diff --git a/include/mbedtls/rsa.h b/include/mbedtls/rsa.h
index 6eea5af..31a8db7 100644
--- a/include/mbedtls/rsa.h
+++ b/include/mbedtls/rsa.h
@@ -404,6 +404,16 @@
 size_t mbedtls_rsa_get_len( const mbedtls_rsa_context *ctx );
 
 /**
+ * \brief          This function retrieves the length of the RSA modulus in bits.
+ *
+ * \param ctx      The initialized RSA context.
+ *
+ * \return         The length of the RSA modulus in bits.
+ *
+ */
+size_t mbedtls_rsa_get_bitlen( const mbedtls_rsa_context *ctx );
+
+/**
  * \brief          This function generates an RSA keypair.
  *
  * \note           mbedtls_rsa_init() must be called before this function,