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#include <ccan/crypto/hkdf_sha256/hkdf_sha256.h>
#include <ccan/crypto/sha256/sha256.h>
#include <common/derive_basepoints.h>
#include <common/utils.h>
#include <wire/wire.h>
#if DEVELOPER
/* If they specify --dev-force-channel-secrets it ends up in here. */
struct secrets *dev_force_channel_secrets;
struct sha256 *dev_force_channel_secrets_shaseed;
void towire_secrets(u8 **pptr, const struct secrets *s)
{
towire_privkey(pptr, &s->funding_privkey);
towire_secret(pptr, &s->revocation_basepoint_secret);
towire_secret(pptr, &s->payment_basepoint_secret);
towire_secret(pptr, &s->delayed_payment_basepoint_secret);
towire_secret(pptr, &s->htlc_basepoint_secret);
}
void fromwire_secrets(const u8 **ptr, size_t *max, struct secrets *s)
{
fromwire_privkey(ptr, max, &s->funding_privkey);
fromwire_secret(ptr, max, &s->revocation_basepoint_secret);
fromwire_secret(ptr, max, &s->payment_basepoint_secret);
fromwire_secret(ptr, max, &s->delayed_payment_basepoint_secret);
fromwire_secret(ptr, max, &s->htlc_basepoint_secret);
}
#else /* !DEVELOPER */
/* Generate code refers to this, but should never be called! */
void towire_secrets(u8 **pptr, const struct secrets *s)
{
abort();
}
void fromwire_secrets(const u8 **ptr, size_t *max, struct secrets *s)
{
abort();
}
#endif
struct keys {
struct privkey f, r, h, p, d;
struct sha256 shaseed;
};
static void derive_keys(const struct secret *seed, struct keys *keys)
{
hkdf_sha256(keys, sizeof(*keys), NULL, 0, seed, sizeof(*seed),
"c-lightning", strlen("c-lightning"));
#if DEVELOPER
if (dev_force_channel_secrets) {
keys->f = dev_force_channel_secrets->funding_privkey;
keys->r.secret = dev_force_channel_secrets->revocation_basepoint_secret;
keys->p.secret = dev_force_channel_secrets->payment_basepoint_secret;
keys->h.secret = dev_force_channel_secrets->htlc_basepoint_secret;
keys->d.secret = dev_force_channel_secrets->delayed_payment_basepoint_secret;
}
if (dev_force_channel_secrets_shaseed)
keys->shaseed = *dev_force_channel_secrets_shaseed;
#endif
}
bool derive_basepoints(const struct secret *seed,
struct pubkey *funding_pubkey,
struct basepoints *basepoints,
struct secrets *secrets,
struct sha256 *shaseed)
{
struct keys keys;
derive_keys(seed, &keys);
if (secrets) {
secrets->funding_privkey = keys.f;
secrets->revocation_basepoint_secret = keys.r.secret;
secrets->payment_basepoint_secret = keys.p.secret;
secrets->htlc_basepoint_secret = keys.h.secret;
secrets->delayed_payment_basepoint_secret = keys.d.secret;
}
if (funding_pubkey) {
if (!pubkey_from_privkey(&keys.f, funding_pubkey))
return false;
}
if (basepoints) {
if (!pubkey_from_privkey(&keys.r, &basepoints->revocation)
|| !pubkey_from_privkey(&keys.p, &basepoints->payment)
|| !pubkey_from_privkey(&keys.h, &basepoints->htlc)
|| !pubkey_from_privkey(&keys.d, &basepoints->delayed_payment))
return false;
}
/* BOLT #3:
*
* A node:
* - MUST select an unguessable 256-bit seed for each connection,
* - MUST NOT reveal the seed.
*/
if (shaseed)
*shaseed = keys.shaseed;
return true;
}
bool per_commit_secret(const struct sha256 *shaseed,
struct secret *commit_secret,
u64 per_commit_index)
{
struct sha256 s;
if (per_commit_index >= (1ULL << SHACHAIN_BITS))
return false;
shachain_from_seed(shaseed, shachain_index(per_commit_index), &s);
BUILD_ASSERT(sizeof(s) == sizeof(*commit_secret));
memcpy(commit_secret, &s, sizeof(s));
return true;
}
bool per_commit_point(const struct sha256 *shaseed,
struct pubkey *commit_point,
u64 per_commit_index)
{
struct secret secret;
if (!per_commit_secret(shaseed, &secret, per_commit_index))
return false;
/* BOLT #3:
*
* The `per_commitment_point` is generated using elliptic-curve
* multiplication:
*
* per_commitment_point = per_commitment_secret * G
*/
if (secp256k1_ec_pubkey_create(secp256k1_ctx,
&commit_point->pubkey,
secret.data) != 1)
return false;
return true;
}
bool derive_payment_basepoint(const struct secret *seed,
struct pubkey *payment_basepoint,
struct secret *payment_secret)
{
struct keys keys;
derive_keys(seed, &keys);
if (payment_basepoint) {
if (!pubkey_from_privkey(&keys.p, payment_basepoint))
return false;
}
if (payment_secret)
*payment_secret = keys.p.secret;
return true;
}
bool derive_delayed_payment_basepoint(const struct secret *seed,
struct pubkey *delayed_payment_basepoint,
struct secret *delayed_payment_secret)
{
struct keys keys;
derive_keys(seed, &keys);
if (delayed_payment_basepoint) {
if (!pubkey_from_privkey(&keys.d, delayed_payment_basepoint))
return false;
}
if (delayed_payment_secret)
*delayed_payment_secret = keys.d.secret;
return true;
}
bool derive_shaseed(const struct secret *seed, struct sha256 *shaseed)
{
struct keys keys;
derive_keys(seed, &keys);
*shaseed = keys.shaseed;
return true;
}
bool derive_funding_key(const struct secret *seed,
struct pubkey *funding_pubkey,
struct privkey *funding_privkey)
{
struct keys keys;
derive_keys(seed, &keys);
if (funding_pubkey) {
if (!pubkey_from_privkey(&keys.f, funding_pubkey))
return false;
}
if (funding_privkey)
*funding_privkey = keys.f;
return true;
}
bool derive_revocation_basepoint(const struct secret *seed,
struct pubkey *revocation_basepoint,
struct secret *revocation_secret)
{
struct keys keys;
derive_keys(seed, &keys);
if (revocation_basepoint) {
if (!pubkey_from_privkey(&keys.r, revocation_basepoint))
return false;
}
if (revocation_secret)
*revocation_secret = keys.r.secret;
return true;
}
bool derive_htlc_basepoint(const struct secret *seed,
struct pubkey *htlc_basepoint,
struct secret *htlc_secret)
{
struct keys keys;
derive_keys(seed, &keys);
if (htlc_basepoint) {
if (!pubkey_from_privkey(&keys.h, htlc_basepoint))
return false;
}
if (htlc_secret)
*htlc_secret = keys.h.secret;
return true;
}
void towire_basepoints(u8 **pptr, const struct basepoints *b)
{
towire_pubkey(pptr, &b->revocation);
towire_pubkey(pptr, &b->payment);
towire_pubkey(pptr, &b->htlc);
towire_pubkey(pptr, &b->delayed_payment);
}
void fromwire_basepoints(const u8 **ptr, size_t *max,
struct basepoints *b)
{
fromwire_pubkey(ptr, max, &b->revocation);
fromwire_pubkey(ptr, max, &b->payment);
fromwire_pubkey(ptr, max, &b->htlc);
fromwire_pubkey(ptr, max, &b->delayed_payment);
}
bool shachain_get_secret(const struct shachain *shachain,
u64 commit_num,
struct secret *preimage)
{
struct sha256 sha;
if (commit_num >= (1ULL << SHACHAIN_BITS))
return false;
if (!shachain_get_hash(shachain, shachain_index(commit_num), &sha))
return false;
BUILD_ASSERT(sizeof(*preimage) == sizeof(sha));
memcpy(preimage, &sha, sizeof(*preimage));
return true;
}