[thirdparty/openssl.git] / doc / man7 / EVP_PKEY-DH.pod

=pod

=head1 NAME

EVP_PKEY-DH, EVP_PKEY-DHX, EVP_KEYMGMT-DH
- EVP_PKEY DH and DHX keytype and algorithm support

=head1 DESCRIPTION

For B<DH> FFC key agreement, two classes of domain parameters can be used:
"safe" domain parameters that are associated with approved named safe-prime
groups, and a class of "FIPS 186-type" domain parameters. FIPS 186-type domain
parameters should only be used for backward compatibility with existing
applications that cannot be upgraded to use the approved safe-prime groups.

See L<EVP_PKEY-FFC(7)> for more information about FFC keys.

The B<DH> key type uses PKCS#3 format which saves p and g, but not the 'q' value.
The B<DHX> key type uses X9.42 format which saves the value of 'q' and this
must be used for FIPS186-4.

For B<DHX> that is not a named group the FIPS186-4 standard specifies that the
values used for FFC parameter generation are also required for parameter
validation. This means that optional FFC domain parameter values for
I<seed>, I<pcounter> and I<gindex> or I<hindex> may need to be stored for
validation purposes.
For B<DHX> the I<seed> and I<pcounter> can be stored in ASN1 data
(but the I<gindex> or I<hindex> can not be stored).

=head2 DH and DHX domain parameters

In addition to the common FCC parameters that all FFC keytypes should support
(see L<EVP_PKEY-FFC(7)/FFC parameters>) the B<DHX> and B<DH> keytype
implementations support the following:

=over 4

=item "group" (B<OSSL_PKEY_PARAM_GROUP_NAME>) <UTF8 string>

Sets or gets a string that associates a B<DH> or B<DHX> named safe prime group
with known values for I<p>, I<q> and I<g>.

The following values can be used by the OpenSSL's default and FIPS providers:
"ffdhe2048", "ffdhe3072", "ffdhe4096", "ffdhe6144", "ffdhe8192",
"modp_2048", "modp_3072", "modp_4096", "modp_6144", "modp_8192".

The following additional values can also be used by OpenSSL's default provider:
"modp_1536", "dh_1024_160", "dh_2048_224", "dh_2048_256".

DH/DHX named groups can be easily validated since the parameters are well known.
For protocols that only transfer I<p> and I<g> the value of I<q> can also be
retrieved.

=back

=head2 DH and DHX additional parameters

=over 4

=item "encoded-pub-key" (B<OSSL_PKEY_PARAM_ENCODED_PUBLIC_KEY>) <octet string>

Used for getting and setting the encoding of the DH public key used in a key
exchange message for the TLS protocol.
See EVP_PKEY_set1_encoded_public_key() and EVP_PKEY_get1_encoded_public_key().

=back

=head2 DH additional domain parameters

=over 4

=item "safeprime-generator" (B<OSSL_PKEY_PARAM_DH_GENERATOR>) <integer>

Used for DH generation of safe primes using the old safe prime generator code.
The default value is 2.
It is recommended to use a named safe prime group instead, if domain parameter
validation is required. 

Randomly generated safe primes are not allowed by FIPS, so setting this value
for the OpenSSL FIPS provider will instead choose a named safe prime group
based on the size of I<p>.

=back

=head2 DH and DHX domain parameter / key generation parameters

In addition to the common FFC key generation parameters that all FFC key types
should support (see L<EVP_PKEY-FFC(7)/FFC key generation parameters>) the
B<DH> and B<DHX> keytype implementation supports the following:

=over 4

=item "type" (B<OSSL_PKEY_PARAM_FFC_TYPE>) <utf8_string>

Sets the type of parameter generation. For B<DH> valid values are:

=over 4

=item "fips186_4"

=item "default"

=item "fips186_2"

These are described in L<EVP_PKEY-FFC(7)/FFC key generation parameters>

=item "group"

This specifies that a named safe prime name will be chosen using the "pbits"
type.

=item "generator"

A safe prime generator. See the "safeprime-generator" type above.
This is only valid for B<DH> keys.

=back

=item "pbits" (B<OSSL_PKEY_PARAM_FFC_PBITS>) <unsigned integer>

Sets the size (in bits) of the prime 'p'.

For "fips186_4" this must be 2048.
For "fips186_2" this must be 1024.
For "group" this can be any one of 2048, 3072, 4096, 6144 or 8192.

=item "priv_len" (B<OSSL_PKEY_PARAM_DH_PRIV_LEN>) <integer>

An optional value to set the maximum length of the generated private key.
The default value used if this is not set is the maximum value of
BN_num_bits(I<q>)). The minimum value that this can be set to is 2 * s.
Where s is the security strength of the key which has values of
112, 128, 152, 176 and 200 for key sizes of 2048, 3072, 4096, 6144 and 8192.

=back

=head1 EXAMPLES

An B<EVP_PKEY> context can be obtained by calling:

    EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_from_name(NULL, "DH", NULL);

A B<DH> key can be generated with a named safe prime group by calling:

    int priv_len = 2 * 112;
    OSSL_PARAM params[3];
    EVP_PKEY *pkey = NULL;
    EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_from_name(NULL, "DH", NULL);

    params[0] = OSSL_PARAM_construct_utf8_string("group", "ffdhe2048", 0);
    /* "priv_len" is optional */
    params[1] = OSSL_PARAM_construct_int("priv_len", &priv_len);
    params[2] = OSSL_PARAM_construct_end();

    EVP_PKEY_keygen_init(pctx);
    EVP_PKEY_CTX_set_params(pctx, params);
    EVP_PKEY_gen(pctx, &pkey);
    ...
    EVP_PKEY_free(key);
    EVP_PKEY_CTX_free(pctx);

B<DHX> domain parameters can be generated according to B<FIPS 186-4> by calling:

    unsigned int pbits = 2048;
    unsigned int qbits = 256;
    OSSL_PARAM params[5];
    EVP_PKEY *param_key = NULL;
    EVP_PKEY_CTX *pctx = NULL;

    pctx = EVP_PKEY_CTX_new_from_name(NULL, "DHX", NULL);
    EVP_PKEY_paramgen_init(pctx);

    params[0] = OSSL_PARAM_construct_uint("pbits", &pbits);
    params[1] = OSSL_PARAM_construct_uint("qbits", &qbits);
    params[2] = OSSL_PARAM_construct_utf8_string("type", "fips186_4", 0);
    params[3] = OSSL_PARAM_construct_utf8_string("digest", "SHA256", 0);
    params[4] = OSSL_PARAM_construct_end();
    EVP_PKEY_CTX_set_params(pctx, params);

    EVP_PKEY_gen(pctx, &param_key);

    EVP_PKEY_print_params(bio_out, param_key, 0, NULL);
    ...
    EVP_PKEY_free(param_key);
    EVP_PKEY_CTX_free(pctx);

A B<DH> key can be generated using domain parameters by calling:

    EVP_PKEY *key = NULL;
    EVP_PKEY_CTX *gctx = EVP_PKEY_CTX_new_from_pkey(NULL, param_key, NULL);

    EVP_PKEY_keygen_init(gctx);
    EVP_PKEY_gen(gctx, &key);
    EVP_PKEY_print_private(bio_out, key, 0, NULL);
    ...
    EVP_PKEY_free(key);
    EVP_PKEY_CTX_free(gctx);

To validate B<FIPS 186-4> B<DHX> domain parameters decoded from B<PEM> or
B<DER> data, additional values used during generation may be required to
be set into the key.

EVP_PKEY_todata(), OSSL_PARAM_merge(), and EVP_PKEY_fromdata() are useful
to add these parameters to the original key or domain parameters before
the actual validation.

    EVP_PKEY *received_domp = ...; /* parameters received and decoded */
    unsigned char *seed = ...;     /* and additional parameters received */
    size_t seedlen = ...;          /* by other means, required */
    int gindex = ...;              /* for the validation */
    int pcounter = ...;
    int hindex = ...;
    OSSL_PARAM extra_params[5];
    OSSL_PARAM *domain_params = NULL;
    OSSL_PARAM *merged_params = NULL;
    EVP_PKEY_CTX *ctx = NULL, *validate_ctx = NULL;
    EVP_PKEY *complete_domp = NULL;

    EVP_PKEY_todata(received_domp, OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
                    &domain_params);
    extra_params[0] = OSSL_PARAM_construct_octet_string("seed", seed, seedlen);
    extra_params[1] = OSSL_PARAM_construct_int("gindex", &gindex);
    extra_params[2] = OSSL_PARAM_construct_int("pcounter", &pcounter);
    extra_params[3] = OSSL_PARAM_construct_int("hindex", &hindex);
    extra_params[4] = OSSL_PARAM_construct_end();
    merged_params = OSSL_PARAM_merge(domain_params, extra_params);

    ctx = EVP_PKEY_CTX_new_from_name(NULL, "DHX", NULL);
    EVP_PKEY_fromdata_init(ctx);
    EVP_PKEY_fromdata(ctx, &complete_domp, OSSL_KEYMGMT_SELECT_ALL,
                      merged_params);

    validate_ctx = EVP_PKEY_CTX_new_from_pkey(NULL, complete_domp, NULL);
    if (EVP_PKEY_param_check(validate_ctx) > 0)
        /* validation_passed(); */
    else
        /* validation_failed(); */

    OSSL_PARAM_free(domain_params);
    OSSL_PARAM_free(merged_params);
    EVP_PKEY_CTX_free(ctx);
    EVP_PKEY_CTX_free(validate_ctx);
    EVP_PKEY_free(complete_domp);

=head1 CONFORMING TO

=over 4

=item RFC 7919 (TLS ffdhe named safe prime groups)

=item RFC 3526 (IKE modp named safe prime groups)

=item RFC 5114 (Additional DH named groups for dh_1024_160", "dh_2048_224"
          and "dh_2048_256").

=back

The following sections of SP800-56Ar3:

=over 4

=item 5.5.1.1 FFC Domain Parameter Selection/Generation

=item Appendix D: FFC Safe-prime Groups

=back

The following sections of FIPS 186-4:

=over 4

=item A.1.1.2 Generation of Probable Primes p and q Using an Approved Hash Function.

=item A.2.3 Generation of canonical generator g.

=item A.2.1 Unverifiable Generation of the Generator g.

=back

=head1 SEE ALSO

L<EVP_PKEY-FFC(7)>,
L<EVP_KEYEXCH-DH(7)>
L<EVP_PKEY(3)>,
L<provider-keymgmt(7)>,
L<EVP_KEYMGMT(3)>,
L<OSSL_PROVIDER-default(7)>,
L<OSSL_PROVIDER-FIPS(7)>

=head1 COPYRIGHT

Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use
this file except in compliance with the License.  You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.

=cut
Commit	Line	Data
b8086652 SL	1	=pod
	2
	3	=head1 NAME
	4
f1ffaaee SL	5	EVP_PKEY-DH, EVP_PKEY-DHX, EVP_KEYMGMT-DH
f1ffaaee SL	6	- EVP_PKEY DH and DHX keytype and algorithm support
b8086652 SL	7
	8	=head1 DESCRIPTION
	9
	10	For B<DH> FFC key agreement, two classes of domain parameters can be used:
	11	"safe" domain parameters that are associated with approved named safe-prime
	12	groups, and a class of "FIPS 186-type" domain parameters. FIPS 186-type domain
	13	parameters should only be used for backward compatibility with existing
	14	applications that cannot be upgraded to use the approved safe-prime groups.
	15
	16	See L<EVP_PKEY-FFC(7)> for more information about FFC keys.
	17
f1ffaaee SL	18	The B<DH> key type uses PKCS#3 format which saves p and g, but not the 'q' value.
	19	The B<DHX> key type uses X9.42 format which saves the value of 'q' and this
	20	must be used for FIPS186-4.
	21
	22	For B<DHX> that is not a named group the FIPS186-4 standard specifies that the
b8086652 SL	23	values used for FFC parameter generation are also required for parameter
b8086652 SL	24	validation. This means that optional FFC domain parameter values for
f1ffaaee SL	25	I<seed>, I<pcounter> and I<gindex> or I<hindex> may need to be stored for
	26	validation purposes.
	27	For B<DHX> the I<seed> and I<pcounter> can be stored in ASN1 data
	28	(but the I<gindex> or I<hindex> can not be stored).
b8086652	29
f1ffaaee	30	=head2 DH and DHX domain parameters
b8086652 SL	31
b8086652 SL	32	In addition to the common FCC parameters that all FFC keytypes should support
f1ffaaee SL	33	(see L<EVP_PKEY-FFC(7)/FFC parameters>) the B<DHX> and B<DH> keytype
f1ffaaee SL	34	implementations support the following:
b8086652 SL	35
	36	=over 4
	37
023b188c	38	=item "group" (B<OSSL_PKEY_PARAM_GROUP_NAME>) <UTF8 string>
b8086652	39
f1ffaaee SL	40	Sets or gets a string that associates a B<DH> or B<DHX> named safe prime group
f1ffaaee SL	41	with known values for I<p>, I<q> and I<g>.
b8086652 SL	42
	43	The following values can be used by the OpenSSL's default and FIPS providers:
	44	"ffdhe2048", "ffdhe3072", "ffdhe4096", "ffdhe6144", "ffdhe8192",
	45	"modp_2048", "modp_3072", "modp_4096", "modp_6144", "modp_8192".
	46
	47	The following additional values can also be used by OpenSSL's default provider:
	48	"modp_1536", "dh_1024_160", "dh_2048_224", "dh_2048_256".
	49
f1ffaaee	50	DH/DHX named groups can be easily validated since the parameters are well known.
b8086652 SL	51	For protocols that only transfer I<p> and I<g> the value of I<q> can also be
	52	retrieved.
	53
f1ffaaee	54	=back
b8086652	55
f1ffaaee	56	=head2 DH and DHX additional parameters
b8086652	57
f1ffaaee	58	=over 4
b8086652	59
5ac8fb58	60	=item "encoded-pub-key" (B<OSSL_PKEY_PARAM_ENCODED_PUBLIC_KEY>) <octet string>
6a9bd929 MC	61
	62	Used for getting and setting the encoding of the DH public key used in a key
	63	exchange message for the TLS protocol.
f1ffaaee SL	64	See EVP_PKEY_set1_encoded_public_key() and EVP_PKEY_get1_encoded_public_key().
	65
	66	=back
	67
	68	=head2 DH additional domain parameters
	69
	70	=over 4
	71
	72	=item "safeprime-generator" (B<OSSL_PKEY_PARAM_DH_GENERATOR>) <integer>
	73
	74	Used for DH generation of safe primes using the old safe prime generator code.
	75	The default value is 2.
	76	It is recommended to use a named safe prime group instead, if domain parameter
	77	validation is required.
	78
	79	Randomly generated safe primes are not allowed by FIPS, so setting this value
	80	for the OpenSSL FIPS provider will instead choose a named safe prime group
	81	based on the size of I<p>.
6a9bd929	82
b8086652 SL	83	=back
b8086652 SL	84
f1ffaaee	85	=head2 DH and DHX domain parameter / key generation parameters
b8086652	86
05fa5fde MC	87	In addition to the common FFC key generation parameters that all FFC key types
05fa5fde MC	88	should support (see L<EVP_PKEY-FFC(7)/FFC key generation parameters>) the
f1ffaaee	89	B<DH> and B<DHX> keytype implementation supports the following:
b8086652 SL	90
	91	=over 4
	92
	93	=item "type" (B<OSSL_PKEY_PARAM_FFC_TYPE>) <utf8_string>
	94
	95	Sets the type of parameter generation. For B<DH> valid values are:
	96
	97	=over 4
	98
	99	=item "fips186_4"
	100
	101	=item "default"
	102
	103	=item "fips186_2"
	104
	105	These are described in L<EVP_PKEY-FFC(7)/FFC key generation parameters>
	106
	107	=item "group"
	108
	109	This specifies that a named safe prime name will be chosen using the "pbits"
	110	type.
	111
	112	=item "generator"
	113
	114	A safe prime generator. See the "safeprime-generator" type above.
f1ffaaee	115	This is only valid for B<DH> keys.
b8086652 SL	116
	117	=back
	118
	119	=item "pbits" (B<OSSL_PKEY_PARAM_FFC_PBITS>) <unsigned integer>
	120
	121	Sets the size (in bits) of the prime 'p'.
	122
	123	For "fips186_4" this must be 2048.
	124	For "fips186_2" this must be 1024.
	125	For "group" this can be any one of 2048, 3072, 4096, 6144 or 8192.
	126
	127	=item "priv_len" (B<OSSL_PKEY_PARAM_DH_PRIV_LEN>) <integer>
	128
	129	An optional value to set the maximum length of the generated private key.
8c1cbc72	130	The default value used if this is not set is the maximum value of
b8086652 SL	131	BN_num_bits(I<q>)). The minimum value that this can be set to is 2 * s.
	132	Where s is the security strength of the key which has values of
	133	112, 128, 152, 176 and 200 for key sizes of 2048, 3072, 4096, 6144 and 8192.
	134
	135	=back
	136
	137	=head1 EXAMPLES
	138
	139	An B<EVP_PKEY> context can be obtained by calling:
	140
	141	EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_from_name(NULL, "DH", NULL);
	142
185e1aa2	143	A B<DH> key can be generated with a named safe prime group by calling:
b8086652 SL	144
	145	int priv_len = 2 * 112;
	146	OSSL_PARAM params[3];
	147	EVP_PKEY *pkey = NULL;
	148	EVP_PKEY_CTX *pctx = EVP_PKEY_CTX_new_from_name(NULL, "DH", NULL);
	149
	150	params[0] = OSSL_PARAM_construct_utf8_string("group", "ffdhe2048", 0);
	151	/* "priv_len" is optional */
	152	params[1] = OSSL_PARAM_construct_int("priv_len", &priv_len);
	153	params[2] = OSSL_PARAM_construct_end();
	154
	155	EVP_PKEY_keygen_init(pctx);
	156	EVP_PKEY_CTX_set_params(pctx, params);
	157	EVP_PKEY_gen(pctx, &pkey);
	158	...
	159	EVP_PKEY_free(key);
	160	EVP_PKEY_CTX_free(pctx);
	161
185e1aa2	162	B<DHX> domain parameters can be generated according to B<FIPS 186-4> by calling:
05fa5fde	163
b8086652 SL	164	unsigned int pbits = 2048;
b8086652 SL	165	unsigned int qbits = 256;
b8086652 SL	166	OSSL_PARAM params[5];
	167	EVP_PKEY *param_key = NULL;
	168	EVP_PKEY_CTX *pctx = NULL;
	169
185e1aa2	170	pctx = EVP_PKEY_CTX_new_from_name(NULL, "DHX", NULL);
b8086652	171	EVP_PKEY_paramgen_init(pctx);
2edb571b	172
b8086652 SL	173	params[0] = OSSL_PARAM_construct_uint("pbits", &pbits);
b8086652 SL	174	params[1] = OSSL_PARAM_construct_uint("qbits", &qbits);
185e1aa2 TM	175	params[2] = OSSL_PARAM_construct_utf8_string("type", "fips186_4", 0);
185e1aa2 TM	176	params[3] = OSSL_PARAM_construct_utf8_string("digest", "SHA256", 0);
b8086652 SL	177	params[4] = OSSL_PARAM_construct_end();
	178	EVP_PKEY_CTX_set_params(pctx, params);
	179
	180	EVP_PKEY_gen(pctx, &param_key);
	181
	182	EVP_PKEY_print_params(bio_out, param_key, 0, NULL);
	183	...
	184	EVP_PKEY_free(param_key);
	185	EVP_PKEY_CTX_free(pctx);
	186
185e1aa2	187	A B<DH> key can be generated using domain parameters by calling:
b8086652 SL	188
	189	EVP_PKEY *key = NULL;
	190	EVP_PKEY_CTX *gctx = EVP_PKEY_CTX_new_from_pkey(NULL, param_key, NULL);
	191
	192	EVP_PKEY_keygen_init(gctx);
	193	EVP_PKEY_gen(gctx, &key);
	194	EVP_PKEY_print_private(bio_out, key, 0, NULL);
	195	...
	196	EVP_PKEY_free(key);
	197	EVP_PKEY_CTX_free(gctx);
	198
185e1aa2 TM	199	To validate B<FIPS 186-4> B<DHX> domain parameters decoded from B<PEM> or
	200	B<DER> data, additional values used during generation may be required to
	201	be set into the key.
	202
	203	EVP_PKEY_todata(), OSSL_PARAM_merge(), and EVP_PKEY_fromdata() are useful
	204	to add these parameters to the original key or domain parameters before
	205	the actual validation.
	206
	207	EVP_PKEY received_domp = ...; / parameters received and decoded */
	208	unsigned char seed = ...; / and additional parameters received */
	209	size_t seedlen = ...; /* by other means, required */
	210	int gindex = ...; /* for the validation */
	211	int pcounter = ...;
	212	int hindex = ...;
	213	OSSL_PARAM extra_params[5];
	214	OSSL_PARAM *domain_params = NULL;
	215	OSSL_PARAM *merged_params = NULL;
	216	EVP_PKEY_CTX ctx = NULL, validate_ctx = NULL;
	217	EVP_PKEY *complete_domp = NULL;
	218
	219	EVP_PKEY_todata(received_domp, OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS,
	220	&domain_params);
	221	extra_params[0] = OSSL_PARAM_construct_octet_string("seed", seed, seedlen);
	222	extra_params[1] = OSSL_PARAM_construct_int("gindex", &gindex);
	223	extra_params[2] = OSSL_PARAM_construct_int("pcounter", &pcounter);
	224	extra_params[3] = OSSL_PARAM_construct_int("hindex", &hindex);
	225	extra_params[4] = OSSL_PARAM_construct_end();
	226	merged_params = OSSL_PARAM_merge(domain_params, extra_params);
	227
	228	ctx = EVP_PKEY_CTX_new_from_name(NULL, "DHX", NULL);
	229	EVP_PKEY_fromdata_init(ctx);
	230	EVP_PKEY_fromdata(ctx, &complete_domp, OSSL_KEYMGMT_SELECT_ALL,
	231	merged_params);
	232
	233	validate_ctx = EVP_PKEY_CTX_new_from_pkey(NULL, complete_domp, NULL);
	234	if (EVP_PKEY_param_check(validate_ctx) > 0)
	235	/* validation_passed(); */
	236	else
	237	/* validation_failed(); */
	238
	239	OSSL_PARAM_free(domain_params);
	240	OSSL_PARAM_free(merged_params);
	241	EVP_PKEY_CTX_free(ctx);
	242	EVP_PKEY_CTX_free(validate_ctx);
	243	EVP_PKEY_free(complete_domp);
b8086652 SL	244
	245	=head1 CONFORMING TO
	246
	247	=over 4
	248
	249	=item RFC 7919 (TLS ffdhe named safe prime groups)
	250
	251	=item RFC 3526 (IKE modp named safe prime groups)
	252
	253	=item RFC 5114 (Additional DH named groups for dh_1024_160", "dh_2048_224"
	254	and "dh_2048_256").
	255
	256	=back
	257
	258	The following sections of SP800-56Ar3:
	259
	260	=over 4
	261
	262	=item 5.5.1.1 FFC Domain Parameter Selection/Generation
	263
	264	=item Appendix D: FFC Safe-prime Groups
	265
	266	=back
	267
	268	The following sections of FIPS 186-4:
	269
	270	=over 4
	271
	272	=item A.1.1.2 Generation of Probable Primes p and q Using an Approved Hash Function.
	273
	274	=item A.2.3 Generation of canonical generator g.
	275
	276	=item A.2.1 Unverifiable Generation of the Generator g.
	277
	278	=back
	279
	280	=head1 SEE ALSO
	281
	282	L<EVP_PKEY-FFC(7)>,
	283	L<EVP_KEYEXCH-DH(7)>
	284	L<EVP_PKEY(3)>,
	285	L<provider-keymgmt(7)>,
	286	L<EVP_KEYMGMT(3)>,
	287	L<OSSL_PROVIDER-default(7)>,
	288	L<OSSL_PROVIDER-FIPS(7)>
	289
	290	=head1 COPYRIGHT
	291
f5afac4b	292	Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved.
b8086652 SL	293
	294	Licensed under the Apache License 2.0 (the "License"). You may not use
	295	this file except in compliance with the License. You can obtain a copy
	296	in the file LICENSE in the source distribution or at
	297	L<https://www.openssl.org/source/license.html>.
	298
	299	=cut