diff --git a/library/error.c b/library/error.c
index db42381..0217767 100644
--- a/library/error.c
+++ b/library/error.c
@@ -331,6 +331,8 @@
             mbedtls_snprintf( buf, buflen, "RSA - The output buffer for decryption is not large enough" );
         if( use_ret == -(MBEDTLS_ERR_RSA_RNG_FAILED) )
             mbedtls_snprintf( buf, buflen, "RSA - The random generator failed to generate non-zeros" );
+        if( use_ret == -(MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION) )
+            mbedtls_snprintf( buf, buflen, "RSA - The implementation doesn't provide the requested operation" );
 #endif /* MBEDTLS_RSA_C */
 
 #if defined(MBEDTLS_SSL_TLS_C)