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Another intermediate save for ephemeral

yamux
John Jones 2017-02-06 19:04:01 -05:00
parent f9ba2f6c0f
commit 030b2b197d
4 changed files with 110 additions and 7 deletions
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109
crypto/ephemeral.c
View File

@ -7,10 +7,11 @@
#include "mbedtls/ctr_drbg.h"
#include "libp2p/crypto/ephemeral.h"
struct EphemeralPrivateKey* libp2p_crypto_ephemeral_key_new(uint64_t priv, uint64_t x, uint64_t y) {
struct EphemeralPrivateKey* libp2p_crypto_ephemeral_key_new(uint64_t priv, uint64_t x, uint64_t y, size_t num_bits) {
struct EphemeralPrivateKey* results = (struct EphemeralPrivateKey*)malloc(sizeof(struct EphemeralPrivateKey));
if (results != NULL) {
results->secret_key = priv;
results->num_bits = num_bits;
results->public_key = (struct EphemeralPublicKey*)malloc(sizeof(struct EphemeralPublicKey));
if (results->public_key == NULL) {
free(results);
@ -18,6 +19,7 @@ struct EphemeralPrivateKey* libp2p_crypto_ephemeral_key_new(uint64_t priv, uint6
} else {
results->public_key->x = x;
results->public_key->y = y;
results->public_key->num_bits = num_bits;
}
}
return results;
@ -31,13 +33,77 @@ void libp2p_crypto_ephemeral_key_free(struct EphemeralPrivateKey* in) {
}
}
void serialize_uint64(const uint64_t in, unsigned char out[8]) {
out[0] = in >> 56;
out[1] = in >> 48;
out[2] = in >> 40;
out[3] = in >> 32;
out[4] = in >> 24;
out[5] = in >> 16;
out[6] = in >> 8;
out[7] = in;
}
uint64_t unserialize_uint64(unsigned char in[8]) {
uint64_t out = 0;
out = (out << 8) | in[0];
out = (out << 8) | in[1];
out = (out << 8) | in[2];
out = (out << 8) | in[3];
out = (out << 8) | in[4];
out = (out << 8) | in[5];
out = (out << 8) | in[6];
out = (out << 8) | in[7];
return out;
}
/***
* Take the public pieces of an ephemeral key and turn them into a byte stream
* @param bit_size the curve bit size
* @param x the x parameter of the ephemeral key
* @param y the y parameter of the ephemeral key
* @param results where to put the bytes
* @param bytes_written how many bytes were written to results
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_crypto_ephemeral_point_marshal(int bit_size, uint64_t x, uint64_t y, unsigned char** results, size_t* bytes_written) {
int byteLen = (bit_size + 7) >> 3;
*results = (unsigned char*)malloc(2*byteLen+1);
*results[0] = 4; // uncompressed point
int uint64_len = 8;
unsigned char buffer[8];
serialize_uint64(x, &buffer[0]);
memcpy(&(*results)[1 + byteLen - uint64_len], &buffer[0], 8);
serialize_uint64(y, &buffer[0]);
memcpy(&(*results)[1 + 2*byteLen - uint64_len], &buffer[0], 8);
*bytes_written = 2 * byteLen + 1;
return 1;
}
int libp2p_crypto_ephemeral_point_unmarshal(int bit_size, unsigned char* buffer, size_t buffer_length, uint64_t* x, uint64_t* y) {
int byteLen = (bit_size + 7) >> 3;
if (buffer_length != 2 * byteLen + 1)
return 0;
if (buffer[0] != 4)
return 0;
unsigned char temp[8];
memcpy((char*)temp, &buffer[1], 8);
*x = unserialize_uint64(temp);
memcpy((char*)temp, &buffer[9], 8);
*y = unserialize_uint64(temp);
return 1;
}
/**
* Generate a Ephemeral Public Key as well as a shared key
* Generate a Ephemeral keypair
* @param curve the curve to use (P-256, P-384, or P-521)
* @param private_key the struct to store the generated key
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_crypto_ephemeral_key_generate(char* curve, struct EphemeralPrivateKey** private_key) {
int libp2p_crypto_ephemeral_keypair_generate(char* curve, struct EphemeralPrivateKey** private_key) {
int retVal = 0;
mbedtls_ecdsa_context ctx;
mbedtls_entropy_context entropy;
@ -64,10 +130,45 @@ int libp2p_crypto_ephemeral_key_generate(char* curve, struct EphemeralPrivateKey
if (mbedtls_ecdsa_genkey(&ctx, selected_curve, mbedtls_ctr_drbg_random, &ctr_drbg) != 0)
goto exit;
*private_key = libp2p_crypto_ephemeral_key_new(*ctx.d.p, *ctx.Q.X.p, *ctx.Q.Y.p);
*private_key = libp2p_crypto_ephemeral_key_new(*ctx.d.p, *ctx.Q.X.p, *ctx.Q.Y.p, ctx.grp.nbits);
retVal = 1;
exit:
return retVal;
}
/**
* Generate a public key from a private key
* @param public key
* @param results the results
* @param bytes_written the number of bytes written
* @returns true(1) on success, otherwise false(0)
*/
int libp2p_crypto_ephemeral_keypair_to_public_bytes(struct EphemeralPublicKey* public_key, unsigned char** results, size_t* bytes_written) {
return libp2p_crypto_ephemeral_point_marshal(public_key->num_bits, public_key->x, public_key->y, results, bytes_written);
}
/***
* Generate a shared secret from a private key
* @param private key
* @param results
*/
int libp2p_crypto_ephemeral_keypair_to_shared_secret(struct EphemeralPrivateKey* private_key, unsigned char** results, size_t* bytes_written) {
// grab a scalar mult
// in GO, ScalarMult turns the bytes of the private key into a multiplier
// for the points
/*
* Multiplication R = m * P
*/
/*
int mbedtls_ecp_mul( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
const mbedtls_mpi *m, const mbedtls_ecp_point *P,
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng )
*/
// turn it into bytes
//TODO: implement
return 0;
}

4
include/libp2p/crypto/ephemeral.h
View File

@ -7,11 +7,13 @@
*/
struct EphemeralPublicKey {
size_t num_bits;
uint64_t x;
uint64_t y;
};
struct EphemeralPrivateKey {
size_t num_bits;
uint64_t secret_key;
struct EphemeralPublicKey* public_key;
};
@ -22,4 +24,4 @@ struct EphemeralPrivateKey {
* @param private_key where to store the private key
* @reutrns true(1) on success, otherwise false(0)
*/
int libp2p_crypto_ephemeral_key_generate(char* curve, struct EphemeralPrivateKey** private_key);
int libp2p_crypto_ephemeral_keypair_generate(char* curve, struct EphemeralPrivateKey** private_key);

2
secio/secio.c
View File

@ -345,7 +345,7 @@ int libp2p_secio_handshake(struct SecureSession* local_session, struct RsaPrivat
// generate EphemeralPubKey
struct EphemeralPrivateKey* e_private_key;
libp2p_crypto_ephemeral_key_generate(local_session->chosen_curve, &e_private_key);
libp2p_crypto_ephemeral_keypair_generate(local_session->chosen_curve, &e_private_key);
// build buffer to sign
char_buffer = libp2p_utils_vector_new();
if (char_buffer == NULL)

2
test/crypto/test_ephemeral.h
View File

@ -6,7 +6,7 @@
*/
int test_ephemeral_key_generate() {
struct EphemeralPrivateKey* private_key;
int retVal = libp2p_crypto_ephemeral_key_generate("P-256", &private_key);
int retVal = libp2p_crypto_ephemeral_keypair_generate("P-256", &private_key);
if (retVal && private_key->secret_key > 0 && private_key->public_key->x > 0 && private_key->public_key->y > 0)
return 1;
return 0;