programs/pluto/pkcs1.c

   1 /* Support of PKCS#1 private key data structures
   2  * Copyright (C) 2005 Jan Hutter, Martin Willi
   3  * Copyright (C) 2002-2005 Andreas Steffen
   4  * Hochschule fuer Technik Rapperswil, Switzerland
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2 of the License, or (at your
   9  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
  10  *
  11  * This program is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * for more details.
  15  *
  16  * RCSID $Id: pkcs1.c,v 1.17 2006/01/04 21:00:43 as Exp $
  17  */
  18
  19 #include <stddef.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22
  23 #include <freeswan.h>
  24
  25 #include "constants.h"
  26 #include "defs.h"
  27 #include "mp_defs.h"
  28 #include "asn1.h"
  29 #include "oid.h"
  30 #include "log.h"
  31 #include "pkcs1.h"
  32 #include "md2.h"
  33 #include "md5.h"
  34 #include "sha1.h"
  35 #include "rnd.h"
  36
  37 const struct fld RSA_private_field[] =
  38 {
  39     { "Modulus",         offsetof(RSA_private_key_t, pub.n) },
  40     { "PublicExponent",  offsetof(RSA_private_key_t, pub.e) },
  41
  42     { "PrivateExponent", offsetof(RSA_private_key_t, d) },
  43     { "Prime1",          offsetof(RSA_private_key_t, p) },
  44     { "Prime2",          offsetof(RSA_private_key_t, q) },
  45     { "Exponent1",       offsetof(RSA_private_key_t, dP) },
  46     { "Exponent2",       offsetof(RSA_private_key_t, dQ) },
  47     { "Coefficient",     offsetof(RSA_private_key_t, qInv) },
  48 };
  49
  50 /* ASN.1 definition of a PKCS#1 RSA private key */
  51
  52 static const asn1Object_t privkeyObjects[] = {
  53   { 0, "RSAPrivateKey",                 ASN1_SEQUENCE,     ASN1_NONE }, /*  0 */
  54   { 1,   "version",                     ASN1_INTEGER,      ASN1_BODY }, /*  1 */
  55   { 1,   "modulus",                     ASN1_INTEGER,      ASN1_BODY }, /*  2 */
  56   { 1,   "publicExponent",              ASN1_INTEGER,      ASN1_BODY }, /*  3 */
  57   { 1,   "privateExponent",             ASN1_INTEGER,      ASN1_BODY }, /*  4 */
  58   { 1,   "prime1",                      ASN1_INTEGER,      ASN1_BODY }, /*  5 */
  59   { 1,   "prime2",                      ASN1_INTEGER,      ASN1_BODY }, /*  6 */
  60   { 1,   "exponent1",                   ASN1_INTEGER,      ASN1_BODY }, /*  7 */
  61   { 1,   "exponent2",                   ASN1_INTEGER,      ASN1_BODY }, /*  8 */
  62   { 1,   "coefficient",                 ASN1_INTEGER,      ASN1_BODY }, /*  9 */
  63   { 1,   "otherPrimeInfos",             ASN1_SEQUENCE,     ASN1_OPT |
  64                                                            ASN1_LOOP }, /* 10 */
  65   { 2,     "otherPrimeInfo",            ASN1_SEQUENCE,     ASN1_NONE }, /* 11 */
  66   { 3,       "prime",                   ASN1_INTEGER,      ASN1_BODY }, /* 12 */
  67   { 3,       "exponent",                ASN1_INTEGER,      ASN1_BODY }, /* 13 */
  68   { 3,       "coefficient",             ASN1_INTEGER,      ASN1_BODY }, /* 14 */
  69   { 1,   "end opt or loop",             ASN1_EOC,          ASN1_END  }  /* 15 */
  70 };
  71
  72 #define PKCS1_PRIV_KEY_VERSION           1
  73 #define PKCS1_PRIV_KEY_MODULUS           2
  74 #define PKCS1_PRIV_KEY_PUB_EXP           3
  75 #define PKCS1_PRIV_KEY_COEFF             9
  76 #define PKCS1_PRIV_KEY_ROOF             16
  77
  78
  79 /*
  80  * forms the FreeS/WAN keyid from the public exponent e and modulus n
  81  */
  82 void
  83 form_keyid(chunk_t e, chunk_t n, char* keyid, unsigned *keysize)
  84 {
  85     /* eliminate leading zero bytes in modulus from ASN.1 coding */
  86     while (n.len > 1 && *n.ptr == 0x00)
  87     {
  88         n.ptr++;  n.len--;
  89     }
  90
  91     /* form the FreeS/WAN keyid */
  92     keyid[0] = '\0';    /* in case of splitkeytoid failure */
  93     splitkeytoid(e.ptr, e.len, n.ptr, n.len, keyid, KEYID_BUF);
  94
  95     /* return the RSA modulus size in octets */
  96     *keysize = n.len;
  97 }
  98
  99 /*
 100  * initialize an RSA_public_key_t object
 101  */
 102 void
 103 init_RSA_public_key(RSA_public_key_t *rsa, chunk_t e, chunk_t n)
 104 {
 105     n_to_mpz(&rsa->e, e.ptr, e.len);
 106     n_to_mpz(&rsa->n, n.ptr, n.len);
 107
 108     form_keyid(e, n, rsa->keyid, &rsa->k);
 109 }
 110
 111 #ifdef DEBUG
 112 static void
 113 RSA_show_key_fields(RSA_private_key_t *k, int fieldcnt)
 114 {
 115     const struct fld *p;
 116
 117     DBG_log(" keyid: *%s", k->pub.keyid);
 118
 119     for (p = RSA_private_field; p < &RSA_private_field[fieldcnt]; p++)
 120     {
 121         MP_INT *n = (MP_INT *) ((char *)k + p->offset);
 122         size_t sz = mpz_sizeinbase(n, 16);
 123         char buf[RSA_MAX_OCTETS * 2 + 2];       /* ought to be big enough */
 124
 125         passert(sz <= sizeof(buf));
 126         mpz_get_str(buf, 16, n);
 127
 128         DBG_log(" %s: 0x%s", p->name, buf);
 129     }
 130 }
 131
 132 /* debugging info that compromises security! */
 133 void
 134 RSA_show_private_key(RSA_private_key_t *k)
 135 {
 136     RSA_show_key_fields(k, elemsof(RSA_private_field));
 137 }
 138
 139 void
 140 RSA_show_public_key(RSA_public_key_t *k)
 141 {
 142     /* Kludge: pretend that it is a private key, but only display the
 143      * first two fields (which are the public key).
 144      */
 145     passert(offsetof(RSA_private_key_t, pub) == 0);
 146     RSA_show_key_fields((RSA_private_key_t *)k, 2);
 147 }
 148 #endif
 149
 150 err_t
 151 RSA_private_key_sanity(RSA_private_key_t *k)
 152 {
 153     /* note that the *last* error found is reported */
 154     err_t ugh = NULL;
 155     mpz_t t, u, q1;
 156
 157 #ifdef DEBUG    /* debugging info that compromises security */
 158     DBG(DBG_PRIVATE, RSA_show_private_key(k));
 159 #endif
 160
 161     /* PKCS#1 1.5 section 6 requires modulus to have at least 12 octets.
 162      * We actually require more (for security).
 163      */
 164     if (k->pub.k < RSA_MIN_OCTETS)
 165         return RSA_MIN_OCTETS_UGH;
 166
 167     /* we picked a max modulus size to simplify buffer allocation */
 168     if (k->pub.k > RSA_MAX_OCTETS)
 169         return RSA_MAX_OCTETS_UGH;
 170
 171     mpz_init(t);
 172     mpz_init(u);
 173     mpz_init(q1);
 174
 175     /* check that n == p * q */
 176     mpz_mul(u, &k->p, &k->q);
 177     if (mpz_cmp(u, &k->pub.n) != 0)
 178         ugh = "n != p * q";
 179
 180     /* check that e divides neither p-1 nor q-1 */
 181     mpz_sub_ui(t, &k->p, 1);
 182     mpz_mod(t, t, &k->pub.e);
 183     if (mpz_cmp_ui(t, 0) == 0)
 184         ugh = "e divides p-1";
 185
 186     mpz_sub_ui(t, &k->q, 1);
 187     mpz_mod(t, t, &k->pub.e);
 188     if (mpz_cmp_ui(t, 0) == 0)
 189         ugh = "e divides q-1";
 190
 191     /* check that d is e^-1 (mod lcm(p-1, q-1)) */
 192     /* see PKCS#1v2, aka RFC 2437, for the "lcm" */
 193     mpz_sub_ui(q1, &k->q, 1);
 194     mpz_sub_ui(u, &k->p, 1);
 195     mpz_gcd(t, u, q1);          /* t := gcd(p-1, q-1) */
 196     mpz_mul(u, u, q1);          /* u := (p-1) * (q-1) */
 197     mpz_divexact(u, u, t);      /* u := lcm(p-1, q-1) */
 198
 199     mpz_mul(t, &k->d, &k->pub.e);
 200     mpz_mod(t, t, u);
 201     if (mpz_cmp_ui(t, 1) != 0)
 202         ugh = "(d * e) mod (lcm(p-1, q-1)) != 1";
 203
 204     /* check that dP is d mod (p-1) */
 205     mpz_sub_ui(u, &k->p, 1);
 206     mpz_mod(t, &k->d, u);
 207     if (mpz_cmp(t, &k->dP) != 0)
 208         ugh = "dP is not congruent to d mod (p-1)";
 209
 210     /* check that dQ is d mod (q-1) */
 211     mpz_sub_ui(u, &k->q, 1);
 212     mpz_mod(t, &k->d, u);
 213     if (mpz_cmp(t, &k->dQ) != 0)
 214         ugh = "dQ is not congruent to d mod (q-1)";
 215
 216     /* check that qInv is (q^-1) mod p */
 217     mpz_mul(t, &k->qInv, &k->q);
 218     mpz_mod(t, t, &k->p);
 219     if (mpz_cmp_ui(t, 1) != 0)
 220         ugh = "qInv is not conguent ot (q^-1) mod p";
 221
 222     mpz_clear(t);
 223     mpz_clear(u);
 224     mpz_clear(q1);
 225     return ugh;
 226 }
 227
 228 /*
 229  * Check the equality of two RSA public keys
 230  */
 231 bool
 232 same_RSA_public_key(const RSA_public_key_t *a, const RSA_public_key_t *b)
 233 {
 234     return a == b
 235     || (a->k == b->k && mpz_cmp(&a->n, &b->n) == 0 && mpz_cmp(&a->e, &b->e) == 0);
 236 }
 237
 238 /*
 239  *  Parses a PKCS#1 private key
 240  */
 241 bool
 242 pkcs1_parse_private_key(chunk_t blob, RSA_private_key_t *key)
 243 {
 244     err_t ugh = NULL;
 245     asn1_ctx_t ctx;
 246     chunk_t object, modulus, exp;
 247     u_int level;
 248     int objectID = 0;
 249
 250     asn1_init(&ctx, blob, 0, FALSE, DBG_PRIVATE);
 251
 252     while (objectID < PKCS1_PRIV_KEY_ROOF) {
 253
 254         if (!extract_object(privkeyObjects, &objectID, &object, &level, &ctx))
 255              return FALSE;
 256
 257         if (objectID == PKCS1_PRIV_KEY_VERSION)
 258         {
 259             if (object.len > 0 && *object.ptr != 0)
 260             {
 261                 plog("  wrong PKCS#1 private key version");
 262                 return FALSE;
 263             }
 264         }
 265         else if (objectID >= PKCS1_PRIV_KEY_MODULUS &&
 266                  objectID <= PKCS1_PRIV_KEY_COEFF)
 267         {
 268             MP_INT *u = (MP_INT *) ((char *)key
 269                 + RSA_private_field[objectID - PKCS1_PRIV_KEY_MODULUS].offset);
 270
 271             n_to_mpz(u, object.ptr, object.len);
 272
 273             if (objectID == PKCS1_PRIV_KEY_MODULUS)
 274                 modulus = object;
 275             else if (objectID == PKCS1_PRIV_KEY_PUB_EXP)
 276                 exp = object;
 277         }
 278         objectID++;
 279     }
 280     form_keyid(exp, modulus, key->pub.keyid, &key->pub.k);
 281     ugh = RSA_private_key_sanity(key);
 282     return (ugh == NULL);
 283 }
 284
 285 /*
 286  *  compute a digest over a binary blob
 287  */
 288 bool
 289 compute_digest(chunk_t tbs, int alg, chunk_t *digest)
 290 {
 291     switch (alg)
 292     {
 293         case OID_MD2:
 294         case OID_MD2_WITH_RSA:
 295         {
 296             MD2_CTX context;
 297             MD2Init(&context);
 298             MD2Update(&context, tbs.ptr, tbs.len);
 299             MD2Final(digest->ptr, &context);
 300             digest->len = MD2_DIGEST_SIZE;
 301             return TRUE;
 302         }
 303         case OID_MD5:
 304         case OID_MD5_WITH_RSA:
 305         {
 306             MD5_CTX context;
 307             MD5Init(&context);
 308             MD5Update(&context, tbs.ptr, tbs.len);
 309             MD5Final(digest->ptr, &context);
 310             digest->len = MD5_DIGEST_SIZE;
 311             return TRUE;
 312         }
 313         case OID_SHA1:
 314         case OID_SHA1_WITH_RSA:
 315         case OID_SHA1_WITH_RSA_OIW:
 316         {
 317             SHA1_CTX context;
 318
 319             SHA1Init(&context);
 320             SHA1Update(&context, tbs.ptr, tbs.len);
 321             SHA1Final(digest->ptr, &context);
 322             digest->len = SHA1_DIGEST_SIZE;
 323             return TRUE;
 324         }
 325         default:
 326             digest->len = 0;
 327             return FALSE;
 328     }
 329 }
 330
 331 /*
 332  * compute an RSA signature with PKCS#1 padding
 333  */
 334 void
 335 sign_hash(const RSA_private_key_t *k, const u_char *hash_val, size_t hash_len
 336     , u_char *sig_val, size_t sig_len)
 337 {
 338     chunk_t ch;
 339     mpz_t t1, t2;
 340     size_t padlen;
 341     u_char *p = sig_val;
 342
 343     DBG(DBG_CONTROL | DBG_CRYPT,
 344         DBG_log("signing hash with RSA Key *%s", k->pub.keyid)
 345     )
 346     /* PKCS#1 v1.5 8.1 encryption-block formatting */
 347     *p++ = 0x00;
 348     *p++ = 0x01;        /* BT (block type) 01 */
 349     padlen = sig_len - 3 - hash_len;
 350     memset(p, 0xFF, padlen);
 351     p += padlen;
 352     *p++ = 0x00;
 353     memcpy(p, hash_val, hash_len);
 354     passert(p + hash_len - sig_val == (ptrdiff_t)sig_len);
 355
 356     /* PKCS#1 v1.5 8.2 octet-string-to-integer conversion */
 357     n_to_mpz(t1, sig_val, sig_len);     /* (could skip leading 0x00) */
 358
 359     /* PKCS#1 v1.5 8.3 RSA computation y = x^c mod n
 360      * Better described in PKCS#1 v2.0 5.1 RSADP.
 361      * There are two methods, depending on the form of the private key.
 362      * We use the one based on the Chinese Remainder Theorem.
 363      */
 364     mpz_init(t2);
 365
 366     mpz_powm(t2, t1, &k->dP, &k->p);    /* m1 = c^dP mod p */
 367
 368     mpz_powm(t1, t1, &k->dQ, &k->q);    /* m2 = c^dQ mod Q */
 369
 370     mpz_sub(t2, t2, t1);        /* h = qInv (m1 - m2) mod p */
 371     mpz_mod(t2, t2, &k->p);
 372     mpz_mul(t2, t2, &k->qInv);
 373     mpz_mod(t2, t2, &k->p);
 374
 375     mpz_mul(t2, t2, &k->q);     /* m = m2 + h q */
 376     mpz_add(t1, t1, t2);
 377
 378     /* PKCS#1 v1.5 8.4 integer-to-octet-string conversion */
 379     ch = mpz_to_n(t1, sig_len);
 380     memcpy(sig_val, ch.ptr, sig_len);
 381     pfree(ch.ptr);
 382
 383     mpz_clear(t1);
 384     mpz_clear(t2);
 385 }
 386
 387 /*
 388  * encrypt data with an RSA public key after padding
 389  */
 390 chunk_t
 391 RSA_encrypt(const RSA_public_key_t *key, chunk_t in)
 392 {
 393     u_char padded[RSA_MAX_OCTETS];
 394     u_char *pos = padded;
 395     int padding = key->k - in.len - 3;
 396     int i;
 397
 398     if (padding < 8 || key->k > RSA_MAX_OCTETS)
 399         return empty_chunk;
 400
 401     /* add padding according to PKCS#1 7.2.1 1.+2. */
 402     *pos++ = 0x00;
 403     *pos++ = 0x02;
 404
 405     /* pad with pseudo random bytes unequal to zero */
 406     get_rnd_bytes(pos, padding);
 407     for (i = 0; i < padding; i++)
 408     {
 409         while (!*pos)
 410           get_rnd_bytes(pos, 1);
 411         pos++;
 412     }
 413
 414     /* append the padding terminator */
 415     *pos++ = 0x00;
 416
 417     /* now add the data */
 418     memcpy(pos, in.ptr, in.len);
 419     DBG(DBG_RAW,
 420         DBG_dump_chunk("data for rsa encryption:\n", in);
 421         DBG_dump("padded data for rsa encryption:\n", padded, key->k)
 422     )
 423
 424     /* convert chunk to integer (PKCS#1 7.2.1 3.a) */
 425     {
 426         chunk_t out;
 427         mpz_t m, c;
 428
 429         mpz_init(c);
 430         n_to_mpz(m, padded, key->k);
 431
 432         /* encrypt(PKCS#1 7.2.1 3.b) */
 433         mpz_powm(c, m, &key->e, &key->n);
 434
 435         /* convert integer back to a chunk (PKCS#1 7.2.1 3.c) */
 436         out = mpz_to_n(c, key->k);
 437         mpz_clear(c);
 438         mpz_clear(m);
 439
 440         DBG(DBG_RAW,
 441             DBG_dump_chunk("rsa encrypted data:\n", out)
 442         )
 443         return out;
 444     }
 445 }
 446
 447 /*
 448  * decrypt data with an RSA private key and remove padding
 449  */
 450 bool
 451 RSA_decrypt(const RSA_private_key_t *key, chunk_t in, chunk_t *out)
 452 {
 453     chunk_t padded;
 454     u_char *pos;
 455     mpz_t t1, t2;
 456
 457     n_to_mpz(t1, in.ptr,in.len);
 458
 459     /* PKCS#1 v1.5 8.3 RSA computation y = x^c mod n
 460      * Better described in PKCS#1 v2.0 5.1 RSADP.
 461      * There are two methods, depending on the form of the private key.
 462      * We use the one based on the Chinese Remainder Theorem.
 463      */
 464     mpz_init(t2);
 465
 466     mpz_powm(t2, t1, &key->dP, &key->p);        /* m1 = c^dP mod p */
 467     mpz_powm(t1, t1, &key->dQ, &key->q);        /* m2 = c^dQ mod Q */
 468
 469     mpz_sub(t2, t2, t1);        /* h = qInv (m1 - m2) mod p */
 470     mpz_mod(t2, t2, &key->p);
 471     mpz_mul(t2, t2, &key->qInv);
 472     mpz_mod(t2, t2, &key->p);
 473
 474     mpz_mul(t2, t2, &key->q);   /* m = m2 + h q */
 475     mpz_add(t1, t1, t2);
 476
 477     padded = mpz_to_n(t1, key->pub.k);
 478     mpz_clear(t1);
 479     mpz_clear(t2);
 480
 481     DBG(DBG_PRIVATE,
 482         DBG_dump_chunk("rsa decrypted data with padding:\n", padded)
 483     )
 484     pos = padded.ptr;
 485
 486     /* PKCS#1 v1.5 8.1 encryption-block formatting (EB = 00 || 02 || PS || 00 || D) */
 487
 488     /* check for hex pattern 00 02 in decrypted message */
 489     if ((*pos++ != 0x00) || (*(pos++) != 0x02))
 490     {
 491         plog("incorrect padding - probably wrong RSA key");
 492         freeanychunk(padded);
 493         return FALSE;
 494     }
 495     padded.len -= 2;
 496
 497     /* the plaintext data starts after first 0x00 byte */
 498     while (padded.len-- > 0 && *pos++ != 0x00)
 499
 500     if (padded.len == 0)
 501     {
 502         plog("no plaintext data");
 503         freeanychunk(padded);
 504         return FALSE;
 505     }
 506
 507     clonetochunk(*out, pos, padded.len, "decrypted data");
 508     freeanychunk(padded);
 509     return TRUE;
 510 }
 511
 512 /*
 513  * build signatureValue
 514  */
 515 chunk_t
 516 pkcs1_build_signature(chunk_t tbs, int hash_alg, const RSA_private_key_t *key
 517 , bool bit_string)
 518 {
 519
 520     size_t siglen = key->pub.k;
 521
 522     u_char digest_buf[MAX_DIGEST_LEN];
 523     chunk_t digest = { digest_buf, MAX_DIGEST_LEN };
 524     chunk_t digestInfo, alg_id, signatureValue;
 525     u_char *pos;
 526
 527     switch (hash_alg)
 528     {
 529     case OID_MD5:
 530     case OID_MD5_WITH_RSA:
 531         alg_id = ASN1_md5_id;
 532         break;
 533     case OID_SHA1:
 534     case OID_SHA1_WITH_RSA:
 535         alg_id = ASN1_sha1_id;
 536         break;
 537     default:
 538         return empty_chunk;
 539     }
 540     compute_digest(tbs, hash_alg, &digest);
 541
 542     /* according to PKCS#1 v2.1 digest must be packaged into
 543      * an ASN.1 structure for encryption
 544      */
 545     digestInfo = asn1_wrap(ASN1_SEQUENCE, "cm"
 546                     , alg_id
 547                     , asn1_simple_object(ASN1_OCTET_STRING, digest));
 548
 549     /* generate the RSA signature */
 550     if (bit_string)
 551     {
 552         pos = build_asn1_object(&signatureValue, ASN1_BIT_STRING, 1 + siglen);
 553         *pos++ = 0x00;
 554     }
 555     else
 556     {
 557         pos = build_asn1_object(&signatureValue, ASN1_OCTET_STRING, siglen);
 558     }
 559     sign_hash(key, digestInfo.ptr, digestInfo.len, pos, siglen);
 560     pfree(digestInfo.ptr);
 561
 562     return signatureValue;
 563 }
 564
 565 /*
 566  * build a DER-encoded PKCS#1 private key object
 567  */
 568 chunk_t
 569 pkcs1_build_private_key(const RSA_private_key_t *key)
 570 {
 571     chunk_t pkcs1 = asn1_wrap(ASN1_SEQUENCE, "cmmmmmmmm"
 572                         , ASN1_INTEGER_0
 573                         , asn1_integer_from_mpz(&key->pub.n)
 574                         , asn1_integer_from_mpz(&key->pub.e)
 575                         , asn1_integer_from_mpz(&key->d)
 576                         , asn1_integer_from_mpz(&key->p)
 577                         , asn1_integer_from_mpz(&key->q)
 578                         , asn1_integer_from_mpz(&key->dP)
 579                         , asn1_integer_from_mpz(&key->dQ)
 580                         , asn1_integer_from_mpz(&key->qInv));
 581
 582     DBG(DBG_PRIVATE,
 583         DBG_dump_chunk("PKCS#1 encoded private key:", pkcs1)
 584     )
 585     return pkcs1;
 586 }
 587
 588 /*
 589  * build a DER-encoded PKCS#1 public key object
 590  */
 591 chunk_t
 592 pkcs1_build_public_key(const RSA_public_key_t *rsa)
 593 {
 594     return asn1_wrap(ASN1_SEQUENCE, "mm"
 595                 , asn1_integer_from_mpz(&rsa->n)
 596                 , asn1_integer_from_mpz(&rsa->e));
 597 }
 598
 599 /*
 600  * build a DER-encoded publicKeyInfo object
 601  */
 602 chunk_t
 603 pkcs1_build_publicKeyInfo(const RSA_public_key_t *rsa)
 604 {
 605     chunk_t publicKey;
 606     chunk_t rawKey = pkcs1_build_public_key(rsa);
 607
 608     u_char *pos = build_asn1_object(&publicKey, ASN1_BIT_STRING
 609                         , 1 + rawKey.len);
 610     *pos++ = 0x00;
 611     mv_chunk(&pos, rawKey);
 612
 613     return asn1_wrap(ASN1_SEQUENCE, "cm"
 614                 , ASN1_rsaEncryption_id
 615                 , publicKey);
 616 }
 617 void
 618 free_RSA_public_content(RSA_public_key_t *rsa)
 619 {
 620     mpz_clear(&rsa->n);
 621     mpz_clear(&rsa->e);
 622 }
 623
 624 void
 625 free_RSA_private_content(RSA_private_key_t *rsak)
 626 {
 627     free_RSA_public_content(&rsak->pub);
 628     mpz_clear(&rsak->d);
 629     mpz_clear(&rsak->p);
 630     mpz_clear(&rsak->q);
 631     mpz_clear(&rsak->dP);
 632     mpz_clear(&rsak->dQ);
 633     mpz_clear(&rsak->qInv);
 634 }
 635