Extend scope of ERR_RSA_UNSUPPORTED_OPERATION error code
diff --git a/include/mbedtls/rsa.h b/include/mbedtls/rsa.h
index 2ffb7ab..562395f 100644
--- a/include/mbedtls/rsa.h
+++ b/include/mbedtls/rsa.h
@@ -48,7 +48,8 @@
 #define MBEDTLS_ERR_RSA_VERIFY_FAILED                     -0x4380  /**< The PKCS#1 verification failed. */
 #define MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE                  -0x4400  /**< The output buffer for decryption is not large enough. */
 #define MBEDTLS_ERR_RSA_RNG_FAILED                        -0x4480  /**< The random generator failed to generate non-zeros. */
-#define MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION             -0x4500  /**< The implementation doesn't provide the requested operation. */
+#define MBEDTLS_ERR_RSA_UNSUPPORTED_OPERATION             -0x4500  /**< The implementation doesn't offer the requested operation,
+                                                                        e.g. because of security violations or lack of functionality */
 
 /*
  * RSA constants
diff --git a/library/error.c b/library/error.c
index 0217767..66e6aa2 100644
--- a/library/error.c
+++ b/library/error.c
@@ -332,7 +332,8 @@
         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" );
+            mbedtls_snprintf( buf, buflen, "RSA - The implementation doesn't offer the requested operation, "\
+                                            "e.g. because of security violations or lack of functionality" );
 #endif /* MBEDTLS_RSA_C */
 
 #if defined(MBEDTLS_SSL_TLS_C)