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Diffstat (limited to 'src/common/crypto_ed25519.c')
| -rw-r--r-- | src/common/crypto_ed25519.c | 353 |
1 files changed, 353 insertions, 0 deletions
diff --git a/src/common/crypto_ed25519.c b/src/common/crypto_ed25519.c new file mode 100644 index 0000000000..408c12b4fd --- /dev/null +++ b/src/common/crypto_ed25519.c @@ -0,0 +1,353 @@ +/* Copyright (c) 2013, 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; +} + |