Add libsodium to the tree and build what's needed from source.

git-svn-id: https://www.unprompted.com/svn/projects/tildefriends/trunk@3859 ed5197a5-7fde-0310-b194-c3ffbd925b24

deps/libsodium/test/default/secretbox7.c

@@ -0,0 +1,36 @@
+
+#define TEST_NAME "secretbox7"
+#include "cmptest.h"
+
+static unsigned char k[crypto_secretbox_KEYBYTES];
+static unsigned char n[crypto_secretbox_NONCEBYTES];
+static unsigned char m[10000];
+static unsigned char c[10000];
+static unsigned char m2[10000];
+
+int
+main(void)
+{
+    size_t mlen;
+    size_t i;
+
+    for (mlen = 0; mlen < 1000 && mlen + crypto_secretbox_ZEROBYTES < sizeof m;
+         ++mlen) {
+        crypto_secretbox_keygen(k);
+        randombytes_buf(n, crypto_secretbox_NONCEBYTES);
+        randombytes_buf(m + crypto_secretbox_ZEROBYTES, mlen);
+        crypto_secretbox(c, m, mlen + crypto_secretbox_ZEROBYTES, n, k);
+        if (crypto_secretbox_open(m2, c, mlen + crypto_secretbox_ZEROBYTES, n,
+                                  k) == 0) {
+            for (i = 0; i < mlen + crypto_secretbox_ZEROBYTES; ++i) {
+                if (m2[i] != m[i]) {
+                    printf("bad decryption\n");
+                    break;
+                }
+            }
+        } else {
+            printf("ciphertext fails verification\n");
+        }
+    }
+    return 0;
+}