diff --git a/library/error.c b/library/error.c
index 3251af0..ab7bfb8 100644
--- a/library/error.c
+++ b/library/error.c
@@ -866,7 +866,7 @@
     if( use_ret == -(MBEDTLS_ERR_SHA512_HW_ACCEL_FAILED) )
         mbedtls_snprintf( buf, buflen, "SHA512 - SHA-512 hardware accelerator failed" );
     if( use_ret == -(MBEDTLS_ERR_SHA512_BAD_INPUT_DATA) )
-        mbedtls_snprintf( buf, buflen, "SHA512 - Invalid input data" );
+        mbedtls_snprintf( buf, buflen, "SHA512 - SHA-512 input data was malformed" );
 #endif /* MBEDTLS_SHA512_C */
 
 #if defined(MBEDTLS_THREADING_C)