struct item *asymmetric_authenticated_decryption(char recipient, struct item *public_key, struct item *private_key, struct item *message) /*@ requires [?f]world(?pub) &*& generated_values(?principal1, ?count1) &*& item(public_key, ?pub_k, pub) &*& pub_k == public_key_item(?principal2, ?count2) &*& item(private_key, ?priv_k, pub) &*& priv_k == private_key_item(?principal3, ?count3) &*& item(message, ?msg, pub); @*/ /*@ ensures [f]world(pub) &*& generated_values(principal1, count1 + 1) &*& item(public_key, pub_k, pub) &*& item(private_key, priv_k, pub) &*& item(message, msg, pub) &*& item(result, ?decrypted, pub) &*& collision_in_run() ? true : msg == pair_item(?enc, ?sig) &*& enc == asymmetric_encrypted_item(?principal4, ?count4, ?pay, _) &*& sig == asymmetric_signature_item(principal2, count2, some(?msg_id), _) &*& msg_id == pair_item(data_item(cons(recipient, nil)), hash_item(some(enc))) &*& principal4 == principal3 && count4 == count3 ? pay == some(decrypted) : [_]pub(decrypted) ; @*/ { check_is_pair(message); struct item* encrypted = pair_get_first(message); check_is_asymmetric_encrypted(encrypted); struct item* signature = pair_get_second(message); struct item* rcp = create_data_item_from_char(recipient); struct item* hash = create_hash(encrypted); struct item* pair = create_pair(rcp, hash); asymmetric_signature_verify(public_key, pair, signature); struct item *result = asymmetric_decryption(private_key, encrypted); item_free(encrypted); item_free(rcp); item_free(pair); item_free(hash); item_free(signature); return result; }
void send_asymmetric_decrypted(struct network_status *net_stat, struct keypair *keypair) /*@ requires [?f0]world(?pub, ?key_clsfy) &*& keypair(keypair, ?attacker_id, ?id, ?info, pub) &*& proof_obligations(pub) &*& network_status(net_stat) &*& principal(attacker_id, ?count1) &*& true == bad(attacker_id); @*/ /*@ ensures [f0]world(pub, key_clsfy) &*& keypair(keypair, attacker_id, id, info, pub) &*& proof_obligations(pub) &*& network_status(net_stat) &*& principal(attacker_id, ?count2); @*/ { struct item *key = network_receive(net_stat); //@ assert item(key, ?k, pub); if (is_private_key(key)) { //@ assert k == private_key_item(?principal2, ?count2); struct item *enc = network_receive(net_stat); //@ assert item(enc, ?e, pub); if (is_asymmetric_encrypted(enc)) { //@ assert e == asymmetric_encrypted_item(?principal3, ?count3, ?pay, ?ent); char tag; //@ close chars(&tag, 1, _); random_buffer_(&tag, 1); //@ open chars(&tag, 1, _); if (tag == TAG_DATA || tag == TAG_PAIR || tag == TAG_NONCE || tag == TAG_HASH || tag == TAG_SYMMETRIC_KEY || tag == TAG_PUBLIC_KEY || tag == TAG_PRIVATE_KEY || tag == TAG_HMAC || tag == TAG_SYMMETRIC_ENC || tag == TAG_ASYMMETRIC_ENC || tag == TAG_ASYMMETRIC_SIG) { struct item *dec = asymmetric_decryption(key, enc, tag); //@ assert item(dec, ?d, pub); //@ open proof_obligations(pub); /*@ if (col) { assert [_]pub(d); } else if (principal2 == principal3 && count2 == count3) { assert pay == some(d); assert is_public_asymmetric_decrypted(?proof, pub); proof(e); } else { assert [_]pub(d); } @*/ network_send(net_stat, dec); //@ close proof_obligations(pub); item_free(dec); } } item_free(enc); } item_free(key); }