core-lightning/common/blindedpath.h
Rusty Russell 3a966191b8 common/blindedpath: enctlv unwrapping primitives.
And we check them on our test vectors.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2021-09-22 09:10:34 +09:30

116 lines
4.0 KiB
C

#ifndef LIGHTNING_COMMON_BLINDEDPATH_H
#define LIGHTNING_COMMON_BLINDEDPATH_H
#include "config.h"
#include <ccan/compiler/compiler.h>
#include <ccan/short_types/short_types.h>
#include <ccan/tal/tal.h>
struct route_info;
struct pubkey;
struct privkey;
struct secret;
/* Fills in *initial_blinding and *final_blinding and returns
* onionmsg_path array for this route */
struct onionmsg_path **make_blindedpath(const tal_t *ctx,
const struct pubkey *route,
struct pubkey *initial_blinding,
struct pubkey *final_blinding);
/**
* create_enctlv - Encrypt an encmsg to form an enctlv.
* @ctx: tal context
* @blinding: e(i), the blinding secret
* @node: the pubkey of the node to encrypt for
* @next_node: the pubkey of the next node, to place in enctlv
* @padlen: if non-zero, the bytes of padding to add (also adds 2 byte padding hdr)
* @override_blinding: the optional blinding point to place in enctlv
* @next_blinding: (out) e(i+1), the next blinding secret.
* @node_alias: (out) the blinded pubkey of the node to tell the recipient.
*
* Returns the enctlv blob, or NULL if the secret is invalid.
*/
u8 *create_enctlv(const tal_t *ctx,
const struct privkey *blinding,
const struct pubkey *node,
const struct pubkey *next_node,
size_t padlen,
const struct pubkey *override_blinding,
struct privkey *next_blinding,
struct pubkey *node_alias)
NON_NULL_ARGS(2, 3, 4, 7, 8);
/**
* create_final_enctlv - Encrypt an encmsg to form the final enctlv.
* @ctx: tal context
* @blinding: e(i), the blinding secret
* @final_node: the pubkey of the node to encrypt for
* @padlen: if non-zero, the bytes of padding to add (also adds 2 byte padding hdr)
* @self_id: secret to include in enctlv, if not NULL.
* @node_alias: (out) the blinded pubkey of the node to tell the recipient.
*
* If it fails, it means one of the privkeys is bad.
*/
u8 *create_final_enctlv(const tal_t *ctx,
const struct privkey *blinding,
const struct pubkey *final_node,
size_t padlen,
const struct secret *self_id,
struct pubkey *node_alias)
NON_NULL_ARGS(2, 3, 6);
/**
* unblind_onion - tweak onion epheremeral key so we can decode it with ours.
* @blinding: E(i), the blinding pubkey the previous peer gave us.
* @ecdh: the ecdh routine (usually ecdh from common/ecdh_hsmd).
* @onion_key: (in, out) the onionpacket->ephemeralkey to tweak.
* @ss: (out) the shared secret we gained from blinding pubkey.
*
* The shared secret is needed to decrypt the enctlv we expect to find, too.
*/
bool unblind_onion(const struct pubkey *blinding,
void (*ecdh)(const struct pubkey *point, struct secret *ss),
struct pubkey *onion_key,
struct secret *ss)
NO_NULL_ARGS;
/**
* decrypt_enctlv - Decrypt an encmsg to form an enctlv.
* @blinding: E(i), the blinding pubkey the previous peer gave us.
* @ss: the blinding secret from unblind_onion().
* @enctlv: the enctlv from the onion (tal, may be NULL).
* @next_node: (out) the next node_id.
* @next_blinding: (out) the next blinding E(i+1).
*
* Returns false if decryption failed or encmsg was malformed.
*/
bool decrypt_enctlv(const struct pubkey *blinding,
const struct secret *ss,
const u8 *enctlv,
struct pubkey *next_node,
struct pubkey *next_blinding)
NON_NULL_ARGS(1, 2, 4, 5);
/**
* decrypt_final_enctlv - Decrypt an encmsg to form an enctlv.
* @ctx: tal context for @self_id
* @blinding: E(i), the blinding pubkey the previous peer gave us.
* @ss: the blinding secret from unblind_onion().
* @enctlv: the enctlv from the onion (tal, may be NULL).
* @my_id: the pubkey of this node.
* @alias: (out) the node_id this was addressed to.
* @self_id: (out) the secret contained in the enctlv, if any.
*
* Returns false if decryption failed or encmsg was malformed.
*/
bool decrypt_final_enctlv(const tal_t *ctx,
const struct pubkey *blinding,
const struct secret *ss,
const u8 *enctlv,
const struct pubkey *my_id,
struct pubkey *alias,
struct secret **self_id)
NON_NULL_ARGS(1, 2, 4, 5);
#endif /* LIGHTNING_COMMON_BLINDEDPATH_H */