prototype of trustless mining

README.md

@@ -3,6 +3,32 @@
 This tool generates vanity ed25519 ([hidden service version 3][v3],
 formely known as proposal 224) onion addresses.
 
+### What is this fork?
+This is my shot at implementing [trustless mining](https://github.com/cathugger/mkp224o/issues/60).
+It's a garbage implementation, but it (kinda?) works.
+
+#### Usage
+```
+$ ./mkp224o --genbase out/base.priv out/base.pub
+writing private base key to 'out/base.priv'
+writing public base key to 'out/base.pub'
+done.
+
+$ ./mkp224o -n 1 -d out -Z --basekey out/base.pub zzz
+
+$ ./mkp224o --combine out/base.priv out/zzz*.onion/hs_ed25519_secret_key
+new pk: [...]
+saving to out/zzzkzmpje34nnp2yvgz7slr7rgpajzlpihsr3rpzgmekrjosnpprf2id.onion/hs_ed25519_secret_key.fixed
+
+$ cp out/zzz*.onion/hs_ed25519_secret_key.fixed /var/lib/tor/hidden_service/hs_ed25519_secret_key
+```
+
+#### the ugly
+* i'm an amateur, the math might not check out
+* horrible code organization - i'm not familiar with this style of codebases at all
+* depends on ed25519-donna
+* only works with slow key generation (-Z)
+
 ### Requirements
 
 * C99 compatible compiler (gcc and clang should work)

main.c

@@ -132,6 +132,13 @@ static void printhelp(FILE *out,const char *progname)
 #endif
 		"      --rawyaml         raw (unprefixed) public/secret keys for -y/-Y\n"
 		"                        (may be useful for tor controller API)\n"
+		"  --basekey base.pub\n"
+		"                        trustless mining: the private keys found will need\n"
+		"                        to be --combine'd with base.priv before use\n"
+		"  --genbase base.priv base.pub\n"
+		"                        generate base keys for trustless mining\n"
+		"  --combine base.priv hs_secret_key\n"
+		"                        combine a mined hs_secret key with a base key\n"
 		"  -h, --help, --usage   print help to stdout and quit\n"
 		"  -V, --version         print version information to stdout and exit\n"
 		,progname,progname);
@@ -262,11 +269,160 @@ enum worker_type {
 	WT_BATCH,
 };
 
+// i'm so sorry for including an implementation header
+// i didn't find another way to get access to the functions
+#include "ed25519/ed25519_impl_pre.h"
+static void genbase(const char *privpath, const char *pubpath)
+{
+	u8 base_sk[32];
+	u8 base_pk[32];
+	hash_512bits base_extsk;
+	ge25519 ALIGN(16) A;
+	bignum256modm ALIGN(16) base;
+	FILE *fp;
+
+	randombytes(base_sk, sizeof base_sk);
+	ed25519_seckey_expand(base_extsk, base_sk);
+	expand256_modm(base, base_extsk, 32);
+	ge25519_scalarmult_base_niels(&A, ge25519_niels_base_multiples, base);
+	ge25519_pack(base_pk, &A);
+
+	printf("writing private base key to '%s'\n", privpath);
+	fp = fopen(privpath, "w");
+	if (!fp) {
+		perror("couldn't open");
+		exit(1);
+	}
+	if (fwrite(base_sk, 1, 32, fp) != 32) {
+		perror("write");
+		exit(1);
+	}
+	fclose(fp);
+
+	printf("writing public base key to '%s'\n", pubpath);
+	fp = fopen(pubpath, "w");
+	if (!fp) {
+		perror("couldn't open");
+		exit(1);
+	}
+	if (fwrite(base_pk, 1, 32, fp) != 32) {
+		perror("write");
+		exit(1);
+	}
+	fclose(fp);
+
+	puts("done.");
+}
+
+static void combine(const char *privpath, const char *hs_secretkey)
+{
+	u8 base_sk[32], secret[96];
+	FILE *fp;
+ 
+	fp = fopen(hs_secretkey, "r");
+	if (fp == NULL) {
+		perror("failed to open hs_secret_key");
+		exit(1);
+	}
+	if (fread(secret, 1, 96, fp) != 96) {
+		perror("failed to read hs_secret_key");
+		exit(1);
+	}
+	if (memcmp(secret, "== ed25519v1-secret: type0 ==\0\0\0", 32) != 0) {
+		fprintf(stderr, "invalid hs_secret_key format.\nare you sure you picked the right file?\n");
+		exit(1);
+	}
+	fclose(fp);
+
+	fp = fopen(privpath, "r");
+	if (fp == NULL) {
+		perror("failed to open base.priv");
+		exit(1);
+	}
+	if (fread(base_sk, 1, sizeof base_sk, fp) != sizeof base_sk) {
+		perror("failed to read base.priv");
+		exit(1);
+	}
+	fclose(fp);
+
+#if 0
+	u8 pk[32];
+
+	hash_512bits base_extsk;
+	ed25519_seckey_expand(base_extsk, base_sk);
+
+	bignum256modm ALIGN(16) base;
+	expand256_modm(base, base_extsk, 32);
+
+	ge25519 ALIGN(16) A, B;
+	ge25519_scalarmult_base_niels(&B, ge25519_niels_base_multiples, base);
+	u8 base_pk[32];
+	ge25519_pack(base_pk, &B);
+	ge25519_unpack_negative_vartime(&B, base_pk);
+	ge25519_pack(base_pk, &B);
+	ge25519_unpack_negative_vartime(&B, base_pk);
+
+	bignum256modm ALIGN(16) a;
+	expand256_modm(a, &secret[SKPREFIX_SIZE], 32);
+	ge25519_scalarmult_base_niels(&A, ge25519_niels_base_multiples, a);
+	ge25519_add(&A, &A, &B);
+	ge25519_pack(pk, &A);
+
+	printf("pk from public: ");
+	for (size_t i = 0; i < sizeof(pk); i++)
+		printf("%02x ", pk[i]);
+	puts("");
+#endif
+
+	hash_512bits base_extsk;
+	bignum256modm ALIGN(16) a, b;
+	ge25519 ALIGN(16) A;
+	u8 pk[32];
+
+	expand256_modm(a, &secret[32], 32);
+	ed25519_seckey_expand(base_extsk, base_sk);
+	expand256_modm(b, base_extsk, 32);
+
+	add256_modm(a, a, b);
+
+	ge25519_scalarmult_base_niels(&A, ge25519_niels_base_multiples, a);
+	ge25519_pack(pk, &A);
+
+	contract256_modm(&secret[32], a);
+
+	expand256_modm(a, &secret[32], 32);
+	ge25519_scalarmult_base_niels(&A, ge25519_niels_base_multiples, a);
+	ge25519_pack(pk, &A);
+
+	printf("new pk: ");
+	for (size_t i = 0; i < sizeof(pk); i++)
+		printf("%02x ", pk[i]);
+	puts("");
+
+	char *newname = malloc(strlen(hs_secretkey) + strlen(".fixed") + 1);
+	strcpy(newname, hs_secretkey);
+	strcat(newname, ".fixed");
+	printf("saving to %s\n", newname);
+
+	fp = fopen(newname, "w");
+	if (!fp) {
+		perror("couldn't open");
+		exit(1);
+	}
+	if (fwrite(secret, 1, sizeof secret, fp) != sizeof secret) {
+		perror("failed to write fixed privkey");
+		exit(1);
+	}
+	fclose(fp);
+}
+#include "ed25519/ed25519_impl_post.h"
+
 int main(int argc,char **argv)
 {
 	const char *outfile = 0;
 	const char *infile = 0;
 	const char *onehostname = 0;
+	const char *basekeyfile = 0;
 	const char *arg;
 	int ignoreargs = 0;
 	int dirnameflag = 0;
@@ -326,6 +482,28 @@ int main(int argc,char **argv)
 					printversion();
 					exit(0);
 				}
+				else if (!strcmp(arg,"combine")) {
+					if (argc != 2) {
+						printhelp(stdout,progname);
+						exit(0);
+					}
+					combine(argv[0],argv[1]);
+					exit(0);
+				}
+				else if (!strcmp(arg,"genbase")) {
+					if (argc != 2) {
+						printhelp(stdout,progname);
+						exit(0);
+					}
+					genbase(argv[0],argv[1]);
+					exit(0);
+				}
+				else if (!strcmp(arg,"basekey")) {
+					if (argc--)
+						basekeyfile = *argv++;
+					else
+						e_additional();
+				}
 				else if (!strcmp(arg,"rawyaml"))
 					yamlraw = 1;
 #ifdef PASSPHRASE
@@ -497,6 +675,28 @@ int main(int argc,char **argv)
 			filters_add(arg);
 	}
 
+	if (wt != WT_SLOW) {
+		fprintf(stderr,"you're not using -Z. this will probably break.");
+	}
+
+	if (basekeyfile) {
+		u8 base_pk[32];
+		FILE *fp = fopen(basekeyfile, "r");
+		if (!fp) {
+			perror("couldn't open basekey");
+			exit(1);
+		}
+		if (fread(base_pk, 1, sizeof base_pk, fp) != sizeof base_pk) {
+			perror("incomplete read of base_pk");
+			exit(1);
+		}
+		fclose(fp);
+		ed25519_pubkey_setbase(base_pk);
+	} else {
+		fprintf(stderr, "This build requires using --basekey.\n");
+		exit(1);
+	}
+
 	if (yamlinput && yamloutput) {
 		fprintf(stderr,"both -y and -Y does not make sense\n");
 		exit(1);

worker.c

@@ -60,6 +60,9 @@ pthread_mutex_t determseed_mutex;
 u8 determseed[SEED_LEN];
 #endif
 
+static int ed25519_pubkey_onbase(u8 *pk,const u8 *sk);
+static void sanitycheck(const u8 *sk, const u8 *pk);
+
 
 char *makesname(void)
 {
@@ -88,16 +91,7 @@ static void onionready(char *sname,const u8 *secret,const u8 *pubonion)
 		pthread_mutex_unlock(&keysgenerated_mutex);
 	}
 
-	// disabled as this was never ever triggered as far as I'm aware
+	sanitycheck(&secret[SKPREFIX_SIZE], &pubonion[PKPREFIX_SIZE]);
-#if 0
-	// Sanity check that the public key matches the private one.
-	ge_p3 ALIGN(16) point;
-	u8 testpk[PUBLIC_LEN];
-	ge_scalarmult_base(&point,&secret[SKPREFIX_SIZE]);
-	ge_p3_tobytes(testpk,&point);
-	if (memcmp(testpk,&pubonion[PKPREFIX_SIZE],PUBLIC_LEN) != 0)
-		abort();
-#endif
 
 	if (!yamloutput) {
 		if (createdir(sname,1) != 0) {
@@ -266,3 +260,48 @@ void worker_init(void)
 	crypto_sign_ed25519_donna_ge_initeightpoint();
 #endif
 }
+
+// there's not really any good place to add ed25519 functions
+// so i just add them there
+// i don't understand how this codebase is organized :(
+
+ge25519 ALIGN(16) PUBKEY_BASE = {0};
+int pubkey_base_initialized;
+
+void ed25519_pubkey_setbase(const u8 base_pk[32])
+{
+	u8 tmp_pk[32];
+	ge25519_unpack_negative_vartime(&PUBKEY_BASE, base_pk);
+	// dumb hack: unpack flips the point. to get the original point
+	//            back, i just pack and unpack it again
+	ge25519_pack(tmp_pk, &PUBKEY_BASE);
+	ge25519_unpack_negative_vartime(&PUBKEY_BASE, tmp_pk);
+	pubkey_base_initialized = 1;
+}
+
+static int ed25519_pubkey_onbase(u8 *pk,const u8 *sk)
+{
+	bignum256modm a;
+	ge25519 ALIGN(16) A;
+
+	if (unlikely(pubkey_base_initialized == 0))
+		abort();
+
+	// ge_scalarmult_base(&A, sk);
+	expand256_modm(a,sk,32);
+	ge25519_scalarmult_base_niels(&A,ge25519_niels_base_multiples,a);
+	ge25519_add(&A, &A, &PUBKEY_BASE);
+	ge25519_pack(pk,&A);
+
+	return 0;
+}
+
+
+static void sanitycheck(const u8 *sk, const u8 *pk) {
+	u8 testpk[PUBLIC_LEN];
+	ed25519_pubkey_onbase(testpk, sk);
+	if (memcmp(testpk,pk,PUBLIC_LEN) != 0) {
+		fprintf(stderr, "Sanity check failed. Either I fucked something up, or you're using an unsupported combination of options. Probably both.\n");
+		abort();
+	}
+}

worker.h

@@ -36,6 +36,7 @@ extern u8 determseed[SEED_LEN];
 #endif
 
 extern void worker_init(void);
+extern void ed25519_pubkey_setbase(const u8 base_pk[32]);
 
 extern char *makesname(void);
 extern size_t worker_batch_memuse(void);

worker_slow.inc.h

@@ -42,7 +42,7 @@ again:
 	if (unlikely(endwork))
 		goto end;
 
-	ed25519_pubkey(pk,sk);
+	ed25519_pubkey_onbase(pk,sk);
 
 #ifdef STATISTICS
 	++st->numcalc.v;