- deraadt@cvs.openbsd.org 2006/03/19 18:51:18

[openssh.git] / rsa.c

diff --git a/rsa.c b/rsa.c
index 626553149528565a04d76bc9120c7fee88b4f3cf..507b73c9c5496cb14d806ddc66530d51afabb4d0 100644 (file)
--- a/rsa.c
+++ b/rsa.c
@@ -60,7 +60,6 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: rsa.c,v 1.21 2001/02/04 15:32:24 stevesk Exp $");
 
 #include "rsa.h"
 #include "log.h"
@@ -119,3 +118,26 @@ rsa_private_decrypt(BIGNUM *out, BIGNUM *in, RSA *key)
        xfree(inbuf);
        return len;
 }
+
+/* calculate p-1 and q-1 */
+void
+rsa_generate_additional_parameters(RSA *rsa)
+{
+       BIGNUM *aux;
+       BN_CTX *ctx;
+
+       if ((aux = BN_new()) == NULL)
+               fatal("rsa_generate_additional_parameters: BN_new failed");
+       if ((ctx = BN_CTX_new()) == NULL)
+               fatal("rsa_generate_additional_parameters: BN_CTX_new failed");
+
+       BN_sub(aux, rsa->q, BN_value_one());
+       BN_mod(rsa->dmq1, rsa->d, aux, ctx);
+
+       BN_sub(aux, rsa->p, BN_value_one());
+       BN_mod(rsa->dmp1, rsa->d, aux, ctx);
+
+       BN_clear_free(aux);
+       BN_CTX_free(ctx);
+}
+