--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nss/lib/freebl/ec.c	Mon Jul 28 10:47:06 2014 +0200
@@ -0,0 +1,1080 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifdef FREEBL_NO_DEPEND
+#include "stubs.h"
+#endif
+
+
+#include "blapi.h"
+#include "prerr.h"
+#include "secerr.h"
+#include "secmpi.h"
+#include "secitem.h"
+#include "mplogic.h"
+#include "ec.h"
+#include "ecl.h"
+
+#ifndef NSS_DISABLE_ECC
+
+/* 
+ * Returns true if pointP is the point at infinity, false otherwise
+ */
+PRBool
+ec_point_at_infinity(SECItem *pointP)
+{
+    unsigned int i;
+
+    for (i = 1; i < pointP->len; i++) {
+	if (pointP->data[i] != 0x00) return PR_FALSE;
+    }
+
+    return PR_TRUE;
+}
+
+/* 
+ * Computes scalar point multiplication pointQ = k1 * G + k2 * pointP for
+ * the curve whose parameters are encoded in params with base point G.
+ */
+SECStatus 
+ec_points_mul(const ECParams *params, const mp_int *k1, const mp_int *k2,
+             const SECItem *pointP, SECItem *pointQ)
+{
+    mp_int Px, Py, Qx, Qy;
+    mp_int Gx, Gy, order, irreducible, a, b;
+#if 0 /* currently don't support non-named curves */
+    unsigned int irr_arr[5];
+#endif
+    ECGroup *group = NULL;
+    SECStatus rv = SECFailure;
+    mp_err err = MP_OKAY;
+    int len;
+
+#if EC_DEBUG
+    int i;
+    char mpstr[256];
+
+    printf("ec_points_mul: params [len=%d]:", params->DEREncoding.len);
+    for (i = 0; i < params->DEREncoding.len; i++) 
+	    printf("%02x:", params->DEREncoding.data[i]);
+    printf("\n");
+
+	if (k1 != NULL) {
+		mp_tohex(k1, mpstr);
+		printf("ec_points_mul: scalar k1: %s\n", mpstr);
+		mp_todecimal(k1, mpstr);
+		printf("ec_points_mul: scalar k1: %s (dec)\n", mpstr);
+	}
+
+	if (k2 != NULL) {
+		mp_tohex(k2, mpstr);
+		printf("ec_points_mul: scalar k2: %s\n", mpstr);
+		mp_todecimal(k2, mpstr);
+		printf("ec_points_mul: scalar k2: %s (dec)\n", mpstr);
+	}
+
+	if (pointP != NULL) {
+		printf("ec_points_mul: pointP [len=%d]:", pointP->len);
+		for (i = 0; i < pointP->len; i++) 
+			printf("%02x:", pointP->data[i]);
+		printf("\n");
+	}
+#endif
+
+	/* NOTE: We only support uncompressed points for now */
+	len = (params->fieldID.size + 7) >> 3;
+	if (pointP != NULL) {
+		if ((pointP->data[0] != EC_POINT_FORM_UNCOMPRESSED) ||
+			(pointP->len != (2 * len + 1))) {
+			PORT_SetError(SEC_ERROR_UNSUPPORTED_EC_POINT_FORM);
+			return SECFailure;
+		};
+	}
+
+	MP_DIGITS(&Px) = 0;
+	MP_DIGITS(&Py) = 0;
+	MP_DIGITS(&Qx) = 0;
+	MP_DIGITS(&Qy) = 0;
+	MP_DIGITS(&Gx) = 0;
+	MP_DIGITS(&Gy) = 0;
+	MP_DIGITS(&order) = 0;
+	MP_DIGITS(&irreducible) = 0;
+	MP_DIGITS(&a) = 0;
+	MP_DIGITS(&b) = 0;
+	CHECK_MPI_OK( mp_init(&Px) );
+	CHECK_MPI_OK( mp_init(&Py) );
+	CHECK_MPI_OK( mp_init(&Qx) );
+	CHECK_MPI_OK( mp_init(&Qy) );
+	CHECK_MPI_OK( mp_init(&Gx) );
+	CHECK_MPI_OK( mp_init(&Gy) );
+	CHECK_MPI_OK( mp_init(&order) );
+	CHECK_MPI_OK( mp_init(&irreducible) );
+	CHECK_MPI_OK( mp_init(&a) );
+	CHECK_MPI_OK( mp_init(&b) );
+
+	if ((k2 != NULL) && (pointP != NULL)) {
+		/* Initialize Px and Py */
+		CHECK_MPI_OK( mp_read_unsigned_octets(&Px, pointP->data + 1, (mp_size) len) );
+		CHECK_MPI_OK( mp_read_unsigned_octets(&Py, pointP->data + 1 + len, (mp_size) len) );
+	}
+
+	/* construct from named params, if possible */
+	if (params->name != ECCurve_noName) {
+		group = ECGroup_fromName(params->name);
+	}
+
+#if 0 /* currently don't support non-named curves */
+	if (group == NULL) {
+		/* Set up mp_ints containing the curve coefficients */
+		CHECK_MPI_OK( mp_read_unsigned_octets(&Gx, params->base.data + 1, 
+										  (mp_size) len) );
+		CHECK_MPI_OK( mp_read_unsigned_octets(&Gy, params->base.data + 1 + len, 
+										  (mp_size) len) );
+		SECITEM_TO_MPINT( params->order, &order );
+		SECITEM_TO_MPINT( params->curve.a, &a );
+		SECITEM_TO_MPINT( params->curve.b, &b );
+		if (params->fieldID.type == ec_field_GFp) {
+			SECITEM_TO_MPINT( params->fieldID.u.prime, &irreducible );
+			group = ECGroup_consGFp(&irreducible, &a, &b, &Gx, &Gy, &order, params->cofactor);
+		} else {
+			SECITEM_TO_MPINT( params->fieldID.u.poly, &irreducible );
+			irr_arr[0] = params->fieldID.size;
+			irr_arr[1] = params->fieldID.k1;
+			irr_arr[2] = params->fieldID.k2;
+			irr_arr[3] = params->fieldID.k3;
+			irr_arr[4] = 0;
+			group = ECGroup_consGF2m(&irreducible, irr_arr, &a, &b, &Gx, &Gy, &order, params->cofactor);
+		}
+	}
+#endif
+	if (group == NULL)
+		goto cleanup;
+
+	if ((k2 != NULL) && (pointP != NULL)) {
+		CHECK_MPI_OK( ECPoints_mul(group, k1, k2, &Px, &Py, &Qx, &Qy) );
+	} else {
+		CHECK_MPI_OK( ECPoints_mul(group, k1, NULL, NULL, NULL, &Qx, &Qy) );
+    }
+
+    /* Construct the SECItem representation of point Q */
+    pointQ->data[0] = EC_POINT_FORM_UNCOMPRESSED;
+    CHECK_MPI_OK( mp_to_fixlen_octets(&Qx, pointQ->data + 1,
+	                              (mp_size) len) );
+    CHECK_MPI_OK( mp_to_fixlen_octets(&Qy, pointQ->data + 1 + len,
+	                              (mp_size) len) );
+
+    rv = SECSuccess;
+
+#if EC_DEBUG
+    printf("ec_points_mul: pointQ [len=%d]:", pointQ->len);
+    for (i = 0; i < pointQ->len; i++) 
+	    printf("%02x:", pointQ->data[i]);
+    printf("\n");
+#endif
+
+cleanup:
+    ECGroup_free(group);
+    mp_clear(&Px);
+    mp_clear(&Py);
+    mp_clear(&Qx);
+    mp_clear(&Qy);
+    mp_clear(&Gx);
+    mp_clear(&Gy);
+    mp_clear(&order);
+    mp_clear(&irreducible);
+    mp_clear(&a);
+    mp_clear(&b);
+    if (err) {
+	MP_TO_SEC_ERROR(err);
+	rv = SECFailure;
+    }
+
+    return rv;
+}
+#endif /* NSS_DISABLE_ECC */
+
+/* Generates a new EC key pair. The private key is a supplied
+ * value and the public key is the result of performing a scalar 
+ * point multiplication of that value with the curve's base point.
+ */
+SECStatus 
+ec_NewKey(ECParams *ecParams, ECPrivateKey **privKey, 
+    const unsigned char *privKeyBytes, int privKeyLen)
+{
+    SECStatus rv = SECFailure;
+#ifndef NSS_DISABLE_ECC
+    PLArenaPool *arena;
+    ECPrivateKey *key;
+    mp_int k;
+    mp_err err = MP_OKAY;
+    int len;
+
+#if EC_DEBUG
+    printf("ec_NewKey called\n");
+#endif
+    MP_DIGITS(&k) = 0;
+
+    if (!ecParams || !privKey || !privKeyBytes || (privKeyLen < 0)) {
+	PORT_SetError(SEC_ERROR_INVALID_ARGS);
+	return SECFailure;
+    }
+
+    /* Initialize an arena for the EC key. */
+    if (!(arena = PORT_NewArena(NSS_FREEBL_DEFAULT_CHUNKSIZE)))
+	return SECFailure;
+
+    key = (ECPrivateKey *)PORT_ArenaZAlloc(arena, sizeof(ECPrivateKey));
+    if (!key) {
+	PORT_FreeArena(arena, PR_TRUE);
+	return SECFailure;
+    }
+
+    /* Set the version number (SEC 1 section C.4 says it should be 1) */
+    SECITEM_AllocItem(arena, &key->version, 1);
+    key->version.data[0] = 1;
+
+    /* Copy all of the fields from the ECParams argument to the
+     * ECParams structure within the private key.
+     */
+    key->ecParams.arena = arena;
+    key->ecParams.type = ecParams->type;
+    key->ecParams.fieldID.size = ecParams->fieldID.size;
+    key->ecParams.fieldID.type = ecParams->fieldID.type;
+    if (ecParams->fieldID.type == ec_field_GFp) {
+	CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.fieldID.u.prime,
+	    &ecParams->fieldID.u.prime));
+    } else {
+	CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.fieldID.u.poly,
+	    &ecParams->fieldID.u.poly));
+    }
+    key->ecParams.fieldID.k1 = ecParams->fieldID.k1;
+    key->ecParams.fieldID.k2 = ecParams->fieldID.k2;
+    key->ecParams.fieldID.k3 = ecParams->fieldID.k3;
+    CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.a,
+	&ecParams->curve.a));
+    CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.b,
+	&ecParams->curve.b));
+    CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curve.seed,
+	&ecParams->curve.seed));
+    CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.base,
+	&ecParams->base));
+    CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.order,
+	&ecParams->order));
+    key->ecParams.cofactor = ecParams->cofactor;
+    CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.DEREncoding,
+	&ecParams->DEREncoding));
+    key->ecParams.name = ecParams->name;
+    CHECK_SEC_OK(SECITEM_CopyItem(arena, &key->ecParams.curveOID,
+	&ecParams->curveOID));
+
+    len = (ecParams->fieldID.size + 7) >> 3;
+    SECITEM_AllocItem(arena, &key->publicValue, 2*len + 1);
+    len = ecParams->order.len;
+    SECITEM_AllocItem(arena, &key->privateValue, len);
+
+    /* Copy private key */
+    if (privKeyLen >= len) {
+	memcpy(key->privateValue.data, privKeyBytes, len);
+    } else {
+	memset(key->privateValue.data, 0, (len - privKeyLen));
+	memcpy(key->privateValue.data + (len - privKeyLen), privKeyBytes, privKeyLen);
+    }
+
+    /* Compute corresponding public key */
+    CHECK_MPI_OK( mp_init(&k) );
+    CHECK_MPI_OK( mp_read_unsigned_octets(&k, key->privateValue.data, 
+	(mp_size) len) );
+
+    rv = ec_points_mul(ecParams, &k, NULL, NULL, &(key->publicValue));
+    if (rv != SECSuccess) goto cleanup;
+    *privKey = key;
+
+cleanup:
+    mp_clear(&k);
+    if (rv)
+	PORT_FreeArena(arena, PR_TRUE);
+
+#if EC_DEBUG
+    printf("ec_NewKey returning %s\n", 
+	(rv == SECSuccess) ? "success" : "failure");
+#endif
+#else
+    PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+
+    return rv;
+
+}
+
+/* Generates a new EC key pair. The private key is a supplied
+ * random value (in seed) and the public key is the result of 
+ * performing a scalar point multiplication of that value with 
+ * the curve's base point.
+ */
+SECStatus 
+EC_NewKeyFromSeed(ECParams *ecParams, ECPrivateKey **privKey, 
+    const unsigned char *seed, int seedlen)
+{
+    SECStatus rv = SECFailure;
+#ifndef NSS_DISABLE_ECC
+    rv = ec_NewKey(ecParams, privKey, seed, seedlen);
+#else
+    PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+    return rv;
+}
+
+#ifndef NSS_DISABLE_ECC
+/* Generate a random private key using the algorithm A.4.1 of ANSI X9.62,
+ * modified a la FIPS 186-2 Change Notice 1 to eliminate the bias in the
+ * random number generator.
+ *
+ * Parameters
+ * - order: a buffer that holds the curve's group order
+ * - len: the length in octets of the order buffer
+ *
+ * Return Value
+ * Returns a buffer of len octets that holds the private key. The caller
+ * is responsible for freeing the buffer with PORT_ZFree.
+ */
+static unsigned char *
+ec_GenerateRandomPrivateKey(const unsigned char *order, int len)
+{
+    SECStatus rv = SECSuccess;
+    mp_err err;
+    unsigned char *privKeyBytes = NULL;
+    mp_int privKeyVal, order_1, one;
+
+    MP_DIGITS(&privKeyVal) = 0;
+    MP_DIGITS(&order_1) = 0;
+    MP_DIGITS(&one) = 0;
+    CHECK_MPI_OK( mp_init(&privKeyVal) );
+    CHECK_MPI_OK( mp_init(&order_1) );
+    CHECK_MPI_OK( mp_init(&one) );
+
+    /* Generates 2*len random bytes using the global random bit generator
+     * (which implements Algorithm 1 of FIPS 186-2 Change Notice 1) then
+     * reduces modulo the group order.
+     */
+    if ((privKeyBytes = PORT_Alloc(2*len)) == NULL) goto cleanup;
+    CHECK_SEC_OK( RNG_GenerateGlobalRandomBytes(privKeyBytes, 2*len) );
+    CHECK_MPI_OK( mp_read_unsigned_octets(&privKeyVal, privKeyBytes, 2*len) );
+    CHECK_MPI_OK( mp_read_unsigned_octets(&order_1, order, len) );
+    CHECK_MPI_OK( mp_set_int(&one, 1) );
+    CHECK_MPI_OK( mp_sub(&order_1, &one, &order_1) );
+    CHECK_MPI_OK( mp_mod(&privKeyVal, &order_1, &privKeyVal) );
+    CHECK_MPI_OK( mp_add(&privKeyVal, &one, &privKeyVal) );
+    CHECK_MPI_OK( mp_to_fixlen_octets(&privKeyVal, privKeyBytes, len) );
+    memset(privKeyBytes+len, 0, len);
+cleanup:
+    mp_clear(&privKeyVal);
+    mp_clear(&order_1);
+    mp_clear(&one);
+    if (err < MP_OKAY) {
+	MP_TO_SEC_ERROR(err);
+	rv = SECFailure;
+    }
+    if (rv != SECSuccess && privKeyBytes) {
+	PORT_Free(privKeyBytes);
+	privKeyBytes = NULL;
+    }
+    return privKeyBytes;
+}
+#endif /* NSS_DISABLE_ECC */
+
+/* Generates a new EC key pair. The private key is a random value and
+ * the public key is the result of performing a scalar point multiplication
+ * of that value with the curve's base point.
+ */
+SECStatus 
+EC_NewKey(ECParams *ecParams, ECPrivateKey **privKey)
+{
+    SECStatus rv = SECFailure;
+#ifndef NSS_DISABLE_ECC
+    int len;
+    unsigned char *privKeyBytes = NULL;
+
+    if (!ecParams) {
+	PORT_SetError(SEC_ERROR_INVALID_ARGS);
+	return SECFailure;
+    }
+
+    len = ecParams->order.len;
+    privKeyBytes = ec_GenerateRandomPrivateKey(ecParams->order.data, len);
+    if (privKeyBytes == NULL) goto cleanup;
+    /* generate public key */
+    CHECK_SEC_OK( ec_NewKey(ecParams, privKey, privKeyBytes, len) );
+
+cleanup:
+    if (privKeyBytes) {
+	PORT_ZFree(privKeyBytes, len);
+    }
+#if EC_DEBUG
+    printf("EC_NewKey returning %s\n", 
+	(rv == SECSuccess) ? "success" : "failure");
+#endif
+#else
+    PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+    
+    return rv;
+}
+
+/* Validates an EC public key as described in Section 5.2.2 of
+ * X9.62. The ECDH primitive when used without the cofactor does
+ * not address small subgroup attacks, which may occur when the
+ * public key is not valid. These attacks can be prevented by 
+ * validating the public key before using ECDH.
+ */
+SECStatus 
+EC_ValidatePublicKey(ECParams *ecParams, SECItem *publicValue)
+{
+#ifndef NSS_DISABLE_ECC
+    mp_int Px, Py;
+    ECGroup *group = NULL;
+    SECStatus rv = SECFailure;
+    mp_err err = MP_OKAY;
+    int len;
+
+    if (!ecParams || !publicValue) {
+	PORT_SetError(SEC_ERROR_INVALID_ARGS);
+	return SECFailure;
+    }
+	
+    /* NOTE: We only support uncompressed points for now */
+    len = (ecParams->fieldID.size + 7) >> 3;
+    if (publicValue->data[0] != EC_POINT_FORM_UNCOMPRESSED) {
+	PORT_SetError(SEC_ERROR_UNSUPPORTED_EC_POINT_FORM);
+	return SECFailure;
+    } else if (publicValue->len != (2 * len + 1)) {
+	PORT_SetError(SEC_ERROR_BAD_KEY);
+	return SECFailure;
+    }
+
+    MP_DIGITS(&Px) = 0;
+    MP_DIGITS(&Py) = 0;
+    CHECK_MPI_OK( mp_init(&Px) );
+    CHECK_MPI_OK( mp_init(&Py) );
+
+    /* Initialize Px and Py */
+    CHECK_MPI_OK( mp_read_unsigned_octets(&Px, publicValue->data + 1, (mp_size) len) );
+    CHECK_MPI_OK( mp_read_unsigned_octets(&Py, publicValue->data + 1 + len, (mp_size) len) );
+
+    /* construct from named params */
+    group = ECGroup_fromName(ecParams->name);
+    if (group == NULL) {
+	/*
+	 * ECGroup_fromName fails if ecParams->name is not a valid
+	 * ECCurveName value, or if we run out of memory, or perhaps
+	 * for other reasons.  Unfortunately if ecParams->name is a
+	 * valid ECCurveName value, we don't know what the right error
+	 * code should be because ECGroup_fromName doesn't return an
+	 * error code to the caller.  Set err to MP_UNDEF because
+	 * that's what ECGroup_fromName uses internally.
+	 */
+	if ((ecParams->name <= ECCurve_noName) ||
+	    (ecParams->name >= ECCurve_pastLastCurve)) {
+	    err = MP_BADARG;
+	} else {
+	    err = MP_UNDEF;
+	}
+	goto cleanup;
+    }
+
+    /* validate public point */
+    if ((err = ECPoint_validate(group, &Px, &Py)) < MP_YES) {
+	if (err == MP_NO) {
+	    PORT_SetError(SEC_ERROR_BAD_KEY);
+	    rv = SECFailure;
+	    err = MP_OKAY;  /* don't change the error code */
+	}
+	goto cleanup;
+    }
+
+    rv = SECSuccess;
+
+cleanup:
+    ECGroup_free(group);
+    mp_clear(&Px);
+    mp_clear(&Py);
+    if (err) {
+	MP_TO_SEC_ERROR(err);
+	rv = SECFailure;
+    }
+    return rv;
+#else
+    PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+    return SECFailure;
+#endif /* NSS_DISABLE_ECC */
+}
+
+/* 
+** Performs an ECDH key derivation by computing the scalar point
+** multiplication of privateValue and publicValue (with or without the
+** cofactor) and returns the x-coordinate of the resulting elliptic
+** curve point in derived secret.  If successful, derivedSecret->data
+** is set to the address of the newly allocated buffer containing the
+** derived secret, and derivedSecret->len is the size of the secret
+** produced. It is the caller's responsibility to free the allocated
+** buffer containing the derived secret.
+*/
+SECStatus 
+ECDH_Derive(SECItem  *publicValue, 
+            ECParams *ecParams,
+            SECItem  *privateValue,
+            PRBool    withCofactor,
+            SECItem  *derivedSecret)
+{
+    SECStatus rv = SECFailure;
+#ifndef NSS_DISABLE_ECC
+    unsigned int len = 0;
+    SECItem pointQ = {siBuffer, NULL, 0};
+    mp_int k; /* to hold the private value */
+    mp_int cofactor;
+    mp_err err = MP_OKAY;
+#if EC_DEBUG
+    int i;
+#endif
+
+    if (!publicValue || !ecParams || !privateValue || 
+	!derivedSecret) {
+	PORT_SetError(SEC_ERROR_INVALID_ARGS);
+	return SECFailure;
+    }
+
+    MP_DIGITS(&k) = 0;
+    memset(derivedSecret, 0, sizeof *derivedSecret);
+    len = (ecParams->fieldID.size + 7) >> 3;  
+    pointQ.len = 2*len + 1;
+    if ((pointQ.data = PORT_Alloc(2*len + 1)) == NULL) goto cleanup;
+
+    CHECK_MPI_OK( mp_init(&k) );
+    CHECK_MPI_OK( mp_read_unsigned_octets(&k, privateValue->data, 
+	                                  (mp_size) privateValue->len) );
+
+    if (withCofactor && (ecParams->cofactor != 1)) {
+	    /* multiply k with the cofactor */
+	    MP_DIGITS(&cofactor) = 0;
+	    CHECK_MPI_OK( mp_init(&cofactor) );
+	    mp_set(&cofactor, ecParams->cofactor);
+	    CHECK_MPI_OK( mp_mul(&k, &cofactor, &k) );
+    }
+
+    /* Multiply our private key and peer's public point */
+    if (ec_points_mul(ecParams, NULL, &k, publicValue, &pointQ) != SECSuccess)
+	goto cleanup;
+    if (ec_point_at_infinity(&pointQ)) {
+	PORT_SetError(SEC_ERROR_BAD_KEY);  /* XXX better error code? */
+	goto cleanup;
+    }
+
+    /* Allocate memory for the derived secret and copy
+     * the x co-ordinate of pointQ into it.
+     */
+    SECITEM_AllocItem(NULL, derivedSecret, len);
+    memcpy(derivedSecret->data, pointQ.data + 1, len);
+
+    rv = SECSuccess;
+
+#if EC_DEBUG
+    printf("derived_secret:\n");
+    for (i = 0; i < derivedSecret->len; i++) 
+	printf("%02x:", derivedSecret->data[i]);
+    printf("\n");
+#endif
+
+cleanup:
+    mp_clear(&k);
+
+    if (err) {
+	MP_TO_SEC_ERROR(err);
+    }
+
+    if (pointQ.data) {
+	PORT_ZFree(pointQ.data, 2*len + 1);
+    }
+#else
+    PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+
+    return rv;
+}
+
+/* Computes the ECDSA signature (a concatenation of two values r and s)
+ * on the digest using the given key and the random value kb (used in
+ * computing s).
+ */
+SECStatus 
+ECDSA_SignDigestWithSeed(ECPrivateKey *key, SECItem *signature, 
+    const SECItem *digest, const unsigned char *kb, const int kblen)
+{
+    SECStatus rv = SECFailure;
+#ifndef NSS_DISABLE_ECC
+    mp_int x1;
+    mp_int d, k;     /* private key, random integer */
+    mp_int r, s;     /* tuple (r, s) is the signature */
+    mp_int n;
+    mp_err err = MP_OKAY;
+    ECParams *ecParams = NULL;
+    SECItem kGpoint = { siBuffer, NULL, 0};
+    int flen = 0;    /* length in bytes of the field size */
+    unsigned olen;   /* length in bytes of the base point order */
+    unsigned obits;  /* length in bits  of the base point order */
+
+#if EC_DEBUG
+    char mpstr[256];
+#endif
+
+    /* Initialize MPI integers. */
+    /* must happen before the first potential call to cleanup */
+    MP_DIGITS(&x1) = 0;
+    MP_DIGITS(&d) = 0;
+    MP_DIGITS(&k) = 0;
+    MP_DIGITS(&r) = 0;
+    MP_DIGITS(&s) = 0;
+    MP_DIGITS(&n) = 0;
+
+    /* Check args */
+    if (!key || !signature || !digest || !kb || (kblen < 0)) {
+	PORT_SetError(SEC_ERROR_INVALID_ARGS);
+	goto cleanup;
+    }
+
+    ecParams = &(key->ecParams);
+    flen = (ecParams->fieldID.size + 7) >> 3;
+    olen = ecParams->order.len;  
+    if (signature->data == NULL) {
+	/* a call to get the signature length only */
+	goto finish;
+    }
+    if (signature->len < 2*olen) {
+	PORT_SetError(SEC_ERROR_OUTPUT_LEN);
+	goto cleanup;
+    }
+
+
+    CHECK_MPI_OK( mp_init(&x1) );
+    CHECK_MPI_OK( mp_init(&d) );
+    CHECK_MPI_OK( mp_init(&k) );
+    CHECK_MPI_OK( mp_init(&r) );
+    CHECK_MPI_OK( mp_init(&s) );
+    CHECK_MPI_OK( mp_init(&n) );
+
+    SECITEM_TO_MPINT( ecParams->order, &n );
+    SECITEM_TO_MPINT( key->privateValue, &d );
+
+    CHECK_MPI_OK( mp_read_unsigned_octets(&k, kb, kblen) );
+    /* Make sure k is in the interval [1, n-1] */
+    if ((mp_cmp_z(&k) <= 0) || (mp_cmp(&k, &n) >= 0)) {
+#if EC_DEBUG
+        printf("k is outside [1, n-1]\n");
+        mp_tohex(&k, mpstr);
+	printf("k : %s \n", mpstr);
+        mp_tohex(&n, mpstr);
+	printf("n : %s \n", mpstr);
+#endif
+	PORT_SetError(SEC_ERROR_NEED_RANDOM);
+	goto cleanup;
+    }
+
+    /*
+    ** We do not want timing information to leak the length of k,
+    ** so we compute k*G using an equivalent scalar of fixed
+    ** bit-length.
+    ** Fix based on patch for ECDSA timing attack in the paper
+    ** by Billy Bob Brumley and Nicola Tuveri at
+    **   http://eprint.iacr.org/2011/232
+    **
+    ** How do we convert k to a value of a fixed bit-length?
+    ** k starts off as an integer satisfying 0 <= k < n.  Hence,
+    ** n <= k+n < 2n, which means k+n has either the same number
+    ** of bits as n or one more bit than n.  If k+n has the same
+    ** number of bits as n, the second addition ensures that the
+    ** final value has exactly one more bit than n.  Thus, we
+    ** always end up with a value that exactly one more bit than n.
+    */
+    CHECK_MPI_OK( mp_add(&k, &n, &k) );
+    if (mpl_significant_bits(&k) <= mpl_significant_bits(&n)) {
+	CHECK_MPI_OK( mp_add(&k, &n, &k) );
+    }
+
+    /* 
+    ** ANSI X9.62, Section 5.3.2, Step 2
+    **
+    ** Compute kG
+    */
+    kGpoint.len = 2*flen + 1;
+    kGpoint.data = PORT_Alloc(2*flen + 1);
+    if ((kGpoint.data == NULL) ||
+	(ec_points_mul(ecParams, &k, NULL, NULL, &kGpoint)
+	    != SECSuccess))
+	goto cleanup;
+
+    /* 
+    ** ANSI X9.62, Section 5.3.3, Step 1
+    **
+    ** Extract the x co-ordinate of kG into x1
+    */
+    CHECK_MPI_OK( mp_read_unsigned_octets(&x1, kGpoint.data + 1, 
+	                                  (mp_size) flen) );
+
+    /* 
+    ** ANSI X9.62, Section 5.3.3, Step 2
+    **
+    ** r = x1 mod n  NOTE: n is the order of the curve
+    */
+    CHECK_MPI_OK( mp_mod(&x1, &n, &r) );
+
+    /*
+    ** ANSI X9.62, Section 5.3.3, Step 3
+    **
+    ** verify r != 0 
+    */
+    if (mp_cmp_z(&r) == 0) {
+	PORT_SetError(SEC_ERROR_NEED_RANDOM);
+	goto cleanup;
+    }
+
+    /*                                  
+    ** ANSI X9.62, Section 5.3.3, Step 4
+    **
+    ** s = (k**-1 * (HASH(M) + d*r)) mod n 
+    */
+    SECITEM_TO_MPINT(*digest, &s);        /* s = HASH(M)     */
+
+    /* In the definition of EC signing, digests are truncated
+     * to the length of n in bits. 
+     * (see SEC 1 "Elliptic Curve Digit Signature Algorithm" section 4.1.*/
+    CHECK_MPI_OK( (obits = mpl_significant_bits(&n)) );
+    if (digest->len*8 > obits) {
+	mpl_rsh(&s,&s,digest->len*8 - obits);
+    }
+
+#if EC_DEBUG
+    mp_todecimal(&n, mpstr);
+    printf("n : %s (dec)\n", mpstr);
+    mp_todecimal(&d, mpstr);
+    printf("d : %s (dec)\n", mpstr);
+    mp_tohex(&x1, mpstr);
+    printf("x1: %s\n", mpstr);
+    mp_todecimal(&s, mpstr);
+    printf("digest: %s (decimal)\n", mpstr);
+    mp_todecimal(&r, mpstr);
+    printf("r : %s (dec)\n", mpstr);
+    mp_tohex(&r, mpstr);
+    printf("r : %s\n", mpstr);
+#endif
+
+    CHECK_MPI_OK( mp_invmod(&k, &n, &k) );      /* k = k**-1 mod n */
+    CHECK_MPI_OK( mp_mulmod(&d, &r, &n, &d) );  /* d = d * r mod n */
+    CHECK_MPI_OK( mp_addmod(&s, &d, &n, &s) );  /* s = s + d mod n */
+    CHECK_MPI_OK( mp_mulmod(&s, &k, &n, &s) );  /* s = s * k mod n */
+
+#if EC_DEBUG
+    mp_todecimal(&s, mpstr);
+    printf("s : %s (dec)\n", mpstr);
+    mp_tohex(&s, mpstr);
+    printf("s : %s\n", mpstr);
+#endif
+
+    /*
+    ** ANSI X9.62, Section 5.3.3, Step 5
+    **
+    ** verify s != 0
+    */
+    if (mp_cmp_z(&s) == 0) {
+	PORT_SetError(SEC_ERROR_NEED_RANDOM);
+	goto cleanup;
+    }
+
+   /*
+    **
+    ** Signature is tuple (r, s)
+    */
+    CHECK_MPI_OK( mp_to_fixlen_octets(&r, signature->data, olen) );
+    CHECK_MPI_OK( mp_to_fixlen_octets(&s, signature->data + olen, olen) );
+finish:
+    signature->len = 2*olen;
+
+    rv = SECSuccess;
+    err = MP_OKAY;
+cleanup:
+    mp_clear(&x1);
+    mp_clear(&d);
+    mp_clear(&k);
+    mp_clear(&r);
+    mp_clear(&s);
+    mp_clear(&n);
+
+    if (kGpoint.data) {
+	PORT_ZFree(kGpoint.data, 2*flen + 1);
+    }
+
+    if (err) {
+	MP_TO_SEC_ERROR(err);
+	rv = SECFailure;
+    }
+
+#if EC_DEBUG
+    printf("ECDSA signing with seed %s\n",
+	(rv == SECSuccess) ? "succeeded" : "failed");
+#endif
+#else
+    PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+
+   return rv;
+}
+
+/*
+** Computes the ECDSA signature on the digest using the given key 
+** and a random seed.
+*/
+SECStatus 
+ECDSA_SignDigest(ECPrivateKey *key, SECItem *signature, const SECItem *digest)
+{
+    SECStatus rv = SECFailure;
+#ifndef NSS_DISABLE_ECC
+    int len;
+    unsigned char *kBytes= NULL;
+
+    if (!key) {
+	PORT_SetError(SEC_ERROR_INVALID_ARGS);
+	return SECFailure;
+    }
+
+    /* Generate random value k */
+    len = key->ecParams.order.len;
+    kBytes = ec_GenerateRandomPrivateKey(key->ecParams.order.data, len);
+    if (kBytes == NULL) goto cleanup;
+
+    /* Generate ECDSA signature with the specified k value */
+    rv = ECDSA_SignDigestWithSeed(key, signature, digest, kBytes, len);
+
+cleanup:    
+    if (kBytes) {
+	PORT_ZFree(kBytes, len);
+    }
+
+#if EC_DEBUG
+    printf("ECDSA signing %s\n",
+	(rv == SECSuccess) ? "succeeded" : "failed");
+#endif
+#else
+    PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+
+    return rv;
+}
+
+/*
+** Checks the signature on the given digest using the key provided.
+*/
+SECStatus 
+ECDSA_VerifyDigest(ECPublicKey *key, const SECItem *signature, 
+                 const SECItem *digest)
+{
+    SECStatus rv = SECFailure;
+#ifndef NSS_DISABLE_ECC
+    mp_int r_, s_;           /* tuple (r', s') is received signature) */
+    mp_int c, u1, u2, v;     /* intermediate values used in verification */
+    mp_int x1;
+    mp_int n;
+    mp_err err = MP_OKAY;
+    ECParams *ecParams = NULL;
+    SECItem pointC = { siBuffer, NULL, 0 };
+    int slen;       /* length in bytes of a half signature (r or s) */
+    int flen;       /* length in bytes of the field size */
+    unsigned olen;  /* length in bytes of the base point order */
+    unsigned obits; /* length in bits  of the base point order */
+
+#if EC_DEBUG
+    char mpstr[256];
+    printf("ECDSA verification called\n");
+#endif
+
+    /* Initialize MPI integers. */
+    /* must happen before the first potential call to cleanup */
+    MP_DIGITS(&r_) = 0;
+    MP_DIGITS(&s_) = 0;
+    MP_DIGITS(&c) = 0;
+    MP_DIGITS(&u1) = 0;
+    MP_DIGITS(&u2) = 0;
+    MP_DIGITS(&x1) = 0;
+    MP_DIGITS(&v)  = 0;
+    MP_DIGITS(&n)  = 0;
+
+    /* Check args */
+    if (!key || !signature || !digest) {
+	PORT_SetError(SEC_ERROR_INVALID_ARGS);
+	goto cleanup;
+    }
+
+    ecParams = &(key->ecParams);
+    flen = (ecParams->fieldID.size + 7) >> 3;  
+    olen = ecParams->order.len;  
+    if (signature->len == 0 || signature->len%2 != 0 ||
+	signature->len > 2*olen) {
+	PORT_SetError(SEC_ERROR_INPUT_LEN);
+	goto cleanup;
+    }
+    slen = signature->len/2;
+
+    SECITEM_AllocItem(NULL, &pointC, 2*flen + 1);
+    if (pointC.data == NULL)
+	goto cleanup;
+
+    CHECK_MPI_OK( mp_init(&r_) );
+    CHECK_MPI_OK( mp_init(&s_) );
+    CHECK_MPI_OK( mp_init(&c)  );
+    CHECK_MPI_OK( mp_init(&u1) );
+    CHECK_MPI_OK( mp_init(&u2) );
+    CHECK_MPI_OK( mp_init(&x1)  );
+    CHECK_MPI_OK( mp_init(&v)  );
+    CHECK_MPI_OK( mp_init(&n)  );
+
+    /*
+    ** Convert received signature (r', s') into MPI integers.
+    */
+    CHECK_MPI_OK( mp_read_unsigned_octets(&r_, signature->data, slen) );
+    CHECK_MPI_OK( mp_read_unsigned_octets(&s_, signature->data + slen, slen) );
+                                          
+    /* 
+    ** ANSI X9.62, Section 5.4.2, Steps 1 and 2
+    **
+    ** Verify that 0 < r' < n and 0 < s' < n
+    */
+    SECITEM_TO_MPINT(ecParams->order, &n);
+    if (mp_cmp_z(&r_) <= 0 || mp_cmp_z(&s_) <= 0 ||
+        mp_cmp(&r_, &n) >= 0 || mp_cmp(&s_, &n) >= 0) {
+	PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
+	goto cleanup; /* will return rv == SECFailure */
+    }
+
+    /*
+    ** ANSI X9.62, Section 5.4.2, Step 3
+    **
+    ** c = (s')**-1 mod n
+    */
+    CHECK_MPI_OK( mp_invmod(&s_, &n, &c) );      /* c = (s')**-1 mod n */
+
+    /*
+    ** ANSI X9.62, Section 5.4.2, Step 4
+    **
+    ** u1 = ((HASH(M')) * c) mod n
+    */
+    SECITEM_TO_MPINT(*digest, &u1);                  /* u1 = HASH(M)     */
+
+    /* In the definition of EC signing, digests are truncated
+     * to the length of n in bits. 
+     * (see SEC 1 "Elliptic Curve Digit Signature Algorithm" section 4.1.*/
+    CHECK_MPI_OK( (obits = mpl_significant_bits(&n)) );
+    if (digest->len*8 > obits) {  /* u1 = HASH(M')     */
+	mpl_rsh(&u1,&u1,digest->len*8 - obits);
+    }
+
+#if EC_DEBUG
+    mp_todecimal(&r_, mpstr);
+    printf("r_: %s (dec)\n", mpstr);
+    mp_todecimal(&s_, mpstr);
+    printf("s_: %s (dec)\n", mpstr);
+    mp_todecimal(&c, mpstr);
+    printf("c : %s (dec)\n", mpstr);
+    mp_todecimal(&u1, mpstr);
+    printf("digest: %s (dec)\n", mpstr);
+#endif
+
+    CHECK_MPI_OK( mp_mulmod(&u1, &c, &n, &u1) );  /* u1 = u1 * c mod n */
+
+    /*
+    ** ANSI X9.62, Section 5.4.2, Step 4
+    **
+    ** u2 = ((r') * c) mod n
+    */
+    CHECK_MPI_OK( mp_mulmod(&r_, &c, &n, &u2) );
+
+    /*
+    ** ANSI X9.62, Section 5.4.3, Step 1
+    **
+    ** Compute u1*G + u2*Q
+    ** Here, A = u1.G     B = u2.Q    and   C = A + B
+    ** If the result, C, is the point at infinity, reject the signature
+    */
+    if (ec_points_mul(ecParams, &u1, &u2, &key->publicValue, &pointC)
+	!= SECSuccess) {
+	rv = SECFailure;
+	goto cleanup;
+    }
+    if (ec_point_at_infinity(&pointC)) {
+	PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
+	rv = SECFailure;
+	goto cleanup;
+    }
+
+    CHECK_MPI_OK( mp_read_unsigned_octets(&x1, pointC.data + 1, flen) );
+
+    /*
+    ** ANSI X9.62, Section 5.4.4, Step 2
+    **
+    ** v = x1 mod n
+    */
+    CHECK_MPI_OK( mp_mod(&x1, &n, &v) );
+
+#if EC_DEBUG
+    mp_todecimal(&r_, mpstr);
+    printf("r_: %s (dec)\n", mpstr);
+    mp_todecimal(&v, mpstr);
+    printf("v : %s (dec)\n", mpstr);
+#endif
+
+    /*
+    ** ANSI X9.62, Section 5.4.4, Step 3
+    **
+    ** Verification:  v == r'
+    */
+    if (mp_cmp(&v, &r_)) {
+	PORT_SetError(SEC_ERROR_BAD_SIGNATURE);
+	rv = SECFailure; /* Signature failed to verify. */
+    } else {
+	rv = SECSuccess; /* Signature verified. */
+    }
+
+#if EC_DEBUG
+    mp_todecimal(&u1, mpstr);
+    printf("u1: %s (dec)\n", mpstr);
+    mp_todecimal(&u2, mpstr);
+    printf("u2: %s (dec)\n", mpstr);
+    mp_tohex(&x1, mpstr);
+    printf("x1: %s\n", mpstr);
+    mp_todecimal(&v, mpstr);
+    printf("v : %s (dec)\n", mpstr);
+#endif
+
+cleanup:
+    mp_clear(&r_);
+    mp_clear(&s_);
+    mp_clear(&c);
+    mp_clear(&u1);
+    mp_clear(&u2);
+    mp_clear(&x1);
+    mp_clear(&v);
+    mp_clear(&n);
+
+    if (pointC.data) SECITEM_FreeItem(&pointC, PR_FALSE);
+    if (err) {
+	MP_TO_SEC_ERROR(err);
+	rv = SECFailure;
+    }
+
+#if EC_DEBUG
+    printf("ECDSA verification %s\n",
+	(rv == SECSuccess) ? "succeeded" : "failed");
+#endif
+#else
+    PORT_SetError(SEC_ERROR_UNSUPPORTED_KEYALG);
+#endif /* NSS_DISABLE_ECC */
+
+    return rv;
+}
+