diff --git a/tests/suites/test_suite_pkcs5.function b/tests/suites/test_suite_pkcs5.function
index ab53326d4..bb7d419a8 100644
--- a/tests/suites/test_suite_pkcs5.function
+++ b/tests/suites/test_suite_pkcs5.function
@@ -14,7 +14,7 @@ void pbkdf2_hmac( int hash, char *hex_password_string,
 {
     unsigned char pw_str[100];
     unsigned char salt_str[100];
-    unsigned char dst_str[100];
+    unsigned char dst_str[200];
 
     mbedtls_md_context_t ctx;
     const mbedtls_md_info_t *info;
@@ -24,9 +24,9 @@ void pbkdf2_hmac( int hash, char *hex_password_string,
 
     mbedtls_md_init( &ctx );
 
-    memset(pw_str, 0x00, 100);
-    memset(salt_str, 0x00, 100);
-    memset(dst_str, 0x00, 100);
+    memset(pw_str, 0x00, sizeof(pw_str));
+    memset(salt_str, 0x00, sizeof(salt_str));
+    memset(dst_str, 0x00, sizeof(dst_str));
 
     pw_len = unhexify( pw_str, hex_password_string );
     salt_len = unhexify( salt_str, hex_salt_string );