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- /* Copyright (c) 2013-2015, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- /* Wrapper code for an ed25519 implementation. */
- #include "orconfig.h"
- #ifdef HAVE_SYS_STAT_H
- #include <sys/stat.h>
- #endif
- #include "crypto.h"
- #include "crypto_curve25519.h"
- #include "crypto_ed25519.h"
- #include "torlog.h"
- #include "util.h"
- #include "ed25519/ref10/ed25519_ref10.h"
- #include <openssl/sha.h>
- /**
- * Initialize a new ed25519 secret key in <b>seckey_out</b>. If
- * <b>extra_strong</b>, take the RNG inputs directly from the operating
- * system. Return 0 on success, -1 on failure.
- */
- int
- ed25519_secret_key_generate(ed25519_secret_key_t *seckey_out,
- int extra_strong)
- {
- int r;
- uint8_t seed[32];
- if (! extra_strong || crypto_strongest_rand(seed, sizeof(seed)) < 0)
- crypto_rand((char*)seed, sizeof(seed));
- r = ed25519_ref10_seckey_expand(seckey_out->seckey, seed);
- memwipe(seed, 0, sizeof(seed));
- return r < 0 ? -1 : 0;
- }
- /**
- * Given a 32-byte random seed in <b>seed</b>, expand it into an ed25519
- * secret key in <b>seckey_out</b>. Return 0 on success, -1 on failure.
- */
- int
- ed25519_secret_key_from_seed(ed25519_secret_key_t *seckey_out,
- const uint8_t *seed)
- {
- if (ed25519_ref10_seckey_expand(seckey_out->seckey, seed) < 0)
- return -1;
- return 0;
- }
- /**
- * Given a secret key in <b>seckey</b>, expand it into an
- * ed25519 public key. Return 0 on success, -1 on failure.
- */
- int
- ed25519_public_key_generate(ed25519_public_key_t *pubkey_out,
- const ed25519_secret_key_t *seckey)
- {
- if (ed25519_ref10_pubkey(pubkey_out->pubkey, seckey->seckey) < 0)
- return -1;
- return 0;
- }
- /** Generate a new ed25519 keypair in <b>keypair_out</b>. If
- * <b>extra_strong</b> is set, try to mix some system entropy into the key
- * generation process. Return 0 on success, -1 on failure. */
- int
- ed25519_keypair_generate(ed25519_keypair_t *keypair_out, int extra_strong)
- {
- if (ed25519_secret_key_generate(&keypair_out->seckey, extra_strong) < 0)
- return -1;
- if (ed25519_public_key_generate(&keypair_out->pubkey,
- &keypair_out->seckey)<0)
- return -1;
- return 0;
- }
- /**
- * Set <b>signature_out</b> to a signature of the <b>len</b>-byte message
- * <b>msg</b>, using the secret and public key in <b>keypair</b>.
- */
- int
- ed25519_sign(ed25519_signature_t *signature_out,
- const uint8_t *msg, size_t len,
- const ed25519_keypair_t *keypair)
- {
- if (ed25519_ref10_sign(signature_out->sig, msg, len,
- keypair->seckey.seckey,
- keypair->pubkey.pubkey) < 0) {
- return -1;
- }
- return 0;
- }
- /**
- * Check whether if <b>signature</b> is a valid signature for the
- * <b>len</b>-byte message in <b>msg</b> made with the key <b>pubkey</b>.
- *
- * Return 0 if the signature is valid; -1 if it isn't.
- */
- int
- ed25519_checksig(const ed25519_signature_t *signature,
- const uint8_t *msg, size_t len,
- const ed25519_public_key_t *pubkey)
- {
- return
- ed25519_ref10_open(signature->sig, msg, len, pubkey->pubkey) < 0 ? -1 : 0;
- }
- /** Validate every signature among those in <b>checkable</b>, which contains
- * exactly <b>n_checkable</b> elements. If <b>okay_out</b> is non-NULL, set
- * the i'th element of <b>okay_out</b> to 1 if the i'th element of
- * <b>checkable</b> is valid, and to 0 otherwise. Return 0 if every signature
- * was valid. Otherwise return -N, where N is the number of invalid
- * signatures.
- */
- int
- ed25519_checksig_batch(int *okay_out,
- const ed25519_checkable_t *checkable,
- int n_checkable)
- {
- int res, i;
- res = 0;
- for (i = 0; i < n_checkable; ++i) {
- const ed25519_checkable_t *ch = &checkable[i];
- int r = ed25519_checksig(&ch->signature, ch->msg, ch->len, ch->pubkey);
- if (r < 0)
- --res;
- if (okay_out)
- okay_out[i] = (r == 0);
- }
- #if 0
- /* This is how we'd do it if we were using ed25519_donna. I'll keep this
- * code around here in case we ever do that. */
- const uint8_t **ms;
- size_t *lens;
- const uint8_t **pks;
- const uint8_t **sigs;
- int *oks;
- ms = tor_malloc(sizeof(uint8_t*)*n_checkable);
- lens = tor_malloc(sizeof(size_t)*n_checkable);
- pks = tor_malloc(sizeof(uint8_t*)*n_checkable);
- sigs = tor_malloc(sizeof(uint8_t*)*n_checkable);
- oks = okay_out ? okay_out : tor_malloc(sizeof(int)*n_checkable);
- for (i = 0; i < n_checkable; ++i) {
- ms[i] = checkable[i].msg;
- lens[i] = checkable[i].len;
- pks[i] = checkable[i].pubkey->pubkey;
- sigs[i] = checkable[i].signature.sig;
- oks[i] = 0;
- }
- ed25519_sign_open_batch_donna_fb(ms, lens, pks, sigs, n_checkable, oks);
- res = 0;
- for (i = 0; i < n_checkable; ++i) {
- if (!oks[i])
- --res;
- }
- tor_free(ms);
- tor_free(lens);
- tor_free(pks);
- if (! okay_out)
- tor_free(oks);
- #endif
- return res;
- }
- /**
- * Given a curve25519 keypair in <b>inp</b>, generate a corresponding
- * ed25519 keypair in <b>out</b>, and set <b>signbit_out</b> to the
- * sign bit of the X coordinate of the ed25519 key.
- *
- * NOTE THAT IT IS PROBABLY NOT SAFE TO USE THE GENERATED KEY FOR ANYTHING
- * OUTSIDE OF WHAT'S PRESENTED IN PROPOSAL 228. In particular, it's probably
- * not a great idea to use it to sign attacker-supplied anything.
- */
- int
- ed25519_keypair_from_curve25519_keypair(ed25519_keypair_t *out,
- int *signbit_out,
- const curve25519_keypair_t *inp)
- {
- const char string[] = "Derive high part of ed25519 key from curve25519 key";
- ed25519_public_key_t pubkey_check;
- SHA512_CTX ctx;
- uint8_t sha512_output[64];
- memcpy(out->seckey.seckey, inp->seckey.secret_key, 32);
- SHA512_Init(&ctx);
- SHA512_Update(&ctx, out->seckey.seckey, 32);
- SHA512_Update(&ctx, string, sizeof(string));
- SHA512_Final(sha512_output, &ctx);
- memcpy(out->seckey.seckey + 32, sha512_output, 32);
- ed25519_public_key_generate(&out->pubkey, &out->seckey);
- *signbit_out = out->pubkey.pubkey[31] >> 7;
- ed25519_public_key_from_curve25519_public_key(&pubkey_check, &inp->pubkey,
- *signbit_out);
- tor_assert(fast_memeq(pubkey_check.pubkey, out->pubkey.pubkey, 32));
- memwipe(&pubkey_check, 0, sizeof(pubkey_check));
- memwipe(&ctx, 0, sizeof(ctx));
- memwipe(sha512_output, 0, sizeof(sha512_output));
- return 0;
- }
- /**
- * Given a curve25519 public key and sign bit of X coordinate of the ed25519
- * public key, generate the corresponding ed25519 public key.
- */
- int
- ed25519_public_key_from_curve25519_public_key(ed25519_public_key_t *pubkey,
- const curve25519_public_key_t *pubkey_in,
- int signbit)
- {
- return ed25519_ref10_pubkey_from_curve25519_pubkey(pubkey->pubkey,
- pubkey_in->public_key,
- signbit);
- }
- /**
- * Given an ed25519 keypair in <b>inp</b>, generate a corresponding
- * ed25519 keypair in <b>out</b>, blinded by the corresponding 32-byte input
- * in 'param'.
- *
- * Tor uses key blinding for the "next-generation" hidden services design:
- * service descriptors are encrypted with a key derived from the service's
- * long-term public key, and then signed with (and stored at a position
- * indexed by) a short-term key derived by blinding the long-term keys.
- */
- int
- ed25519_keypair_blind(ed25519_keypair_t *out,
- const ed25519_keypair_t *inp,
- const uint8_t *param)
- {
- ed25519_public_key_t pubkey_check;
- ed25519_ref10_blind_secret_key(out->seckey.seckey,
- inp->seckey.seckey, param);
- ed25519_public_blind(&pubkey_check, &inp->pubkey, param);
- ed25519_public_key_generate(&out->pubkey, &out->seckey);
- tor_assert(fast_memeq(pubkey_check.pubkey, out->pubkey.pubkey, 32));
- memwipe(&pubkey_check, 0, sizeof(pubkey_check));
- return 0;
- }
- /**
- * Given an ed25519 public key in <b>inp</b>, generate a corresponding blinded
- * public key in <b>out</b>, blinded with the 32-byte parameter in
- * <b>param</b>. Return 0 on sucess, -1 on railure.
- */
- int
- ed25519_public_blind(ed25519_public_key_t *out,
- const ed25519_public_key_t *inp,
- const uint8_t *param)
- {
- ed25519_ref10_blind_public_key(out->pubkey, inp->pubkey, param);
- return 0;
- }
- /**
- * Store seckey unencrypted to <b>filename</b>, marking it with <b>tag</b>.
- * Return 0 on success, -1 on failure.
- */
- int
- ed25519_seckey_write_to_file(const ed25519_secret_key_t *seckey,
- const char *filename,
- const char *tag)
- {
- return crypto_write_tagged_contents_to_file(filename,
- "ed25519v1-secret",
- tag,
- seckey->seckey,
- sizeof(seckey->seckey));
- }
- /**
- * Read seckey unencrypted from <b>filename</b>, storing it into
- * <b>seckey_out</b>. Set *<b>tag_out</> to the tag it was marked with.
- * Return 0 on success, -1 on failure.
- */
- int
- ed25519_seckey_read_from_file(ed25519_secret_key_t *seckey_out,
- char **tag_out,
- const char *filename)
- {
- ssize_t len;
- len = crypto_read_tagged_contents_from_file(filename, "ed25519v1-secret",
- tag_out, seckey_out->seckey,
- sizeof(seckey_out->seckey));
- if (len != sizeof(seckey_out->seckey))
- return -1;
- return 0;
- }
- /**
- * Store pubkey unencrypted to <b>filename</b>, marking it with <b>tag</b>.
- * Return 0 on success, -1 on failure.
- */
- int
- ed25519_pubkey_write_to_file(const ed25519_public_key_t *pubkey,
- const char *filename,
- const char *tag)
- {
- return crypto_write_tagged_contents_to_file(filename,
- "ed25519v1-public",
- tag,
- pubkey->pubkey,
- sizeof(pubkey->pubkey));
- }
- /**
- * Store pubkey unencrypted to <b>filename</b>, marking it with <b>tag</b>.
- * Return 0 on success, -1 on failure.
- */
- int
- ed25519_pubkey_read_from_file(ed25519_public_key_t *pubkey_out,
- char **tag_out,
- const char *filename)
- {
- ssize_t len;
- len = crypto_read_tagged_contents_from_file(filename, "ed25519v1-public",
- tag_out, pubkey_out->pubkey,
- sizeof(pubkey_out->pubkey));
- if (len != sizeof(pubkey_out->pubkey))
- return -1;
- return 0;
- }
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