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mirror of git://git.gnupg.org/gnupg.git synced 2025-02-14 18:43:03 +01:00

Curve25519 support.

* agent/cvt-openpgp.c (get_keygrip): Handle Curve25519.
(convert_secret_key, convert_transfer_key): Ditto.
* common/openpgp-oid.c (oidtable): Add Curve25519.
(oid_crv25519, openpgp_oid_is_crv25519): New.
* common/util.h (openpgp_oid_is_crv25519): New.
* g10/ecdh.c (pk_ecdh_encrypt_with_shared_point): Handle the case
with Montgomery curve which uses x-only coordinate.
* g10/keygen.c (gen_ecc): Handle Curve25519.
(ask_curve): Change the API and second arg is to return subkey algo.
(generate_keypair, generate_subkeypair): Follow chage of ask_curve.
* g10/keyid.c (keygrip_from_pk): Handle Curve25519.
* g10/pkglue.c (pk_encrypt): Handle Curve25519.
* g10/pubkey-enc.c (get_it): Handle the case with Montgomery curve.
* scd/app-openpgp.c (ECC_FLAG_DJB_TWEAK): New.
(send_key_attr): Work with general ECC, Ed25519, and Curve25519.
(get_public_key): Likewise.
(ecc_writekey): Handle flag_djb_tweak.

--

When libgcrypt has Curve25519, GnuPG now supports Curve25519.
This commit is contained in:
NIIBE Yutaka 2015-08-06 17:00:41 +09:00
parent a6e4053089
commit e5891a82c3
9 changed files with 181 additions and 105 deletions

View File

@ -83,14 +83,25 @@ get_keygrip (int pubkey_algo, const char *curve, gcry_mpi_t *pkey,
case GCRY_PK_ECC:
if (!curve)
err = gpg_error (GPG_ERR_BAD_SECKEY);
else if (!strcmp (curve, openpgp_curve_to_oid ("Ed25519", NULL)))
err = gcry_sexp_build (&s_pkey, NULL,
"(public-key(ecc(curve %s)(flags eddsa)(q%m)))",
"Ed25519", pkey[0]);
else
err = gcry_sexp_build (&s_pkey, NULL,
"(public-key(ecc(curve %s)(q%m)))",
curve, pkey[0]);
{
const char *format;
if (!strcmp (curve, openpgp_curve_to_oid ("Ed25519", NULL)))
{
format = "(public-key(ecc(curve %s)(flags eddsa)(q%m)))";
curve = "Ed25519";
}
else if (!strcmp (curve, openpgp_curve_to_oid ("Curve25519", NULL)))
{
format = "(public-key(ecc(curve %s)(flags djb-tweak)(q%m)))";
curve = "Curve25519";
}
else
format = "(public-key(ecc(curve %s)(q%m)))";
err = gcry_sexp_build (&s_pkey, NULL, format, curve, pkey[0]);
}
break;
default:
@ -146,19 +157,27 @@ convert_secret_key (gcry_sexp_t *r_key, int pubkey_algo, gcry_mpi_t *skey,
case GCRY_PK_ECC:
if (!curve)
err = gpg_error (GPG_ERR_BAD_SECKEY);
else if (!strcmp (curve, openpgp_curve_to_oid ("Ed25519", NULL)))
{
/* Do not store the OID as name but the real name and the
EdDSA flag. */
err = gcry_sexp_build (&s_skey, NULL,
"(private-key(ecc(curve%s)(flags eddsa)"
"(q%m)(d%m)))",
"Ed25519", skey[0], skey[1]);
}
else
err = gcry_sexp_build (&s_skey, NULL,
"(private-key(ecc(curve%s)(q%m)(d%m)))",
curve, skey[0], skey[1]);
{
const char *format;
if (!strcmp (curve, openpgp_curve_to_oid ("Ed25519", NULL)))
{
/* Do not store the OID as name but the real name and the
EdDSA flag. */
format = "(private-key(ecc(curve %s)(flags eddsa)(q%m)(d%m)))";
curve = "Ed25519";
}
else if (!strcmp (curve, openpgp_curve_to_oid ("Curve25519", NULL)))
{
format = "(private-key(ecc(curve %s)(flags djb-tweak)(q%m)(d%m)))";
curve = "Curve25519";
}
else
format = "(private-key(ecc(curve %s)(q%m)(d%m)))";
err = gcry_sexp_build (&s_skey, NULL, format, curve, skey[0], skey[1]);
}
break;
default:
@ -216,22 +235,30 @@ convert_transfer_key (gcry_sexp_t *r_key, int pubkey_algo, gcry_mpi_t *skey,
case GCRY_PK_ECC:
if (!curve)
err = gpg_error (GPG_ERR_BAD_SECKEY);
else if (!strcmp (curve, openpgp_curve_to_oid ("Ed25519", NULL)))
{
/* Do not store the OID as name but the real name and the
EdDSA flag. */
err = gcry_sexp_build
(&s_skey, NULL,
"(protected-private-key(ecc(curve%s)(flags eddsa)(q%m)"
"(protected openpgp-native%S)))",
"Ed25519", skey[0], transfer_key);
}
else
err = gcry_sexp_build
(&s_skey, NULL,
"(protected-private-key(ecc(curve%s)(q%m)"
"(protected openpgp-native%S)))",
curve, skey[0], transfer_key);
{
const char *format;
if (!strcmp (curve, openpgp_curve_to_oid ("Ed25519", NULL)))
{
/* Do not store the OID as name but the real name and the
EdDSA flag. */
format = "(protected-private-key(ecc(curve %s)(flags eddsa)(q%m)"
"(protected openpgp-native%S)))";
curve = "Ed25519";
}
else if (!strcmp (curve, openpgp_curve_to_oid ("Curve25519", NULL)))
{
format = "(protected-private-key(ecc(curve %s)(flags djb-tweak)(q%m)"
"(protected openpgp-native%S)))";
curve = "Curve25519";
}
else
format = "(protected-private-key(ecc(curve %s)(q%m)"
"(protected openpgp-native%S)))";
err = gcry_sexp_build (&s_skey, NULL, format, curve, skey[0], transfer_key);
}
break;
default:

View File

@ -45,6 +45,7 @@ static struct {
const char *alias; /* NULL or alternative name of the curve. */
} oidtable[] = {
{ "Curve25519", "1.3.6.1.4.1.3029.1.5.1", 255, "crv25519" },
{ "Ed25519", "1.3.6.1.4.1.11591.15.1", 255, "ed25519" },
{ "NIST P-256", "1.2.840.10045.3.1.7", 256, "nistp256" },
@ -65,6 +66,10 @@ static struct {
static const char oid_ed25519[] =
{ 0x09, 0x2b, 0x06, 0x01, 0x04, 0x01, 0xda, 0x47, 0x0f, 0x01 };
/* The OID for Curve25519 in OpenPGP format. */
static const char oid_crv25519[] =
{ 0x0a, 0x2b, 0x06, 0x01, 0x04, 0x01, 0x97, 0x55, 0x01, 0x05, 0x01 };
/* Helper for openpgp_oid_from_str. */
static size_t
@ -291,6 +296,22 @@ openpgp_oid_is_ed25519 (gcry_mpi_t a)
}
int
openpgp_oid_is_crv25519 (gcry_mpi_t a)
{
const unsigned char *buf;
unsigned int nbits;
size_t n;
if (!a || !gcry_mpi_get_flag (a, GCRYMPI_FLAG_OPAQUE))
return 0;
buf = gcry_mpi_get_opaque (a, &nbits);
n = (nbits+7)/8;
return (n == DIM (oid_crv25519)
&& !memcmp (buf, oid_crv25519, DIM (oid_crv25519)));
}
/* Map the Libgcrypt ECC curve NAME to an OID. If R_NBITS is not NULL
store the bit size of the curve there. Returns NULL for unknown

View File

@ -322,6 +322,7 @@ size_t percent_unescape_inplace (char *string, int nulrepl);
gpg_error_t openpgp_oid_from_str (const char *string, gcry_mpi_t *r_mpi);
char *openpgp_oid_to_str (gcry_mpi_t a);
int openpgp_oid_is_ed25519 (gcry_mpi_t a);
int openpgp_oid_is_crv25519 (gcry_mpi_t a);
const char *openpgp_curve_to_oid (const char *name, unsigned int *r_nbits);
const char *openpgp_oid_to_curve (const char *oid, int canon);
const char *openpgp_enum_curves (int *idxp);

View File

@ -134,9 +134,12 @@ pk_ecdh_encrypt_with_shared_point (int is_encrypt, gcry_mpi_t shared_mpi,
}
secret_x_size = (nbits+7)/8;
assert (nbytes > secret_x_size);
memmove (secret_x, secret_x+1, secret_x_size);
memset (secret_x+secret_x_size, 0, nbytes-secret_x_size);
assert (nbytes >= secret_x_size);
if ((nbytes & 1))
/* Remove the "04" prefix of non-compressed format. */
memmove (secret_x, secret_x+1, secret_x_size);
if (nbytes - secret_x_size)
memset (secret_x+secret_x_size, 0, nbytes-secret_x_size);
if (DBG_CRYPTO)
log_printhex ("ECDH shared secret X is:", secret_x, secret_x_size );

View File

@ -1520,6 +1520,13 @@ gen_ecc (int algo, const char *curve, kbnode_t pub_root,
(((keygen_flags & KEYGEN_FLAG_TRANSIENT_KEY)
&& (keygen_flags & KEYGEN_FLAG_NO_PROTECTION))?
" transient-key" : ""));
else if (algo == PUBKEY_ALGO_ECDH && !strcmp (curve, "Curve25519"))
keyparms = xtryasprintf
("(genkey(ecc(curve %zu:%s)(flags djb-tweak comp%s)))",
strlen (curve), curve,
(((keygen_flags & KEYGEN_FLAG_TRANSIENT_KEY)
&& (keygen_flags & KEYGEN_FLAG_NO_PROTECTION))?
" transient-key" : ""));
else
keyparms = xtryasprintf
("(genkey(ecc(curve %zu:%s)(flags nocomp%s)))",
@ -2125,7 +2132,7 @@ ask_keysize (int algo, unsigned int primary_keysize)
function may adjust. Returns a malloced string with the name of
the curve. BOTH tells that gpg creates a primary and subkey. */
static char *
ask_curve (int *algo, int both)
ask_curve (int *algo, int *subkey_algo)
{
struct {
const char *name;
@ -2176,7 +2183,7 @@ ask_curve (int *algo, int both)
continue;
if (!gcry_pk_get_curve (keyparms, 0, NULL))
continue;
if (both && curves[idx].fix_curve)
if (subkey_algo && curves[idx].fix_curve)
{
/* Both Curve 25519 keys are to be created. Check that
Libgcrypt also supports the real Curve25519. */
@ -2241,6 +2248,11 @@ ask_curve (int *algo, int both)
if ((*algo == PUBKEY_ALGO_ECDSA || *algo == PUBKEY_ALGO_EDDSA)
&& curves[idx].fix_curve)
{
if (subkey_algo && *subkey_algo == PUBKEY_ALGO_ECDSA)
{
*subkey_algo = PUBKEY_ALGO_EDDSA;
result = xstrdup ("Ed25519");
}
*algo = PUBKEY_ALGO_EDDSA;
result = xstrdup ("Ed25519");
}
@ -3672,7 +3684,7 @@ generate_keypair (ctrl_t ctrl, int full, const char *fname,
|| algo == PUBKEY_ALGO_EDDSA
|| algo == PUBKEY_ALGO_ECDH)
{
curve = ask_curve (&algo, both);
curve = ask_curve (&algo, &subkey_algo);
r = xmalloc_clear( sizeof *r + 20 );
r->key = pKEYTYPE;
sprintf( r->u.value, "%d", algo);
@ -3743,7 +3755,7 @@ generate_keypair (ctrl_t ctrl, int full, const char *fname,
|| algo == PUBKEY_ALGO_EDDSA
|| algo == PUBKEY_ALGO_ECDH)
{
curve = ask_curve (&algo, 0);
curve = ask_curve (&algo, NULL);
nbits = 0;
r = xmalloc_clear (sizeof *r + strlen (curve));
r->key = pKEYCURVE;
@ -4292,7 +4304,7 @@ generate_subkeypair (ctrl_t ctrl, kbnode_t keyblock)
else if (algo == PUBKEY_ALGO_ECDSA
|| algo == PUBKEY_ALGO_EDDSA
|| algo == PUBKEY_ALGO_ECDH)
curve = ask_curve (&algo, 0);
curve = ask_curve (&algo, NULL);
else
nbits = ask_keysize (algo, 0);

View File

@ -766,9 +766,12 @@ keygrip_from_pk (PKT_public_key *pk, unsigned char *array)
else
{
err = gcry_sexp_build (&s_pkey, NULL,
pk->pubkey_algo == PUBKEY_ALGO_EDDSA ?
"(public-key(ecc(curve%s)(flags eddsa)(q%m)))"
: "(public-key(ecc(curve%s)(q%m)))",
pk->pubkey_algo == PUBKEY_ALGO_EDDSA?
"(public-key(ecc(curve%s)(flags eddsa)(q%m)))":
(pk->pubkey_algo == PUBKEY_ALGO_ECDH
&& openpgp_oid_is_crv25519 (pk->pkey[0]))?
"(public-key(ecc(curve%s)(flags djb-tweak)(q%m)))":
"(public-key(ecc(curve%s)(q%m)))",
curve, pk->pkey[1]);
xfree (curve);
}

View File

@ -228,9 +228,13 @@ pk_encrypt (pubkey_algo_t algo, gcry_mpi_t *resarr, gcry_mpi_t data,
rc = gpg_error_from_syserror ();
else
{
int with_djb_tweak_flag = openpgp_oid_is_crv25519 (pkey[0]);
/* Now use the ephemeral secret to compute the shared point. */
rc = gcry_sexp_build (&s_pkey, NULL,
"(public-key(ecdh(curve%s)(q%m)))",
with_djb_tweak_flag ?
"(public-key(ecdh(curve%s)(flags djb-tweak)(q%m)))"
: "(public-key(ecdh(curve%s)(q%m)))",
curve, pkey[1]);
xfree (curve);
/* Put K into a simplified S-expression. */

View File

@ -250,8 +250,8 @@ get_it (PKT_pubkey_enc *enc, DEK *dek, PKT_public_key *sk, u32 *keyid)
if(err)
goto leave;
/* Reuse NFRAME, which size is sufficient to include the session key. */
err = gcry_mpi_print (GCRYMPI_FMT_USG, frame, nframe, &nframe, decoded);
xfree (frame);
err = gcry_mpi_aprint (GCRYMPI_FMT_USG, &frame, &nframe, decoded);
mpi_release (decoded);
if (err)
goto leave;

View File

@ -235,7 +235,7 @@ struct app_local_s {
} keyattr[3];
};
#define ECC_FLAG_EDDSA (1 << 0)
#define ECC_FLAG_DJB_TWEAK (1 << 0)
/***** Local prototypes *****/
@ -909,8 +909,9 @@ send_key_attr (ctrl_t ctrl, app_t app, const char *keyword, int keyno)
{
snprintf (buffer, sizeof buffer, "%d %d %s",
keyno+1,
app->app_local->keyattr[keyno].ecc.flags? PUBKEY_ALGO_EDDSA:
(keyno==1? PUBKEY_ALGO_ECDH: PUBKEY_ALGO_ECDSA),
keyno==1? PUBKEY_ALGO_ECDH :
app->app_local->keyattr[keyno].ecc.flags?
PUBKEY_ALGO_EDDSA : PUBKEY_ALGO_ECDSA,
openpgp_oid_to_curve (app->app_local->keyattr[keyno].ecc.oid, 0));
}
else
@ -1378,59 +1379,52 @@ get_public_key (app_t app, int keyno)
}
}
mbuf = xtrymalloc ( mlen + 1);
mbuf = xtrymalloc (mlen + 1);
if (!mbuf)
{
err = gpg_error_from_syserror ();
goto leave;
}
/* Prepend numbers with a 0 if needed. */
if ((app->app_local->keyattr[keyno].key_type == KEY_TYPE_RSA
|| (app->app_local->keyattr[keyno].key_type == KEY_TYPE_ECC
&& !app->app_local->keyattr[keyno].ecc.flags))
&& mlen && (*m & 0x80))
{
{ /* Prepend numbers with a 0 if needed for MPI. */
*mbuf = 0;
memcpy (mbuf+1, m, mlen);
mlen++;
}
else if (app->app_local->keyattr[keyno].key_type == KEY_TYPE_ECC
&& app->app_local->keyattr[keyno].ecc.flags)
{ /* Prepend 0x40 prefix. */
*mbuf = 0x40;
memcpy (mbuf+1, m, mlen);
mlen++;
}
else
memcpy (mbuf, m, mlen);
ebuf = xtrymalloc ( elen + 1);
if (!ebuf)
{
err = gpg_error_from_syserror ();
goto leave;
}
/* Prepend numbers with a 0 if needed. */
if (elen && (*e & 0x80))
{
*ebuf = 0;
memcpy (ebuf+1, e, elen);
elen++;
}
else
memcpy (ebuf, e, elen);
if (app->app_local->keyattr[keyno].key_type == KEY_TYPE_RSA)
{
err = gcry_sexp_build (&s_pkey, NULL, "(public-key(rsa(n%b)(e%b)))",
(int)mlen, mbuf, (int)elen, ebuf);
if (err)
goto leave;
len = gcry_sexp_sprint (s_pkey, GCRYSEXP_FMT_CANON, NULL, 0);
keybuf = xtrymalloc (len);
if (!keybuf)
ebuf = xtrymalloc (elen + 1);
if (!ebuf)
{
gcry_sexp_release (s_pkey);
err = gpg_error_from_syserror ();
goto leave;
}
gcry_sexp_sprint (s_pkey, GCRYSEXP_FMT_CANON, keybuf, len);
gcry_sexp_release (s_pkey);
/* Prepend numbers with a 0 if needed. */
if (elen && (*e & 0x80))
{
*ebuf = 0;
memcpy (ebuf+1, e, elen);
elen++;
}
else
memcpy (ebuf, e, elen);
err = gcry_sexp_build (&s_pkey, NULL, "(public-key(rsa(n%b)(e%b)))",
(int)mlen, mbuf, (int)elen, ebuf);
}
else if (app->app_local->keyattr[keyno].key_type == KEY_TYPE_ECC)
{
@ -1438,32 +1432,32 @@ get_public_key (app_t app, int keyno)
if (!app->app_local->keyattr[keyno].ecc.flags)
format = "(public-key(ecc(curve%s)(q%b)))";
else if (keyno == 1)
format = "(public-key(ecc(curve%s)(flags djb-tweak)(q%b)))";
else
format = "(public-key(ecc(curve%s)(flags eddsa)(q%b)))";
err = gcry_sexp_build (&s_pkey, NULL, format,
openpgp_oid_to_curve (app->app_local->keyattr[keyno].ecc.oid, 1),
(int)mlen, mbuf);
if (err)
goto leave;
len = gcry_sexp_sprint (s_pkey, GCRYSEXP_FMT_CANON, NULL, 0);
keybuf = xtrymalloc (len);
if (!keybuf)
{
gcry_sexp_release (s_pkey);
err = gpg_error_from_syserror ();
goto leave;
}
gcry_sexp_sprint (s_pkey, GCRYSEXP_FMT_CANON, keybuf, len);
gcry_sexp_release (s_pkey);
}
else
err = gpg_error (GPG_ERR_NOT_IMPLEMENTED);
if (err)
goto leave;
len = gcry_sexp_sprint (s_pkey, GCRYSEXP_FMT_CANON, NULL, 0);
keybuf = xtrymalloc (len);
if (!keybuf)
{
err = gpg_error (GPG_ERR_NOT_IMPLEMENTED);
gcry_sexp_release (s_pkey);
err = gpg_error_from_syserror ();
goto leave;
}
gcry_sexp_sprint (s_pkey, GCRYSEXP_FMT_CANON, keybuf, len);
gcry_sexp_release (s_pkey);
app->app_local->pk[keyno].key = (unsigned char*)keybuf;
app->app_local->pk[keyno].keylen = len - 1; /* Decrement for trailing '\0' */
@ -3171,7 +3165,7 @@ ecc_writekey (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
size_t ecc_q_len, ecc_d_len;
u32 created_at = 0;
const char *oidstr = NULL;
int flag_eddsa = 0;
int flag_djb_tweak = 0;
int algo;
/* (private-key(ecc(curve%s)(q%m)(d%m))(created-at%d)):
@ -3216,8 +3210,12 @@ ecc_writekey (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
if ((err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen)))
goto leave;
if (tok && toklen == 5 && !memcmp (tok, "eddsa", 5))
flag_eddsa = 1;
if (tok)
{
if ((toklen == 5 && !memcmp (tok, "eddsa", 5))
|| (toklen == 9 && !memcmp (tok, "djb-tweak", 9)))
flag_djb_tweak = 1;
}
}
else if (tok && toklen == 1)
{
@ -3237,7 +3235,7 @@ ecc_writekey (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
}
if ((err = parse_sexp (&buf, &buflen, &depth, &tok, &toklen)))
goto leave;
if (tok && buf2 && !flag_eddsa)
if (tok && buf2 && !flag_djb_tweak)
/* It's MPI. Strip off leading zero bytes and save. */
for (;toklen && !*tok; toklen--, tok++)
;
@ -3300,7 +3298,7 @@ ecc_writekey (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
err = gpg_error (GPG_ERR_INV_VALUE);
goto leave;
}
if (flag_eddsa && keyno != 1)
if (flag_djb_tweak && keyno != 1)
algo = PUBKEY_ALGO_EDDSA;
else if (keyno == 1)
algo = PUBKEY_ALGO_ECDH;
@ -3309,7 +3307,7 @@ ecc_writekey (app_t app, gpg_error_t (*pincb)(void*, const char *, char **),
if (app->app_local->keyattr[keyno].key_type != KEY_TYPE_ECC
|| app->app_local->keyattr[keyno].ecc.oid != oidstr
|| app->app_local->keyattr[keyno].ecc.flags != flag_eddsa)
|| app->app_local->keyattr[keyno].ecc.flags != flag_djb_tweak)
{
log_error ("key attribute on card doesn't match\n");
err = gpg_error (GPG_ERR_INV_VALUE);
@ -4469,11 +4467,18 @@ parse_algorithm_attribute (app_t app, int keyno)
{
app->app_local->keyattr[keyno].key_type = KEY_TYPE_ECC;
app->app_local->keyattr[keyno].ecc.oid = oid;
app->app_local->keyattr[keyno].ecc.flags = (*buffer == PUBKEY_ALGO_EDDSA);
if (*buffer == PUBKEY_ALGO_EDDSA
|| (*buffer == PUBKEY_ALGO_ECDH
&& !strcmp (app->app_local->keyattr[keyno].ecc.oid,
"1.3.6.1.4.1.3029.1.5.1")))
app->app_local->keyattr[keyno].ecc.flags = ECC_FLAG_DJB_TWEAK;
else
app->app_local->keyattr[keyno].ecc.flags = 0;
if (opt.verbose)
log_printf
("ECC, curve=%s%s\n", app->app_local->keyattr[keyno].ecc.oid,
app->app_local->keyattr[keyno].ecc.flags ? " (eddsa)": "");
!app->app_local->keyattr[keyno].ecc.flags ? "":
keyno==1? " (djb-tweak)": " (eddsa)");
}
}
else if (opt.verbose)