xref: /openbsd-src/usr.bin/openssl/ecparam.c (revision 3374c67d44f9b75b98444cbf63020f777792342e)
1 /* $OpenBSD: ecparam.c,v 1.22 2022/11/11 17:07:38 joshua Exp $ */
2 /*
3  * Written by Nils Larsch for the OpenSSL project.
4  */
5 /* ====================================================================
6  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  *
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  *
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in
17  *    the documentation and/or other materials provided with the
18  *    distribution.
19  *
20  * 3. All advertising materials mentioning features or use of this
21  *    software must display the following acknowledgment:
22  *    "This product includes software developed by the OpenSSL Project
23  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
24  *
25  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
26  *    endorse or promote products derived from this software without
27  *    prior written permission. For written permission, please contact
28  *    openssl-core@openssl.org.
29  *
30  * 5. Products derived from this software may not be called "OpenSSL"
31  *    nor may "OpenSSL" appear in their names without prior written
32  *    permission of the OpenSSL Project.
33  *
34  * 6. Redistributions of any form whatsoever must retain the following
35  *    acknowledgment:
36  *    "This product includes software developed by the OpenSSL Project
37  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
38  *
39  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
40  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
41  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
42  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
43  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
45  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
46  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
48  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
49  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
50  * OF THE POSSIBILITY OF SUCH DAMAGE.
51  * ====================================================================
52  *
53  * This product includes cryptographic software written by Eric Young
54  * (eay@cryptsoft.com).  This product includes software written by Tim
55  * Hudson (tjh@cryptsoft.com).
56  *
57  */
58 /* ====================================================================
59  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
60  *
61  * Portions of the attached software ("Contribution") are developed by
62  * SUN MICROSYSTEMS, INC., and are contributed to the OpenSSL project.
63  *
64  * The Contribution is licensed pursuant to the OpenSSL open source
65  * license provided above.
66  *
67  * The elliptic curve binary polynomial software is originally written by
68  * Sheueling Chang Shantz and Douglas Stebila of Sun Microsystems Laboratories.
69  *
70  */
71 
72 #include <openssl/opensslconf.h>
73 
74 #ifndef OPENSSL_NO_EC
75 
76 #include <stdio.h>
77 #include <stdlib.h>
78 #include <string.h>
79 #include <time.h>
80 
81 #include "apps.h"
82 
83 #include <openssl/bio.h>
84 #include <openssl/bn.h>
85 #include <openssl/ec.h>
86 #include <openssl/err.h>
87 #include <openssl/pem.h>
88 #include <openssl/x509.h>
89 
90 static int ecparam_print_var(BIO *, BIGNUM *, const char *, int,
91     unsigned char *);
92 
93 static struct {
94 	int C;
95 	int asn1_flag;
96 	int check;
97 	char *curve_name;
98 	point_conversion_form_t form;
99 	int genkey;
100 	char *infile;
101 	int informat;
102 	int list_curves;
103 	int new_asn1_flag;
104 	int new_form;
105 	int no_seed;
106 	int noout;
107 	char *outfile;
108 	int outformat;
109 	int text;
110 } ecparam_config;
111 
112 static int
113 ecparam_opt_form(char *arg)
114 {
115 	if (strcmp(arg, "compressed") == 0)
116 		ecparam_config.form = POINT_CONVERSION_COMPRESSED;
117 	else if (strcmp(arg, "uncompressed") == 0)
118 		ecparam_config.form = POINT_CONVERSION_UNCOMPRESSED;
119 	else if (strcmp(arg, "hybrid") == 0)
120 		ecparam_config.form = POINT_CONVERSION_HYBRID;
121 	else
122 		return (1);
123 
124 	ecparam_config.new_form = 1;
125 	return (0);
126 }
127 
128 static int
129 ecparam_opt_enctype(char *arg)
130 {
131 	if (strcmp(arg, "explicit") == 0)
132 		ecparam_config.asn1_flag = 0;
133 	else if (strcmp(arg, "named_curve") == 0)
134 		ecparam_config.asn1_flag = OPENSSL_EC_NAMED_CURVE;
135 	else
136 		return (1);
137 
138 	ecparam_config.new_asn1_flag = 1;
139 	return (0);
140 }
141 
142 static const struct option ecparam_options[] = {
143 	{
144 		.name = "C",
145 		.desc = "Convert the EC parameters into C code",
146 		.type = OPTION_FLAG,
147 		.opt.flag = &ecparam_config.C,
148 	},
149 	{
150 		.name = "check",
151 		.desc = "Validate the elliptic curve parameters",
152 		.type = OPTION_FLAG,
153 		.opt.flag = &ecparam_config.check,
154 	},
155 	{
156 		.name = "conv_form",
157 		.argname = "form",
158 		.desc = "Specify point conversion form:\n"
159 		    "  compressed, uncompressed (default), hybrid",
160 		.type = OPTION_ARG_FUNC,
161 		.opt.argfunc = ecparam_opt_form,
162 	},
163 	{
164 		.name = "genkey",
165 		.desc = "Generate an EC private key using the specified "
166 		    "parameters",
167 		.type = OPTION_FLAG,
168 		.opt.flag = &ecparam_config.genkey,
169 	},
170 	{
171 		.name = "in",
172 		.argname = "file",
173 		.desc = "Input file to read parameters from (default stdin)",
174 		.type = OPTION_ARG,
175 		.opt.arg = &ecparam_config.infile,
176 	},
177 	{
178 		.name = "inform",
179 		.argname = "format",
180 		.desc = "Input format (DER or PEM)",
181 		.type = OPTION_ARG_FORMAT,
182 		.opt.value = &ecparam_config.informat,
183 	},
184 	{
185 		.name = "list_curves",
186 		.desc = "Print list of all currently implemented EC "
187 		    "parameter names",
188 		.type = OPTION_FLAG,
189 		.opt.flag = &ecparam_config.list_curves,
190 	},
191 	{
192 		.name = "name",
193 		.argname = "curve",
194 		.desc = "Use the EC parameters with the specified name",
195 		.type = OPTION_ARG,
196 		.opt.arg = &ecparam_config.curve_name,
197 	},
198 	{
199 		.name = "no_seed",
200 		.desc = "Do not output seed with explicit parameter encoding",
201 		.type = OPTION_FLAG,
202 		.opt.flag = &ecparam_config.no_seed,
203 	},
204 	{
205 		.name = "noout",
206 		.desc = "Do not output encoded version of EC parameters",
207 		.type = OPTION_FLAG,
208 		.opt.flag = &ecparam_config.noout,
209 	},
210 	{
211 		.name = "out",
212 		.argname = "file",
213 		.desc = "Output file to write parameters to (default stdout)",
214 		.type = OPTION_ARG,
215 		.opt.arg = &ecparam_config.outfile,
216 	},
217 	{
218 		.name = "outform",
219 		.argname = "format",
220 		.desc = "Output format (DER or PEM)",
221 		.type = OPTION_ARG_FORMAT,
222 		.opt.value = &ecparam_config.outformat,
223 	},
224 	{
225 		.name = "param_enc",
226 		.argname = "type",
227 		.desc = "Specify EC parameter ASN.1 encoding type:\n"
228 		    "  explicit, named_curve (default)",
229 		.type = OPTION_ARG_FUNC,
230 		.opt.argfunc = ecparam_opt_enctype,
231 	},
232 	{
233 		.name = "text",
234 		.desc = "Print out the EC parameters in human readable form",
235 		.type = OPTION_FLAG,
236 		.opt.flag = &ecparam_config.text,
237 	},
238 	{NULL},
239 };
240 
241 static void
242 ecparam_usage(void)
243 {
244 	fprintf(stderr, "usage: ecparam [-C] [-check] [-conv_form arg] "
245 	    " [-genkey]\n"
246 	    "    [-in file] [-inform DER | PEM] [-list_curves] [-name arg]\n"
247 	    "    [-no_seed] [-noout] [-out file] [-outform DER | PEM]\n"
248 	    "    [-param_enc arg] [-text]\n\n");
249 	options_usage(ecparam_options);
250 }
251 
252 int
253 ecparam_main(int argc, char **argv)
254 {
255 	BIGNUM *ec_p = NULL, *ec_a = NULL, *ec_b = NULL, *ec_gen = NULL;
256 	BIGNUM *ec_order = NULL, *ec_cofactor = NULL;
257 	EC_GROUP *group = NULL;
258 	unsigned char *buffer = NULL;
259 	BIO *in = NULL, *out = NULL;
260 	int i, ret = 1;
261 
262 	if (pledge("stdio cpath wpath rpath", NULL) == -1) {
263 		perror("pledge");
264 		exit(1);
265 	}
266 
267 	memset(&ecparam_config, 0, sizeof(ecparam_config));
268 	ecparam_config.asn1_flag = OPENSSL_EC_NAMED_CURVE;
269 	ecparam_config.form = POINT_CONVERSION_UNCOMPRESSED;
270 	ecparam_config.informat = FORMAT_PEM;
271 	ecparam_config.outformat = FORMAT_PEM;
272 
273 	if (options_parse(argc, argv, ecparam_options, NULL, NULL) != 0) {
274 		ecparam_usage();
275 		goto end;
276 	}
277 
278 	in = BIO_new(BIO_s_file());
279 	out = BIO_new(BIO_s_file());
280 	if ((in == NULL) || (out == NULL)) {
281 		ERR_print_errors(bio_err);
282 		goto end;
283 	}
284 	if (ecparam_config.infile == NULL)
285 		BIO_set_fp(in, stdin, BIO_NOCLOSE);
286 	else {
287 		if (BIO_read_filename(in, ecparam_config.infile) <= 0) {
288 			perror(ecparam_config.infile);
289 			goto end;
290 		}
291 	}
292 	if (ecparam_config.outfile == NULL) {
293 		BIO_set_fp(out, stdout, BIO_NOCLOSE);
294 	} else {
295 		if (BIO_write_filename(out, ecparam_config.outfile) <= 0) {
296 			perror(ecparam_config.outfile);
297 			goto end;
298 		}
299 	}
300 
301 	if (ecparam_config.list_curves) {
302 		EC_builtin_curve *curves = NULL;
303 		size_t crv_len = 0;
304 		size_t n = 0;
305 
306 		crv_len = EC_get_builtin_curves(NULL, 0);
307 
308 		curves = reallocarray(NULL, crv_len, sizeof(EC_builtin_curve));
309 		if (curves == NULL)
310 			goto end;
311 
312 		if (!EC_get_builtin_curves(curves, crv_len)) {
313 			free(curves);
314 			goto end;
315 		}
316 		for (n = 0; n < crv_len; n++) {
317 			const char *comment;
318 			const char *sname;
319 			comment = curves[n].comment;
320 			sname = OBJ_nid2sn(curves[n].nid);
321 			if (comment == NULL)
322 				comment = "CURVE DESCRIPTION NOT AVAILABLE";
323 			if (sname == NULL)
324 				sname = "";
325 
326 			BIO_printf(out, "  %-10s: ", sname);
327 			BIO_printf(out, "%s\n", comment);
328 		}
329 
330 		free(curves);
331 		ret = 0;
332 		goto end;
333 	}
334 	if (ecparam_config.curve_name != NULL) {
335 		int nid;
336 
337 		/*
338 		 * workaround for the SECG curve names secp192r1 and
339 		 * secp256r1 (which are the same as the curves prime192v1 and
340 		 * prime256v1 defined in X9.62)
341 		 */
342 		if (!strcmp(ecparam_config.curve_name, "secp192r1")) {
343 			BIO_printf(bio_err, "using curve name prime192v1 "
344 			    "instead of secp192r1\n");
345 			nid = NID_X9_62_prime192v1;
346 		} else if (!strcmp(ecparam_config.curve_name, "secp256r1")) {
347 			BIO_printf(bio_err, "using curve name prime256v1 "
348 			    "instead of secp256r1\n");
349 			nid = NID_X9_62_prime256v1;
350 		} else
351 			nid = OBJ_sn2nid(ecparam_config.curve_name);
352 
353 		if (nid == 0)
354 			nid = EC_curve_nist2nid(ecparam_config.curve_name);
355 
356 		if (nid == 0) {
357 			BIO_printf(bio_err, "unknown curve name (%s)\n",
358 			    ecparam_config.curve_name);
359 			goto end;
360 		}
361 		group = EC_GROUP_new_by_curve_name(nid);
362 		if (group == NULL) {
363 			BIO_printf(bio_err, "unable to create curve (%s)\n",
364 			    ecparam_config.curve_name);
365 			goto end;
366 		}
367 		EC_GROUP_set_asn1_flag(group, ecparam_config.asn1_flag);
368 		EC_GROUP_set_point_conversion_form(group, ecparam_config.form);
369 	} else if (ecparam_config.informat == FORMAT_ASN1) {
370 		group = d2i_ECPKParameters_bio(in, NULL);
371 	} else if (ecparam_config.informat == FORMAT_PEM) {
372 		group = PEM_read_bio_ECPKParameters(in, NULL, NULL, NULL);
373 	} else {
374 		BIO_printf(bio_err, "bad input format specified\n");
375 		goto end;
376 	}
377 
378 	if (group == NULL) {
379 		BIO_printf(bio_err,
380 		    "unable to load elliptic curve parameters\n");
381 		ERR_print_errors(bio_err);
382 		goto end;
383 	}
384 	if (ecparam_config.new_form)
385 		EC_GROUP_set_point_conversion_form(group, ecparam_config.form);
386 
387 	if (ecparam_config.new_asn1_flag)
388 		EC_GROUP_set_asn1_flag(group, ecparam_config.asn1_flag);
389 
390 	if (ecparam_config.no_seed)
391 		EC_GROUP_set_seed(group, NULL, 0);
392 
393 	if (ecparam_config.text) {
394 		if (!ECPKParameters_print(out, group, 0))
395 			goto end;
396 	}
397 	if (ecparam_config.check) {
398 		BIO_printf(bio_err, "checking elliptic curve parameters: ");
399 		if (!EC_GROUP_check(group, NULL)) {
400 			BIO_printf(bio_err, "failed\n");
401 			ERR_print_errors(bio_err);
402 		} else
403 			BIO_printf(bio_err, "ok\n");
404 
405 	}
406 	if (ecparam_config.C) {
407 		size_t buf_len = 0, tmp_len = 0;
408 		const EC_POINT *point;
409 		int is_prime, len = 0;
410 		const EC_METHOD *meth = EC_GROUP_method_of(group);
411 
412 		if ((ec_p = BN_new()) == NULL || (ec_a = BN_new()) == NULL ||
413 		    (ec_b = BN_new()) == NULL || (ec_gen = BN_new()) == NULL ||
414 		    (ec_order = BN_new()) == NULL ||
415 		    (ec_cofactor = BN_new()) == NULL) {
416 			perror("malloc");
417 			goto end;
418 		}
419 		is_prime = (EC_METHOD_get_field_type(meth) ==
420 		    NID_X9_62_prime_field);
421 
422 		if (!EC_GROUP_get_curve(group, ec_p, ec_a, ec_b, NULL))
423 			goto end;
424 
425 		if ((point = EC_GROUP_get0_generator(group)) == NULL)
426 			goto end;
427 		if (!EC_POINT_point2bn(group, point,
428 			EC_GROUP_get_point_conversion_form(group), ec_gen,
429 			NULL))
430 			goto end;
431 		if (!EC_GROUP_get_order(group, ec_order, NULL))
432 			goto end;
433 		if (!EC_GROUP_get_cofactor(group, ec_cofactor, NULL))
434 			goto end;
435 
436 		len = BN_num_bits(ec_order);
437 
438 		if ((tmp_len = (size_t) BN_num_bytes(ec_p)) > buf_len)
439 			buf_len = tmp_len;
440 		if ((tmp_len = (size_t) BN_num_bytes(ec_a)) > buf_len)
441 			buf_len = tmp_len;
442 		if ((tmp_len = (size_t) BN_num_bytes(ec_b)) > buf_len)
443 			buf_len = tmp_len;
444 		if ((tmp_len = (size_t) BN_num_bytes(ec_gen)) > buf_len)
445 			buf_len = tmp_len;
446 		if ((tmp_len = (size_t) BN_num_bytes(ec_order)) > buf_len)
447 			buf_len = tmp_len;
448 		if ((tmp_len = (size_t) BN_num_bytes(ec_cofactor)) > buf_len)
449 			buf_len = tmp_len;
450 
451 		buffer = malloc(buf_len);
452 
453 		if (buffer == NULL) {
454 			perror("malloc");
455 			goto end;
456 		}
457 		ecparam_print_var(out, ec_p, "ec_p", len, buffer);
458 		ecparam_print_var(out, ec_a, "ec_a", len, buffer);
459 		ecparam_print_var(out, ec_b, "ec_b", len, buffer);
460 		ecparam_print_var(out, ec_gen, "ec_gen", len, buffer);
461 		ecparam_print_var(out, ec_order, "ec_order", len, buffer);
462 		ecparam_print_var(out, ec_cofactor, "ec_cofactor", len,
463 		    buffer);
464 
465 		BIO_printf(out, "\n\n");
466 
467 		BIO_printf(out, "EC_GROUP *get_ec_group_%d(void)\n\t{\n", len);
468 		BIO_printf(out, "\tint ok=0;\n");
469 		BIO_printf(out, "\tEC_GROUP *group = NULL;\n");
470 		BIO_printf(out, "\tEC_POINT *point = NULL;\n");
471 		BIO_printf(out, "\tBIGNUM   *tmp_1 = NULL, *tmp_2 = NULL, "
472 		    "*tmp_3 = NULL;\n\n");
473 		BIO_printf(out, "\tif ((tmp_1 = BN_bin2bn(ec_p_%d, "
474 		    "sizeof(ec_p_%d), NULL)) == NULL)\n\t\t"
475 		    "goto err;\n", len, len);
476 		BIO_printf(out, "\tif ((tmp_2 = BN_bin2bn(ec_a_%d, "
477 		    "sizeof(ec_a_%d), NULL)) == NULL)\n\t\t"
478 		    "goto err;\n", len, len);
479 		BIO_printf(out, "\tif ((tmp_3 = BN_bin2bn(ec_b_%d, "
480 		    "sizeof(ec_b_%d), NULL)) == NULL)\n\t\t"
481 		    "goto err;\n", len, len);
482 		if (is_prime) {
483 			BIO_printf(out, "\tif ((group = EC_GROUP_new_curve_"
484 			    "GFp(tmp_1, tmp_2, tmp_3, NULL)) == NULL)"
485 			    "\n\t\tgoto err;\n\n");
486 		} else {
487 			BIO_printf(out, "\tif ((group = EC_GROUP_new_curve_"
488 			    "GF2m(tmp_1, tmp_2, tmp_3, NULL)) == NULL)"
489 			    "\n\t\tgoto err;\n\n");
490 		}
491 		BIO_printf(out, "\t/* build generator */\n");
492 		BIO_printf(out, "\tif ((tmp_1 = BN_bin2bn(ec_gen_%d, "
493 		    "sizeof(ec_gen_%d), tmp_1)) == NULL)"
494 		    "\n\t\tgoto err;\n", len, len);
495 		BIO_printf(out, "\tpoint = EC_POINT_bn2point(group, tmp_1, "
496 		    "NULL, NULL);\n");
497 		BIO_printf(out, "\tif (point == NULL)\n\t\tgoto err;\n");
498 		BIO_printf(out, "\tif ((tmp_2 = BN_bin2bn(ec_order_%d, "
499 		    "sizeof(ec_order_%d), tmp_2)) == NULL)"
500 		    "\n\t\tgoto err;\n", len, len);
501 		BIO_printf(out, "\tif ((tmp_3 = BN_bin2bn(ec_cofactor_%d, "
502 		    "sizeof(ec_cofactor_%d), tmp_3)) == NULL)"
503 		    "\n\t\tgoto err;\n", len, len);
504 		BIO_printf(out, "\tif (!EC_GROUP_set_generator(group, point,"
505 		    " tmp_2, tmp_3))\n\t\tgoto err;\n");
506 		BIO_printf(out, "\n\tok=1;\n");
507 		BIO_printf(out, "err:\n");
508 		BIO_printf(out, "\tif (tmp_1)\n\t\tBN_free(tmp_1);\n");
509 		BIO_printf(out, "\tif (tmp_2)\n\t\tBN_free(tmp_2);\n");
510 		BIO_printf(out, "\tif (tmp_3)\n\t\tBN_free(tmp_3);\n");
511 		BIO_printf(out, "\tif (point)\n\t\tEC_POINT_free(point);\n");
512 		BIO_printf(out, "\tif (!ok)\n");
513 		BIO_printf(out, "\t\t{\n");
514 		BIO_printf(out, "\t\tEC_GROUP_free(group);\n");
515 		BIO_printf(out, "\t\tgroup = NULL;\n");
516 		BIO_printf(out, "\t\t}\n");
517 		BIO_printf(out, "\treturn(group);\n\t}\n");
518 	}
519 	if (!ecparam_config.noout) {
520 		if (ecparam_config.outformat == FORMAT_ASN1)
521 			i = i2d_ECPKParameters_bio(out, group);
522 		else if (ecparam_config.outformat == FORMAT_PEM)
523 			i = PEM_write_bio_ECPKParameters(out, group);
524 		else {
525 			BIO_printf(bio_err, "bad output format specified for"
526 			    " outfile\n");
527 			goto end;
528 		}
529 		if (!i) {
530 			BIO_printf(bio_err, "unable to write elliptic "
531 			    "curve parameters\n");
532 			ERR_print_errors(bio_err);
533 			goto end;
534 		}
535 	}
536 	if (ecparam_config.genkey) {
537 		EC_KEY *eckey = EC_KEY_new();
538 
539 		if (eckey == NULL)
540 			goto end;
541 
542 		if (EC_KEY_set_group(eckey, group) == 0) {
543 			EC_KEY_free(eckey);
544 			goto end;
545 		}
546 
547 		if (!EC_KEY_generate_key(eckey)) {
548 			EC_KEY_free(eckey);
549 			goto end;
550 		}
551 		if (ecparam_config.outformat == FORMAT_ASN1)
552 			i = i2d_ECPrivateKey_bio(out, eckey);
553 		else if (ecparam_config.outformat == FORMAT_PEM)
554 			i = PEM_write_bio_ECPrivateKey(out, eckey, NULL,
555 			    NULL, 0, NULL, NULL);
556 		else {
557 			BIO_printf(bio_err, "bad output format specified "
558 			    "for outfile\n");
559 			EC_KEY_free(eckey);
560 			goto end;
561 		}
562 		EC_KEY_free(eckey);
563 	}
564 	ret = 0;
565 
566  end:
567 	BN_free(ec_p);
568 	BN_free(ec_a);
569 	BN_free(ec_b);
570 	BN_free(ec_gen);
571 	BN_free(ec_order);
572 	BN_free(ec_cofactor);
573 
574 	free(buffer);
575 
576 	BIO_free(in);
577 	BIO_free_all(out);
578 	EC_GROUP_free(group);
579 
580 	return (ret);
581 }
582 
583 static int
584 ecparam_print_var(BIO * out, BIGNUM * in, const char *var,
585     int len, unsigned char *buffer)
586 {
587 	BIO_printf(out, "static unsigned char %s_%d[] = {", var, len);
588 	if (BN_is_zero(in))
589 		BIO_printf(out, "\n\t0x00");
590 	else {
591 		int i, l;
592 
593 		l = BN_bn2bin(in, buffer);
594 		for (i = 0; i < l - 1; i++) {
595 			if ((i % 12) == 0)
596 				BIO_printf(out, "\n\t");
597 			BIO_printf(out, "0x%02X,", buffer[i]);
598 		}
599 		if ((i % 12) == 0)
600 			BIO_printf(out, "\n\t");
601 		BIO_printf(out, "0x%02X", buffer[i]);
602 	}
603 	BIO_printf(out, "\n\t};\n\n");
604 	return 1;
605 }
606 #endif
607