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-rw-r--r--libcmix-crypto/elgamal/elgamal.c1
-rw-r--r--libcmix-crypto/elgamal/elgamal.h2
-rw-r--r--libcmix-crypto/elgamal/gcrypt/gcrypt_elgamal.c82
3 files changed, 63 insertions, 22 deletions
diff --git a/libcmix-crypto/elgamal/elgamal.c b/libcmix-crypto/elgamal/elgamal.c
index dbfccb9..1525618 100644
--- a/libcmix-crypto/elgamal/elgamal.c
+++ b/libcmix-crypto/elgamal/elgamal.c
@@ -20,6 +20,7 @@ struct Api get_elgamal_implementation()
.derive_shared_key = elgamal_derive_shared_key,
.free_shared_key = elgamal_delete_shared_key,
.encrypt = elgamal_encrypt,
+ .invert = elgamal_invert,
.deinitialize = elgamal_deinitialize
};
}
diff --git a/libcmix-crypto/elgamal/elgamal.h b/libcmix-crypto/elgamal/elgamal.h
index 21bf58a..1fcb044 100644
--- a/libcmix-crypto/elgamal/elgamal.h
+++ b/libcmix-crypto/elgamal/elgamal.h
@@ -42,6 +42,8 @@ extern SharedKeyDeleter elgamal_delete_shared_key;
extern Encrypter elgamal_encrypt;
+extern Inverter elgamal_invert;
+
extern Deinitializer elgamal_deinitialize;
/*!
diff --git a/libcmix-crypto/elgamal/gcrypt/gcrypt_elgamal.c b/libcmix-crypto/elgamal/gcrypt/gcrypt_elgamal.c
index 1824ccc..8a6fb7e 100644
--- a/libcmix-crypto/elgamal/gcrypt/gcrypt_elgamal.c
+++ b/libcmix-crypto/elgamal/gcrypt/gcrypt_elgamal.c
@@ -9,6 +9,7 @@
static gcry_mpi_t p;
static gcry_mpi_t q;
static gcry_mpi_t g;
+static unsigned int nr_bytes = 2;
void check(gcry_error_t error) {
if (error) {
@@ -44,9 +45,13 @@ void gcrypt_elgamal_initialize(void) {
gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
//leading 0 as specified by libgcrypt
- char p_hex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
- char q_hex[] = "08CF83642A709A097B447997640129DA299B1A47D1EB3750BA308B0FE64F5FBD3";
- char g_hex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
+ //char p_hex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
+ //char q_hex[] = "08CF83642A709A097B447997640129DA299B1A47D1EB3750BA308B0FE64F5FBD3";
+ //char g_hex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
+
+ char p_hex[] = "0b";
+ char q_hex[] = "00";
+ char g_hex[] = "02";
size_t nr_bytes_scanned;
gcry_error_t error;
@@ -66,11 +71,15 @@ struct KeyPair gcrypt_elgamal_create_keypair() {
size_t parse_error_offset;
gcry_error_t error;
- void* bytes = gcry_random_bytes_secure(2048/8, GCRY_VERY_STRONG_RANDOM);
- gcry_mpi_t x;
- error = gcry_mpi_scan(&x, GCRYMPI_FMT_USG, bytes, 2048/8, &parse_error_offset);
- check(error);
-
+ gcry_mpi_t x = NULL;
+ do {
+ gcry_mpi_release(x);
+ void* bytes = gcry_random_bytes_secure(nr_bytes, GCRY_VERY_STRONG_RANDOM);
+ error = gcry_mpi_scan(&x, GCRYMPI_FMT_USG, bytes, nr_bytes, &parse_error_offset);
+ gcry_free(bytes);
+ check(error);
+ gcry_mpi_mod(x, x, p); //bias needs to be removed.
+ } while(gcry_mpi_cmp_ui(x, 0) == 0 || gcry_mpi_cmp(x, p) != -1);
gcry_mpi_t y = gcry_mpi_new(0);
gcry_mpi_powm(y, g, x, p);
@@ -82,7 +91,6 @@ struct KeyPair gcrypt_elgamal_create_keypair() {
check(error);
gcry_sexp_release(priv_key);
- gcry_free(bytes);
return (struct KeyPair){
x,
@@ -115,7 +123,7 @@ void* gcrypt_elgamal_array_to_element(char const* buffer, size_t len, bool secur
gcry_mpi_t mpi;
error = gcry_mpi_scan(&mpi, GCRYMPI_FMT_USG, buffer, len, &error_pos);
- gcry_mpi_set_flag(mpi, GCRYMPI_FLAG_SECURE);
+ //gcry_mpi_set_flag(mpi, GCRYMPI_FLAG_SECURE);
check(error);
return mpi;
@@ -125,14 +133,18 @@ void* gcrypt_elgamal_get_group_element(bool secure) {
size_t parse_error_offset;
gcry_error_t error;
- void* bytes = gcry_random_bytes_secure(2048/8, GCRY_VERY_STRONG_RANDOM);
- gcry_mpi_t a;
- error = gcry_mpi_scan(&a, GCRYMPI_FMT_USG, bytes, 2048/8, &parse_error_offset);
+ gcry_mpi_t a = NULL;
+ do {
+ gcry_mpi_release(a);
+ void* bytes = gcry_random_bytes_secure(nr_bytes, GCRY_VERY_STRONG_RANDOM);
+ error = gcry_mpi_scan(&a, GCRYMPI_FMT_USG, bytes, nr_bytes, &parse_error_offset);
+ check(error);
+ gcry_mpi_mod(a, a, p); //BIAS REMOVE THIS.
+ gcry_free(bytes);
+ } while(gcry_mpi_cmp_ui(a, 0) == 0 || gcry_mpi_cmp(a, p) != -1);
//random bytes generated with GCRY{,_VERY}_STRONG_RANDOM are generated in "secure memory"
//so secure is unused.
- check(error);
- gcry_free(bytes);
return a;
}
@@ -153,17 +165,21 @@ GroupElement gcrypt_elgamal_multiply(GroupElement lh, GroupElement rh, bool secu
}
GroupElement gcrypt_elgamal_get_decryption_share(GroupElement r, GroupElement e) {
- gcry_mpi_t inve = gcry_mpi_snew(0);
- gcry_mpi_invm(inve, (gcry_mpi_t)e, p);
+ //gcry_mpi_t inve = gcry_mpi_snew(0);
+ //gcry_mpi_invm(inve, (gcry_mpi_t)e, p);
+
+ gcry_mpi_t inv_d = gcry_mpi_snew(0);
+ gcry_mpi_powm(inv_d, (gcry_mpi_t)r, (gcry_mpi_t)e, p);
gcry_mpi_t d = gcry_mpi_snew(0);
- gcry_mpi_powm(d, (gcry_mpi_t)r, inve, p);
- gcry_mpi_release(inve);
+ gcry_mpi_invm(d, inv_d, p);
+
+ gcry_mpi_release(inv_d);
return d;
}
size_t gcrypt_elgamal_get_group_element_array_size() {
- return 256u;
+ return nr_bytes;
}
void gcrypt_elgamal_delete_group_element(void* el) {
@@ -213,7 +229,22 @@ void gcrypt_elgamal_delete_shared_key(struct SharedKey* s) {
}
void gcrypt_elgamal_encrypt(GroupElement* random_element, GroupElement* message_element, GroupElement value, GroupElement key) {
- gcry_error_t error;
+
+ GroupElement random = gcrypt_elgamal_get_group_element(true);
+
+ *random_element = gcry_mpi_new(0);
+ gcry_mpi_powm((gcry_mpi_t) *random_element, g, (gcry_mpi_t) random, p);
+
+ gcry_mpi_t key_pow_random = gcry_mpi_snew(0);
+ gcry_mpi_powm(key_pow_random, (gcry_mpi_t) key, (gcry_mpi_t) random, p);
+
+ *message_element = gcry_mpi_snew(0);
+ gcry_mpi_mulm((gcry_mpi_t)*message_element, (gcry_mpi_t) value, key_pow_random, p);
+
+ gcry_mpi_release((gcry_mpi_t) random);
+ gcry_mpi_release(key_pow_random);
+
+/* gcry_error_t error;
size_t parse_error_pos;
gcry_sexp_t pubkey_expr;
@@ -232,7 +263,13 @@ void gcrypt_elgamal_encrypt(GroupElement* random_element, GroupElement* message_
gcry_sexp_release(enc_expr);
gcry_sexp_release(value_expr);
- gcry_sexp_release(pubkey_expr);
+ gcry_sexp_release(pubkey_expr); */
+}
+
+GroupElement gcrypt_elgamal_invert(GroupElement const x) {
+ gcry_mpi_t inv_x = gcry_mpi_new(0);
+ gcry_mpi_invm(inv_x, (gcry_mpi_t)x, p);
+ return inv_x;
}
void gcrypt_elgamal_deinitialize(void) {
@@ -257,4 +294,5 @@ PublicShareAdder elgamal_add_public_share = &gcrypt_elgamal_add_public_share;
SharedKeyDeriver elgamal_derive_shared_key = &gcrypt_elgamal_derive_shared_key;
SharedKeyDeleter elgamal_delete_shared_key = &gcrypt_elgamal_delete_shared_key;
Encrypter elgamal_encrypt = &gcrypt_elgamal_encrypt;
+Inverter elgamal_invert = &gcrypt_elgamal_invert;
Deinitializer elgamal_deinitialize = &gcrypt_elgamal_deinitialize; \ No newline at end of file
generated by cgit v1.2.3-70-g09d2 (git 2.49.0) at 2025-12-16 11:35:19 +0000