=blocklen",
@@ -158,15 +131,7 @@ static struct t_vector {
 	},
 	{
 		"NIST CSRC example 4 (49-byte key)",
-		{
-			0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
-			0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
-			0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
-			0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
-			0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
-			0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
-			0x30,
-		},
+		t_seq8,
 		49,
 		"Sample message for keylen<blocklen, with truncated tag",
 		{