do more work

1 files changed, 48 insertions, 2 deletions

diff --git a/keygen.cpp b/keygen.cpp
index 560d45b..24aa12a 100644
--- a/keygen.cpp
+++ b/keygen.cpp
@@ -6,6 +6,7 @@
 
 #include "keygen.h"
 #include "miller_rabin.h"
+#define DEBUG
 
 /* forward declaration of variables from keygen_args.h */
 extern char *pubkey;
@@ -60,6 +61,12 @@ int main(int argc, char **argv)
 
     /* n = p * q */
     unsigned long n = prime_p * prime_q;
+    if (n <= 127)
+    {
+        fprintf(stderr, "p * q needs to be bigger than 127\n");
+        exit(EXIT_FAILURE);
+    }
+
     /* phi = (p-1)(q-1) */
     unsigned long phi = (prime_p-1) * (prime_q-1);
 
@@ -67,6 +74,7 @@ int main(int argc, char **argv)
     unsigned long e;
     /* find e, 1 < e < phi, such that gcd(e, phi) = 1 */
     int i;
+    fprintf(stdout, "computing e... ");
     for (i = 0; i < 4; i++)
     {
         e = fermat_primes[i];
@@ -78,6 +86,19 @@ int main(int argc, char **argv)
         fprintf(stderr, "error, could not find e\n");
         exit(EXIT_FAILURE);
     }
+    fprintf(stdout, "done\n");
+
+    /* find d */
+    unsigned long d = 1;
+    fprintf(stdout, "computing d... ");
+    while (1)
+    {
+        if ( (e*d - 1) / phi )
+            break;
+        else
+            d++;
+    }
+    fprintf(stdout, "done\n");
 
 #ifdef DEBUG
     fprintf(stdout, "debug: pubkey = \"%s\"\n"
@@ -86,10 +107,35 @@ int main(int argc, char **argv)
                     "       q      = \"%ld\"\n"
                     "       n      = \"%lu\"\n"
                     "       phi    = \"%lu\"\n"
-                    "       e      = \"%lu\"\n",
-            pubkey, prikey, prime_p, prime_q, n, phi, e);
+                    "       e      = \"%lu\"\n"
+                    "       d      = \"%lu\"\n",
+            pubkey, prikey, prime_p, prime_q, n, phi, e, d);
 #endif
 
+    /* save to xml files */
+    FILE *public_key =  fopen(pubkey, "w");
+    FILE *private_key = fopen(prikey, "w");
+    if (public_key == NULL || private_key == NULL)
+    {
+        perror("fopen");
+        exit(EXIT_FAILURE);
+    }
+
+    fprintf(public_key, "<rsakey>\n");
+    fprintf(public_key, "\t<evalue>%lu</evalue>\n", e);
+    fprintf(public_key, "\t<nvalue>%lu</nvalue>\n", n);
+    fprintf(public_key, "</rsakey>\n");
+    fprintf(stdout, "wrote \"%s\" file\n", pubkey);
+
+    fprintf(private_key, "<rsakey>\n");
+    fprintf(private_key, "\t<dvalue>%lu</dvalue>\n", d);
+    fprintf(private_key, "\t<nvalue>%lu</nvalue>\n", n);
+    fprintf(private_key, "</rsakey>\n");
+    fprintf(stdout, "wrote \"%s\" file\n", prikey);
+
+    fclose(public_key);
+    fclose(private_key);
+
     return 0;
 }