--- /dev/null
+#include "config.h"
+#include <stdio.h>
+#include <string.h>
+
+/**
+ * crypto/siphash24 - implementation of SipHash-2-4.
+ *
+ * SipHash was designed as a mitigation to hash-flooding DoS
+ * attacks. It is now used in the hash tables implementation of
+ * Python, Ruby, Perl 5, etc.
+ *
+ * SipHash was designed by Jean-Philippe Aumasson and Daniel J. Bernstein.
+ *
+ * License: CC0
+ * Maintainer: Rusty Russell <rusty@rustcorp.com.au>
+ *
+ * Example:
+ * // Dumb example to print siphash of words, and all strung together.
+ * #include <ccan/crypto/siphash24/siphash24.h>
+ * #include <stdio.h>
+ * #include <stdlib.h>
+ * #include <string.h>
+ * #include <inttypes.h>
+ *
+ * int main(int argc, char *argv[])
+ * {
+ * struct siphash_seed seed;
+ * struct siphash24_ctx ctx;
+ * int i;
+ *
+ * if (argc < 3) {
+ * fprintf(stderr, "Need at least seed1 and seed2 arguments");
+ * exit(1);
+ * }
+ *
+ * seed.u.u64[0] = atoi(argv[1]);
+ * seed.u.u64[1] = atoi(argv[2]);
+ * siphash24_init(&ctx, &seed);
+ * for (i = 3; i < argc; i++) {
+ * printf("Hash of '%s' = %"PRIu64,
+ * argv[i], siphash24(&seed, argv[i], strlen(argv[i])));
+ * siphash24_update(&ctx, argv[i], strlen(argv[i]));
+ * }
+ * printf("Hash of concatenated args = %"PRIu64, siphash24_done(&ctx));
+ * return 0;
+ * }
+ */
+int main(int argc, char *argv[])
+{
+ /* Expect exactly one argument */
+ if (argc != 2)
+ return 1;
+
+ if (strcmp(argv[1], "depends") == 0) {
+ printf("ccan/endian\n");
+ return 0;
+ }
+
+ return 1;
+}