diff --git a/programs/x509/cert_req.c b/programs/x509/cert_req.c
index dcfc141..9518447 100644
--- a/programs/x509/cert_req.c
+++ b/programs/x509/cert_req.c
@@ -56,6 +56,7 @@
 #include <string.h>
 
 #define DFL_FILENAME            "keyfile.key"
+#define DFL_PASSWORD            NULL
 #define DFL_DEBUG_LEVEL         0
 #define DFL_OUTPUT_FILENAME     "cert.req"
 #define DFL_SUBJECT_NAME        "CN=Cert,O=mbed TLS,C=UK"
@@ -67,6 +68,7 @@
     "\n usage: cert_req param=<>...\n"                  \
     "\n acceptable parameters:\n"                       \
     "    filename=%%s         default: keyfile.key\n"   \
+    "    password=%%s         default: NULL\n"          \
     "    debug_level=%%d      default: 0 (disabled)\n"  \
     "    output_file=%%s      default: cert.req\n"      \
     "    subject_name=%%s     default: CN=Cert,O=mbed TLS,C=UK\n"   \
@@ -101,6 +103,7 @@
 struct options
 {
     const char *filename;       /* filename of the key file             */
+    const char *password;       /* password for the key file            */
     int debug_level;            /* level of debugging                   */
     const char *output_file;    /* where to store the constructed key file  */
     const char *subject_name;   /* subject name for certificate request */
@@ -167,6 +170,7 @@
     }
 
     opt.filename            = DFL_FILENAME;
+    opt.password            = DFL_PASSWORD;
     opt.debug_level         = DFL_DEBUG_LEVEL;
     opt.output_file         = DFL_OUTPUT_FILENAME;
     opt.subject_name        = DFL_SUBJECT_NAME;
@@ -184,6 +188,8 @@
 
         if( strcmp( p, "filename" ) == 0 )
             opt.filename = q;
+        else if( strcmp( p, "password" ) == 0 )
+            opt.password = q;
         else if( strcmp( p, "output_file" ) == 0 )
             opt.output_file = q;
         else if( strcmp( p, "debug_level" ) == 0 )
@@ -347,7 +353,7 @@
     mbedtls_printf( "  . Loading the private key ..." );
     fflush( stdout );
 
-    ret = mbedtls_pk_parse_keyfile( &key, opt.filename, NULL );
+    ret = mbedtls_pk_parse_keyfile( &key, opt.filename, opt.password );
 
     if( ret != 0 )
     {