2 * keyid.c - Routines to calculate key IDs.
4 * Jonathan McDowell <noodles@earth.li>
6 * Copyright 2002 Project Purple
12 #include "keystructs.h"
19 * get_keyid - Given a public key returns the keyid.
20 * @publickey: The key to calculate the id for.
22 uint64_t get_keyid(struct openpgp_publickey *publickey)
24 return (get_packetid(publickey->publickey));
28 * get_fingerprint - Given a public key returns the fingerprint.
29 * @publickey: The key to calculate the id for.
30 * @fingerprint: The fingerprint (must be at least 20 bytes of space).
31 * @len: The length of the returned fingerprint.
33 * This function returns the fingerprint for a given public key. As Type 3
34 * fingerprints are 16 bytes and Type 4 are 20 the len field indicates
35 * which we've returned.
37 unsigned char *get_fingerprint(struct openpgp_packet *packet,
38 unsigned char *fingerprint,
44 unsigned char *buff = NULL;
45 size_t modlen, explen;
47 assert(fingerprint != NULL);
52 switch (packet->data[0]) {
58 * MD5 the modulus and exponent.
60 modlen = ((packet->data[8] << 8) +
61 packet->data[9] + 7) >> 3;
62 md5_write(&md5_ctx, &packet->data[10], modlen);
64 explen = ((packet->data[10+modlen] << 8) +
65 packet->data[11+modlen] + 7) >> 3;
66 md5_write(&md5_ctx, &packet->data[12 + modlen], explen);
69 buff = md5_read(&md5_ctx);
72 memcpy(fingerprint, buff, *len);
79 * TODO: Can this be 0x99? Are all public key packets old
80 * format with 2 bytes of length data?
83 sha1_write(&sha_ctx, &c, sizeof(c));
84 c = packet->length >> 8;
85 sha1_write(&sha_ctx, &c, sizeof(c));
86 c = packet->length & 0xFF;
87 sha1_write(&sha_ctx, &c, sizeof(c));
88 sha1_write(&sha_ctx, packet->data,
91 buff = sha1_read(&sha_ctx);
94 memcpy(fingerprint, buff, *len);
97 logthing(LOGTHING_ERROR, "Unknown key type: %d",
106 * get_packetid - Given a PGP packet returns the keyid.
107 * @packet: The packet to calculate the id for.
109 uint64_t get_packetid(struct openpgp_packet *packet)
115 unsigned char buff[20];
117 assert(packet != NULL);
119 switch (packet->data[0]) {
123 * For a type 2 or 3 key the keyid is the last 64 bits of the
124 * public modulus n, which is stored as an MPI from offset 8
127 * We need to ensure it's an RSA key.
129 if (packet->data[7] == 1) {
130 offset = (packet->data[8] << 8) +
132 offset = ((offset + 7) / 8) + 2;
134 for (keyid = 0, i = 0; i < 8; i++) {
136 keyid += packet->data[offset++];
139 logthing(LOGTHING_ERROR,
140 "Type 2 or 3 key, but not RSA.");
144 get_fingerprint(packet, buff, &length);
146 for (keyid = 0, i = 12; i < 20; i++) {
153 logthing(LOGTHING_ERROR, "Unknown key type: %d",