Add doxygen for the platform-functions
diff --git a/include/mbedtls/platform_util.h b/include/mbedtls/platform_util.h
index 92283ad..a1ca785 100644
--- a/include/mbedtls/platform_util.h
+++ b/include/mbedtls/platform_util.h
@@ -164,12 +164,70 @@
*/
void mbedtls_platform_zeroize( void *buf, size_t len );
+/**
+ * \brief Secure memset
+ *
+ * This function is meant to provide a more secure way to do
+ * memset. It starts by initialising the given memory area
+ * from random tail location with random data. After tail is
+ * initialised, the remaining head of the buffer is initialised
+ * with random data. After initialisation, the original memset
+ * is performed
+ *
+ * \param ptr Buffer to be set.
+ * \param value Value to be used when setting the buffer.
+ * \param num The length of the buffer in bytes.
+ *
+ */
void mbedtls_platform_memset( void *ptr, int value, size_t num );
+/**
+ * \brief Secure memcpy
+ *
+ * This function is meant to provide a more secure way to do
+ * memcpy. It starts by initialising the given memory area
+ * with random data. After initialisation, the original memcpy
+ * is performed by starting first copying from random tail
+ * location of the buffer. After tail has been copied, the
+ * remaining head is copied as well.
+ *
+ * \param dst Destination buffer where the data is being copied to.
+ * \param src Source buffer where the data is being copied from.
+ * \param num The length of the buffers in bytes.
+ *
+ */
void mbedtls_platform_memcpy( void *dst, const void *src, size_t num );
+/**
+ * \brief Secure memcmp
+ *
+ * This function is meant to provide a more secure way to do
+ * memcmp. It starts comparing from a random offset and goes
+ * through the tail part of buffers first byte by byte. After
+ * that it starts going through the head part of buffer. In the
+ * end, the number of equal bytes is compared to the length of the
+ * buffers, thus making the function a fixed time memcmp.
+ *
+ * \param buf1 First buffer to compare.
+ * \param buf2 Second buffer to compare against.
+ * \param num The length of the buffers in bytes.
+ *
+ */
int mbedtls_platform_memcmp( const void *buf1, const void *buf2, size_t num );
+/**
+ * \brief A global RNG-function
+ *
+ * This function is meant to provide a global RNG to be used
+ * throughout Mbed TLS for hardening the library. It is used
+ * for generating a random delay, random data or random offset
+ * for utility functions. It is not meant to be a
+ * cryptographically secure RNG, but provide an RNG for utility
+ * functions.
+ *
+ * \param num Max-value for the generated random number.
+ *
+ */
size_t mbedtls_platform_random_in_range( size_t num );
#if defined(MBEDTLS_HAVE_TIME_DATE)