3 * Encrypt session key with public key.
5 * Copyright (c) 2005 Marko Kreen
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
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15 * documentation and/or other materials provided with the distribution.
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20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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29 * $PostgreSQL: pgsql/contrib/pgcrypto/pgp-pubenc.c,v 1.5 2009/06/11 14:48:52 momjian Exp $
38 * padded msg: 02 || non-zero pad bytes || 00 || msg
41 pad_eme_pkcs1_v15(uint8 *data, int data_len, int res_len, uint8 **res_p)
46 int pad_len = res_len - 2 - data_len;
51 buf = px_alloc(res_len);
53 res = px_get_random_bytes(buf + 1, pad_len);
60 /* pad must not contain zero bytes */
62 while (p < buf + 1 + pad_len)
66 res = px_get_random_bytes(p, 1);
76 memset(buf, 0, res_len);
82 memcpy(buf + pad_len + 2, data, data_len);
89 create_secmsg(PGP_Context *ctx, PGP_MPI **msg_p, int full_bytes)
95 int klen = ctx->sess_key_len;
100 for (i = 0; i < klen; i++)
101 cksum += ctx->sess_key[i];
104 * create "secret message"
106 secmsg = px_alloc(klen + 3);
107 secmsg[0] = ctx->cipher_algo;
108 memcpy(secmsg + 1, ctx->sess_key, klen);
109 secmsg[klen + 1] = (cksum >> 8) & 0xFF;
110 secmsg[klen + 2] = cksum & 0xFF;
113 * now create a large integer of it
115 res = pad_eme_pkcs1_v15(secmsg, klen + 3, full_bytes, &padded);
118 /* first byte will be 0x02 */
119 int full_bits = full_bytes * 8 - 6;
121 res = pgp_mpi_create(padded, full_bits, &m);
126 memset(padded, 0, full_bytes);
129 memset(secmsg, 0, klen + 3);
139 encrypt_and_write_elgamal(PGP_Context *ctx, PGP_PubKey *pk, PushFilter *pkt)
146 /* create padded msg */
147 res = create_secmsg(ctx, &m, pk->pub.elg.p->bytes - 1);
152 res = pgp_elgamal_encrypt(pk, m, &c1, &c2);
157 res = pgp_mpi_write(pkt, c1);
160 res = pgp_mpi_write(pkt, c2);
170 encrypt_and_write_rsa(PGP_Context *ctx, PGP_PubKey *pk, PushFilter *pkt)
176 /* create padded msg */
177 res = create_secmsg(ctx, &m, pk->pub.rsa.n->bytes - 1);
182 res = pgp_rsa_encrypt(pk, m, &c);
187 res = pgp_mpi_write(pkt, c);
196 pgp_write_pubenc_sesskey(PGP_Context *ctx, PushFilter *dst)
199 PGP_PubKey *pk = ctx->pub_key;
201 PushFilter *pkt = NULL;
206 px_debug("no pubkey?\n");
215 res = pgp_create_pkt_writer(dst, PGP_PKT_PUBENCRYPTED_SESSKEY, &pkt);
218 res = pushf_write(pkt, &ver, 1);
221 res = pushf_write(pkt, pk->key_id, 8);
224 res = pushf_write(pkt, &algo, 1);
230 case PGP_PUB_ELG_ENCRYPT:
231 res = encrypt_and_write_elgamal(ctx, pk, pkt);
233 case PGP_PUB_RSA_ENCRYPT:
234 case PGP_PUB_RSA_ENCRYPT_SIGN:
235 res = encrypt_and_write_rsa(ctx, pk, pkt);
242 * done, signal packet end
244 res = pushf_flush(pkt);