nostril

nostril.c (26094B)

---

 
 #include <stdio.h>
 #include <time.h>
 #include <stdlib.h>
 #include <assert.h>
 #include <errno.h>
 #include <inttypes.h>
 #include <unistd.h>
 
 #include "secp256k1.h"
 #include "secp256k1_ecdh.h"
 #include "secp256k1_schnorrsig.h"
 
 #include "cursor.h"
 #include "hex.h"
 #include "nip44.h"
 #include "base64.h"
 #include "aes.h"
 #include "sha256.h"
 #include "random.h"
 #include "proof.h"
 
 #define VERSION "0.1.3"
 
 #define MAX_TAGS 1024
 #define MAX_TAG_ELEMS 64
 
 #define HAS_CREATED_AT (1<<1)
 #define HAS_KIND (1<<2)
 #define HAS_ENVELOPE (1<<3)
 #define HAS_ENCRYPT (1<<4)
 #define HAS_DIFFICULTY (1<<5)
 #define HAS_MINE_PUBKEY (1<<6)
 #define HAS_GIFTWRAP (1<<7)
 
 struct key {
 	secp256k1_keypair pair;
 	unsigned char secret[32];
 	unsigned char pubkey[32];
 };
 
 struct args {
 	unsigned int flags;
 	int kind;
 	int difficulty;
 
 	unsigned char encrypt_to[32];
 	const char *sec;
 	const char *tags;
 	const char *content;
 
 	uint64_t created_at;
 };
 
 struct nostr_tag {
 	const char *strs[MAX_TAG_ELEMS];
 	int num_elems;
 };
 
 struct nostr_event {
 	unsigned char id[32];
 	unsigned char pubkey[32];
 	unsigned char sig[64];
 
 	const char *content;
 
 	uint64_t created_at;
 	int kind;
 
 	const char *explicit_tags;
 
 	struct nostr_tag tags[MAX_TAGS];
 	int num_tags;
 };
 
 void usage()
 {
 	printf("usage: nostril [OPTIONS]\n");
 	printf("\n");
 	printf("  OPTIONS\n");
 	printf("\n");
 	printf("      --content <string>              the content of the note\n");
 	printf("      --dm <hex pubkey>               make an encrypted dm to said pubkey. sets kind and tags.\n");
 	printf("      --giftwrap-to <hex pubkey>      make an encrypted giftwrap to said pubkey.\n");
 	printf("      --envelope                      wrap in [\"EVENT\",...] for easy relaying\n");
 	printf("      --kind <number>                 set kind\n");
 	printf("      --created-at <unix timestamp>   set a specific created-at time\n");
 	printf("      --sec <hex seckey>              set the secret key for signing, otherwise one will be randomly generated\n");
 	printf("      --pow <difficulty>              number of leading 0 bits of the id to mine\n");
 	printf("      --mine-pubkey                   mine a pubkey instead of id\n");
 	printf("      --tag <key> <value>             add a tag\n");
 	printf("      --tagn <N> <tags * N...>        add a tag with N elements. eg: `--tagn 3 a b c`, `--tagn 0`\n");
 	printf("      -e <event_id>                   shorthand for --tag e <event_id>\n");
 	printf("      -p <pubkey>                     shorthand for --tag p <pubkey>\n");
 	printf("      -t <hashtag>                    shorthand for --tag t <hashtag>\n");
 	exit(1);
 }
 
 
 inline static int cursor_push_escaped_char(struct cursor *cur, char c)
 {
         switch (c) {
         case '"':  return cursor_push_str(cur, "\\\"");
         case '\\': return cursor_push_str(cur, "\\\\");
         case '\b': return cursor_push_str(cur, "\\b");
         case '\f': return cursor_push_str(cur, "\\f");
         case '\n': return cursor_push_str(cur, "\\n");
         case '\r': return cursor_push_str(cur, "\\r");
         case '\t': return cursor_push_str(cur, "\\t");
         // TODO: \u hex hex hex hex
         }
         return cursor_push_byte(cur, c);
 }
 
 static int cursor_push_jsonstr(struct cursor *cur, const char *str)
 {
 	int i;
         int len;
 
 	len = strlen(str);
 
         if (!cursor_push_byte(cur, '"'))
                 return 0;
 
         for (i = 0; i < len; i++) {
                 if (!cursor_push_escaped_char(cur, str[i]))
                         return 0;
         }
 
         if (!cursor_push_byte(cur, '"'))
                 return 0;
 
         return 1;
 }
 
 static int cursor_push_tag(struct cursor *cur, struct nostr_tag *tag)
 {
         int i;
 
         if (!cursor_push_byte(cur, '['))
                 return 0;
 
         for (i = 0; i < tag->num_elems; i++) {
                 if (!cursor_push_jsonstr(cur, tag->strs[i]))
                         return 0;
                 if (i != tag->num_elems-1) {
                         if (!cursor_push_byte(cur, ','))
                                 return 0;
                 }
         }
 
         return cursor_push_byte(cur, ']');
 }
 
 static int cursor_push_tags(struct cursor *cur, struct nostr_event *ev)
 {
         int i;
 
 	if (ev->explicit_tags) {
 		return cursor_push_str(cur, ev->explicit_tags);
 	}
 
         if (!cursor_push_byte(cur, '['))
                 return 0;
 
         for (i = 0; i < ev->num_tags; i++) {
                 if (!cursor_push_tag(cur, &ev->tags[i]))
                         return 0;
                 if (i != ev->num_tags-1) {
                         if (!cursor_push_str(cur, ","))
                                 return 0;
                 }
         }
 
         return cursor_push_byte(cur, ']');
 }
 
 
 int event_commitment(struct nostr_event *ev, unsigned char *buf, int buflen)
 {
 	char timebuf[16] = {0};
 	char kindbuf[16] = {0};
 	char pubkey[65];
 	struct cursor cur;
 	int ok;
 
 	ok = hex_encode(ev->pubkey, sizeof(ev->pubkey), pubkey, sizeof(pubkey));
 	assert(ok);
 
 	make_cursor(buf, buf + buflen, &cur);
 
 	snprintf(timebuf, sizeof(timebuf), "%" PRIu64 "", ev->created_at);
         snprintf(kindbuf, sizeof(kindbuf), "%d", ev->kind);
 
 	ok =
                 cursor_push_str(&cur, "[0,\"") &&
                 cursor_push_str(&cur, pubkey) &&
                 cursor_push_str(&cur, "\",") &&
                 cursor_push_str(&cur, timebuf) &&
                 cursor_push_str(&cur, ",") &&
                 cursor_push_str(&cur, kindbuf) &&
                 cursor_push_str(&cur, ",") &&
                 cursor_push_tags(&cur, ev) &&
                 cursor_push_str(&cur, ",") &&
                 cursor_push_jsonstr(&cur, ev->content) &&
                 cursor_push_str(&cur, "]");
 
 	if (!ok)
 		return 0;
 
 	return cur.p - cur.start;
 }
 
 static int make_sig(secp256k1_context *ctx, struct key *key,
 		unsigned char *id, unsigned char sig[64])
 {
 	unsigned char aux[32];
 
 	if (!fill_random(aux, sizeof(aux))) {
 		return 0;
 	}
 
 	return secp256k1_schnorrsig_sign32(ctx, sig, id, &key->pair, aux);
 }
 
 static int create_key(secp256k1_context *ctx, struct key *key)
 {
 	secp256k1_xonly_pubkey pubkey;
 
 	/* Try to create a keypair with a valid context, it should only
 	 * fail if the secret key is zero or out of range. */
 	if (!secp256k1_keypair_create(ctx, &key->pair, key->secret))
 		return 0;
 
 	if (!secp256k1_keypair_xonly_pub(ctx, &pubkey, NULL, &key->pair))
 		return 0;
 
 	/* Serialize the public key. Should always return 1 for a valid public key. */
 	return secp256k1_xonly_pubkey_serialize(ctx, key->pubkey, &pubkey);
 }
 
 static int decode_key(secp256k1_context *ctx, const char *secstr, struct key *key)
 {
 	if (!hex_decode(secstr, strlen(secstr), key->secret, 32)) {
 		fprintf(stderr, "could not hex decode secret key\n");
 		return 0;
 	}
 
 	return create_key(ctx, key);
 }
 
 static inline void xor_mix(unsigned char *dest, const unsigned char *a, const unsigned char *b, int size)
 {
     int i;
     for (i = 0; i < size; i++)
         dest[i] = a[i] ^ b[i];
 }
 
 static int generate_key(secp256k1_context *ctx, struct key *key, int *difficulty)
 {
 	uint64_t attempts = 0;
 	uint64_t duration;
 	int bits;
 	double pers;
 	struct timespec t1, t2;
 
 	/* If the secret key is zero or out of range (bigger than secp256k1's
 	 * order), we try to sample a new key. Note that the probability of this
 	 * happening is negligible. */
 	if (!fill_random(key->secret, sizeof(key->secret))) {
 		return 0;
 	}
 
 	if (difficulty == NULL) {
 		return create_key(ctx, key);
 	}
 
 	clock_gettime(CLOCK_MONOTONIC, &t1);
 	while (1) {
 		if (!create_key(ctx, key))
 			return 0;
 
 		attempts++;
 
 		if ((bits = count_leading_zero_bits(key->pubkey)) >= *difficulty) {
 			clock_gettime(CLOCK_MONOTONIC, &t2);
 			duration = ((t2.tv_sec - t1.tv_sec) * 1e9L + (t2.tv_nsec - t1.tv_nsec)) / 1e6L;
 			pers = (double)attempts / (double)duration;
 			fprintf(stderr, "mined pubkey with %d bits after %" PRIu64 " attempts, %" PRId64 " ms, %f attempts per ms\n", bits, attempts, duration, pers);
 			return 1;
 		}
 
 		// NOTE: Get a new secret key by xor mixing the current secret
 		// key with the current public key. This doesn't rely on the
 		// system's crypto number generator so it should be fast. There
 		// shouldn't be any secret key entropy issues since we got a
 		// good source of entropy from the first fill_random call at
 		// the start of the function.
 		xor_mix(key->secret, key->secret, key->pubkey, 32);
 	}
 }
 
 
 static int init_secp_context(secp256k1_context **ctx)
 {
 	unsigned char randomize[32];
 
 	*ctx = secp256k1_context_create(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY);
 	if (!fill_random(randomize, sizeof(randomize))) {
 		return 0;
 	}
 
 	/* Randomizing the context is recommended to protect against side-channel
 	 * leakage See `secp256k1_context_randomize` in secp256k1.h for more
 	 * information about it. This should never fail. */
 	return secp256k1_context_randomize(*ctx, randomize);
 }
 
 static int generate_event_id(struct nostr_event *ev,
 			     unsigned char *buf, size_t bufsize)
 {
 	int len;
 
 	if (!(len = event_commitment(ev, buf, bufsize))) {
 		fprintf(stderr, "event_commitment: buffer out of space\n");
 		return 0;
 	}
 
 	//fprintf(stderr, "commitment: '%.*s'\n", len, buf);
 
 	sha256((struct sha256*)ev->id, buf, len);
 
 	return 1;
 }
 
 static int sign_event(secp256k1_context *ctx, struct key *key, struct nostr_event *ev)
 {
 	if (!make_sig(ctx, key, ev->id, ev->sig))
 		return 0;
 
 	return 1;
 }
 
 static int all_zeros(unsigned char *buf, size_t bufsize)
 {
 	int i;
 
 	for (i = 0; i < bufsize; i++) {
 		if (buf[i] != 0)
 			return 0;
 	}
 
 	return 1;
 }
 
 static int event_to_json(struct cursor *c, struct nostr_event *ev, int envelope)
 {
 	char shortbuf[128];
 
 	if (envelope) {
 		if (!cursor_push_str(c, "[\"EVENT\","))
 			return 0;
 	}
 
 	if (!cursor_push_str(c, "{\"id\":\"")) return 0;
 	if (!cursor_push_hex(c, ev->id, 32)) return 0;
 	if (!cursor_push_str(c, "\",")) return 0;
 	if (!cursor_push_str(c, "\"pubkey\":\"")) return 0;
 	if (!cursor_push_hex(c, ev->pubkey, 32)) return 0;
 	if (!cursor_push_str(c, "\",")) return 0;
 	sprintf(shortbuf, "\"created_at\":%" PRIu64 ",", ev->created_at);
 	if (!cursor_push_str(c, shortbuf)) return 0;
 	sprintf(shortbuf, "\"kind\":%d,", ev->kind);
 	if (!cursor_push_str(c, shortbuf)) return 0;
 	if (!cursor_push_str(c, "\"tags\":")) return 0;
 	if (!cursor_push_tags(c, ev)) return 0;
 	if (!cursor_push_str(c, ",\"content\":")) return 0;
 	if (!cursor_push_jsonstr(c, ev->content)) return 0;
 
 	if (!all_zeros(ev->sig, 64)) {
 		if (!cursor_push_str(c,  ",\"sig\":\"")) return 0;
 		if (!cursor_push_hex(c,  ev->sig, 64)) return 0;
 		if (!cursor_push_byte(c, '"')) return 0;
 	}
 
 	if (!cursor_push_str(c, "}")) return 0;
 
 	if (envelope) {
 		return cursor_push_c_str(c, "]");
 	} else {
 		return cursor_push_byte(c, 0);
 	}
 }
 
 static int print_event(struct nostr_event *ev, int envelope,
 		       unsigned char *buf, size_t bufsize)
 {
 	struct cursor cur;
 	make_cursor(buf, buf+bufsize, &cur);
 
 	if (!event_to_json(&cur, ev, envelope))
 		return 0;
 
 	printf("%s\n", buf);
 
 	return 1;
 }
 
 static void make_event_from_args(struct nostr_event *ev, struct args *args)
 {
 	ev->created_at = args->flags & HAS_CREATED_AT? args->created_at : time(NULL);
 	ev->content = args->content;
 	ev->kind = args->flags & HAS_KIND ? args->kind : 1;
 }
 
 static int parse_num(const char *arg, uint64_t *t)
 {
 	*t = strtol(arg, NULL, 10);
 	return errno != EINVAL;
 }
 
 static int nostr_add_tag_n(struct nostr_event *ev, const char **ts, int n_ts)
 {
 	int i;
 	struct nostr_tag *tag;
 
 	if (ev->num_tags + 1 > MAX_TAGS)
 		return 0;
 
 	tag = &ev->tags[ev->num_tags++];
 
 	tag->num_elems = n_ts;
 	for (i = 0; i < n_ts; i++) {
 		tag->strs[i] = ts[i];
 	}
 
 	return 1;
 }
 
 static int nostr_add_tag(struct nostr_event *ev, const char *t1, const char *t2)
 {
 	const char *ts[] = {t1, t2};
 	return nostr_add_tag_n(ev, ts, 2);
 }
 
 static int nostr_add_arg_tags(struct nostr_event *ev, int *argc, const char **argv[])
 {
 	struct nostr_tag *tag;
 	int i;
 	uint64_t n;
 	uint16_t small_n;
 	const char *arg;
 
 	if (*argc == 0) {
 		fprintf(stderr, "expected more arguments to --tagn\n");
 		return 0;
 	}
 
 	arg = *(*argv)++; (*argc)--;
 
 	if (!parse_num(arg, &n)) {
 		fprintf(stderr, "expected X to be a number in --tagn X ...\n");
 		return 0;
 	}
 
 	if (n > MAX_TAG_ELEMS) {
 		fprintf(stderr, "too many --tagn arguments (%"PRIu64" > %d)\n", n, MAX_TAG_ELEMS);
 		return 0;
 	}
 
 	small_n = (uint16_t)n;
 
 	if (ev->num_tags + small_n > MAX_TAGS) {
 		fprintf(stderr, "too many tags (%d + %d > %d)\n", ev->num_tags, small_n, MAX_TAG_ELEMS);
 		return 0;
 	}
 
 	tag = &ev->tags[ev->num_tags++];
 	tag->num_elems = 0;
 
 	for (i = 0; i < small_n; i++) {
 		if (*argc <= 0) {
 			fprintf(stderr, "expected %d tags: --tagn %d ..., got %d args\n", small_n, small_n, i);
 			return 0;
 		}
 		arg = *(*argv)++; (*argc)--;
 		//fprintf(stderr, "got arg '%s' argc(%d)\n", arg, *argc);
 		tag->strs[i] = arg;
 		tag->num_elems++;
 	}
 
 	return 1;
 }
 
 static int parse_args(int argc, const char *argv[], struct args *args, struct nostr_event *ev)
 {
 	const char *arg, *arg2;
 	uint64_t n;
 	int has_added_tags = 0;
 
 	argv++; argc--;
 	for (; argc; ) {
 		arg = *argv++; argc--;
 
 		if (!strcmp(arg, "--help")) {
 			usage();
 		}
 
 		if (!argc) {
 			fprintf(stderr, "expected argument: '%s'\n", arg);
 			return 0;
 		}
 
 		if (!strcmp(arg, "--sec")) {
 			args->sec = *argv++; argc--;
 		} else if (!strcmp(arg, "--created-at")) {
 			arg = *argv++; argc--;
 			if (!parse_num(arg, &args->created_at)) {
 				fprintf(stderr, "created-at must be a unix timestamp\n");
 				return 0;
 			} else {
 				args->flags |= HAS_CREATED_AT;
 			}
 		} else if (!strcmp(arg, "--kind")) {
 			arg = *argv++; argc--;
 			if (!parse_num(arg, &n)) {
 				fprintf(stderr, "kind should be a number, got '%s'\n", arg);
 				return 0;
 			}
 			args->kind = (int)n;
 			args->flags |= HAS_KIND;
 		} else if (!strcmp(arg, "--envelope")) {
 			args->flags |= HAS_ENVELOPE;
 		} else if (!strcmp(arg, "--tags")) {
 			if (args->flags & HAS_DIFFICULTY) {
 				fprintf(stderr, "can't combine --tags and --pow (yet)\n");
 				return 0;
 			}
 			if (has_added_tags) {
 				fprintf(stderr, "can't combine --tags and --tag (yet)");
 				return 0;
 			}
 			arg = *argv++; argc--;
 			args->tags = arg;
 		} else if (!strcmp(arg, "-e")) {
 			has_added_tags = 1;
 			arg = *argv++; argc--;
 			if (!nostr_add_tag(ev, "e", arg)) {
 				fprintf(stderr, "couldn't add e tag");
 				return 0;
 			}
 		} else if (!strcmp(arg, "-p")) {
 			has_added_tags = 1;
 			arg = *argv++; argc--;
 			if (!nostr_add_tag(ev, "p", arg)) {
 				fprintf(stderr, "couldn't add p tag");
 				return 0;
 			}
 		} else if (!strcmp(arg, "-t")) {
 			has_added_tags = 1;
 			arg = *argv++; argc--;
 			if (!nostr_add_tag(ev, "t", arg)) {
 				fprintf(stderr, "couldn't add t tag");
 				return 0;
 			}
 		} else if (!strcmp(arg, "--tagn")) {
 			if (!nostr_add_arg_tags(ev, &argc, &argv)) {
 				return 0;
 			}
 			has_added_tags = 1;
 		} else if (!strcmp(arg, "--tag")) {
 			has_added_tags = 1;
 			if (args->tags) {
 				fprintf(stderr, "can't combine --tag and --tags (yet)");
 				return 0;
 			}
 			arg = *argv++; argc--;
 			if (argc == 0) {
 				fprintf(stderr, "expected two arguments to --tag\n");
 				return 0;
 			}
 			arg2 = *argv++; argc--;
 			if (!nostr_add_tag(ev, arg, arg2)) {
 				fprintf(stderr, "couldn't add tag '%s' '%s'\n", arg, arg2);
 				return 0;
 			}
 		} else if (!strcmp(arg, "--mine-pubkey")) {
 			args->flags |= HAS_MINE_PUBKEY;
 		} else if (!strcmp(arg, "--pow")) {
 			if (args->tags) {
 				fprintf(stderr, "can't combine --tags and --pow (yet)\n");
 				return 0;
 			}
 			arg = *argv++; argc--;
 			if (!parse_num(arg, &n)) {
 				fprintf(stderr, "could not parse difficulty as number: '%s'\n", arg);
 				return 0;
 			}
 			args->difficulty = n;
 			args->flags |= HAS_DIFFICULTY;
 		} else if (!strcmp(arg, "--dm")) {
 			arg = *argv++; argc--;
 			if (!hex_decode(arg, strlen(arg), args->encrypt_to, 32)) {
 				fprintf(stderr, "could not decode encrypt-to pubkey");
 				return 0;
 			}
 			args->flags |= HAS_ENCRYPT;
 		} else if (!strcmp(arg, "--content")) {
 			arg = *argv++; argc--;
 			args->content = arg;
 		} else if (!strcmp(arg, "--giftwrap-to")) {
 			arg = *argv++; argc--;
 			if (!hex_decode(arg, strlen(arg), args->encrypt_to, 32)) {
 				fprintf(stderr, "could not decode giftwrap-to pubkey");
 				return 0;
 			}
 			args->flags |= HAS_GIFTWRAP;
 		} else {
 			fprintf(stderr, "unexpected argument '%s'\n", arg);
 			return 0;
 		}
 	}
 
 	if (!args->content)
 		args->content = "";
 
 	return 1;
 }
 
 static int aes_encrypt(unsigned char *key, unsigned char *iv,
 		unsigned char *buf, size_t buflen)
 {
 	struct AES_ctx ctx;
 	unsigned char padding;
 	int i;
 	struct cursor cur;
 
 	padding = 16 - (buflen % 16);
 	make_cursor(buf, buf + buflen + padding, &cur);
 	cur.p += buflen;
 	//fprintf(stderr, "aes_encrypt: len %ld, padding %d\n", buflen, padding);
 
 	for (i = 0; i < padding; i++) {
 		if (!cursor_push_byte(&cur, padding)) {
 			return 0;
 		}
 	}
 	assert(cur.p == cur.end);
 	assert((cur.p - cur.start) % 16 == 0);
 
 	AES_init_ctx_iv(&ctx, key, iv);
 	//fprintf(stderr, "encrypting %ld bytes: ", cur.p - cur.start);
 	//print_hex(cur.start, cur.p - cur.start);
 	AES_CBC_encrypt_buffer(&ctx, cur.start, cur.p - cur.start);
 
 	return cur.p - cur.start;
 }
 
 static int copyx(unsigned char *output, const unsigned char *x32, const unsigned char *y32, void *data) {
 	memcpy(output, x32, 32);
 	return 1;
 }
 
 static int ensure_nonce_tag(struct nostr_event *ev, int target, int *index)
 {
 	char *str_target = malloc(8);
 	struct nostr_tag *tag;
 	int i;
 
 	for (i = 0; i < ev->num_tags; i++) {
 		tag = &ev->tags[i];
 		if (tag->num_elems == 2 && !strcmp(tag->strs[0], "nonce")) {
 			*index = i;
 			return 1;
 		}
 	}
 
 	*index = ev->num_tags;
 
 	snprintf(str_target, 7, "%d", target);
 	const char *ts[] = { "nonce", "0", str_target };
 
 	return nostr_add_tag_n(ev, ts, 3);
 }
 
 static int mine_event(struct nostr_event *ev, int difficulty,
 		      unsigned char *buf, size_t bufsize)
 {
 	char *strnonce = malloc(33);
 	struct nostr_tag *tag;
 	uint64_t nonce;
 	int index, res;
 
 	if (!ensure_nonce_tag(ev, difficulty, &index))
 		return 0;
 
 	tag = &ev->tags[index];
 	assert(tag->num_elems == 3);
 	assert(!strcmp(tag->strs[0], "nonce"));
 	tag->strs[1] = strnonce;
 
 	for (nonce = 0;; nonce++) {
 		snprintf(strnonce, 32, "%" PRIu64, nonce);
 
 		if (!generate_event_id(ev, buf, bufsize))
 			return 0;
 
 		if ((res = count_leading_zero_bits(ev->id)) >= difficulty) {
 			fprintf(stderr, "mined %d bits\n", res);
 			return 1;
 		}
 	}
 
 	return 0;
 }
 
 static int make_giftwrap(secp256k1_context *ctx, struct key *key,
 		struct nostr_event *rumor, unsigned char receiver_pubkey[32],
 		unsigned char *buf, size_t bufsize,
 		int is_envelope)
 {
 	struct nostr_event giftwrap = {0};
 	struct nostr_event seal = {0};
 	struct key wrap_key;
 	char *b64, *json;
 	struct cursor arena, *c;
 	ssize_t b64_len;
 	enum ndb_decrypt_result ok;
 
 	c = &arena;
 	make_cursor(buf, buf+bufsize, c);
 	if (!fill_random(wrap_key.secret, sizeof(wrap_key.secret)))
 		return 0;
 	create_key(ctx, &wrap_key); /* giftwrap key */
 
 	memcpy(rumor->pubkey, key->pubkey, 32);
 	if (!generate_event_id(rumor, c->p, cursor_remaining_capacity(c)))
 		return 0;
 
 	/* rumor data */
 	json = (char*)c->p;
 	if (!event_to_json(c, rumor, 0))
 		return 0;
 
 	ok = nip44_encrypt(ctx, key->secret, receiver_pubkey,
 			   (unsigned char *)json, c->p - (unsigned char *)json-1,
 			   c->p, cursor_remaining_capacity(c),
 			   &b64, &b64_len);
 
 	if (ok != NIP44_OK) {
 		fprintf(stderr, "rumor nip44 encrypt failed: %s\n",
 				nip44_err_msg(ok));
 		return 0;
 	}
 	assert(b64_len % 4 == 0);
 	c->p = b64 + b64_len;
 	if (!cursor_push_byte(c, 0))
 		return 0;
 
 	fprintf(stderr, "rumor %s\n\n", json);
 
 	/* seal data */
 	seal.kind = 13;
 	seal.created_at = rumor->created_at;
 	seal.content = b64;
 	assert(strlen(b64) % 4 == 0);
 
 	memcpy(seal.pubkey, key->pubkey, 32);
 	if (!generate_event_id(&seal, c->p, cursor_remaining_capacity(c)))
 		return 0;
 	if (!sign_event(ctx, key, &seal))
 		return 0;
 
 	json = (char*)c->p;
 	if (!event_to_json(c, &seal, 0)) {
 		fprintf(stderr, "seal -> json failed, not enough space?\n");
 		return 0;
 	}
 	fprintf(stderr, "seal %.*s\n\n", (int)(c->p - (unsigned char*)json), json);
 
 	/* encrypt seal for giftwrap contents */
 	ok = nip44_encrypt(ctx, wrap_key.secret, receiver_pubkey,
 			  (unsigned char *)json, c->p - (unsigned char *)json - 1,
 			  c->p, cursor_remaining_capacity(c),
 			  &b64, &b64_len);
 
 	if (ok != NIP44_OK) {
 		fprintf(stderr, "seal nip44 encrypt failed: %s\n",
 				nip44_err_msg(ok));
 		return 0;
 	}
 
 	assert(b64_len % 4 == 0);
 	c->p = b64 + b64_len;
 	if (!cursor_push_byte(c, 0))
 		return 0;
 
 	giftwrap.content = b64;
 
 	/* giftwrap data */
 	json = (char*)c->p;
 	if (!cursor_push_hex(c, wrap_key.secret, 32)) {
 		fprintf(stderr, "buffer too small, bug jb55 to increase\n");
 		return 0;
 	}
 	fprintf(stderr, "giftwrap_sec %.*s\n\n", 64, json);
 
 	giftwrap.created_at = rumor->created_at;
 	giftwrap.kind = 1059;
 	memcpy(giftwrap.pubkey, wrap_key.pubkey, 32);
 
 	json = (char*)c->p;
 	cursor_push_hex(c, receiver_pubkey, 32);
 	cursor_push_byte(c, 0);
 	nostr_add_tag(&giftwrap, "p", json);
 
 	if (!generate_event_id(&giftwrap, c->p, cursor_remaining_capacity(c)))
 		return 0;
 	if (!sign_event(ctx, &wrap_key, &giftwrap))
 		return 0;
 
 	json = (char*)c->p;
 	if (!event_to_json(c, &giftwrap, is_envelope)) {
 		fprintf(stderr, "buffer too small, bug jb55 to increase\n");
 		return 0;
 	}
 
 	printf("%s\n", json);
 
 	free(buf);
 	return 1;
 }
 
 static int make_encrypted_dm(secp256k1_context *ctx, struct key *key,
 		struct nostr_event *ev, unsigned char nostr_pubkey[32], int kind)
 {
 	size_t inl = strlen(ev->content);
 	int enclen = inl + 16;
 	size_t buflen = enclen * 3 + 65 * 10;
 	unsigned char *buf = malloc(buflen);
 	unsigned char shared_secret[32];
 	unsigned char iv[16];
 	unsigned char compressed_pubkey[33];
 	int content_len = strlen(ev->content);
 	unsigned char encbuf[content_len + (content_len % 16) + 1];
 	struct cursor cur;
 	secp256k1_pubkey pubkey;
 
 	compressed_pubkey[0] = 2;
 	memcpy(&compressed_pubkey[1], nostr_pubkey, 32);
 
 	make_cursor(buf, buf + buflen, &cur);
 
         if (!secp256k1_ec_seckey_verify(ctx, key->secret)) {
 		fprintf(stderr, "make_encrypted_dm: ec_seckey_verify failed\n");
 		return 0;
 	}
 
 	if (!secp256k1_ec_pubkey_parse(ctx, &pubkey, compressed_pubkey,
 				       sizeof(compressed_pubkey))) {
 		fprintf(stderr, "make_encrypted_dm: ec_pubkey_parse failed\n");
 		return 0;
 	}
 
 	if (!secp256k1_ecdh(ctx, shared_secret, &pubkey, key->secret, copyx, NULL)) {
 		fprintf(stderr, "make_encrypted_dm: secp256k1_ecdh failed\n");
 		return 0;
 	}
 
 	if (!fill_random(iv, sizeof(iv))) {
 		fprintf(stderr, "make_encrypted_dm: fill_random failed\n");
 		return 0;
 	}
 
 	fprintf(stderr, "shared_secret ");
 	print_hex(shared_secret, 32);
 
 	memcpy(encbuf, ev->content, strlen(ev->content));
 	enclen = aes_encrypt(shared_secret, iv, encbuf, strlen(ev->content));
 	if (enclen == 0) {
 		fprintf(stderr, "make_encrypted_dm: aes_encrypt failed\n");
 		free(buf);
 		return 0;
 	}
 
 	if ((enclen = base64_encode((char *)buf, buflen, (const char*)encbuf, enclen)) == -1) {
 		fprintf(stderr, "make_encrypted_dm: base64 encode of encrypted fata failed\n");
 		return 0;
 	}
 	cur.p += enclen;
 
 	if (!cursor_push_str(&cur, "?iv=")) {
 		fprintf(stderr, "make_encrypted_dm: buffer too small\n");
 		return 0;
 	}
 
 	if ((enclen = base64_encode((char *)cur.p, cur.end - cur.p, (const char*)iv, 16)) == -1) {
 		fprintf(stderr, "make_encrypted_dm: base64 encode of iv failed\n");
 		return 0;
 	}
 	cur.p += enclen;
 
 	if (!cursor_push_byte(&cur, 0)) {
 		fprintf(stderr, "make_encrypted_dm: out of memory by 1 byte!\n");
 		return 0;
 	}
 
 	ev->content = (const char*)cur.start;
 	ev->kind = kind;
 
 	if (!hex_encode(nostr_pubkey, 32, (char*)cur.p, cur.end - cur.p))
 		return 0;
 
 	if (!nostr_add_tag(ev, "p", (const char*)cur.p)) {
 		fprintf(stderr, "too many tags\n");
 		return 0;
 	}
 
 	cur.p += 65;
 
 	return 1;
 }
 
 static void try_subcommand(int argc, const char *argv[])
 {
 	static char buf[128] = {0};
 	const char *sub = argv[1];
 	if (strlen(sub) >= 1 && sub[0] != '-') {
 		snprintf(buf, sizeof(buf)-1, "nostril-%s", sub);
 		execvp(buf, (char * const *)argv+1);
 	}
 }
 
 
 int main(int argc, const char *argv[])
 {
 	struct args args = {0};
 	struct nostr_event ev = {0};
 	struct key key;
 	unsigned char *buf;
 	size_t bufsize;
         secp256k1_context *ctx;
 
 	if (argc < 2)
 		usage();
 
         if (!init_secp_context(&ctx))
 		return 2;
 
 	try_subcommand(argc, argv);
 
 	if (!parse_args(argc, argv, &args, &ev)) {
 		usage();
 		return 10;
 	}
 
 	if (args.tags) {
 		ev.explicit_tags = args.tags;
 	}
 
 	make_event_from_args(&ev, &args);
 
 	if (args.sec) {
 		if (!decode_key(ctx, args.sec, &key)) {
 			return 8;
 		}
 	} else {
 		int *difficulty = NULL;
 		if ((args.flags & HAS_DIFFICULTY) && (args.flags & HAS_MINE_PUBKEY)) {
 			difficulty = &args.difficulty;
 		}
 
 		if (!generate_key(ctx, &key, difficulty)) {
 			fprintf(stderr, "could not generate key\n");
 			return 4;
 		}
 		fprintf(stderr, "secret_key ");
 		print_hex(key.secret, sizeof(key.secret));
 		fprintf(stderr, "\n");
 	}
 
 	/* 8 MiB */
 	bufsize = 2 << 22;
 	buf = malloc(bufsize);
 
 	if (args.flags & HAS_ENCRYPT) {
 		int kind = args.flags & HAS_KIND? args.kind : 4;
 		if (!make_encrypted_dm(ctx, &key, &ev, args.encrypt_to, kind)) {
 			fprintf(stderr, "error making encrypted dm\n");
 			return 1;
 		}
 	} else if (args.flags & HAS_GIFTWRAP) {
 		if (!make_giftwrap(ctx, &key, &ev, args.encrypt_to,
 				   buf, bufsize, args.flags & HAS_ENVELOPE)) {
 			fprintf(stderr, "error making encrypted dm\n");
 			return 1;
 		}
 		return 0;
 	}
 
 	// set the event's pubkey
 	memcpy(ev.pubkey, key.pubkey, 32);
 
 	if (args.flags & HAS_DIFFICULTY && !(args.flags & HAS_MINE_PUBKEY)) {
 		if (!mine_event(&ev, args.difficulty, buf, bufsize)) {
 			fprintf(stderr, "error when mining id\n");
 			return 22;
 		}
 	} else {
 		if (!generate_event_id(&ev, buf, bufsize)) {
 			fprintf(stderr, "could not generate event id\n");
 			return 5;
 		}
 	}
 
 	if (!sign_event(ctx, &key, &ev)) {
 		fprintf(stderr, "could not sign event\n");
 		return 6;
 	}
 
 	if (!print_event(&ev, args.flags & HAS_ENVELOPE, buf, bufsize)) {
 		fprintf(stderr, "buffer too small\n");
 		return 88;
 	}
 
 	free(buf);
 
 	return 0;
 }