OSX/libsecurity_cryptkit/lib/feeDigitalSignature.c

   1 /* Copyright (c) 1998,2011,2014 Apple Inc.  All Rights Reserved.
   2  *
   3  * NOTICE: USE OF THE MATERIALS ACCOMPANYING THIS NOTICE IS SUBJECT
   4  * TO THE TERMS OF THE SIGNED "FAST ELLIPTIC ENCRYPTION (FEE) REFERENCE
   5  * SOURCE CODE EVALUATION AGREEMENT" BETWEEN APPLE, INC. AND THE
   6  * ORIGINAL LICENSEE THAT OBTAINED THESE MATERIALS FROM APPLE,
   7  * INC.  ANY USE OF THESE MATERIALS NOT PERMITTED BY SUCH AGREEMENT WILL
   8  * EXPOSE YOU TO LIABILITY.
   9  ***************************************************************************
  10  *
  11  * feeDigitalSignature.c
  12  *
  13  * Revision History
  14  * ----------------
  15  * 10/06/98             ap
  16  *      Changed to compile with C++.
  17  *  9 Sep 98 at NeXT
  18  *      Major changes to use projective elliptic algebra for
  19  *              Weierstrass curves.
  20  * 15 Jan 97 at NeXT
  21  *      FEE_SIG_VERSION = 3 (removed code for compatibilty with all older
  22  *              versions).
  23  *      Was modg(), is curveOrderJustify()
  24  *      Use plus curve for ellipic algebra per IEEE standards
  25  * 22 Aug 96 at NeXT
  26  *      Ported guts of Blaine Garst's NSFEEDigitalSignature.m to C.
  27  */
  28
  29 #include "ckconfig.h"
  30 #include "feeTypes.h"
  31 #include "feePublicKey.h"
  32 #include "feePublicKeyPrivate.h"
  33 #include "feeDigitalSignature.h"
  34 #include "giantIntegers.h"
  35 #include "elliptic.h"
  36 #include "feeRandom.h"
  37 #include "curveParams.h"
  38 #include "falloc.h"
  39 #include "ckutilities.h"
  40 #include "feeDebug.h"
  41 #include "platform.h"
  42 #include "byteRep.h"
  43 #include "feeECDSA.h"
  44 #if     CRYPTKIT_DER_ENABLE
  45 #include "CryptKitDER.h"
  46 #endif
  47
  48 #include <stdlib.h>
  49 #include "ellipticProj.h"
  50
  51 #define SIG_DEBUG               0
  52 #if     SIG_DEBUG
  53 int     sigDebug=1;             // tweakable at runtime via debugger
  54 #endif  // SIG_DEBUG
  55
  56 #define SIG_CURVE               DEFAULT_CURVE
  57
  58 /*
  59  * true : justify randGiant to [2, x1OrderPlus-2]
  60  * false : no truncate or mod of randGiant
  61  */
  62 #define RAND_JUST_X1_ORDER_PLUS 1
  63
  64 #define FEE_SIG_VERSION         4
  65 #define FEE_SIG_VERSION_MIN     4
  66
  67 #ifndef max
  68 #define max(a,b) ((a)>(b)? (a) : (b))
  69 #endif  // max
  70
  71 typedef struct {
  72         giant           PmX;            // m 'o' P1; m = random
  73         #if     CRYPTKIT_ELL_PROJ_ENABLE
  74         giant           PmY;            // y-coord of m 'o' P1 if we're
  75                                         //  using projective coords
  76         #endif  /* CRYPTKIT_ELL_PROJ_ENABLE */
  77
  78         giant           u;
  79         giant           randGiant;      // random m as giant - only known
  80                                         //  when signing
  81 } sigInst;
  82
  83 static sigInst *sinstAlloc()
  84 {
  85         sigInst *sinst = (sigInst*) fmalloc(sizeof(sigInst));
  86
  87         bzero(sinst, sizeof(sigInst));
  88         return sinst;
  89 }
  90
  91 /*
  92  * Create new feeSig object, including a random large integer 'randGiant' for
  93  * possible use in salting a feeHash object, and 'PmX', equal to
  94  * randGiant 'o' P1. Note that this is not called when *verifying* a
  95  * signature, only when signing.
  96  */
  97 feeSig feeSigNewWithKey(
  98         feePubKey               pubKey,
  99         feeRandFcn              randFcn,                /* optional */
 100         void                    *randRef)
 101 {
 102         sigInst         *sinst = sinstAlloc();
 103         feeRand         frand;
 104         unsigned char   *randBytes;
 105         unsigned        randBytesLen;
 106         curveParams     *cp;
 107
 108         if(pubKey == NULL) {
 109                 return NULL;
 110         }
 111         cp = feePubKeyCurveParams(pubKey);
 112         if(cp == NULL) {
 113                 return NULL;
 114         }
 115
 116         /*
 117          * Generate random m, a little larger than key size, save as randGiant
 118          */
 119         randBytesLen = (feePubKeyBitsize(pubKey) / 8) + 1 + 8; // +8bytes (64bits) to reduce the biais when with reduction mod prime. Per FIPS186-4 - "Using Extra Random Bits"
 120         randBytes = (unsigned char*) fmalloc(randBytesLen);
 121         if(randFcn) {
 122                 randFcn(randRef, randBytes, randBytesLen);
 123         }
 124         else {
 125                 frand = feeRandAlloc();
 126                 feeRandBytes(frand, randBytes, randBytesLen);
 127                 feeRandFree(frand);
 128         }
 129         sinst->randGiant = giant_with_data(randBytes, randBytesLen);
 130         memset(randBytes, 0, randBytesLen);
 131         ffree(randBytes);
 132
 133         #if     FEE_DEBUG
 134         if(isZero(sinst->randGiant)) {
 135                 printf("feeSigNewWithKey: randGiant = 0!\n");
 136         }
 137         #endif  // FEE_DEBUG
 138
 139         /*
 140          * Justify randGiant to be in [2, x1OrderPlus]
 141          */
 142         x1OrderPlusJustify(sinst->randGiant, cp);
 143
 144         /* PmX := randGiant 'o' P1 */
 145         sinst->PmX = newGiant(cp->maxDigits);
 146
 147         #if     CRYPTKIT_ELL_PROJ_ENABLE
 148
 149         if(cp->curveType == FCT_Weierstrass) {
 150
 151                 pointProjStruct pt0;
 152
 153                 sinst->PmY = newGiant(cp->maxDigits);
 154
 155                 /* cook up pt0 as P1 */
 156                 pt0.x = sinst->PmX;
 157                 pt0.y = sinst->PmY;
 158                 pt0.z = borrowGiant(cp->maxDigits);
 159                 gtog(cp->x1Plus, pt0.x);
 160                 gtog(cp->y1Plus, pt0.y);
 161                 int_to_giant(1, pt0.z);
 162
 163                 /* pt0 := P1 'o' randGiant */
 164                 ellMulProjSimple(&pt0, sinst->randGiant, cp);
 165
 166                 returnGiant(pt0.z);
 167         }
 168         else {
 169                 if(SIG_CURVE == CURVE_PLUS) {
 170                         gtog(cp->x1Plus, sinst->PmX);
 171                 }
 172                 else {
 173                         gtog(cp->x1Minus, sinst->PmX);
 174                 }
 175                 elliptic_simple(sinst->PmX, sinst->randGiant, cp);
 176         }
 177         #else   /* CRYPTKIT_ELL_PROJ_ENABLE */
 178
 179         if(SIG_CURVE == CURVE_PLUS) {
 180                 gtog(cp->x1Plus, sinst->PmX);
 181         }
 182         else {
 183                 gtog(cp->x1Minus, sinst->PmX);
 184         }
 185         elliptic_simple(sinst->PmX, sinst->randGiant, cp);
 186
 187         #endif  /* CRYPTKIT_ELL_PROJ_ENABLE */
 188
 189         return sinst;
 190 }
 191
 192 void feeSigFree(feeSig sig)
 193 {
 194         sigInst *sinst = (sigInst*) sig;
 195
 196         if(sinst->PmX) {
 197                 clearGiant(sinst->PmX);
 198                 freeGiant(sinst->PmX);
 199         }
 200         #if     CRYPTKIT_ELL_PROJ_ENABLE
 201         if(sinst->PmY) {
 202                 clearGiant(sinst->PmY);
 203                 freeGiant(sinst->PmY);
 204         }
 205         #endif  /* CRYPTKIT_ELL_PROJ_ENABLE */
 206         if(sinst->u) {
 207                 clearGiant(sinst->u);
 208                 freeGiant(sinst->u);
 209         }
 210         if(sinst->randGiant) {
 211                 clearGiant(sinst->randGiant);
 212                 freeGiant(sinst->randGiant);
 213         }
 214         ffree(sinst);
 215 }
 216
 217 /*
 218  * Obtain Pm after feeSigNewWithKey() or feeSigParse()
 219  */
 220 unsigned char *feeSigPm(feeSig sig,
 221         unsigned *PmLen)
 222 {
 223         sigInst *sinst = (sigInst*) sig;
 224         unsigned char *Pm;
 225
 226         if(sinst->PmX == NULL) {
 227                 dbgLog(("feeSigPm: no PmX!\n"));
 228                 return NULL;
 229         }
 230         else {
 231                 Pm = mem_from_giant(sinst->PmX, PmLen);
 232                 #if     SIG_DEBUG
 233                 if(sigDebug)
 234                 {
 235                     int i;
 236
 237                     printf("Pm : "); printGiant(sinst->PmX);
 238                     printf("PmData: ");
 239                     for(i=0; i<*PmLen; i++) {
 240                         printf("%x:", Pm[i]);
 241                     }
 242                     printf("\n");
 243                 }
 244                 #endif  // SIG_DEBUG
 245         }
 246         return Pm;
 247 }
 248
 249 /*
 250  * Sign specified block of data (most likely a hash result) using
 251  * specified feePubKey.
 252  */
 253 feeReturn feeSigSign(feeSig sig,
 254         const unsigned char *data,              // data to be signed
 255         unsigned dataLen,                       // in bytes
 256         feePubKey pubKey)
 257 {
 258         sigInst                 *sinst = (sigInst*) sig;
 259         giant                   messageGiant = NULL;
 260         unsigned                maxlen;
 261         giant                   privGiant;
 262         unsigned                privGiantBytes;
 263         feeReturn               frtn = FR_Success;
 264         unsigned                randBytesLen;
 265         unsigned                uDigits;        // alloc'd digits in sinst->u
 266         curveParams             *cp;
 267
 268         if(pubKey == NULL) {
 269                 return FR_BadPubKey;
 270         }
 271         cp = feePubKeyCurveParams(pubKey);
 272         if(cp == NULL) {
 273                 return FR_BadPubKey;
 274         }
 275
 276         privGiant = feePubKeyPrivData(pubKey);
 277         if(privGiant == NULL) {
 278                 dbgLog(("Attempt to Sign without private data\n"));
 279                 frtn = FR_IllegalArg;
 280                 goto abort;
 281         }
 282         privGiantBytes = abs(privGiant->sign) * GIANT_BYTES_PER_DIGIT;
 283
 284         /*
 285          * Note PmX = m 'o' P1.
 286          * Get message/digest as giant. May be significantly different
 287          * in size from pubKey's basePrime.
 288          */
 289         messageGiant = giant_with_data(data, dataLen);      // M(text)
 290         randBytesLen = feePubKeyBitsize(pubKey) / 8;
 291         maxlen = max(randBytesLen, dataLen);
 292
 293         /* leave plenty of room.... */
 294         uDigits = (3 * (privGiantBytes + maxlen)) / GIANT_BYTES_PER_DIGIT;
 295         sinst->u = newGiant(uDigits);
 296         gtog(privGiant, sinst->u);                          // u := ourPri
 297         mulg(messageGiant, sinst->u);                       // u *= M(text)
 298         addg(sinst->randGiant, sinst->u);                   // u += m
 299
 300         /*
 301          * Paranoia: we're using the curveParams from the caller's pubKey;
 302          * this cp will have a valid x1OrderPlusRecip if pubKey is the same
 303          * as the one passed to feeSigNewWithKey() (since feeSigNewWithKey
 304          * called x1OrderPlusJustify()). But the caller could conceivably be
 305          * using a different instance of their pubKey, in which case
 306          * the key's cp->x1OrderPlusRecip may not be valid.
 307          */
 308         calcX1OrderPlusRecip(cp);
 309
 310         /* u := u mod x1OrderPlus */
 311         #if     SIG_DEBUG
 312         if(sigDebug) {
 313                 printf("sigSign:\n");
 314                 printf("u pre-modg  : ");
 315                 printGiant(sinst->u);
 316         }
 317         #endif
 318         modg_via_recip(cp->x1OrderPlus, cp->x1OrderPlusRecip, sinst->u);
 319
 320         #if     SIG_DEBUG
 321         if(sigDebug) {
 322                 printf("privGiant   : ");
 323                 printGiant(privGiant);
 324                 printf("u           : ");
 325                 printGiant(sinst->u);
 326                 printf("messageGiant: ");
 327                 printGiant(messageGiant);
 328                 printf("curveParams :\n");
 329                 printCurveParams(cp);
 330         }
 331         #endif  // SIG_DEBUG
 332 abort:
 333         if(messageGiant) {
 334                 freeGiant(messageGiant);
 335         }
 336         return frtn;
 337 }
 338
 339 /*
 340  * Given a feeSig processed by feeSigSign, obtain a malloc'd byte
 341  * array representing the signature.
 342  * See ByteRep.doc for info on the format of the signature string;
 343  * PLEASE UPDATE THIS DOCUMENT WHEN YOU MAKE CHANGES TO THE STRING FORMAT.
 344  */
 345 feeReturn feeSigData(feeSig sig,
 346         unsigned char **sigData,                // IGNORED....malloc'd and RETURNED
 347         unsigned *sigDataLen)                   // RETURNED
 348 {
 349         sigInst  *sinst = (sigInst*) sig;
 350
 351         #if             CRYPTKIT_DER_ENABLE
 352         return feeDEREncodeElGamalSignature(sinst->u, sinst->PmX, sigData, sigDataLen);
 353         #else
 354         *sigDataLen = lengthOfByteRepSig(sinst->u, sinst->PmX);
 355         *sigData = (unsigned char*) fmalloc(*sigDataLen);
 356         sigToByteRep(FEE_SIG_MAGIC,
 357                 FEE_SIG_VERSION,
 358                 FEE_SIG_VERSION_MIN,
 359                 sinst->u,
 360                 sinst->PmX,
 361                 *sigData);
 362         return FR_Success;
 363         #endif
 364 }
 365
 366 /*
 367  * Obtain a feeSig object by parsing an existing signature block.
 368  * Note that if Pm is used to salt a hash of the signed data, this must
 369  * function must be called prior to hashing.
 370  */
 371 feeReturn feeSigParse(const unsigned char *sigData,
 372         size_t sigDataLen,
 373         feeSig *sig)                            // RETURNED
 374 {
 375         sigInst         *sinst = NULL;
 376         feeReturn       frtn;
 377         #if     !CRYPTKIT_DER_ENABLE
 378         int                     version;
 379         int                     magic;
 380         int                     minVersion;
 381         int                     rtn;
 382         #endif
 383
 384         sinst = sinstAlloc();
 385         #if             CRYPTKIT_DER_ENABLE
 386         frtn = feeDERDecodeElGamalSignature(sigData, sigDataLen, &sinst->u, &sinst->PmX);
 387         if(frtn) {
 388                 goto abort;
 389         }
 390         #else
 391         rtn = byteRepToSig(sigData,
 392                 sigDataLen,
 393                 FEE_SIG_VERSION,
 394                 &magic,
 395                 &version,
 396                 &minVersion,
 397                 &sinst->u,
 398                 &sinst->PmX);
 399         if(rtn == 0) {
 400                 frtn = FR_BadSignatureFormat;
 401                 goto abort;
 402         }
 403         switch(magic) {
 404             case FEE_ECDSA_MAGIC:
 405                 frtn = FR_WrongSignatureType;           // ECDSA!
 406                 goto abort;
 407             case FEE_SIG_MAGIC:
 408                 break;                                  // proceed
 409             default:
 410                 frtn = FR_BadSignatureFormat;
 411                 goto abort;
 412         }
 413         #endif          /* CRYPTKIT_DER_ENABLE */
 414
 415         #if     SIG_DEBUG
 416         if(sigDebug) {
 417                 printf("sigParse: \n");
 418                 printf("u: ");
 419                 printGiant(sinst->u);
 420         }
 421         #endif  // SIG_DEBUG
 422
 423         *sig = sinst;
 424         return FR_Success;
 425
 426 abort:
 427         if(sinst) {
 428                 feeSigFree(sinst);
 429         }
 430         return frtn;
 431 }
 432
 433 /*
 434  * Verify signature, obtained via feeSigParse, for specified
 435  * data (most likely a hash result) and feePubKey. Returns non-zero if
 436  * signature valid.
 437  */
 438
 439 #define LOG_BAD_SIG     0
 440
 441 #if     CRYPTKIT_ELL_PROJ_ENABLE
 442
 443 feeReturn feeSigVerifyNoProj(feeSig sig,
 444         const unsigned char *data,
 445         unsigned dataLen,
 446         feePubKey pubKey);
 447
 448 static void borrowPointProj(pointProj pt, unsigned maxDigits)
 449 {
 450         pt->x = borrowGiant(maxDigits);
 451         pt->y = borrowGiant(maxDigits);
 452         pt->z = borrowGiant(maxDigits);
 453 }
 454
 455 static void returnPointProj(pointProj pt)
 456 {
 457         returnGiant(pt->x);
 458         returnGiant(pt->y);
 459         returnGiant(pt->z);
 460 }
 461
 462 feeReturn feeSigVerify(feeSig sig,
 463         const unsigned char *data,
 464         unsigned dataLen,
 465         feePubKey pubKey)
 466 {
 467         pointProjStruct Q;
 468         giant           messageGiant = NULL;
 469         pointProjStruct scratch;
 470         sigInst         *sinst = (sigInst*) sig;
 471         feeReturn       frtn;
 472         curveParams     *cp;
 473         key             origKey;                // may be plus or minus key
 474
 475         if(sinst->PmX == NULL) {
 476                 dbgLog(("sigVerify without parse!\n"));
 477                 return FR_IllegalArg;
 478         }
 479
 480         cp = feePubKeyCurveParams(pubKey);
 481         if(cp->curveType != FCT_Weierstrass) {
 482                 return feeSigVerifyNoProj(sig, data, dataLen, pubKey);
 483         }
 484
 485         borrowPointProj(&Q, cp->maxDigits);
 486         borrowPointProj(&scratch, cp->maxDigits);
 487
 488         /*
 489          * Q := P1
 490          */
 491         gtog(cp->x1Plus, Q.x);
 492         gtog(cp->y1Plus, Q.y);
 493         int_to_giant(1, Q.z);
 494
 495         messageGiant =  giant_with_data(data, dataLen); // M(ciphertext)
 496
 497         /* Q := u 'o' P1 */
 498         ellMulProjSimple(&Q, sinst->u, cp);
 499
 500         /* scratch := theirPub */
 501         origKey = feePubKeyPlusCurve(pubKey);
 502         gtog(origKey->x, scratch.x);
 503         gtog(origKey->y, scratch.y);
 504         int_to_giant(1, scratch.z);
 505
 506         #if     SIG_DEBUG
 507         if(sigDebug) {
 508                 printf("verify origKey:\n");
 509                 printKey(origKey);
 510                 printf("messageGiant: ");
 511                 printGiant(messageGiant);
 512                 printf("curveParams:\n");
 513                 printCurveParams(cp);
 514         }
 515         #endif  // SIG_DEBUG
 516
 517         /* scratch := M 'o' theirPub */
 518         ellMulProjSimple(&scratch, messageGiant, cp);
 519
 520         #if     SIG_DEBUG
 521         if(sigDebug) {
 522                 printf("signature_compare, with\n");
 523                 printf("p0 = Q:\n");
 524                 printGiant(Q.x);
 525                 printf("p1 = Pm:\n");
 526                 printGiant(sinst->PmX);
 527                 printf("p2 = scratch = R:\n");
 528                 printGiant(scratch.x);
 529         }
 530         #endif  // SIG_DEBUG
 531
 532         if(signature_compare(Q.x, sinst->PmX, scratch.x, cp)) {
 533
 534                 frtn = FR_InvalidSignature;
 535                 #if     LOG_BAD_SIG
 536                 printf("***yup, bad sig***\n");
 537                 #endif  // LOG_BAD_SIG
 538         }
 539         else {
 540                 frtn = FR_Success;
 541         }
 542         freeGiant(messageGiant);
 543
 544         returnPointProj(&Q);
 545         returnPointProj(&scratch);
 546         return frtn;
 547 }
 548
 549 #else   /* CRYPTKIT_ELL_PROJ_ENABLE */
 550
 551 #define feeSigVerifyNoProj(s, d, l, k) feeSigVerify(s, d, l, k)
 552
 553 #endif  /* CRYPTKIT_ELL_PROJ_ENABLE */
 554
 555 /*
 556  * FEE_SIG_USING_PROJ true  : this is the "no Weierstrass" case
 557  * feeSigVerifyNoProj false : this is redefined to feeSigVerify
 558  */
 559 feeReturn feeSigVerifyNoProj(feeSig sig,
 560         const unsigned char *data,
 561         unsigned dataLen,
 562         feePubKey pubKey)
 563 {
 564         giant           Q = NULL;
 565         giant           messageGiant = NULL;
 566         giant           scratch = NULL;
 567         sigInst         *sinst = (sigInst*) sig;
 568         feeReturn       frtn;
 569         curveParams     *cp;
 570         key             origKey;                // may be plus or minus key
 571
 572         if(sinst->PmX == NULL) {
 573                 dbgLog(("sigVerify without parse!\n"));
 574                 frtn = FR_IllegalArg;
 575                 goto out;
 576         }
 577
 578         cp = feePubKeyCurveParams(pubKey);
 579         Q = newGiant(cp->maxDigits);
 580
 581         /*
 582          * pick a key (+/-)
 583          * Q := P1
 584          */
 585         if(SIG_CURVE == CURVE_PLUS) {
 586                 origKey = feePubKeyPlusCurve(pubKey);
 587                 gtog(cp->x1Plus, Q);
 588         }
 589         else {
 590                 origKey = feePubKeyMinusCurve(pubKey);
 591                 gtog(cp->x1Minus, Q);
 592         }
 593
 594         messageGiant =  giant_with_data(data, dataLen); // M(ciphertext)
 595
 596         /* Q := u 'o' P1 */
 597         elliptic_simple(Q, sinst->u, cp);
 598
 599         /* scratch := theirPub */
 600         scratch = newGiant(cp->maxDigits);
 601         gtog(origKey->x, scratch);
 602
 603         #if     SIG_DEBUG
 604         if(sigDebug) {
 605                 printf("verify origKey:\n");
 606                 printKey(origKey);
 607                 printf("messageGiant: ");
 608                 printGiant(messageGiant);
 609                 printf("curveParams:\n");
 610                 printCurveParams(cp);
 611         }
 612         #endif  // SIG_DEBUG
 613
 614         /* scratch := M 'o' theirPub */
 615         elliptic_simple(scratch, messageGiant, cp);
 616
 617         #if     SIG_DEBUG
 618         if(sigDebug) {
 619                 printf("signature_compare, with\n");
 620                 printf("p0 = Q:\n");
 621                 printGiant(Q);
 622                 printf("p1 = Pm:\n");
 623                 printGiant(sinst->PmX);
 624                 printf("p2 = scratch = R:\n");
 625                 printGiant(scratch);
 626         }
 627         #endif  // SIG_DEBUG
 628
 629         if(signature_compare(Q, sinst->PmX, scratch, cp)) {
 630
 631                 frtn = FR_InvalidSignature;
 632                 #if     LOG_BAD_SIG
 633                 printf("***yup, bad sig***\n");
 634                 #endif  // LOG_BAD_SIG
 635         }
 636         else {
 637                 frtn = FR_Success;
 638         }
 639 out:
 640         if(messageGiant != NULL) {
 641             freeGiant(messageGiant);
 642         }
 643         if(Q != NULL) {
 644             freeGiant(Q);
 645         }
 646         if(scratch != NULL) {
 647             freeGiant(scratch);
 648         }
 649         return frtn;
 650 }
 651
 652 /*
 653  * For given key, calculate maximum signature size.
 654  */
 655 feeReturn feeSigSize(
 656         feePubKey pubKey,
 657         unsigned *maxSigLen)
 658 {
 659         /* For now, assume that u and Pm.x in the signature are
 660          * same size as the key's associated curveParams->basePrime.
 661          * We might have to pad this a bit....
 662          */
 663         curveParams     *cp = feePubKeyCurveParams(pubKey);
 664
 665         if(cp == NULL) {
 666                 return FR_BadPubKey;
 667         }
 668         #if     CRYPTKIT_DER_ENABLE
 669         *maxSigLen = feeSizeOfDERSig(cp->basePrime, cp->basePrime);
 670         #else
 671         *maxSigLen = (unsigned)lengthOfByteRepSig(cp->basePrime, cp->basePrime);
 672         #endif
 673         return FR_Success;
 674 }