Security-57740.1.18.tar.gz

[apple/security.git] / OSX / libsecurity_cryptkit / lib / feePublicKey.c

/* Copyright (c) 1998,2011-2012,2014 Apple Inc.  All Rights Reserved.
 *
 * NOTICE: USE OF THE MATERIALS ACCOMPANYING THIS NOTICE IS SUBJECT
 * TO THE TERMS OF THE SIGNED "FAST ELLIPTIC ENCRYPTION (FEE) REFERENCE
 * SOURCE CODE EVALUATION AGREEMENT" BETWEEN APPLE, INC. AND THE
 * ORIGINAL LICENSEE THAT OBTAINED THESE MATERIALS FROM APPLE,
 * INC.  ANY USE OF THESE MATERIALS NOT PERMITTED BY SUCH AGREEMENT WILL
 * EXPOSE YOU TO LIABILITY.
 ***************************************************************************
 *
 * feePublicKey.c - Portable FEE public key object.
 *
 * Revision History
 * ----------------
 * 11/27/98     dmitch
 *      Added ECDSA_VERIFY_ONLY dependencies.
 * 10/06/98     ap
 *      Changed to compile with C++.
 *  9 Sep 98 at NeXT
 *      Major changes for IEEE P1363 compliance.
 * 23 Mar 98 at Apple
 *      Added blob support.
 * 21 Jan 98 at Apple
 *      Fixed feePubKeyBitsize bitlen bug for PT_GENERAL case.
 * 05 Jan 98 at Apple
 *      ECDSA now uses SHA-1 hash. Imcompatible with old ECDSA signatures.
 * 17 Jul 97 at Apple
 *      Added ECDSA signature routines.
 * 12 Jun 97 at Apple
 *      Added feePubKeyInitGiants()
 *      Deleted obsolete code
 *      Changes for lesserX1OrderJustify (was curveOrderJustify)
 * 31 Mar 97 at Apple
 *      Fixed leak in feePubKeyCreateKeyString()
 * 15 Jan 97 at NeXT
 *      PUBLIC_KEY_STRING_VERSION = 3; broke compatibility with all older
 *              versions.
 *      Cleaned up which_curve/index code to use CURVE_MINUS/CURVE_PLUS.
 * 12 Dec 96 at NeXT
 *      Added initFromEnc64KeyStr().
 * 20 Aug 96 at NeXT
 *      Ported to C.
 *  ???? 1994   Blaine Garst at NeXT
 *      Created.
 */

#include "ckconfig.h"
#include "feePublicKey.h"
#include "feePublicKeyPrivate.h"
#include "ckutilities.h"
#include "giantIntegers.h"
#include "elliptic.h"
#include "curveParams.h"
#include "falloc.h"
#include "feeTypes.h"
#include "feeDebug.h"
#include "feeHash.h"
#include "ckSHA1.h"
#include "feeDigitalSignature.h"
#include "feeECDSA.h"
#include "platform.h"
#include "enc64.h"
#include "feeDES.h"
#include "byteRep.h"
#if     CRYPTKIT_DER_ENABLE
#include "CryptKitDER.h"
#endif
#include <stdio.h>

/*
 * 11/27/98 dmitch: The ECDSA_VERIFY_ONLY symbol, when #defined, disables all
 * of the code in this module except that which is necessary for ECDSA
 * siggnature verification.
 */
 
#ifndef NULL
#define NULL ((void *)0)
#endif  // NULL

/*
 * Magic number for a portable key blobs. Must be in sync with static
 * final PUBLIC_KEY_STRING_MAGIC in JavaFee/PublicKey.java.
 */
#define PUBLIC_KEY_BLOB_MAGIC_PUB               0xfeeddeef
#define PUBLIC_KEY_BLOB_MAGIC_PRIV      0xfeeddeed
#define PUBLIC_KEY_BLOB_VERSION                 6
#define PUBLIC_KEY_BLOB_MINVERSION              6

#if     CRYPTKIT_DER_ENABLE
#define PUBLIC_DER_KEY_BLOB_VERSION             1
#endif

/*
 * Private data. All "instance" routines are passed a feePubKey (actually
 * a void *) which is actually a pointer to one of these.
 */
typedef struct {
        key                     plus;
        key                     minus;          // not needed for ECDSA
        curveParams     *cp;            // common params shared by minus, plus
        giant           privGiant;      // private key
} pubKeyInst;

static feeReturn feeGenPrivate(pubKeyInst *pkinst,
        const unsigned char *passwd,
        unsigned passwdLen,
        char hashPasswd);
static pubKeyInst *pubKeyInstAlloc(void);
static void pubKeyInstFree(pubKeyInst *pkinst);
#if             GIANTS_VIA_STACK
static void feePubKeyInitGiants(void);
#endif
static feeReturn createKeyBlob(pubKeyInst *pkinst,
        int isPrivate,                  // 0 : public   1 : private
        unsigned char **keyBlob,        // mallocd and RETURNED
        unsigned *keyBlobLen);          // RETURNED
static feeReturn feePubKeyInitFromKeyBlob(feePubKey pubKey,
        unsigned char *keyBlob,
        unsigned keyBlobLen);

#pragma mark --- General public API function ---

/*
 * Obatin a newly allocated feePubKey.
 */
feePubKey feePubKeyAlloc(void)
{
        pubKeyInst *pkinst = pubKeyInstAlloc();

        #if             GIANTS_VIA_STACK
        feePubKeyInitGiants();
        #endif
        return pkinst;
}

void feePubKeyFree(feePubKey pubKey)
{
        pubKeyInstFree((pubKeyInst*) pubKey);
}

#ifndef ECDSA_VERIFY_ONLY
/*
 * Init feePubKey from private key data.
 */
feeReturn feePubKeyInitFromPrivDataKeyBits(feePubKey pubKey,
        const unsigned char *privData,
        unsigned privDataLen,
        unsigned keyBits,                       /* key size in bits */
        feePrimeType primeType,         /* FPT_Fefault means "best one" */
        feeCurveType curveType,         /* FCT_Default means "best one" */
        char hashPrivData)
{
        feeReturn frtn;
        feeDepth depth;
        
        frtn = feeKeyBitsToDepth(keyBits, primeType, curveType, &depth);
        if(frtn) {
                return frtn;
        }
        return feePubKeyInitFromPrivDataDepth(pubKey,
                privData, 
                privDataLen,
                depth,
                hashPrivData);
}

feeReturn feePubKeyInitFromPrivDataDepth(feePubKey pubKey,
        const unsigned char *privData,
        unsigned privDataLen,
        feeDepth depth,
        char hashPrivData)
{
        pubKeyInst *pkinst = (pubKeyInst *) pubKey;
        feeReturn  frtn;

        #if     ENGINE_127_BITS
        if(depth != FEE_DEPTH_127_1) {
                dbgLog(("Illegal Depth\n"));
                return FR_IllegalDepth;
        }
        #endif  // ENGINE_127_BITS
        if(depth > FEE_DEPTH_MAX) {
                dbgLog(("Illegal Depth\n"));
                return FR_IllegalDepth;
        }

        pkinst->cp = curveParamsForDepth(depth);
        pkinst->plus  = new_public(pkinst->cp, CURVE_PLUS);
        if(pkinst->cp->x1Minus != NULL) {
                pkinst->minus = new_public(pkinst->cp, CURVE_MINUS);
        }
        /* else only usable for ECDSA */
        
        frtn = feeGenPrivate(pkinst, privData, privDataLen, hashPrivData);
        if(frtn) {
                return frtn;
        }
        set_priv_key_giant(pkinst->plus, pkinst->privGiant);
        if(pkinst->cp->x1Minus != NULL) {
                set_priv_key_giant(pkinst->minus, pkinst->privGiant);
        }
        return FR_Success;
}

#endif  /* ECDSA_VERIFY_ONLY */

/*
 * Init feePubKey from curve parameters matching existing oldKey.
 */
feeReturn feePubKeyInitFromKey(feePubKey pubKey,
        const unsigned char *privData,
        unsigned privDataLen,
        feePubKey oldKey,
        char hashPrivData)
{
        pubKeyInst *pkinst = (pubKeyInst *) pubKey;
        pubKeyInst *oldInst = (pubKeyInst *) oldKey;
        feeReturn  frtn;

        if(oldKey == NULL) {
                dbgLog(("NULL existing key\n"));
                return FR_BadPubKey;
        }

        pkinst->cp = curveParamsCopy(oldInst->cp);
        if(pkinst->cp->x1Minus != NULL) {
                pkinst->minus = new_public(pkinst->cp, CURVE_MINUS);
                if(pkinst->minus == NULL) {
                        goto abort;
                }
        }
        /* else this curve only usable for ECDSA */
        
        pkinst->plus = new_public(pkinst->cp, CURVE_PLUS);
        if(pkinst->plus == NULL) {
                goto abort;
        }
        frtn = feeGenPrivate(pkinst, privData, privDataLen, hashPrivData);
        if(frtn) {
                return frtn;
        }
        set_priv_key_giant(pkinst->plus, pkinst->privGiant);
        if(pkinst->cp->x1Minus != NULL) {
                set_priv_key_giant(pkinst->minus, pkinst->privGiant);
        }
        return FR_Success;

abort:
        dbgLog(("Bad Existing Public Key\n"));
        return FR_BadPubKey;
}

/***
 *** Public KeyString support. 
 ***/
/*
 * Init feePubKey from a public key string.
 *
 * See ByteRep.doc for info on the format of the public key string and blobs;
 * PLEASE UPDATE THIS DOCUMENT WHEN YOU MAKE CHANGES TO THE STRING FORMAT.
 */
feeReturn feePubKeyInitFromKeyString(feePubKey pubKey,
        const char *keyStr,
        unsigned keyStrLen)
{
        unsigned char   *blob = NULL;
        unsigned                blobLen;
        feeReturn               frtn;

        blob = dec64((unsigned char *)keyStr, keyStrLen, &blobLen);
        if(blob == NULL) {
                dbgLog(("Bad Public Key String (not enc64)\n"));
                return FR_BadPubKeyString;
        }
        frtn = feePubKeyInitFromKeyBlob(pubKey, blob, blobLen);
        ffree(blob);
        return frtn;
}

/*
 * Create a public key in the form of a null-terminated C string.
 * This string contains an encoded version of all of our ivars except for
 * privGiant.
 *
 * See ByteRep.doc for info on the format of the public key string and blobs;
 * PLEASE UPDATE THIS DOCUMENT WHEN YOU MAKE CHANGES TO THE STRING FORMAT.
 */
feeReturn feePubKeyCreateKeyString(feePubKey pubKey,
        char **pubKeyString,            /* RETURNED */
        unsigned *pubKeyStringLen)      /* RETURNED */
{
        unsigned char   *blob;
        unsigned        blobLen;
        feeReturn       frtn;
        pubKeyInst      *pkinst = (pubKeyInst *)pubKey;

        /* get binary pub blob, encode the blob, free the blob */
        frtn = createKeyBlob(pkinst,
                0,              // isPrivate
                &blob,
                &blobLen);
        if(frtn) {
                return frtn;
        }

        *pubKeyString = (char *)enc64(blob, blobLen, pubKeyStringLen);
        ffree(blob);
        return FR_Success;
}

/*** 
 *** Native key blob support.
 ***/
 
#ifndef ECDSA_VERIFY_ONLY

/*
 * Obtain portable public and private key blobs from a key.
 */
feeReturn feePubKeyCreatePubBlob(feePubKey pubKey,
        unsigned char **keyBlob,        // mallocd and RETURNED
        unsigned *keyBlobLen)           // RETURNED
{
        pubKeyInst *pkinst = (pubKeyInst *)pubKey;

        return createKeyBlob(pkinst,
                0,
                keyBlob,
                keyBlobLen);
}

feeReturn feePubKeyCreatePrivBlob(feePubKey pubKey,
        unsigned char **keyBlob,        // mallocd and RETURNED
        unsigned *keyBlobLen)           // RETURNED
{
        pubKeyInst *pkinst = (pubKeyInst *)pubKey;

        if(pkinst->privGiant == NULL) {
                return FR_IncompatibleKey;
        }
        return createKeyBlob(pkinst,
                1,
                keyBlob,
                keyBlobLen);
}

/* 
 * Given private-capable privKey, initialize pubKey to be its corresponding 
 * public key.
 */
feeReturn feePubKeyInitPubKeyFromPriv(feePubKey privKey,
        feePubKey pubKey)
{
        pubKeyInst *privInst = (pubKeyInst *)privKey;
        pubKeyInst *pubInst  = (pubKeyInst *)pubKey;

        if((privInst == NULL) || (pubInst == NULL)) {
                return FR_BadPubKey;
        }
        if(privInst->privGiant == NULL) {
                return FR_IncompatibleKey;
        }
        pubInst->cp = curveParamsCopy(privInst->cp);
        if(pubInst == NULL) {
                return FR_Memory;
        }
        pubInst->plus   = new_public_with_key(privInst->plus,  pubInst->cp);
        if(pubInst->plus == NULL) {
                return FR_Memory;
        } 
        if(pubInst->cp->x1Minus != NULL) {
                pubInst->minus  = new_public_with_key(privInst->minus, pubInst->cp);
                if(pubInst->minus == NULL) {
                        return FR_Memory;
                } 
        }
        return FR_Success;
}

#endif  /* ECDSA_VERIFY_ONLY */

/*
 * Returns non-zero if two keys are equivalent.
 */
int feePubKeyIsEqual(feePubKey key1, feePubKey key2)
{
        pubKeyInst *pkinst1 = (pubKeyInst *) key1;
        pubKeyInst *pkinst2 = (pubKeyInst *) key2;

        if ((pkinst1 == NULL) || (pkinst2 == NULL)) {
                return 0;
        }
        if((pkinst1->minus != NULL) && (pkinst2->minus != NULL)) {
                if(key_equal(pkinst1->minus, pkinst2->minus) == 0) {
                        return 0;
                }
        }
        if(key_equal(pkinst1->plus, pkinst2->plus) == 0) {
                return 0;
        }
        return 1;
}

/*
 * Returns non-zero if key is private-capable (i.e., capable of signing
 * and decrypting).
 */
int feePubKeyIsPrivate(feePubKey key)
{
        pubKeyInst *myPkinst = (pubKeyInst *)key;

        return ((myPkinst->privGiant != NULL) ? 1 : 0);
}

#ifndef ECDSA_VERIFY_ONLY

#if     CRYPTKIT_KEY_EXCHANGE

feeReturn feePubKeyCreatePad(feePubKey myKey,
        feePubKey theirKey,
        unsigned char **padData,        /* RETURNED */
        unsigned *padDataLen)           /* RETURNED padData length in bytes */
{
        pubKeyInst *myPkinst = (pubKeyInst *) myKey;
        pubKeyInst *theirPkinst = (pubKeyInst *) theirKey;
        giant pad;
        unsigned char *result;
        unsigned padLen;
        key pkey;

        /*
         * Do some compatibility checking (myKey, theirKey) here...?
         */
        if(DEFAULT_CURVE == CURVE_PLUS) {
                pkey = theirPkinst->plus;
        }
        else {
                pkey = theirPkinst->minus;
        }
        pad = make_pad(myPkinst->privGiant, pkey);
        result = mem_from_giant(pad, &padLen);
        freeGiant(pad);

        /*
         * Ensure we have a the minimum necessary for DES. A bit of a hack,
         * to be sure.
         */
        if(padLen >= FEE_DES_MIN_STATE_SIZE) {
                *padData = result;
                *padDataLen = padLen;
        }
        else {
                *padData = (unsigned char*) fmalloc(FEE_DES_MIN_STATE_SIZE);
                *padDataLen = FEE_DES_MIN_STATE_SIZE;
                bzero(*padData, FEE_DES_MIN_STATE_SIZE);
                bcopy(result, *padData, padLen);
                ffree(result);
        }
        return FR_Success;
}

#endif  /* CRYPTKIT_KEY_EXCHANGE */

#if     CRYPTKIT_HIGH_LEVEL_SIG

#warning HLS
/*
 * Generate digital signature, ElGamal style.
 */
feeReturn feePubKeyCreateSignature(feePubKey pubKey,
        const unsigned char *data,
        unsigned dataLen,
        unsigned char **signature,      /* fmalloc'd and RETURNED */
        unsigned *signatureLen)         /* RETURNED */
{
        pubKeyInst      *pkinst = (pubKeyInst *) pubKey;
        feeHash         hash;
        feeSig          sig;
        unsigned char   *Pm = NULL;
        unsigned        PmLen;
        feeReturn       frtn;

        if(pkinst->privGiant == NULL) {
                dbgLog(("feePubKeyCreateSignature: Attempt to Sign without"
                        " private data\n"));
                return FR_BadPubKey;
        }
        hash = feeHashAlloc();
        sig = feeSigNewWithKey(pubKey, NULL, NULL);
        if(sig == NULL) {
                /*
                 * Shouldn't happen, but...
                 */
                feeHashFree(hash);
                return FR_BadPubKey;
        }

        /*
         * Get Pm to salt hash object
         */
        Pm = feeSigPm(sig, &PmLen);
        feeHashAddData(hash, Pm, PmLen);

        /*
         * Now hash the data proper, then sign the hash
         */
        feeHashAddData(hash, data, dataLen);
        frtn = feeSigSign(sig,
                feeHashDigest(hash),
                feeHashDigestLen(),
                pubKey);
        if(frtn == FR_Success) {
                frtn = feeSigData(sig, signature, signatureLen);
        }
        feeHashFree(hash);
        feeSigFree(sig);
        ffree(Pm);
        return frtn;
}

/*
 * Verify digital signature, ElGamal style. If the signature is ECDSA,
 * we'll use that format for compatibility.
 */
feeReturn feePubKeyVerifySignature(feePubKey pubKey,
        const unsigned char *data,
        unsigned dataLen,
        const unsigned char *signature,
        unsigned signatureLen)
{
        feeHash                 hash;
        feeSig                  sig;
        unsigned char   *Pm = NULL;
        unsigned                PmLen;
        feeReturn               frtn;

        hash = feeHashAlloc();
        frtn = feeSigParse(signature, signatureLen, &sig);
        if(frtn) {
                feeHashFree(hash);
                #if CRYPTKIT_ECDSA_ENABLE
                if(frtn == FR_WrongSignatureType) {
                        return feePubKeyVerifyECDSASignature(pubKey,
                                data,
                                dataLen,
                                signature,
                                signatureLen);
                }
                #endif  /* CRYPTKIT_ECDSA_ENABLE */
                return frtn;
        }

        /*
         * Get PM as salt; eat salt, then hash data
         */
        Pm = feeSigPm(sig, &PmLen);
        feeHashAddData(hash, Pm, PmLen);
        feeHashAddData(hash, data, dataLen);
        frtn = feeSigVerify(sig,
                feeHashDigest(hash),
                feeHashDigestLen(),
                pubKey);

        feeHashFree(hash);
        feeSigFree(sig);
        ffree(Pm);
        return frtn;
}

#pragma mark --- ECDSA signature: high level routines ---

#if     CRYPTKIT_ECDSA_ENABLE
/*
 * Generate digital signature, ECDSA style.
 */
feeReturn feePubKeyCreateECDSASignature(feePubKey pubKey,
        const unsigned char *data,
        unsigned dataLen,
        unsigned char **signature,      /* fmalloc'd and RETURNED */
        unsigned *signatureLen)         /* RETURNED */
{
        pubKeyInst      *pkinst = (pubKeyInst *) pubKey;
        sha1Obj         sha1;
        feeReturn       frtn;

        if(pkinst->privGiant == NULL) {
                dbgLog(("feePubKeyCreateECDSASignature: Attempt to Sign "
                        "without private data\n"));
                return FR_BadPubKey;
        }
        sha1 = sha1Alloc();
        sha1AddData(sha1, data, dataLen);
        frtn = feeECDSASign(pubKey,
                sha1Digest(sha1),
                sha1DigestLen(),
                NULL,                   // randFcn
                NULL,
                signature,
                signatureLen);
        sha1Free(sha1);
        return frtn;
}
#endif  /* CRYPTKIT_ECDSA_ENABLE */
#endif  /* CRYPTKIT_HIGH_LEVEL_SIG */
#endif  /* ECDSA_VERIFY_ONLY */

#if     CRYPTKIT_HIGH_LEVEL_SIG

#if     CRYPTKIT_ECDSA_ENABLE

/*
 * Verify digital signature, ECDSA style.
 */
feeReturn feePubKeyVerifyECDSASignature(feePubKey pubKey,
        const unsigned char *data,
        unsigned dataLen,
        const unsigned char *signature,
        unsigned signatureLen)
{
        sha1Obj         sha1;
        feeReturn       frtn;

        sha1 = sha1Alloc();
        sha1AddData(sha1, data, dataLen);
        frtn = feeECDSAVerify(signature,
                signatureLen,
                sha1Digest(sha1),
                sha1DigestLen(),
                pubKey);
        sha1Free(sha1);
        return frtn;
}

#endif  /* CRYPTKIT_ECDSA_ENABLE */

#endif  /* CRYPTKIT_HIGH_LEVEL_SIG */

#pragma mark --- ECDH ---

/* 
 * Diffie-Hellman. Public key is specified either as a feePubKey or 
 * a ANSI X9.62 format public key string (0x04 | x | y). In either case
 * the caller must ensure that the two keys are on the same curve. 
 * Output data is fmalloc'd here; caller must free. Output data is 
 * exactly the size of the curve's modulus in bytes. 
 */
feeReturn feePubKeyECDH(
        feePubKey privKey,
        /* one of the following two is non-NULL */
        feePubKey pubKey,
        const unsigned char *pubKeyStr,
        unsigned pubKeyStrLen,
        /* output fmallocd and RETURNED here */
        unsigned char **output,
        unsigned *outputLen)
{
        feePubKey theirPub = pubKey;
        feeReturn frtn = FR_Success;
        pubKeyInst *privInst = (pubKeyInst *) privKey;
        
        if(privInst->privGiant == NULL) {
                dbgLog(("feePubKeyECDH: privKey not a private key\n"));
                return FR_IncompatibleKey;
        }
        
        if(theirPub == NULL) {
                if(pubKeyStr == NULL) {
                        return FR_IllegalArg;
                }
                
                /* Cook up a public key with the same curveParams as the private key */
                feeDepth depth;
                frtn = curveParamsDepth(privInst->cp, &depth);
                if(frtn) {
                        return frtn;
                }
                theirPub = feePubKeyAlloc();
                if(theirPub == NULL) {
                        return FR_Memory;
                }
                frtn = feePubKeyInitFromECDSAPubBlob(theirPub, pubKeyStr, pubKeyStrLen, depth);
                if(frtn) {
                        goto errOut;
                }
        }
        
        pubKeyInst *pubInst = (pubKeyInst *) theirPub;
        
        giant outputGiant = make_pad(privInst->privGiant, pubInst->plus);
        if(outputGiant == NULL) {
                dbgLog(("feePubKeyECDH: make_pad error\n"));
                frtn = FR_Internal;
        }
        else {
                *outputLen = (privInst->cp->q + 7) / 8;
                *output = (unsigned char *)fmalloc(*outputLen);
                if(*output == NULL) {
                        frtn = FR_Memory;
                        goto errOut;
                }
                serializeGiant(outputGiant, *output, *outputLen);
                freeGiant(outputGiant);
        }
errOut:
        if((pubKey == NULL) && (theirPub != NULL)) {
                feePubKeyFree(theirPub);
        }
        return frtn;
}

#pragma mark --- feePubKey data accessors ---

unsigned feePubKeyBitsize(feePubKey pubKey)
{
        pubKeyInst *pkinst = (pubKeyInst *) pubKey;
        switch(pkinst->cp->primeType) {
                case FPT_General:       /* cp->q is here for just this purpose */
                case FPT_Mersenne:
                        return pkinst->cp->q;
                case FPT_FEE:           /* could be larger or smaller than 2^q-1 */
                default:
                        return bitlen(pkinst->cp->basePrime);   
        }
        /* NOT REACHED */
        return 0;
}

/*
 * Accessor routines.
 */
/* private only...*/
key feePubKeyPlusCurve(feePubKey pubKey)
{
        pubKeyInst *pkinst = (pubKeyInst *) pubKey;

        return pkinst->plus;
}

key feePubKeyMinusCurve(feePubKey pubKey)
{
        pubKeyInst *pkinst = (pubKeyInst *) pubKey;

        return pkinst->minus;
}

curveParams *feePubKeyCurveParams(feePubKey pubKey)
{
        pubKeyInst *pkinst = (pubKeyInst *) pubKey;

        return pkinst->cp;
}

giant feePubKeyPrivData(feePubKey pubKey)
{
        pubKeyInst *pkinst = (pubKeyInst *) pubKey;

        return pkinst->privGiant;
}

const char *feePubKeyAlgorithmName(void)
{
        return "Elliptic Curve - FEE by Apple Computer";
}

#pragma mark --- Private functions ---

/*
 * alloc, free pubKeyInst
 */
static pubKeyInst *pubKeyInstAlloc(void)
{
        pubKeyInst *pkinst = (pubKeyInst *) fmalloc(sizeof(pubKeyInst));

        bzero(pkinst, sizeof(pubKeyInst));
        return pkinst;
}

static void pubKeyInstFree(pubKeyInst *pkinst)
{
        if(pkinst->minus) {
                free_key(pkinst->minus);
        }
        if(pkinst->plus) {
                free_key(pkinst->plus);
        }
        if(pkinst->cp) {
                freeCurveParams(pkinst->cp);
        }
        if(pkinst->privGiant) {
                /*
                 * Zero out the private data...
                 */
                clearGiant(pkinst->privGiant);
                freeGiant(pkinst->privGiant);
        }
        ffree(pkinst);
}

#ifndef ECDSA_VERIFY_ONLY

/*
 * Create a pubKeyInst.privGiant given a password of
 * arbitrary length.
 * Currently, the only error is "private data too short" (FR_IllegalArg).
 */

#define NO_PRIV_MUNGE           0       /* skip this step */

static feeReturn feeGenPrivate(pubKeyInst *pkinst,
        const unsigned char *passwd,
        unsigned passwdLen,
        char hashPasswd)
{
        unsigned                privLen;                        // desired size of pkinst->privData
        feeHash                 *hash = NULL;           // a malloc'd array
        unsigned                digestLen;                      // size of MD5 digest
        unsigned                dataSize;                       // min(privLen, passwdLen)
        unsigned                numDigests = 0;
        unsigned                i;
        unsigned char   *cp;
        unsigned                toMove;                         // for this digest
        unsigned                moved;                          // total digested
        unsigned char   *digest = NULL;
        unsigned char   *privData = NULL;       // temp, before modg(curveOrder)
        giant                   corder;                         // lesser of two curve orders
        
        /*
         * generate privData which is just larger than the smaller
         * curve order.
         * We'll take the result mod the curve order when we're done.
         * Note we do *not* have to free corder - it's a pointer to a giant
         * in pkinst->cp.
         */
        corder = lesserX1Order(pkinst->cp);
        CKASSERT(!isZero(corder));
        privLen = (bitlen(corder) / 8) + 1;

        if(!hashPasswd) {
                /* 
                 * Caller trusts the incoming entropy. Verify it's big enough and proceed. 
                 */
                if(passwdLen < privLen) {
                        return FR_ShortPrivData;
                }
                privLen = passwdLen;
                privData = (unsigned char *)passwd;
                goto finishUp;
        }
        if(passwdLen < 2) {
                return FR_IllegalArg;
        }


        /*
         * Calculate how many MD5 digests we'll generate.
         */
        if(privLen > passwdLen) {
                dataSize = passwdLen;
        }
        else {
                dataSize = privLen;
        }
        digestLen = feeHashDigestLen();
        numDigests = (dataSize + digestLen - 1) / digestLen;

        hash = (void**) fmalloc(numDigests * sizeof(feeHash));
        for(i=0; i<numDigests; i++) {
                hash[i] = feeHashAlloc();
        }

        /*
         * fill digests with passwd data, digestLen (or resid length)
         * at a time. If (passwdLen > privLen), last digest will hash all
         * remaining passwd data.
         */
        cp = (unsigned char *)passwd;
        moved = 0;
        for(i=0; i<numDigests; i++) {
                if(i == (numDigests - 1)) {                 // last digest
                    toMove = passwdLen - moved;
                }
                else {
                    toMove = digestLen;
                }
                feeHashAddData(hash[i], cp, toMove);
                cp += toMove;
                moved += toMove;
        }

        /*
         * copy digests to privData, up to privLen bytes. Pad with
         * additional copies of digests if necessary.
         */
        privData = (unsigned char*) fmalloc(privLen);
        cp = privData;
        moved = 0;
        i = 0;                  // digest number
        for(moved=0; moved<privLen; ) {
                if((moved + digestLen) > privLen) {
                   toMove = privLen - moved;
                }
                else {
                   toMove = digestLen;
                }
                digest = feeHashDigest(hash[i++]);
                bcopy(digest, cp, toMove);
                cp += toMove;
                moved += toMove;
                if(i == numDigests) {
                    i = 0;              // wrap to 0, start padding
                }
        }
        
finishUp:
        /*
         * Convert to giant, justify result to within [2, lesserX1Order]
         */
        pkinst->privGiant = giant_with_data(privData, privLen);

        #if     FEE_DEBUG
        if(isZero(pkinst->privGiant)) {
                printf("feeGenPrivate: privData = 0!\n");
        }
        #endif  // FEE_DEBUG

        lesserX1OrderJustify(pkinst->privGiant, pkinst->cp);
        if(hashPasswd) {
                memset(privData, 0, privLen);
                ffree(privData);
                for(i=0; i<numDigests; i++) {
                        feeHashFree(hash[i]);
                }
                ffree(hash);
        }
        return FR_Success;
}

#endif  /* ECDSA_VERIFY_ONLY */

#if     FEE_DEBUG

void printPubKey(feePubKey pubKey)
{
        pubKeyInst *pkinst = pubKey;

        printf("\ncurveParams:\n");
        printCurveParams(pkinst->cp);
        printf("plus:\n");
        printKey(pkinst->plus);
        printf("minus:\n");
        printKey(pkinst->minus);
        if(pkinst->privGiant != NULL) {
            printf("privGiant : ");
            printGiant(pkinst->privGiant);
        }
}

#else   // FEE_DEBUG
void printPubKey(feePubKey pubKey) {}
#endif  // FEE_DEBUG

/*
 * Prime the curveParams and giants modules for quick allocs of giants.
 */
#if             GIANTS_VIA_STACK

static int giantsInitd = 0;

static void feePubKeyInitGiants(void)
{
        if(giantsInitd) {
                return;
        }
        curveParamsInitGiants();
        giantsInitd = 1;
}
#endif

#pragma mark --- Native (custom) key blob formatting ---

/*
 * Exported key blob support. New, 23 Mar 1998.
 *
 * Convert to public or private key blob.
 */

#ifndef ECDSA_VERIFY_ONLY

/***
 *** Common native blob support 
 ***/
static feeReturn createKeyBlob(pubKeyInst *pkinst,
        int                     isPrivate,              // 0 : public   1 : private
        unsigned char   **keyBlob,              // mallocd and RETURNED
        unsigned                *keyBlobLen)    // RETURNED
{
        unsigned char   *s;             // running ptr into *origS
        unsigned                sLen;
        int                             magic;

        /* common blob elements */
        sLen = (4 * sizeof(int)) +              // magic, version, minVersion,
                                                                        // spare
            lengthOfByteRepCurveParams(pkinst->cp);
        if(isPrivate) {
            /* private only */
            sLen += lengthOfByteRepGiant(pkinst->privGiant);
            magic = PUBLIC_KEY_BLOB_MAGIC_PRIV;
        }
        else {
            /* public only */
            sLen += (lengthOfByteRepKey(pkinst->plus) +
                     lengthOfByteRepKey(pkinst->minus));
            magic = PUBLIC_KEY_BLOB_MAGIC_PUB;
        }
        *keyBlob = s = (unsigned char*) fmalloc(sLen);
        s += intToByteRep(magic, s);
        s += intToByteRep(PUBLIC_KEY_BLOB_VERSION, s);
        s += intToByteRep(PUBLIC_KEY_BLOB_MINVERSION, s);
        s += intToByteRep(0, s);                        // spare
        s += curveParamsToByteRep(pkinst->cp, s);
        if(isPrivate) {
            s += giantToByteRep(pkinst->privGiant, s);
        }
        else {
            /* keyToByteRep writes y for plus curve only */
            s += keyToByteRep(pkinst->plus, s);
                if(pkinst->minus != NULL) {
                        s += keyToByteRep(pkinst->minus, s);
                }
                else {
                        /* TBD */
                        dbgLog(("work needed here for blobs with no minus key\n"));
                }
        }
        *keyBlobLen = sLen;
        return FR_Success;
}

#endif  /* ECDSA_VERIFY_ONLY */

/*
 * Init an empty feePubKey from a native blob (non-DER format).
 */
static feeReturn feePubKeyInitFromKeyBlob(feePubKey pubKey,
        unsigned char *keyBlob,
        unsigned keyBlobLen)
{
        pubKeyInst              *pkinst = (pubKeyInst *) pubKey;
        unsigned char   *s;             // running pointer
        unsigned                sLen;           // bytes remaining in *s
        int                             magic;
        unsigned                len;            // for length of individual components
        int                     minVersion;
        int                             version;
        int                             isPrivate;

        s = keyBlob;
        sLen = keyBlobLen;
        if(sLen < (4 * sizeof(int))) {  // magic, version, minVersion, spare
                /*
                 * Too short for all the ints we need
                 */
                dbgLog(("feePublicKey: key blob (1)\n"));
                return FR_BadKeyBlob;
        }

        magic = byteRepToInt(s);
        s += sizeof(int);
        sLen -= sizeof(int);
        switch(magic) {
            case PUBLIC_KEY_BLOB_MAGIC_PUB:
                isPrivate = 0;
                break;
            case PUBLIC_KEY_BLOB_MAGIC_PRIV:
                isPrivate = 1;
                break;
            default:
                dbgLog(("feePublicKey: Bad Public Key Magic Number\n"));
                return FR_BadKeyBlob;
        }

        /*
         * Switch on this for version-specific cases
         */
        version = byteRepToInt(s);
        s += sizeof(int);
        sLen -= sizeof(int);

        minVersion = byteRepToInt(s);
        s += sizeof(int);
        sLen -= sizeof(int);
        if(minVersion > PUBLIC_KEY_BLOB_VERSION) {
                /*
                 * old code, newer key blob - can't parse
                 */
                dbgLog(("feePublicKey: Incompatible Public Key (1)\n"));
                return FR_BadKeyBlob;
        }

        s += sizeof(int);                       // skip spare
        sLen -= sizeof(int);

        pkinst->cp = byteRepToCurveParams(s, sLen, &len);
        if(pkinst->cp == NULL) {
                dbgLog(("feePublicKey: Bad Key Blob(2)\n"));
                return FR_BadKeyBlob;
        }
        s += len;
        sLen -= len;

        /*
         * Private key blob: privGiant.
         * Public Key blob:  plusX, minusX, plusY.
         */
        if(isPrivate) {
                pkinst->privGiant = byteRepToGiant(s, sLen, &len);
                if(pkinst->privGiant == NULL) {
                        dbgLog(("feePublicKey: Bad Key Blob(3)\n"));
                        return FR_BadKeyBlob;
                }
                s += len;
                sLen -= len;
        }
        else {
                /* this writes x and y */
                pkinst->plus = byteRepToKey(s,
                        sLen,
                        CURVE_PLUS,             // twist
                        pkinst->cp,
                        &len);
                if(pkinst->plus == NULL) {
                        dbgLog(("feePublicKey: Bad Key Blob(4)\n"));
                        return FR_BadKeyBlob;
                }
                s += len;
                sLen -= len;

                /* this only writes x */
                pkinst->minus = byteRepToKey(s,
                        sLen,
                        CURVE_MINUS,            // twist
                        pkinst->cp,
                        &len);
                if(pkinst->minus == NULL) {
                        dbgLog(("feePublicKey: Bad Key Blob(5)\n"));
                        return FR_BadKeyBlob;
                }
                s += len;
                sLen -= len;
        }

        /*
         * One more thing: cook up public plusX and minusX for private key
         * blob case.
         */
        if(isPrivate) {
                pkinst->plus  = new_public(pkinst->cp, CURVE_PLUS);
                pkinst->minus = new_public(pkinst->cp, CURVE_MINUS);
                set_priv_key_giant(pkinst->plus, pkinst->privGiant);
                set_priv_key_giant(pkinst->minus, pkinst->privGiant);
        }
        return FR_Success;

}

feeReturn feePubKeyInitFromPubBlob(feePubKey pubKey,
        unsigned char *keyBlob,
        unsigned keyBlobLen)
{
        return feePubKeyInitFromKeyBlob(pubKey, keyBlob, keyBlobLen);
}

#ifndef ECDSA_VERIFY_ONLY

feeReturn feePubKeyInitFromPrivBlob(feePubKey pubKey,
        unsigned char *keyBlob,
        unsigned keyBlobLen)
{
        return feePubKeyInitFromKeyBlob(pubKey, keyBlob, keyBlobLen);   
}

#endif  /* ECDSA_VERIFY_ONLY */

#if     CRYPTKIT_DER_ENABLE
#ifndef ECDSA_VERIFY_ONLY

/* 
 * DER format support. 
 * Obtain portable public and private DER-encoded key blobs from a key.
 */
feeReturn feePubKeyCreateDERPubBlob(feePubKey pubKey,
        unsigned char **keyBlob,        // mallocd and RETURNED
        unsigned *keyBlobLen)           // RETURNED
{
        pubKeyInst *pkinst = (pubKeyInst *)pubKey;

        if(pkinst == NULL) {
                return FR_BadPubKey;
        }
        if(pkinst->minus == NULL) {
                /* Only ECDSA key formats supported */
                return FR_IncompatibleKey;
        }
        return feeDEREncodePublicKey(PUBLIC_DER_KEY_BLOB_VERSION,
                pkinst->cp,
                pkinst->plus->x,
                pkinst->minus->x,
                isZero(pkinst->plus->y) ? NULL : pkinst->plus->y, 
                keyBlob,
                keyBlobLen);
}

feeReturn feePubKeyCreateDERPrivBlob(feePubKey pubKey,
        unsigned char **keyBlob,        // mallocd and RETURNED
        unsigned *keyBlobLen)           // RETURNED
{
        pubKeyInst *pkinst = (pubKeyInst *)pubKey;

        if(pkinst == NULL) {
                return FR_BadPubKey;
        }
        if(pkinst->privGiant == NULL) {
                return FR_IncompatibleKey;
        }
        if(pkinst->minus == NULL) {
                /* Only ECDSA key formats supported */
                return FR_IncompatibleKey;
        }
        return feeDEREncodePrivateKey(PUBLIC_DER_KEY_BLOB_VERSION,
                pkinst->cp,
                pkinst->privGiant,
                keyBlob,
                keyBlobLen);
}

#endif  /* ECDSA_VERIFY_ONLY */

/*
 * Init an empty feePubKey from a DER-encoded blob, public and private key versions. 
 */
feeReturn feePubKeyInitFromDERPubBlob(feePubKey pubKey,
        unsigned char *keyBlob,
        size_t keyBlobLen)
{
        pubKeyInst      *pkinst = (pubKeyInst *) pubKey;
        feeReturn       frtn;
        int                     version;
        
        if(pkinst == NULL) {
                return FR_BadPubKey;
        }
        
        /* kind of messy, maybe we should clean this up. But new_public() does too
         * much - e.g., it allocates the x and y which we really don't want */
         memset(pkinst, 0, sizeof(pubKeyInst));
         pkinst->plus = (key) fmalloc(sizeof(keystruct));
         pkinst->minus = (key) fmalloc(sizeof(keystruct));
         if((pkinst->plus == NULL) || (pkinst->minus == NULL)) {
                return FR_Memory;
         }
         memset(pkinst->plus, 0, sizeof(keystruct));
         memset(pkinst->minus, 0, sizeof(keystruct));
         pkinst->cp = NULL;
         pkinst->privGiant = NULL;
         pkinst->plus->twist  = CURVE_PLUS;
         pkinst->minus->twist = CURVE_MINUS;
         frtn = feeDERDecodePublicKey(keyBlob, 
                (unsigned)keyBlobLen,
                &version,                       // currently unused
                &pkinst->cp,
                &pkinst->plus->x,
                &pkinst->minus->x,
                &pkinst->plus->y);
        if(frtn) {
                return frtn;
        }
        /* minus curve, y is not used */
        pkinst->minus->y = newGiant(1);
        int_to_giant(0, pkinst->minus->y);
        pkinst->plus->cp = pkinst->minus->cp = pkinst->cp;
        return FR_Success;
}

#ifndef ECDSA_VERIFY_ONLY

feeReturn feePubKeyInitFromDERPrivBlob(feePubKey pubKey,
        unsigned char *keyBlob,
        size_t keyBlobLen)
{
        pubKeyInst      *pkinst = (pubKeyInst *) pubKey;
        int                     version;
        feeReturn       frtn;
        
        if(pkinst == NULL) {
                return FR_BadPubKey;
        }
        memset(pkinst, 0, sizeof(pubKeyInst));
        frtn = feeDERDecodePrivateKey(keyBlob, 
                (unsigned)keyBlobLen,
                &version,               // currently unused
                &pkinst->cp,
                &pkinst->privGiant);
        if(frtn) {
                return frtn;
        }
        
        /* since this blob only had the private data, infer the remaining fields */
        pkinst->plus  = new_public(pkinst->cp, CURVE_PLUS);
        pkinst->minus = new_public(pkinst->cp, CURVE_MINUS);
        set_priv_key_giant(pkinst->plus, pkinst->privGiant);
        set_priv_key_giant(pkinst->minus, pkinst->privGiant);
        return FR_Success;
}

#endif  /* ECDSA_VERIFY_ONLY */

#pragma mark --- X509 (public) and PKCS8 (private) key formatting ---

feeReturn feePubKeyCreateX509Blob(
        feePubKey pubKey,                       // public key
        unsigned char **keyBlob,        // mallocd and RETURNED
        unsigned *keyBlobLen)           // RETURNED
{
        pubKeyInst *pkinst = (pubKeyInst *) pubKey;
        unsigned char *xyStr = NULL;
        unsigned xyStrLen = 0;
        feeReturn frtn = feeCreateECDSAPubBlob(pubKey, &xyStr, &xyStrLen);
        if(frtn) {
                return frtn;
        }
        frtn = feeDEREncodeX509PublicKey(xyStr, xyStrLen, pkinst->cp, keyBlob, keyBlobLen);
        ffree(xyStr);
        return frtn;
}

feeReturn feePubKeyCreatePKCS8Blob(
        feePubKey pubKey,                       // private key
        unsigned char **keyBlob,        // mallocd and RETURNED
        unsigned *keyBlobLen)           // RETURNED
{
        pubKeyInst *pkinst = (pubKeyInst *) pubKey;
        unsigned char *privStr = NULL;
        unsigned privStrLen = 0;
        feeReturn frtn = feeCreateECDSAPrivBlob(pubKey, &privStr, &privStrLen);
        if(frtn) {
                return frtn;
        }
        unsigned char *pubStr = NULL;
        unsigned pubStrLen = 0;
        frtn = feeCreateECDSAPubBlob(pubKey, &pubStr, &pubStrLen);
        if(frtn) {
                goto errOut;
        }
        frtn = feeDEREncodePKCS8PrivateKey(privStr, privStrLen, 
                pubStr, pubStrLen,
                pkinst->cp, keyBlob, keyBlobLen);
errOut:
        if(privStr) {
                ffree(privStr);
        }
        if(pubStr) {
                ffree(pubStr);
        }
        return frtn;
}

feeReturn feePubKeyInitFromX509Blob(
        feePubKey pubKey,                       // public key 
        unsigned char *keyBlob,
        size_t keyBlobLen)
{
        feeDepth depth;
        unsigned char *xyStr = NULL;
        unsigned xyStrLen = 0;
        
        /* obtain x/y and depth from X509 encoding */
        feeReturn frtn = feeDERDecodeX509PublicKey(keyBlob, (unsigned)keyBlobLen, &depth,
                &xyStr, &xyStrLen);
        if(frtn) {
                return frtn;
        }
        
        frtn = feePubKeyInitFromECDSAPubBlob(pubKey, xyStr, xyStrLen, depth);
        ffree(xyStr);
        return frtn;
}


feeReturn feePubKeyInitFromPKCS8Blob(
        feePubKey pubKey,                       // private key 
        unsigned char *keyBlob,
        size_t keyBlobLen)
{
        feeDepth depth;
        unsigned char *privStr = NULL;
        unsigned privStrLen = 0;
        
        /* obtain x/y and depth from PKCS8 encoding */
        /* For now we ignore the possible public key string */
        feeReturn frtn = feeDERDecodePKCS8PrivateKey(keyBlob, (unsigned)keyBlobLen, &depth,
                &privStr, &privStrLen, NULL, NULL);
        if(frtn) {
                return frtn;
        }
        
        frtn = feePubKeyInitFromECDSAPrivBlob(pubKey, privStr, privStrLen, depth);
        ffree(privStr);
        return frtn;
}

#pragma mark --- OpenSSL key formatting ---

/*
 * The native OpenSSL ECDSA key format contains both the private and public
 * components in one blob. This throws a bit of a monkey wrench into the API
 * here, as we only have one encoder - which requires a private key - and one
 * decoder, which can result in the decoding of either a public or a private
 * key.
 */
feeReturn feePubKeyCreateOpenSSLBlob(
        feePubKey pubKey,                       // private key
        unsigned char **keyBlob,        // mallocd and RETURNED
        unsigned *keyBlobLen)           // RETURNED
{
        pubKeyInst *pkinst = (pubKeyInst *) pubKey;
        unsigned char *privStr = NULL;
        unsigned privStrLen = 0;
        feeReturn frtn = feeCreateECDSAPrivBlob(pubKey, &privStr, &privStrLen);
        if(frtn) {
                return frtn;
        }
        unsigned char *pubStr = NULL;
        unsigned pubStrLen = 0;
        frtn = feeCreateECDSAPubBlob(pubKey, &pubStr, &pubStrLen);
        if(frtn) {
                goto errOut;
        }
        frtn = feeDEREncodeOpenSSLPrivateKey(privStr, privStrLen, 
                pubStr, pubStrLen,
                pkinst->cp, keyBlob, keyBlobLen);
errOut:
        if(privStr) {
                ffree(privStr);
        }
        if(pubStr) {
                ffree(pubStr);
        }
        return frtn;
}

feeReturn feePubKeyInitFromOpenSSLBlob(
        feePubKey pubKey,                       // private or public key 
        int pubOnly,
        unsigned char *keyBlob,
        size_t keyBlobLen)
{
        feeDepth depth;
        unsigned char *privStr = NULL;
        unsigned privStrLen = 0;
        unsigned char *pubStr = NULL;
        unsigned pubStrLen = 0;
        
        /* obtain x/y, public bit string, and depth from PKCS8 encoding */
        feeReturn frtn = feeDERDecodeOpenSSLKey(keyBlob, (unsigned)keyBlobLen, &depth,
                &privStr, &privStrLen, &pubStr, &pubStrLen);
        if(frtn) {
                return frtn;
        }
        
        if(pubOnly) {
                frtn = feePubKeyInitFromECDSAPubBlob(pubKey, pubStr, pubStrLen, depth);
        }
        else {
                frtn = feePubKeyInitFromECDSAPrivBlob(pubKey, privStr, privStrLen, depth);
        }
        if(privStr) {
                ffree(privStr);
        }
        if(pubStr) {
                ffree(pubStr);
        }
        return frtn;
}

#endif  /* CRYPTKIT_DER_ENABLE */

/*
 * ANSI X9.62/Certicom key support.
 * Public key is 04 || x || y
 * Private key is privData per Certicom SEC1 C.4.
 */
feeReturn feeCreateECDSAPubBlob(feePubKey pubKey,
        unsigned char **keyBlob,
        unsigned *keyBlobLen)
{
        pubKeyInst *pkinst = (pubKeyInst *)pubKey;
        if(pkinst == NULL) {
                return FR_BadPubKey;
        }
        
        unsigned giantBytes = (pkinst->cp->q + 7) / 8;
        unsigned blobSize = 1 + (2 * giantBytes);
        unsigned char *blob = fmalloc(blobSize);
        if(blob == NULL) {
                return FR_Memory;
        }
        *blob = 0x04;
        serializeGiant(pkinst->plus->x, blob+1, giantBytes);
        serializeGiant(pkinst->plus->y, blob+1+giantBytes, giantBytes);
        *keyBlob = blob;
        *keyBlobLen = blobSize;
        return FR_Success;
}

feeReturn feeCreateECDSAPrivBlob(feePubKey pubKey,
        unsigned char **keyBlob,
        unsigned *keyBlobLen)
{
        pubKeyInst *pkinst = (pubKeyInst *)pubKey;
        if(pkinst == NULL) {
                return FR_BadPubKey;
        }
        if(pkinst->privGiant == NULL) {
                return FR_IncompatibleKey;
        }

        /* 
         * Return the raw private key bytes padded with zeroes in
         * the m.s. end to fill exactly one prime-size byte array.
         */
        unsigned giantBytes = (pkinst->cp->q + 7) / 8;
        unsigned char *blob = fmalloc(giantBytes);
        if(blob == NULL) {
                return FR_Memory;
        }
        serializeGiant(pkinst->privGiant, blob, giantBytes);
        *keyBlob = blob;
        *keyBlobLen = giantBytes;
        return FR_Success;
}

/* Caller determines depth from other sources (e.g. AlgId.Params) */
feeReturn feePubKeyInitFromECDSAPubBlob(feePubKey pubKey,
        const unsigned char *keyBlob,
        unsigned keyBlobLen,
        feeDepth depth)
{
        pubKeyInst *pkinst = (pubKeyInst *)pubKey;
        if(pkinst == NULL) {
                return FR_BadPubKey;
        }
        curveParams *cp = curveParamsForDepth(depth);
        if(cp == NULL) {
                return FR_IllegalDepth;
        }
        unsigned giantBytes = (cp->q + 7) / 8;
        unsigned blobSize = 1 + (2 * giantBytes);
        if(keyBlobLen != blobSize) {
                dbgLog(("feePubKeyInitFromECDSAPubBlob: bad blobLen\n"));
                return FR_BadKeyBlob;
        }
        if(*keyBlob != 0x04) {
                dbgLog(("feePubKeyInitFromECDSAPubBlob: bad blob leader\n"));
                return FR_BadKeyBlob;
        }
        
        pkinst->cp = cp;
        pkinst->plus = new_public(cp, CURVE_PLUS);
        deserializeGiant(keyBlob+1, pkinst->plus->x, giantBytes);
        deserializeGiant(keyBlob+1+giantBytes, pkinst->plus->y, giantBytes);
        return FR_Success;
}

feeReturn feePubKeyInitFromECDSAPrivBlob(feePubKey pubKey,
        const unsigned char *keyBlob,
        unsigned keyBlobLen,
        feeDepth depth)
{
        pubKeyInst *pkinst = (pubKeyInst *)pubKey;
        if(pkinst == NULL) {
                return FR_BadPubKey;
        }
        curveParams *cp = curveParamsForDepth(depth);
        if(cp == NULL) {
                return FR_IllegalDepth;
        }
        unsigned giantDigits = cp->basePrime->sign;
        unsigned giantBytes = (cp->q + 7) / 8;

        /* 
         * The specified private key can be one byte smaller than the modulus */
        if((keyBlobLen > giantBytes) || (keyBlobLen < (giantBytes - 1))) {
                dbgLog(("feePubKeyInitFromECDSAPrivBlob: bad blobLen\n"));
                return FR_BadKeyBlob;
        }
        
        pkinst->cp = cp;
        
        /* cook up a new private giant */
        pkinst->privGiant = newGiant(giantDigits);
        if(pkinst->privGiant == NULL) {
                return FR_Memory;
        }
        deserializeGiant(keyBlob, pkinst->privGiant, keyBlobLen);

        /* since this blob only had the private data, infer the remaining fields */
        pkinst->plus  = new_public(pkinst->cp, CURVE_PLUS);
        set_priv_key_giant(pkinst->plus, pkinst->privGiant);
        return FR_Success;
}