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'g10/gpg2 --encrypt --debug 15 -r ecdsa -a -o _e.asc _' and 'g10/gpg2 --debug 15 _e.asc', as well as decoding of an old message posted on https://sites.google.com/site/brainhub/pgpecckeys work.

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This is the milestone 2 that brings in ECDH support from http://code.google.com/p/gnupg-ecc/source/detail?r=15 .

This corresponds to the commit 899386826c85f1e757e75bcc5d5b2159d05676a0 in libgcrypt
This commit is contained in:
Andrey Jivsov 2011-01-10 20:24:14 -08:00
parent b0c55d08a8
commit 5761a9ba74
6 changed files with 73 additions and 131 deletions
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3
g10/call-agent.c
View File

@ -1744,7 +1744,6 @@ inq_ciphertext_cb (void *opaque, const char *line)
gpg_error_t
agent_pkdecrypt (ctrl_t ctrl, const char *keygrip, const char *desc,
gcry_sexp_t s_ciphertext,
const byte sk_fp[MAX_FINGERPRINT_LEN],
unsigned char **r_buf, size_t *r_buflen)
{
gpg_error_t err;
@ -1753,8 +1752,6 @@ agent_pkdecrypt (ctrl_t ctrl, const char *keygrip, const char *desc,
size_t n, len;
char *p, *buf, *endp;
/*TODO: use sk_fp */
if (!keygrip || strlen(keygrip) != 40 || !s_ciphertext || !r_buf || !r_buflen)
return gpg_error (GPG_ERR_INV_VALUE);
*r_buf = NULL;

1
g10/call-agent.h
View File

@ -168,7 +168,6 @@ gpg_error_t agent_pksign (ctrl_t ctrl, const char *cache_nonce,
/* Decrypt a ciphertext. */
gpg_error_t agent_pkdecrypt (ctrl_t ctrl, const char *keygrip, const char *desc,
gcry_sexp_t s_ciphertext,
const byte sk_fp[MAX_FINGERPRINT_LEN],
unsigned char **r_buf, size_t *r_buflen);
/* Retrieve a key encryption key. */

82
g10/ecdh.c
View File

@ -76,8 +76,6 @@ pk_ecdh_default_params_to_mpi( int qbits ) {
*/
byte *
pk_ecdh_default_params( int qbits, size_t *sizeout ) {
gpg_error_t err;
gcry_mpi_t result;
/* Defaults are the strongest possible choices. Performance is not an issue here, only interoperability. */
byte kek_params[4] = {
3 /*size of following field*/,
@ -370,6 +368,29 @@ pk_ecdh_encrypt_with_shared_point ( int is_encrypt, gcry_mpi_t shared_mpi,
return rc;
}
static gcry_mpi_t
gen_k (unsigned nbits)
{
gcry_mpi_t k;
k = gcry_mpi_snew (nbits);
if (DBG_CIPHER)
log_debug ("choosing a random k of %u bits\n", nbits);
gcry_mpi_randomize (k, nbits-1, GCRY_STRONG_RANDOM);
if( DBG_CIPHER ) {
unsigned char *buffer;
if (gcry_mpi_aprint (GCRYMPI_FMT_HEX, &buffer, NULL, k))
BUG ();
log_debug("ephemeral scalar MPI #0: %s\n", buffer);
gcry_free( buffer );
}
return k;
}
/* Perform ECDH encryption, which involves ECDH key generation.
*/
int
@ -377,25 +398,17 @@ pk_ecdh_encrypt (gcry_mpi_t * resarr, const byte pk_fp[MAX_FINGERPRINT_LEN], gcr
{
gcry_sexp_t s_ciph, s_data, s_pkey;
PKT_public_key *pk_eph;
int nbits;
int rc;
gcry_mpi_t k;
nbits = pubkey_nbits( PUBKEY_ALGO_ECDH, pkey );
/*** Generate an ephemeral key ***/
rc = pk_ecc_keypair_gen( &pk_eph, PUBKEY_ALGO_ECDH, KEYGEN_FLAG_TRANSIENT_KEY | KEYGEN_FLAG_NO_PROTECTION /*this is ephemeral*/, "", nbits );
if( rc )
return rc;
if( DBG_CIPHER ) {
unsigned char *buffer;
if (gcry_mpi_aprint (GCRYMPI_FMT_HEX, &buffer, NULL, pk_eph->pkey[1]))
BUG ();
log_debug("ephemeral key MPI #0: %s\n", buffer);
gcry_free( buffer );
}
free_public_key (pk_eph);
/*** Generate an ephemeral key, actually, a scalar ***/
k = gen_k (nbits);
if( k == NULL )
BUG ();
/*** Done with ephemeral key generation.
* Now use ephemeral secret to get the shared secret. ***/
@ -406,7 +419,7 @@ pk_ecdh_encrypt (gcry_mpi_t * resarr, const byte pk_fp[MAX_FINGERPRINT_LEN], gcr
BUG ();
/* put the data into a simple list */
if (gcry_sexp_build (&s_data, NULL, "%m", pk_eph->pkey[3])) /* ephemeral scalar goes as data */
if (gcry_sexp_build (&s_data, NULL, "%m", k)) /* ephemeral scalar goes as data */
BUG ();
/* pass it to libgcrypt */
@ -421,7 +434,7 @@ pk_ecdh_encrypt (gcry_mpi_t * resarr, const byte pk_fp[MAX_FINGERPRINT_LEN], gcr
{
gcry_mpi_t shared = mpi_from_sexp (s_ciph, "a"); /* ... and get the shared point */
gcry_sexp_release (s_ciph);
resarr[0] = pk_eph->pkey[1]; /* ephemeral public key */
resarr[0] = mpi_from_sexp (s_ciph, "b"); /* ephemeral public key */
if( DBG_CIPHER ) {
unsigned char *buffer;
@ -441,37 +454,10 @@ pk_ecdh_encrypt (gcry_mpi_t * resarr, const byte pk_fp[MAX_FINGERPRINT_LEN], gcr
/* Perform ECDH decryption.
*/
int
pk_ecdh_decrypt (gcry_mpi_t * result, const byte sk_fp[MAX_FINGERPRINT_LEN], gcry_mpi_t *data, gcry_mpi_t * skey) {
gcry_sexp_t s_skey, s_data, s_ciph;
int rc;
if (!data[0] || !data[1])
pk_ecdh_decrypt (gcry_mpi_t * result, const byte sk_fp[MAX_FINGERPRINT_LEN], gcry_mpi_t data, gcry_mpi_t shared, gcry_mpi_t * skey) {
if (!data)
return gpg_error (GPG_ERR_BAD_MPI);
rc = gcry_sexp_build (&s_skey, NULL,
"(public-key(ecdh(c%m)(q%m)(p%m)))",
skey[0]/*curve*/, data[0]/*ephemeral key*/, skey[2]/*KDF params*/);
if (rc)
BUG ();
/* put the data into a simple list */
if (gcry_sexp_build (&s_data, NULL, "%m", skey[3])) /* static private key (scalar) goes as data */
BUG ();
rc = gcry_pk_encrypt (&s_ciph, s_data, s_skey); /* encrypting ephemeral key with our private scalar yields the shared point */
gcry_sexp_release (s_skey);
gcry_sexp_release (s_data);
if (rc)
return rc;
{
gcry_mpi_t shared = mpi_from_sexp (s_ciph, "a"); /* get the shared point */
gcry_sexp_release (s_ciph);
rc = pk_ecdh_encrypt_with_shared_point ( 0 /*=decryption*/, shared, sk_fp, data[1]/*encr data as an MPI*/, skey, result );
mpi_release( shared );
}
return rc;
return pk_ecdh_encrypt_with_shared_point ( 0 /*=decryption*/, shared, sk_fp, data/*encr data as an MPI*/, skey, result );
}

74
g10/pkglue.c
View File

@ -257,80 +257,6 @@ pk_encrypt (int algo, gcry_mpi_t * resarr, gcry_mpi_t data, const byte pk_fp[MAX
return rc;
}
/****************
* Emulate our old PK interface here - sometime in the future we might
* change the internal design to directly fit to libgcrypt.
*/
int
pk_decrypt (int algo, gcry_mpi_t * result, const byte sk_fp[MAX_FINGERPRINT_LEN], gcry_mpi_t * data,
gcry_mpi_t * skey)
{
gcry_sexp_t s_skey, s_data, s_plain;
int rc;
*result = NULL;
/* make a sexp from skey */
if (algo == GCRY_PK_ELG || algo == GCRY_PK_ELG_E)
{
rc = gcry_sexp_build (&s_skey, NULL,
"(private-key(elg(p%m)(g%m)(y%m)(x%m)))",
skey[0], skey[1], skey[2], skey[3]);
}
else if (algo == GCRY_PK_RSA || algo == GCRY_PK_RSA_E)
{
rc = gcry_sexp_build (&s_skey, NULL,
"(private-key(rsa(n%m)(e%m)(d%m)(p%m)(q%m)(u%m)))",
skey[0], skey[1], skey[2], skey[3], skey[4],
skey[5]);
}
else if( algo == PUBKEY_ALGO_ECDH ) {
return pk_ecdh_decrypt( result, sk_fp, data, skey );
}
else
return GPG_ERR_PUBKEY_ALGO;
if (rc)
BUG ();
/* put data into a S-Exp s_data */
if (algo == GCRY_PK_ELG || algo == GCRY_PK_ELG_E)
{
if (!data[0] || !data[1])
rc = gpg_error (GPG_ERR_BAD_MPI);
else
rc = gcry_sexp_build (&s_data, NULL,
"(enc-val(elg(a%m)(b%m)))", data[0], data[1]);
}
else if (algo == GCRY_PK_RSA || algo == GCRY_PK_RSA_E)
{
if (!data[0])
rc = gpg_error (GPG_ERR_BAD_MPI);
else
rc = gcry_sexp_build (&s_data, NULL, "(enc-val(rsa(a%m)))", data[0]);
}
else
BUG ();
if (rc)
BUG ();
rc = gcry_pk_decrypt (&s_plain, s_data, s_skey);
gcry_sexp_release (s_skey);
gcry_sexp_release (s_data);
if (rc)
return rc;
*result = gcry_sexp_nth_mpi (s_plain, 0, 0);
gcry_sexp_release (s_plain);
if (!*result)
return -1; /* oops */
return 0;
}
/* Check whether SKEY is a suitable secret key. */
int
pk_check_secret_key (int algo, gcry_mpi_t *skey)

4
g10/pkglue.h
View File

@ -33,8 +33,8 @@ int pk_decrypt (int algo, gcry_mpi_t *result, const byte fp[MAX_FINGERPRINT_LEN]
gcry_mpi_t *skey);
int pk_check_secret_key (int algo, gcry_mpi_t *skey);
int pk_ecdh_encrypt (gcry_mpi_t * resarr, const byte pk_fp[MAX_FINGERPRINT_LEN], gcry_mpi_t data, gcry_mpi_t * pkey);
int pk_ecdh_decrypt (gcry_mpi_t * result, const byte sk_fp[MAX_FINGERPRINT_LEN], gcry_mpi_t *data, gcry_mpi_t * skey);
int pk_ecdh_encrypt (gcry_mpi_t * resarr, const byte pk_fp[MAX_FINGERPRINT_LEN], gcry_mpi_t data, gcry_mpi_t * pkey);
int pk_ecdh_decrypt (gcry_mpi_t * result, const byte sk_fp[MAX_FINGERPRINT_LEN], gcry_mpi_t data, gcry_mpi_t shared, gcry_mpi_t * skey);
gcry_mpi_t pk_ecdh_default_params_to_mpi( int qbits );
byte *pk_ecdh_default_params( int qbits, size_t *sizeout );

40
g10/pubkey-enc.c
View File

@ -147,14 +147,16 @@ get_it (PKT_pubkey_enc *enc, DEK *dek, PKT_public_key *sk, u32 *keyid)
char *keygrip;
byte fp[MAX_FINGERPRINT_LEN];
size_t fpn;
const int gcry_pkalgo = map_pk_openpgp_to_gcry( sk->pubkey_algo );
/* Get the keygrip. */
err = hexkeygrip_from_pk (sk, &keygrip);
if (err)
goto leave;
/* Convert the data to an S-expression. */
if (sk->pubkey_algo == GCRY_PK_ELG || sk->pubkey_algo == GCRY_PK_ELG_E)
if (gcry_pkalgo == GCRY_PK_ELG ||gcry_pkalgo == GCRY_PK_ELG_E)
{
if (!enc->data[0] || !enc->data[1])
err = gpg_error (GPG_ERR_BAD_MPI);
@ -162,7 +164,7 @@ get_it (PKT_pubkey_enc *enc, DEK *dek, PKT_public_key *sk, u32 *keyid)
err = gcry_sexp_build (&s_data, NULL, "(enc-val(elg(a%m)(b%m)))",
enc->data[0], enc->data[1]);
}
else if (sk->pubkey_algo == GCRY_PK_RSA || sk->pubkey_algo == GCRY_PK_RSA_E)
else if (gcry_pkalgo == GCRY_PK_RSA || gcry_pkalgo == GCRY_PK_RSA_E)
{
if (!enc->data[0])
err = gpg_error (GPG_ERR_BAD_MPI);
@ -170,6 +172,14 @@ get_it (PKT_pubkey_enc *enc, DEK *dek, PKT_public_key *sk, u32 *keyid)
err = gcry_sexp_build (&s_data, NULL, "(enc-val(rsa(a%m)))",
enc->data[0]);
}
else if (gcry_pkalgo == GCRY_PK_ECDH )
{
if (!enc->data[0] || !enc->data[1])
err = gpg_error (GPG_ERR_BAD_MPI);
else
err = gcry_sexp_build (&s_data, NULL, "(enc-val(ecdh(a%m)(b%m)))",
enc->data[0], enc->data[1]);
}
else
err = gpg_error (GPG_ERR_BUG);
@ -181,7 +191,7 @@ get_it (PKT_pubkey_enc *enc, DEK *dek, PKT_public_key *sk, u32 *keyid)
/* Decrypt. */
desc = gpg_format_keydesc (sk, 0, 1);
err = agent_pkdecrypt (NULL, keygrip, desc, s_data, fp, &frame, &nframe);
err = agent_pkdecrypt (NULL, keygrip, desc, s_data, &frame, &nframe);
xfree (desc);
gcry_sexp_release (s_data);
if (err)
@ -233,6 +243,30 @@ get_it (PKT_pubkey_enc *enc, DEK *dek, PKT_public_key *sk, u32 *keyid)
}
}
else {
gcry_mpi_t shared_mpi;
gcry_mpi_t decoded;
/* at the beginning the frame is the bytes of shared point MPI */
err = gcry_mpi_scan (&shared_mpi, GCRYMPI_FMT_USG, frame, nframe, NULL);
if (err) {
log_fatal ("mpi_scan failed: %s\n", gpg_strerror (err));
goto leave;
}
err = pk_ecdh_decrypt (&decoded, fp, enc->data[1]/*encr data as an MPI*/, shared_mpi, sk->pkey);
mpi_release( shared_mpi );
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);
mpi_release( decoded );
if( err )
goto leave;
/* Now the frame is the bytes decrypted but padded session key */
/* Allow double padding for the benefit of DEK size concealment.
* Higher than this is wasteful.
*/