Initial implementation of ChaCha20
diff --git a/library/error.c b/library/error.c
index 222d85b..2aaf359 100644
--- a/library/error.c
+++ b/library/error.c
@@ -69,6 +69,10 @@
 #include "mbedtls/ccm.h"
 #endif
 
+#if defined(MBEDTLS_CHACHA20_C)
+#include "mbedtls/chacha20.h"
+#endif
+
 #if defined(MBEDTLS_CIPHER_C)
 #include "mbedtls/cipher.h"
 #endif
@@ -653,6 +657,11 @@
         mbedtls_snprintf( buf, buflen, "CCM - CCM hardware accelerator failed" );
 #endif /* MBEDTLS_CCM_C */
 
+#if defined(MBEDTLS_CHACHA20_C)
+    if( use_ret == -(MBEDTLS_ERR_CHACHA20_BAD_INPUT_DATA) )
+        mbedtls_snprintf( buf, buflen, "CHACHA20 - Invalid input parameter(s)" );
+#endif /* MBEDTLS_CHACHA20_C */
+
 #if defined(MBEDTLS_CMAC_C)
     if( use_ret == -(MBEDTLS_ERR_CMAC_HW_ACCEL_FAILED) )
         mbedtls_snprintf( buf, buflen, "CMAC - CMAC hardware accelerator failed" );