diff --git a/tests/suites/test_suite_aes.function b/tests/suites/test_suite_aes.function
index bc2d535..754a167 100644
--- a/tests/suites/test_suite_aes.function
+++ b/tests/suites/test_suite_aes.function
@@ -321,17 +321,15 @@
 /* BEGIN_CASE depends_on:MBEDTLS_CIPHER_MODE_OFB */
 void aes_encrypt_ofb( int fragment_size, data_t *key_str,
                       data_t *iv_str, data_t *src_str,
-                      char *expected_output_string)
+                      data_t *expected_output )
 {
     unsigned char output[32];
-    unsigned char output_string[65];
     mbedtls_aes_context ctx;
     size_t iv_offset = 0;
     int in_buffer_len;
     unsigned char* src_str_next;
 
     memset( output, 0x00, sizeof( output ) );
-    memset( output_string, 0x00, sizeof( output_string ) );
     mbedtls_aes_init( &ctx );
 
     TEST_ASSERT( (size_t)fragment_size < sizeof( output ) );
@@ -346,12 +344,10 @@
         TEST_ASSERT( mbedtls_aes_crypt_ofb( &ctx, fragment_size, &iv_offset,
                                             iv_str->x, src_str_next, output ) == 0 );
 
-        mbedtls_test_hexify( output_string, output, fragment_size );
-        TEST_ASSERT( strncmp( (char *) output_string, expected_output_string,
-                              ( 2 * fragment_size ) ) == 0 );
+        TEST_ASSERT( memcmp( output, expected_output->x, fragment_size ) == 0 );
 
         in_buffer_len -= fragment_size;
-        expected_output_string += ( fragment_size * 2 );
+        expected_output->x += fragment_size;
         src_str_next += fragment_size;
 
         if( in_buffer_len < fragment_size )
diff --git a/tests/suites/test_suite_aria.function b/tests/suites/test_suite_aria.function
index d08c39d..3cc683b 100644
--- a/tests/suites/test_suite_aria.function
+++ b/tests/suites/test_suite_aria.function
@@ -207,14 +207,12 @@
 
 /* BEGIN_CASE */
 void aria_encrypt_ecb( data_t *key_str, data_t *src_str,
-                       char *hex_dst_string, int setkey_result )
+                       data_t *expected_output, int setkey_result )
 {
-    unsigned char dst_str[ARIA_MAX_DATA_STR];
     unsigned char output[ARIA_MAX_DATASIZE];
     mbedtls_aria_context ctx;
     size_t i;
 
-    memset( dst_str, 0x00, sizeof( dst_str ) );
     memset( output, 0x00, sizeof( output ) );
     mbedtls_aria_init( &ctx );
 
@@ -227,9 +225,9 @@
             TEST_ASSERT( mbedtls_aria_crypt_ecb( &ctx, src_str->x + i,
                                                  output + i ) == 0 );
         }
-        mbedtls_test_hexify( dst_str, output, src_str->len );
 
-        TEST_ASSERT( strcasecmp( (char *) dst_str, hex_dst_string ) == 0 );
+        TEST_ASSERT( !memcmp( output,
+                              expected_output->x, expected_output->len) );
     }
 
 exit:
@@ -239,14 +237,12 @@
 
 /* BEGIN_CASE */
 void aria_decrypt_ecb( data_t *key_str, data_t *src_str,
-                       char *hex_dst_string, int setkey_result )
+                       data_t *expected_output, int setkey_result )
 {
-    unsigned char dst_str[ARIA_MAX_DATA_STR];
     unsigned char output[ARIA_MAX_DATASIZE];
     mbedtls_aria_context ctx;
     size_t i;
 
-    memset( dst_str, 0x00, sizeof( dst_str ) );
     memset( output, 0x00, sizeof( output ) );
     mbedtls_aria_init( &ctx );
 
@@ -259,9 +255,9 @@
             TEST_ASSERT( mbedtls_aria_crypt_ecb( &ctx, src_str->x + i,
                                                  output + i ) == 0 );
         }
-        mbedtls_test_hexify( dst_str, output, src_str->len );
 
-        TEST_ASSERT( strcasecmp( (char *) dst_str, hex_dst_string ) == 0 );
+        TEST_ASSERT( !memcmp( output,
+                              expected_output->x, expected_output->len) );
     }
 
 exit:
@@ -271,14 +267,12 @@
 
 /* BEGIN_CASE depends_on:MBEDTLS_CIPHER_MODE_CBC */
 void aria_encrypt_cbc( data_t *key_str, data_t *iv_str,
-                       data_t *src_str, char *hex_dst_string,
+                       data_t *src_str, data_t *expected_output,
                        int cbc_result )
 {
-    unsigned char dst_str[ARIA_MAX_DATA_STR];
     unsigned char output[ARIA_MAX_DATASIZE];
     mbedtls_aria_context ctx;
 
-    memset( dst_str, 0x00, sizeof( dst_str ) );
     memset( output, 0x00, sizeof( output ) );
     mbedtls_aria_init( &ctx );
 
@@ -288,9 +282,8 @@
                                          output ) == cbc_result );
     if( cbc_result == 0 )
     {
-        mbedtls_test_hexify( dst_str, output, src_str->len );
-
-        TEST_ASSERT( strcasecmp( (char *) dst_str, hex_dst_string ) == 0 );
+        TEST_ASSERT( !memcmp( output,
+                              expected_output->x, expected_output->len) );
     }
 
 exit:
@@ -300,14 +293,12 @@
 
 /* BEGIN_CASE depends_on:MBEDTLS_CIPHER_MODE_CBC */
 void aria_decrypt_cbc( data_t *key_str, data_t *iv_str,
-                       data_t *src_str, char *hex_dst_string,
+                       data_t *src_str, data_t *expected_output,
                        int cbc_result )
 {
-    unsigned char dst_str[ARIA_MAX_DATA_STR];
     unsigned char output[ARIA_MAX_DATASIZE];
     mbedtls_aria_context ctx;
 
-    memset( dst_str, 0x00, sizeof( dst_str ) );
     memset( output, 0x00, sizeof( output ) );
     mbedtls_aria_init( &ctx );
 
@@ -317,9 +308,8 @@
                                          output ) == cbc_result );
     if( cbc_result == 0 )
     {
-        mbedtls_test_hexify( dst_str, output, src_str->len );
-
-        TEST_ASSERT( strcasecmp( (char *) dst_str, hex_dst_string ) == 0 );
+        TEST_ASSERT( !memcmp( output,
+                              expected_output->x, expected_output->len) );
     }
 
 exit:
@@ -329,15 +319,13 @@
 
 /* BEGIN_CASE depends_on:MBEDTLS_CIPHER_MODE_CFB */
 void aria_encrypt_cfb128( data_t *key_str, data_t *iv_str,
-                          data_t *src_str, char *hex_dst_string,
+                          data_t *src_str, data_t *expected_output,
                           int result )
 {
-    unsigned char dst_str[ARIA_MAX_DATA_STR];
     unsigned char output[ARIA_MAX_DATASIZE];
     mbedtls_aria_context ctx;
     size_t iv_offset = 0;
 
-    memset( dst_str, 0x00, sizeof( dst_str ) );
     memset( output, 0x00, sizeof( output ) );
     mbedtls_aria_init( &ctx );
 
@@ -346,9 +334,8 @@
                                             src_str->len, &iv_offset,
                                             iv_str->x, src_str->x, output )
                  == result );
-    mbedtls_test_hexify( dst_str, output, src_str->len );
 
-    TEST_ASSERT( strcasecmp( (char *) dst_str, hex_dst_string ) == 0 );
+    TEST_ASSERT( !memcmp( output, expected_output->x, expected_output->len) );
 
 exit:
     mbedtls_aria_free( &ctx );
@@ -357,15 +344,13 @@
 
 /* BEGIN_CASE depends_on:MBEDTLS_CIPHER_MODE_CFB */
 void aria_decrypt_cfb128( data_t *key_str, data_t *iv_str,
-                          data_t *src_str, char *hex_dst_string,
+                          data_t *src_str, data_t *expected_output,
                           int result  )
 {
-    unsigned char dst_str[ARIA_MAX_DATA_STR];
     unsigned char output[ARIA_MAX_DATASIZE];
     mbedtls_aria_context ctx;
     size_t iv_offset = 0;
 
-    memset( dst_str, 0x00, sizeof( dst_str ) );
     memset( output, 0x00, sizeof( output ) );
     mbedtls_aria_init( &ctx );
 
@@ -374,9 +359,8 @@
                                             src_str->len, &iv_offset,
                                             iv_str->x, src_str->x, output )
                  == result );
-    mbedtls_test_hexify( dst_str, output, src_str->len );
 
-    TEST_ASSERT( strcasecmp( (char *) dst_str, hex_dst_string ) == 0 );
+    TEST_ASSERT( !memcmp( output, expected_output->x, expected_output->len) );
 
 exit:
     mbedtls_aria_free( &ctx );
@@ -385,16 +369,14 @@
 
 /* BEGIN_CASE depends_on:MBEDTLS_CIPHER_MODE_CTR */
 void aria_encrypt_ctr( data_t *key_str, data_t *iv_str,
-                       data_t *src_str, char *hex_dst_string,
+                       data_t *src_str, data_t *expected_output,
                        int result )
 {
-    unsigned char dst_str[ARIA_MAX_DATA_STR];
     unsigned char output[ARIA_MAX_DATASIZE];
     unsigned char blk[MBEDTLS_ARIA_BLOCKSIZE];
     mbedtls_aria_context ctx;
     size_t iv_offset = 0;
 
-    memset( dst_str, 0x00, sizeof( dst_str ) );
     memset( output, 0x00, sizeof( output ) );
     mbedtls_aria_init( &ctx );
 
@@ -402,9 +384,8 @@
     TEST_ASSERT( mbedtls_aria_crypt_ctr( &ctx, src_str->len, &iv_offset,
                                          iv_str->x, blk, src_str->x, output )
                  == result );
-    mbedtls_test_hexify( dst_str, output, src_str->len );
 
-    TEST_ASSERT( strcasecmp( (char *) dst_str, hex_dst_string ) == 0 );
+    TEST_ASSERT( !memcmp( output, expected_output->x, expected_output->len) );
 
 exit:
     mbedtls_aria_free( &ctx );
@@ -413,16 +394,14 @@
 
 /* BEGIN_CASE depends_on:MBEDTLS_CIPHER_MODE_CTR */
 void aria_decrypt_ctr( data_t *key_str, data_t *iv_str,
-                       data_t *src_str, char *hex_dst_string,
+                       data_t *src_str, data_t *expected_output,
                        int result )
 {
-    unsigned char dst_str[ARIA_MAX_DATA_STR];
     unsigned char output[ARIA_MAX_DATASIZE];
     unsigned char blk[MBEDTLS_ARIA_BLOCKSIZE];
     mbedtls_aria_context ctx;
     size_t iv_offset = 0;
 
-    memset( dst_str, 0x00, sizeof( dst_str ) );
     memset( output, 0x00, sizeof( output ) );
     mbedtls_aria_init( &ctx );
 
@@ -430,9 +409,8 @@
     TEST_ASSERT( mbedtls_aria_crypt_ctr( &ctx, src_str->len, &iv_offset,
                                          iv_str->x, blk, src_str->x, output )
                  == result );
-    mbedtls_test_hexify( dst_str, output, src_str->len );
 
-    TEST_ASSERT( strcasecmp( (char *) dst_str, hex_dst_string ) == 0 );
+    TEST_ASSERT( !memcmp( output, expected_output->x, expected_output->len) );
 
 exit:
     mbedtls_aria_free( &ctx );
diff --git a/tests/suites/test_suite_chacha20.function b/tests/suites/test_suite_chacha20.function
index afe2418..968a9e9 100644
--- a/tests/suites/test_suite_chacha20.function
+++ b/tests/suites/test_suite_chacha20.function
@@ -17,13 +17,6 @@
     unsigned char output[375];
     mbedtls_chacha20_context ctx;
 
-    /*
-     * Buffers to store the ASCII string representation of output and
-     * expected_output_str.
-     */
-    unsigned char output_string[751] = { '\0' };
-    unsigned char expected_output_string[751] = { '\0' };
-
     memset( output, 0x00, sizeof( output ) );
 
     TEST_ASSERT( src_str->len   == expected_output_str->len );
@@ -35,12 +28,8 @@
      */
     TEST_ASSERT( mbedtls_chacha20_crypt( key_str->x, nonce_str->x, counter, src_str->len, src_str->x, output ) == 0 );
 
-    mbedtls_test_hexify( expected_output_string,
-                         expected_output_str->x,
-                         expected_output_str->len);
-    mbedtls_test_hexify( output_string, output, src_str->len );
-    TEST_ASSERT( strcmp( (char *)output_string,
-                         (char *)expected_output_string ) == 0 );
+    TEST_ASSERT( !memcmp( output, expected_output_str->x,
+                          expected_output_str->len ) );
 
     /*
      * Test the streaming API
@@ -54,9 +43,8 @@
     memset( output, 0x00, sizeof( output ) );
     TEST_ASSERT( mbedtls_chacha20_update( &ctx, src_str->len, src_str->x, output ) == 0 );
 
-    mbedtls_test_hexify( output_string, output, src_str->len );
-    TEST_ASSERT( strcmp( (char *)output_string,
-                         (char *)expected_output_string ) == 0 );
+    TEST_ASSERT( !memcmp( output, expected_output_str->x,
+                          expected_output_str->len ) );
 
     /*
      * Test the streaming API again, piecewise
@@ -71,9 +59,8 @@
     TEST_ASSERT( mbedtls_chacha20_update( &ctx, src_str->len - 1,
                                           src_str->x + 1, output + 1 ) == 0 );
 
-    mbedtls_test_hexify( output_string, output, src_str->len );
-    TEST_ASSERT( strcmp( (char *)output_string,
-                         (char *)expected_output_string ) == 0 );
+    TEST_ASSERT( !memcmp( output, expected_output_str->x,
+                          expected_output_str->len ) );
 
     mbedtls_chacha20_free( &ctx );
 }
diff --git a/tests/suites/test_suite_hkdf.function b/tests/suites/test_suite_hkdf.function
index 967df36..1e41f50 100644
--- a/tests/suites/test_suite_hkdf.function
+++ b/tests/suites/test_suite_hkdf.function
@@ -14,13 +14,6 @@
 {
     int ret;
     unsigned char okm[128] = { '\0' };
-    /*
-     * okm_string and expected_okm_string are the ASCII string representations
-     * of km and expected_okm, so their size should be twice the size of
-     * okm and expected_okm, and an extra null-termination.
-     */
-    unsigned char okm_string[257] = { '\0' };
-    unsigned char expected_okm_string[257] = { '\0' };
 
     const mbedtls_md_info_t *md = mbedtls_md_info_from_type( md_alg );
     TEST_ASSERT( md != NULL );
@@ -31,14 +24,7 @@
                         info->x, info->len, okm, expected_okm->len );
     TEST_ASSERT( ret == 0 );
 
-    /*
-     * Run mbedtls_test_hexify on okm and expected_okm so that it looks nicer
-     * if the assertion fails.
-     */
-    mbedtls_test_hexify( okm_string, okm, expected_okm->len );
-    mbedtls_test_hexify( expected_okm_string,
-                         expected_okm->x, expected_okm->len );
-    TEST_ASSERT( !strcmp( (char *)okm_string, (char *)expected_okm_string ) );
+    TEST_ASSERT( !memcmp( okm, expected_okm->x, expected_okm->len ) );
 }
 /* END_CASE */
 
diff --git a/tests/suites/test_suite_poly1305.function b/tests/suites/test_suite_poly1305.function
index 44617d9..0fc1f60 100644
--- a/tests/suites/test_suite_poly1305.function
+++ b/tests/suites/test_suite_poly1305.function
@@ -9,14 +9,12 @@
  */
 
 /* BEGIN_CASE */
-void mbedtls_poly1305( data_t *key, char *hex_mac_string, data_t *src_str )
+void mbedtls_poly1305( data_t *key, data_t *expected_mac, data_t *src_str )
 {
     unsigned char mac[16]; /* size set by the standard */
-    unsigned char mac_str[33]; /* hex expansion of the above */
     mbedtls_poly1305_context ctx;
 
-    memset( mac_str, 0x00, sizeof( mac_str ) );
-    memset( mac,     0x00, sizeof( mac ) );
+    memset( mac, 0x00, sizeof( mac ) );
 
     /*
      * Test the integrated API
@@ -24,8 +22,7 @@
     TEST_ASSERT( mbedtls_poly1305_mac( key->x, src_str->x,
                                        src_str->len, mac ) == 0 );
 
-    mbedtls_test_hexify( mac_str, mac, 16 );
-    TEST_ASSERT( strcmp( (char *) mac_str, hex_mac_string ) == 0 );
+    TEST_ASSERT( !memcmp( mac, expected_mac->x, expected_mac->len ) );
 
     /*
      * Test the streaming API
@@ -38,8 +35,7 @@
 
     TEST_ASSERT( mbedtls_poly1305_finish( &ctx, mac ) == 0 );
 
-    mbedtls_test_hexify( mac_str, mac, 16 );
-    TEST_ASSERT( strcmp( (char *) mac_str, hex_mac_string ) == 0 );
+    TEST_ASSERT( !memcmp( mac, expected_mac->x, expected_mac->len ) );
 
     /*
      * Test the streaming API again, piecewise
@@ -56,8 +52,7 @@
 
         TEST_ASSERT( mbedtls_poly1305_finish( &ctx, mac ) == 0 );
 
-        mbedtls_test_hexify( mac_str, mac, 16 );
-        TEST_ASSERT( strcmp( (char *) mac_str, hex_mac_string ) == 0 );
+        TEST_ASSERT( !memcmp( mac, expected_mac->x, expected_mac->len ) );
     }
 
     /*
@@ -73,8 +68,7 @@
 
         TEST_ASSERT( mbedtls_poly1305_finish( &ctx, mac ) == 0 );
 
-        mbedtls_test_hexify( mac_str, mac, 16 );
-        TEST_ASSERT( strcmp( (char *) mac_str, hex_mac_string ) == 0 );
+        TEST_ASSERT( !memcmp( mac, expected_mac->x, expected_mac->len ) );
     }
 
     mbedtls_poly1305_free( &ctx );