Implement fixed-window exponentiation to mitigate hyper-threading

[openssl.git] / crypto / dsa / dsa.h

diff --git a/crypto/dsa/dsa.h b/crypto/dsa/dsa.h
index c7ba059f251f48535ec05806fb2727bedf1d18da..b12db98b1303a60fc62284433747c9d4ae3f72ca 100644 (file)
--- a/crypto/dsa/dsa.h
+++ b/crypto/dsa/dsa.h
@@ -85,6 +85,13 @@
 #endif
 
 #define DSA_FLAG_CACHE_MONT_P  0x01
+#define DSA_FLAG_NO_EXP_CONSTTIME       0x02 /* new with 0.9.7h; the built-in DSA
+                                              * implementation now uses constant time
+                                              * modular exponentiation for secret exponents
+                                              * by default. This flag causes the
+                                              * faster variable sliding window method to
+                                              * be used for all exponents.
+                                              */
 
 #ifdef  __cplusplus
 extern "C" {