begin crypt

1 files changed, 85 insertions, 0 deletions

diff --git a/crypt.cpp b/crypt.cpp
new file mode 100644
index 0000000..e72bd97
--- /dev/null
+++ b/crypt.cpp
@@ -0,0 +1,85 @@
+/*
+ * crypt.cpp
+ *
+ *
+ */
+
+#include "crypt.h"
+#define DEBUG
+
+/* forward declaration of variables from crypt_args.h */
+extern char *fname;
+extern char *keyfname;
+extern char *outfname;
+
+struct rsakey_t
+{
+    long unsigned e, d, n;
+};
+
+/* parse pubkey xml file */
+struct rsakey_t parse_key(FILE *file)
+{
+    struct rsakey_t key = { 0, 0, 0};
+
+    /* used for line reading */
+    size_t line_sz = 80;
+    char *line = (char *) malloc(sizeof(char) * line_sz);
+
+    while (getline(&line, &line_sz, file) != -1)
+    {
+        sscanf(line, "\t<dvalue>%lu</dvalue>\n", &key.d);
+        sscanf(line, "\t<evalue>%lu</evalue>\n", &key.e);
+        sscanf(line, "\t<nvalue>%lu</nvalue>\n", &key.n);
+    }
+
+    free(line);
+    return key;
+}
+
+int main(int argc, char **argv)
+{
+    if (crypt_args(argc, argv) == 0)
+        cout << "read arguments successfully" << endl;
+
+#ifdef DEBUG
+    printf("debug: filename        = \"%s\"\n"
+           "       key filename    = \"%s\"\n"
+           "       result filename = \"%s\"\n",
+           fname, keyfname, outfname);
+#endif
+
+    /* open file for reading and writing */
+    FILE *fname_fl =  fopen(fname, "r");
+    FILE *keyfname_fl = fopen(keyfname, "r");
+    FILE *outfname_fl = fopen(outfname, "w");
+    if (fname_fl == NULL || keyfname_fl == NULL || outfname_fl == NULL)
+    {
+        perror("fopen");
+        exit(EXIT_FAILURE);
+    }
+
+    int mode = -1;
+    struct rsakey_t key = parse_key(keyfname_fl);
+
+    if (key.d == 0 && key.e && key.n)
+    {
+        cout << "public key (" << key.e << ", " << key.n
+             << ") detected, will perform encryption" << endl;
+        mode = 0;
+    }
+    else if (key.e == 0 && key.d && key.n)
+    {
+        cout << "private key (" << key.d << ", " << key.n
+             << ") detected, will perform decryption" << endl;
+        mode = 1;
+    }
+    else
+    {
+        fprintf(stderr, "could not determine mode (encryption/decryption)\n");
+        exit(EXIT_FAILURE);
+    }
+
+    return 0;
+}
+