diff --git a/include/polarssl/x509.h b/include/polarssl/x509.h
index 0dece06..cd01539 100644
--- a/include/polarssl/x509.h
+++ b/include/polarssl/x509.h
@@ -82,17 +82,21 @@
  * \name X509 Verify codes
  * \{
  */
+/* Reminder: update x509_crt_verify_strings[] in library/x509_crt.c */
 #define BADCERT_EXPIRED             0x01  /**< The certificate validity has expired. */
 #define BADCERT_REVOKED             0x02  /**< The certificate has been revoked (is on a CRL). */
 #define BADCERT_CN_MISMATCH         0x04  /**< The certificate Common Name (CN) does not match with the expected CN. */
 #define BADCERT_NOT_TRUSTED         0x08  /**< The certificate is not correctly signed by the trusted CA. */
-#define BADCRL_NOT_TRUSTED          0x10  /**< CRL is not correctly signed by the trusted CA. */
-#define BADCRL_EXPIRED              0x20  /**< CRL is expired. */
+#define BADCRL_NOT_TRUSTED          0x10  /**< The CRL is not correctly signed by the trusted CA. */
+#define BADCRL_EXPIRED              0x20  /**< The CRL is expired. */
 #define BADCERT_MISSING             0x40  /**< Certificate was missing. */
 #define BADCERT_SKIP_VERIFY         0x80  /**< Certificate verification was skipped. */
 #define BADCERT_OTHER             0x0100  /**< Other reason (can be used by verify callback) */
 #define BADCERT_FUTURE            0x0200  /**< The certificate validity starts in the future. */
 #define BADCRL_FUTURE             0x0400  /**< The CRL is from the future */
+#define BADCERT_KEY_USAGE         0x0800  /**< Usage does not match the keyUsage extension. */
+#define BADCERT_EXT_KEY_USAGE     0x1000  /**< Usage does not match the extendedKeyUsage extension. */
+#define BADCERT_NS_CERT_TYPE      0x2000  /**< Usage does not match the nsCertType extension. */
 /* \} name */
 /* \} addtogroup x509_module */
 
diff --git a/include/polarssl/x509_crt.h b/include/polarssl/x509_crt.h
index fe27007..24f7c7a 100644
--- a/include/polarssl/x509_crt.h
+++ b/include/polarssl/x509_crt.h
@@ -203,6 +203,21 @@
                    const x509_crt *crt );
 
 /**
+ * \brief          Returns an informational string about the
+ *                 verification status of a certificate.
+ *
+ * \param buf      Buffer to write to
+ * \param size     Maximum size of buffer
+ * \param prefix   A line prefix
+ * \param flags    Verification flags created by x509_crt_verify()
+ *
+ * \return         The amount of data written to the buffer, or -1 in
+ *                 case of an error.
+ */
+int x509_crt_verify_info( char *buf, size_t size, const char *prefix,
+                          int flags );
+
+/**
  * \brief          Verify the certificate signature
  *
  *                 The verify callback is a user-supplied callback that
@@ -219,6 +234,9 @@
  *                 are also returned to the application. The function should
  *                 return 0 for anything but a fatal error.
  *
+ * \note           In case verification failed, the results can be displayed
+ *                 using \c x509_crt_verify_info()
+ *
  * \param crt      a certificate to be verified
  * \param trust_ca the trusted CA chain
  * \param ca_crl   the CRL chain for trusted CA's
@@ -229,12 +247,8 @@
  * \param p_vrfy   verification parameter
  *
  * \return         0 if successful or POLARSSL_ERR_X509_SIG_VERIFY_FAILED,
- *                 in which case *flags will have one or more of
- *                 the following values set:
- *                      BADCERT_EXPIRED --
- *                      BADCERT_REVOKED --
- *                      BADCERT_CN_MISMATCH --
- *                      BADCERT_NOT_TRUSTED
+ *                 in which case *flags will have one or more BADCERT_XXX or
+ *                 BADCRL_XXX flags set,
  *                 or another error in case of a fatal error encountered
  *                 during the verification process.
  */