- djm@cvs.openbsd.org 2004/03/03 09:31:20

[openssh.git] / rsa.c

diff --git a/rsa.c b/rsa.c
index 739f92ce20dc050ae824fabcec441ea3c149c277..66561a4213b5cd3b78c527116b1b80ab4dac99b7 100644 (file)
--- a/rsa.c
+++ b/rsa.c
@@ -60,7 +60,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: rsa.c,v 1.20 2001/01/29 19:47:30 markus Exp $");
+RCSID("$OpenBSD: rsa.c,v 1.24 2001/12/27 18:22:16 markus Exp $");
 
 #include "rsa.h"
 #include "log.h"
@@ -119,3 +119,26 @@ 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);
+}
+