dlls/rsaenh/implglue.c

   1 /*
   2  * dlls/rsaenh/implglue.c
   3  * Glueing the RSAENH specific code to the crypto library
   4  *
   5  * Copyright (c) 2004, 2005 Michael Jung
   6  * Copyright (c) 2007 Vijay Kiran Kamuju
   7  *
   8  * based on code by Mike McCormack and David Hammerton
   9  *
  10  * This library is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2.1 of the License, or (at your option) any later version.
  14  *
  15  * This library is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with this library; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  23  */
  24 #include "config.h"
  25
  26 #include "wine/port.h"
  27 #include "wine/library.h"
  28
  29 #include "windef.h"
  30 #include "wincrypt.h"
  31
  32 #include "implglue.h"
  33
  34 #include <stdio.h>
  35
  36 /* Function prototypes copied from dlls/advapi32/crypt_md4.c */
  37 VOID WINAPI MD4Init( MD4_CTX *ctx );
  38 VOID WINAPI MD4Update( MD4_CTX *ctx, const unsigned char *buf, unsigned int len );
  39 VOID WINAPI MD4Final( MD4_CTX *ctx );
  40 /* Function prototypes copied from dlls/advapi32/crypt_md5.c */
  41 VOID WINAPI MD5Init( MD5_CTX *ctx );
  42 VOID WINAPI MD5Update( MD5_CTX *ctx, const unsigned char *buf, unsigned int len );
  43 VOID WINAPI MD5Final( MD5_CTX *ctx );
  44 /* Function prototypes copied from dlls/advapi32/crypt_sha.c */
  45 VOID WINAPI A_SHAInit(PSHA_CTX Context);
  46 VOID WINAPI A_SHAUpdate(PSHA_CTX Context, const unsigned char *Buffer, UINT BufferSize);
  47 VOID WINAPI A_SHAFinal(PSHA_CTX Context, PULONG Result);
  48 /* Function prototype copied from dlls/advapi32/crypt.c */
  49 BOOL WINAPI SystemFunction036(PVOID pbBuffer, ULONG dwLen);
  50
  51 BOOL init_hash_impl(ALG_ID aiAlgid, HASH_CONTEXT *pHashContext)
  52 {
  53     switch (aiAlgid)
  54     {
  55         case CALG_MD2:
  56             md2_init(&pHashContext->md2);
  57             break;
  58
  59         case CALG_MD4:
  60             MD4Init(&pHashContext->md4);
  61             break;
  62
  63         case CALG_MD5:
  64             MD5Init(&pHashContext->md5);
  65             break;
  66
  67         case CALG_SHA:
  68             A_SHAInit(&pHashContext->sha);
  69             break;
  70
  71         case CALG_SHA_256:
  72             SHA256_Init(&pHashContext->sha256);
  73             break;
  74
  75         case CALG_SHA_384:
  76             SHA384_Init(&pHashContext->sha384);
  77             break;
  78
  79         case CALG_SHA_512:
  80             SHA512_Init(&pHashContext->sha512);
  81             break;
  82     }
  83
  84     return TRUE;
  85 }
  86
  87 BOOL update_hash_impl(ALG_ID aiAlgid, HASH_CONTEXT *pHashContext, CONST BYTE *pbData,
  88                       DWORD dwDataLen)
  89 {
  90     switch (aiAlgid)
  91     {
  92         case CALG_MD2:
  93             md2_process(&pHashContext->md2, pbData, dwDataLen);
  94             break;
  95
  96         case CALG_MD4:
  97             MD4Update(&pHashContext->md4, pbData, dwDataLen);
  98             break;
  99
 100         case CALG_MD5:
 101             MD5Update(&pHashContext->md5, pbData, dwDataLen);
 102             break;
 103
 104         case CALG_SHA:
 105             A_SHAUpdate(&pHashContext->sha, pbData, dwDataLen);
 106             break;
 107
 108         case CALG_SHA_256:
 109             SHA256_Update(&pHashContext->sha256, pbData, dwDataLen);
 110             break;
 111
 112         case CALG_SHA_384:
 113             SHA384_Update(&pHashContext->sha384, pbData, dwDataLen);
 114             break;
 115
 116         case CALG_SHA_512:
 117             SHA512_Update(&pHashContext->sha512, pbData, dwDataLen);
 118             break;
 119
 120         default:
 121             SetLastError(NTE_BAD_ALGID);
 122             return FALSE;
 123     }
 124
 125     return TRUE;
 126 }
 127
 128 BOOL finalize_hash_impl(ALG_ID aiAlgid, HASH_CONTEXT *pHashContext, BYTE *pbHashValue)
 129 {
 130     switch (aiAlgid)
 131     {
 132         case CALG_MD2:
 133             md2_done(&pHashContext->md2, pbHashValue);
 134             break;
 135
 136         case CALG_MD4:
 137             MD4Final(&pHashContext->md4);
 138             memcpy(pbHashValue, pHashContext->md4.digest, 16);
 139             break;
 140
 141         case CALG_MD5:
 142             MD5Final(&pHashContext->md5);
 143             memcpy(pbHashValue, pHashContext->md5.digest, 16);
 144             break;
 145
 146         case CALG_SHA:
 147             A_SHAFinal(&pHashContext->sha, (PULONG)pbHashValue);
 148             break;
 149
 150         case CALG_SHA_256:
 151             SHA256_Final(pbHashValue, &pHashContext->sha256);
 152             break;
 153
 154         case CALG_SHA_384:
 155             SHA384_Final(pbHashValue, &pHashContext->sha384);
 156             break;
 157
 158         case CALG_SHA_512:
 159             SHA512_Final(pbHashValue, &pHashContext->sha512);
 160             break;
 161
 162         default:
 163             SetLastError(NTE_BAD_ALGID);
 164             return FALSE;
 165     }
 166
 167     return TRUE;
 168 }
 169
 170 BOOL duplicate_hash_impl(ALG_ID aiAlgid, CONST HASH_CONTEXT *pSrcHashContext,
 171                          HASH_CONTEXT *pDestHashContext)
 172 {
 173     *pDestHashContext = *pSrcHashContext;
 174
 175     return TRUE;
 176 }
 177
 178 BOOL new_key_impl(ALG_ID aiAlgid, KEY_CONTEXT *pKeyContext, DWORD dwKeyLen)
 179 {
 180     switch (aiAlgid)
 181     {
 182         case CALG_RSA_KEYX:
 183         case CALG_RSA_SIGN:
 184             if (rsa_make_key((int)dwKeyLen, 65537, &pKeyContext->rsa) != CRYPT_OK) {
 185                 SetLastError(NTE_FAIL);
 186                 return FALSE;
 187             }
 188             return TRUE;
 189     }
 190
 191     return TRUE;
 192 }
 193
 194 BOOL free_key_impl(ALG_ID aiAlgid, KEY_CONTEXT *pKeyContext)
 195 {
 196     switch (aiAlgid)
 197     {
 198         case CALG_RSA_KEYX:
 199         case CALG_RSA_SIGN:
 200             rsa_free(&pKeyContext->rsa);
 201     }
 202
 203     return TRUE;
 204 }
 205
 206 BOOL setup_key_impl(ALG_ID aiAlgid, KEY_CONTEXT *pKeyContext, DWORD dwKeyLen,
 207                     DWORD dwEffectiveKeyLen, DWORD dwSaltLen, BYTE *abKeyValue)
 208 {
 209     switch (aiAlgid)
 210     {
 211         case CALG_RC4:
 212             rc4_start(&pKeyContext->rc4);
 213             rc4_add_entropy(abKeyValue, dwKeyLen + dwSaltLen, &pKeyContext->rc4);
 214             rc4_ready(&pKeyContext->rc4);
 215             break;
 216
 217         case CALG_RC2:
 218             rc2_setup(abKeyValue, dwKeyLen + dwSaltLen, dwEffectiveKeyLen ?
 219                       dwEffectiveKeyLen : dwKeyLen << 3, 0, &pKeyContext->rc2);
 220             break;
 221
 222         case CALG_3DES:
 223             des3_setup(abKeyValue, 24, 0, &pKeyContext->des3);
 224             break;
 225
 226         case CALG_3DES_112:
 227             memcpy(abKeyValue+16, abKeyValue, 8);
 228             des3_setup(abKeyValue, 24, 0, &pKeyContext->des3);
 229             break;
 230
 231         case CALG_DES:
 232             des_setup(abKeyValue, 8, 0, &pKeyContext->des);
 233             break;
 234
 235         case CALG_AES:
 236         case CALG_AES_128:
 237             aes_setup(abKeyValue, 16, 0, &pKeyContext->aes);
 238             break;
 239
 240         case CALG_AES_192:
 241             aes_setup(abKeyValue, 24, 0, &pKeyContext->aes);
 242             break;
 243
 244         case CALG_AES_256:
 245             aes_setup(abKeyValue, 32, 0, &pKeyContext->aes);
 246             break;
 247     }
 248
 249     return TRUE;
 250 }
 251
 252 BOOL duplicate_key_impl(ALG_ID aiAlgid, CONST KEY_CONTEXT *pSrcKeyContext,
 253                         KEY_CONTEXT *pDestKeyContext)
 254 {
 255     switch (aiAlgid)
 256     {
 257         case CALG_RC4:
 258         case CALG_RC2:
 259         case CALG_3DES:
 260         case CALG_3DES_112:
 261         case CALG_DES:
 262         case CALG_AES:
 263         case CALG_AES_128:
 264         case CALG_AES_192:
 265         case CALG_AES_256:
 266             *pDestKeyContext = *pSrcKeyContext;
 267             break;
 268         case CALG_RSA_KEYX:
 269         case CALG_RSA_SIGN:
 270             pDestKeyContext->rsa.type = pSrcKeyContext->rsa.type;
 271             mp_init_copy(&pDestKeyContext->rsa.e, &pSrcKeyContext->rsa.e);
 272             mp_init_copy(&pDestKeyContext->rsa.d, &pSrcKeyContext->rsa.d);
 273             mp_init_copy(&pDestKeyContext->rsa.N, &pSrcKeyContext->rsa.N);
 274             mp_init_copy(&pDestKeyContext->rsa.p, &pSrcKeyContext->rsa.p);
 275             mp_init_copy(&pDestKeyContext->rsa.q, &pSrcKeyContext->rsa.q);
 276             mp_init_copy(&pDestKeyContext->rsa.qP, &pSrcKeyContext->rsa.qP);
 277             mp_init_copy(&pDestKeyContext->rsa.dP, &pSrcKeyContext->rsa.dP);
 278             mp_init_copy(&pDestKeyContext->rsa.dQ, &pSrcKeyContext->rsa.dQ);
 279             break;
 280
 281         default:
 282             SetLastError(NTE_BAD_ALGID);
 283             return FALSE;
 284     }
 285
 286     return TRUE;
 287 }
 288
 289 static inline void reverse_bytes(BYTE *pbData, DWORD dwLen) {
 290     BYTE swap;
 291     DWORD i;
 292
 293     for (i=0; i<dwLen/2; i++) {
 294         swap = pbData[i];
 295         pbData[i] = pbData[dwLen-i-1];
 296         pbData[dwLen-i-1] = swap;
 297     }
 298 }
 299
 300 BOOL encrypt_block_impl(ALG_ID aiAlgid, DWORD dwKeySpec, KEY_CONTEXT *pKeyContext, CONST BYTE *in, BYTE *out,
 301                         DWORD enc)
 302 {
 303     unsigned long inlen, outlen;
 304     BYTE *in_reversed = NULL;
 305
 306     switch (aiAlgid) {
 307         case CALG_RC2:
 308             if (enc) {
 309                 rc2_ecb_encrypt(in, out, &pKeyContext->rc2);
 310             } else {
 311                 rc2_ecb_decrypt(in, out, &pKeyContext->rc2);
 312             }
 313             break;
 314
 315         case CALG_3DES:
 316         case CALG_3DES_112:
 317             if (enc) {
 318                 des3_ecb_encrypt(in, out, &pKeyContext->des3);
 319             } else {
 320                 des3_ecb_decrypt(in, out, &pKeyContext->des3);
 321             }
 322             break;
 323
 324         case CALG_DES:
 325             if (enc) {
 326                 des_ecb_encrypt(in, out, &pKeyContext->des);
 327             } else {
 328                 des_ecb_decrypt(in, out, &pKeyContext->des);
 329             }
 330             break;
 331
 332         case CALG_AES:
 333         case CALG_AES_128:
 334         case CALG_AES_192:
 335         case CALG_AES_256:
 336             if (enc) {
 337                 aes_ecb_encrypt(in, out, &pKeyContext->aes);
 338             } else {
 339                 aes_ecb_decrypt(in, out, &pKeyContext->aes);
 340             }
 341             break;
 342
 343         case CALG_RSA_KEYX:
 344         case CALG_RSA_SIGN:
 345         case CALG_SSL3_SHAMD5:
 346             outlen = inlen = (mp_count_bits(&pKeyContext->rsa.N)+7)/8;
 347             if (enc) {
 348                 if (rsa_exptmod(in, inlen, out, &outlen, dwKeySpec, &pKeyContext->rsa) != CRYPT_OK) {
 349                     SetLastError(NTE_FAIL);
 350                     return FALSE;
 351                 }
 352                 reverse_bytes(out, outlen);
 353             } else {
 354                 in_reversed = HeapAlloc(GetProcessHeap(), 0, inlen);
 355                 if (!in_reversed) {
 356                     SetLastError(NTE_NO_MEMORY);
 357                     return FALSE;
 358                 }
 359                 memcpy(in_reversed, in, inlen);
 360                 reverse_bytes(in_reversed, inlen);
 361                 if (rsa_exptmod(in_reversed, inlen, out, &outlen, dwKeySpec, &pKeyContext->rsa) != CRYPT_OK) {
 362                     HeapFree(GetProcessHeap(), 0, in_reversed);
 363                     SetLastError(NTE_FAIL);
 364                     return FALSE;
 365                 }
 366                 HeapFree(GetProcessHeap(), 0, in_reversed);
 367             }
 368             break;
 369
 370         default:
 371             SetLastError(NTE_BAD_ALGID);
 372             return FALSE;
 373     }
 374
 375     return TRUE;
 376 }
 377
 378 BOOL encrypt_stream_impl(ALG_ID aiAlgid, KEY_CONTEXT *pKeyContext, BYTE *stream, DWORD dwLen)
 379 {
 380     switch (aiAlgid) {
 381         case CALG_RC4:
 382             rc4_read(stream, dwLen, &pKeyContext->rc4);
 383             break;
 384
 385         default:
 386             SetLastError(NTE_BAD_ALGID);
 387             return FALSE;
 388     }
 389
 390     return TRUE;
 391 }
 392
 393 BOOL gen_rand_impl(BYTE *pbBuffer, DWORD dwLen)
 394 {
 395     return SystemFunction036(pbBuffer, dwLen);
 396 }
 397
 398 BOOL export_public_key_impl(BYTE *pbDest, const KEY_CONTEXT *pKeyContext, DWORD dwKeyLen,DWORD *pdwPubExp)
 399 {
 400     mp_to_unsigned_bin(&pKeyContext->rsa.N, pbDest);
 401     reverse_bytes(pbDest, mp_unsigned_bin_size(&pKeyContext->rsa.N));
 402     if (mp_unsigned_bin_size(&pKeyContext->rsa.N) < dwKeyLen)
 403         memset(pbDest + mp_unsigned_bin_size(&pKeyContext->rsa.N), 0,
 404                dwKeyLen - mp_unsigned_bin_size(&pKeyContext->rsa.N));
 405     *pdwPubExp = (DWORD)mp_get_int(&pKeyContext->rsa.e);
 406     return TRUE;
 407 }
 408
 409 BOOL import_public_key_impl(CONST BYTE *pbSrc, KEY_CONTEXT *pKeyContext, DWORD dwKeyLen,
 410                             DWORD dwPubExp)
 411 {
 412     BYTE *pbTemp;
 413
 414     if (mp_init_multi(&pKeyContext->rsa.e, &pKeyContext->rsa.d, &pKeyContext->rsa.N,
 415                       &pKeyContext->rsa.dQ,&pKeyContext->rsa.dP,&pKeyContext->rsa.qP,
 416                       &pKeyContext->rsa.p, &pKeyContext->rsa.q, NULL) != MP_OKAY)
 417     {
 418         SetLastError(NTE_FAIL);
 419         return FALSE;
 420     }
 421
 422     pbTemp = HeapAlloc(GetProcessHeap(), 0, dwKeyLen);
 423     if (!pbTemp) return FALSE;
 424     memcpy(pbTemp, pbSrc, dwKeyLen);
 425
 426     pKeyContext->rsa.type = PK_PUBLIC;
 427     reverse_bytes(pbTemp, dwKeyLen);
 428     mp_read_unsigned_bin(&pKeyContext->rsa.N, pbTemp, dwKeyLen);
 429     HeapFree(GetProcessHeap(), 0, pbTemp);
 430     mp_set_int(&pKeyContext->rsa.e, dwPubExp);
 431
 432     return TRUE;
 433 }
 434
 435 BOOL export_private_key_impl(BYTE *pbDest, const KEY_CONTEXT *pKeyContext, DWORD dwKeyLen,
 436                              DWORD *pdwPubExp)
 437 {
 438     mp_to_unsigned_bin(&pKeyContext->rsa.N, pbDest);
 439     reverse_bytes(pbDest, mp_unsigned_bin_size(&pKeyContext->rsa.N));
 440     if (mp_unsigned_bin_size(&pKeyContext->rsa.N) < dwKeyLen)
 441         memset(pbDest + mp_unsigned_bin_size(&pKeyContext->rsa.N), 0,
 442                dwKeyLen - mp_unsigned_bin_size(&pKeyContext->rsa.N));
 443     pbDest += dwKeyLen;
 444     mp_to_unsigned_bin(&pKeyContext->rsa.p, pbDest);
 445     reverse_bytes(pbDest, mp_unsigned_bin_size(&pKeyContext->rsa.p));
 446     if (mp_unsigned_bin_size(&pKeyContext->rsa.p) < (dwKeyLen+1)>>1)
 447         memset(pbDest + mp_unsigned_bin_size(&pKeyContext->rsa.p), 0,
 448                ((dwKeyLen+1)>>1) - mp_unsigned_bin_size(&pKeyContext->rsa.p));
 449     pbDest += (dwKeyLen+1)>>1;
 450     mp_to_unsigned_bin(&pKeyContext->rsa.q, pbDest);
 451     reverse_bytes(pbDest, mp_unsigned_bin_size(&pKeyContext->rsa.q));
 452     if (mp_unsigned_bin_size(&pKeyContext->rsa.q) < (dwKeyLen+1)>>1)
 453         memset(pbDest + mp_unsigned_bin_size(&pKeyContext->rsa.q), 0,
 454                ((dwKeyLen+1)>>1) - mp_unsigned_bin_size(&pKeyContext->rsa.q));
 455     pbDest += (dwKeyLen+1)>>1;
 456     mp_to_unsigned_bin(&pKeyContext->rsa.dP, pbDest);
 457     reverse_bytes(pbDest, mp_unsigned_bin_size(&pKeyContext->rsa.dP));
 458     if (mp_unsigned_bin_size(&pKeyContext->rsa.dP) < (dwKeyLen+1)>>1)
 459         memset(pbDest + mp_unsigned_bin_size(&pKeyContext->rsa.dP), 0,
 460                ((dwKeyLen+1)>>1) - mp_unsigned_bin_size(&pKeyContext->rsa.dP));
 461     pbDest += (dwKeyLen+1)>>1;
 462     mp_to_unsigned_bin(&pKeyContext->rsa.dQ, pbDest);
 463     reverse_bytes(pbDest, mp_unsigned_bin_size(&pKeyContext->rsa.dQ));
 464     if (mp_unsigned_bin_size(&pKeyContext->rsa.dQ) < (dwKeyLen+1)>>1)
 465         memset(pbDest + mp_unsigned_bin_size(&pKeyContext->rsa.dQ), 0,
 466                ((dwKeyLen+1)>>1) - mp_unsigned_bin_size(&pKeyContext->rsa.dQ));
 467     pbDest += (dwKeyLen+1)>>1;
 468     mp_to_unsigned_bin(&pKeyContext->rsa.qP, pbDest);
 469     reverse_bytes(pbDest, mp_unsigned_bin_size(&pKeyContext->rsa.qP));
 470     if (mp_unsigned_bin_size(&pKeyContext->rsa.qP) < (dwKeyLen+1)>>1)
 471         memset(pbDest + mp_unsigned_bin_size(&pKeyContext->rsa.qP), 0,
 472                ((dwKeyLen+1)>>1) - mp_unsigned_bin_size(&pKeyContext->rsa.qP));
 473     pbDest += (dwKeyLen+1)>>1;
 474     mp_to_unsigned_bin(&pKeyContext->rsa.d, pbDest);
 475     reverse_bytes(pbDest, mp_unsigned_bin_size(&pKeyContext->rsa.d));
 476     if (mp_unsigned_bin_size(&pKeyContext->rsa.d) < dwKeyLen)
 477         memset(pbDest + mp_unsigned_bin_size(&pKeyContext->rsa.d), 0,
 478                dwKeyLen - mp_unsigned_bin_size(&pKeyContext->rsa.d));
 479     *pdwPubExp = (DWORD)mp_get_int(&pKeyContext->rsa.e);
 480
 481     return TRUE;
 482 }
 483
 484 BOOL import_private_key_impl(CONST BYTE *pbSrc, KEY_CONTEXT *pKeyContext, DWORD dwKeyLen,
 485                              DWORD dwDataLen, DWORD dwPubExp)
 486 {
 487     BYTE *pbTemp, *pbBigNum;
 488
 489     if (mp_init_multi(&pKeyContext->rsa.e, &pKeyContext->rsa.d, &pKeyContext->rsa.N,
 490                       &pKeyContext->rsa.dQ,&pKeyContext->rsa.dP,&pKeyContext->rsa.qP,
 491                       &pKeyContext->rsa.p, &pKeyContext->rsa.q, NULL) != MP_OKAY)
 492     {
 493         SetLastError(NTE_FAIL);
 494         return FALSE;
 495     }
 496
 497     pbTemp = HeapAlloc(GetProcessHeap(), 0, 2*dwKeyLen+5*((dwKeyLen+1)>>1));
 498     if (!pbTemp) return FALSE;
 499     memcpy(pbTemp, pbSrc, min(dwDataLen, 2*dwKeyLen+5*((dwKeyLen+1)>>1)));
 500     pbBigNum = pbTemp;
 501
 502     pKeyContext->rsa.type = PK_PRIVATE;
 503     reverse_bytes(pbBigNum, dwKeyLen);
 504     mp_read_unsigned_bin(&pKeyContext->rsa.N, pbBigNum, dwKeyLen);
 505     pbBigNum += dwKeyLen;
 506     reverse_bytes(pbBigNum, (dwKeyLen+1)>>1);
 507     mp_read_unsigned_bin(&pKeyContext->rsa.p, pbBigNum, (dwKeyLen+1)>>1);
 508     pbBigNum += (dwKeyLen+1)>>1;
 509     reverse_bytes(pbBigNum, (dwKeyLen+1)>>1);
 510     mp_read_unsigned_bin(&pKeyContext->rsa.q, pbBigNum, (dwKeyLen+1)>>1);
 511     pbBigNum += (dwKeyLen+1)>>1;
 512     reverse_bytes(pbBigNum, (dwKeyLen+1)>>1);
 513     mp_read_unsigned_bin(&pKeyContext->rsa.dP, pbBigNum, (dwKeyLen+1)>>1);
 514     pbBigNum += (dwKeyLen+1)>>1;
 515     reverse_bytes(pbBigNum, (dwKeyLen+1)>>1);
 516     mp_read_unsigned_bin(&pKeyContext->rsa.dQ, pbBigNum, (dwKeyLen+1)>>1);
 517     pbBigNum += (dwKeyLen+1)>>1;
 518     reverse_bytes(pbBigNum, (dwKeyLen+1)>>1);
 519     mp_read_unsigned_bin(&pKeyContext->rsa.qP, pbBigNum, (dwKeyLen+1)>>1);
 520     pbBigNum += (dwKeyLen+1)>>1;
 521     /* The size of the private exponent d is inferred from the remaining
 522      * data length.
 523      */
 524     dwKeyLen = min(dwKeyLen, dwDataLen - (pbBigNum - pbTemp));
 525     reverse_bytes(pbBigNum, dwKeyLen);
 526     mp_read_unsigned_bin(&pKeyContext->rsa.d, pbBigNum, dwKeyLen);
 527     mp_set_int(&pKeyContext->rsa.e, dwPubExp);
 528
 529     HeapFree(GetProcessHeap(), 0, pbTemp);
 530     return TRUE;
 531 }