Initial data commit

Task/RSA-code/C/rsa-code.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <gmp.h>
+
+int main(void)
+{
+    mpz_t n, d, e, pt, ct;
+
+    mpz_init(pt);
+    mpz_init(ct);
+    mpz_init_set_str(n, "9516311845790656153499716760847001433441357", 10);
+    mpz_init_set_str(e, "65537", 10);
+    mpz_init_set_str(d, "5617843187844953170308463622230283376298685", 10);
+
+    const char *plaintext = "Rossetta Code";
+    mpz_import(pt, strlen(plaintext), 1, 1, 0, 0, plaintext);
+
+    if (mpz_cmp(pt, n) > 0)
+        abort();
+
+    mpz_powm(ct, pt, e, n);
+    gmp_printf("Encoded:   %Zd\n", ct);
+
+    mpz_powm(pt, ct, d, n);
+    gmp_printf("Decoded:   %Zd\n", pt);
+
+    char buffer[64];
+    mpz_export(buffer, NULL, 1, 1, 0, 0, pt);
+    printf("As String: %s\n", buffer);
+
+    mpz_clears(pt, ct, n, e, d, NULL);
+    return 0;
+}