1ssl(3) Erlang Module Definition ssl(3)
2
6 ssl - Interface Functions for Secure Socket Layer
7
9 This module contains interface functions for the SSL/TLS/DTLS protocol.
10 For detailed information about the supported standards see ssl(6).
11
13 Types used in SSL/TLS/DTLS
14 socket() = gen_tcp:socket()
15 sslsocket() = any()
17 An opaque reference to the TLS/DTLS connection, may be used for
19 equality matching.
20 tls_option() = tls_client_option() | tls_server_option()
22 tls_client_option() =
24 client_option() |
25 common_option() |
26 socket_option() |
27 transport_option()
28 tls_server_option() =
30 server_option() |
31 common_option() |
32 socket_option() |
33 transport_option()
34 socket_option() =
36 gen_tcp:connect_option() |
37 gen_tcp:listen_option() |
38 gen_udp:option()
39 The default socket options are [{mode,list},{packet, 0},{header,
41 0},{active, true}].
42 For valid options, see the inet(3), gen_tcp(3) and gen_udp(3)
44 manual pages in Kernel. Note that stream oriented options such
45 as packet are only relevant for SSL/TLS and not DTLS
46 active_msgs() =
48 {ssl, sslsocket(), Data :: binary() | list()} |
49 {ssl_closed, sslsocket()} |
50 {ssl_error, sslsocket(), Reason :: any()} |
51 {ssl_passive, sslsocket()}
52 When a TLS/DTLS socket is in active mode (the default), data
54 from the socket is delivered to the owner of the socket in the
55 form of messages as described above.
56 The ssl_passive message is sent only when the socket is in
58 {active, N} mode and the counter dropped to 0. It indicates that
59 the socket has transitioned to passive ({active, false}) mode.
60 transport_option() =
62 {cb_info,
63 {CallbackModule :: atom(),
64 DataTag :: atom(),
65 ClosedTag :: atom(),
66 ErrTag :: atom()}} |
67 {cb_info,
68 {CallbackModule :: atom(),
69 DataTag :: atom(),
70 ClosedTag :: atom(),
71 ErrTag :: atom(),
72 PassiveTag :: atom()}}
73 Defaults to {gen_tcp, tcp, tcp_closed, tcp_error, tcp_passive}
75 for TLS (for backward compatibility a four tuple will be con‐
76 verted to a five tuple with the last element "second_ele‐
77 ment"_passive) and {gen_udp, udp, udp_closed, udp_error} for
78 DTLS (might also be changed to five tuple in the future). Can be
79 used to customize the transport layer. The tag values should be
80 the values used by the underlying transport in its active mode
81 messages. For TLS the callback module must implement a reliable
82 transport protocol, behave as gen_tcp, and have functions corre‐
83 sponding to inet:setopts/2, inet:getopts/2, inet:peername/1,
84 inet:sockname/1, and inet:port/1. The callback gen_tcp is
85 treated specially and calls inet directly. For DTLS this feature
86 must be considered exprimental.
87 host() = hostname() | ip_address()
89 hostname() = string()
91 ip_address() = inet:ip_address()
93 protocol_version() = tls_version() | dtls_version()
95 tls_version() =
97 tlsv1 | 'tlsv1.1' | 'tlsv1.2' | 'tlsv1.3' | legacy_version()
98 dtls_version() = dtlsv1 | 'dtlsv1.2'
100 legacy_version() = sslv3
102 prf_random() = client_random | server_random
104 verify_type() = verify_none | verify_peer
106 ciphers() = [erl_cipher_suite()] | string()
108 erl_cipher_suite() =
110 #{key_exchange := kex_algo(),
111 cipher := cipher(),
112 mac := hash() | aead,
113 prf := hash() | default_prf}
114 cipher() =
116 aes_128_cbc |
117 aes_256_cbc |
118 aes_128_gcm |
119 aes_256_gcm |
120 chacha20_poly1305 |
121 legacy_cipher()
122 legacy_cipher() = rc4_128 | des_cbc | '3des_ede_cbc'
124 cipher_filters() =
126 [{key_exchange | cipher | mac | prf, algo_filter()}]
127 hash() = sha | sha2() | legacy_hash()
129 sha2() = sha224 | sha256 | sha384 | sha512
131 legacy_hash() = md5
133 old_cipher_suite() =
135 {kex_algo(), cipher(), hash()} |
136 {kex_algo(), cipher(), hash() | aead, hash()}
137 signature_algs() = [{hash(), sign_algo()}]
139 sign_algo() = rsa | dsa | ecdsa
141 kex_algo() =
143 rsa |
144 dhe_rsa |
145 dhe_dss |
146 ecdhe_ecdsa |
147 ecdh_ecdsa |
148 ecdh_rsa |
149 srp_rsa |
150 srp_dss |
151 psk |
152 dhe_psk |
153 rsa_psk |
154 dh_anon |
155 ecdh_anon |
156 srp_anon
157 algo_filter() =
159 fun((kex_algo() | cipher() | hash() | aead | default_prf) ->
160 true | false)
161 named_curve() =
163 sect571r1 |
164 sect571k1 |
165 secp521r1 |
166 brainpoolP512r1 |
167 sect409k1 |
168 sect409r1 |
169 brainpoolP384r1 |
170 secp384r1 |
171 sect283k1 |
172 sect283r1 |
173 brainpoolP256r1 |
174 secp256k1 |
175 secp256r1 |
176 sect239k1 |
177 sect233k1 |
178 sect233r1 |
179 secp224k1 |
180 secp224r1 |
181 sect193r1 |
182 sect193r2 |
183 secp192k1 |
184 secp192r1 |
185 sect163k1 |
186 sect163r1 |
187 sect163r2 |
188 secp160k1 |
189 secp160r1 |
190 secp160r2
191 psk_identity() = string()
193 srp_identity() = {Username :: string(), Password :: string()}
195 srp_param_type() =
197 srp_1024 |
198 srp_1536 |
199 srp_2048 |
200 srp_3072 |
201 srp_4096 |
202 srp_6144 |
203 srp_8192
204 app_level_protocol() = binary()
206 protocol_extensions() =
208 #{renegotiation_info => binary(),
209 signature_algs => signature_algs(),
210 alpn => app_level_protocol(),
211 srp => binary(),
212 next_protocol => app_level_protocol(),
213 ec_point_formats => [0..2],
214 elliptic_curves => [public_key:oid()],
215 sni => hostname()}
216 error_alert() =
218 {tls_alert, {tls_alert(), Description :: string()}}
219 tls_alert() =
221 close_notify |
222 unexpected_message |
223 bad_record_mac |
224 record_overflow |
225 handshake_failure |
226 bad_certificate |
227 unsupported_certificate |
228 certificate_revoked |
229 certificate_expired |
230 certificate_unknown |
231 illegal_parameter |
232 unknown_ca |
233 access_denied |
234 decode_error |
235 decrypt_error |
236 export_restriction |
237 protocol_version |
238 insufficient_security |
239 internal_error |
240 inappropriate_fallback |
241 user_canceled |
242 no_renegotiation |
243 unsupported_extension |
244 certificate_unobtainable |
245 unrecognized_name |
246 bad_certificate_status_response |
247 bad_certificate_hash_value |
248 unknown_psk_identity |
249 no_application_protocol
250 reason() = any()
252 TLS/DTLS OPTION DESCRIPTIONS - COMMON for SERVER and CLIENT
254 common_option() =
255 {protocol, protocol()} |
256 {handshake, handshake_completion()} |
257 {cert, cert()} |
258 {certfile, cert_pem()} |
259 {key, key()} |
260 {keyfile, key_pem()} |
261 {password, key_password()} |
262 {ciphers, cipher_suites()} |
263 {secure_renegotiate, secure_renegotiation()} |
264 {depth, allowed_cert_chain_length()} |
265 {verify_fun, custom_verify()} |
266 {crl_check, crl_check()} |
267 {crl_cache, crl_cache_opts()} |
268 {max_handshake_size, handshake_size()} |
269 {partial_chain, root_fun()} |
270 {versions, protocol_versions()} |
271 {user_lookup_fun, custom_user_lookup()} |
272 {log_alert, log_alert()} |
273 {hibernate_after, hibernate_after()} |
274 {padding_check, padding_check()} |
275 {beast_mitigation, beast_mitigation()} |
276 {ssl_imp, ssl_imp()}
277 protocol() = tls | dtls
279 Choose TLS or DTLS protocol for the transport layer security.
281 Defaults to tls. For DTLS other transports than UDP are not yet
282 supported.
283 handshake_completion() = hello | full
285 Defaults to full. If hello is specified the handshake will pause
287 after the hello message and give the user a possibility make
288 decisions based on hello extensions before continuing or abort‐
289 ing the handshake by calling handshake_continue/3 or hand‐
290 shake_cancel/1
291 cert() = public_key:der_encoded()
293 The DER-encoded users certificate. If this option is supplied,
295 it overrides option certfile.
296 cert_pem() = file:filename()
298 Path to a file containing the user certificate on PEM format.
300 key() =
302 {'RSAPrivateKey' |
303 'DSAPrivateKey' |
304 'ECPrivateKey' |
305 'PrivateKeyInfo',
306 public_key:der_encoded()} |
307 #{algorithm := rsa | dss | ecdsa,
308 engine := crypto:engine_ref(),
309 key_id := crypto:key_id(),
310 password => crypto:password()}
311 The DER-encoded user's private key or a map refering to a crypto
313 engine and its key reference that optionally can be password
314 protected, seealso crypto:engine_load/4 and Crypto's Users
315 Guide. If this option is supplied, it overrides option keyfile.
316 key_pem() = file:filename()
318 Path to the file containing the user's private PEM-encoded key.
320 As PEM-files can contain several entries, this option defaults
321 to the same file as given by option certfile.
322 key_password() = string()
324 String containing the user's password. Only used if the private
326 keyfile is password-protected.
327 cipher_suites() = ciphers()
329 Supported cipher suites. The function cipher_suites/2 can be
331 used to find all ciphers that are supported by default.
332 cipher_suites(all, 'tlsv1.2') can be called to find all avail‐
333 able cipher suites. Pre-Shared Key (RFC 4279 and RFC 5487),
334 Secure Remote Password (RFC 5054), RC4, 3DES, DES cipher suites,
335 and anonymous cipher suites only work if explicitly enabled by
336 this option; they are supported/enabled by the peer also. Anony‐
337 mous cipher suites are supported for testing purposes only and
338 are not be used when security matters.
339 secure_renegotiation() = boolean()
341 Specifies if to reject renegotiation attempt that does not live
343 up to RFC 5746. By default secure_renegotiate is set to true,
344 that is, secure renegotiation is enforced. If set to false
345 secure renegotiation will still be used if possible, but it
346 falls back to insecure renegotiation if the peer does not sup‐
347 port RFC 5746.
348 allowed_cert_chain_length() = integer()
350 Maximum number of non-self-issued intermediate certificates that
352 can follow the peer certificate in a valid certification path.
353 So, if depth is 0 the PEER must be signed by the trusted ROOT-CA
354 directly; if 1 the path can be PEER, CA, ROOT-CA; if 2 the path
355 can be PEER, CA, CA, ROOT-CA, and so on. The default value is 1.
356 custom_verify() =
358 {Verifyfun :: function(), InitialUserState :: term()}
359 The verification fun is to be defined as follows:
361 fun(OtpCert :: #'OTPCertificate'{}, Event :: {bad_cert, Reason :: atom() |
363 {revoked, atom()}} |
364 {extension, #'Extension'{}}, InitialUserState :: term()) ->
365 {valid, UserState :: term()} | {valid_peer, UserState :: term()} |
366 {fail, Reason :: term()} | {unknown, UserState :: term()}.
367 The verification fun is called during the X509-path validation
370 when an error or an extension unknown to the SSL application is
371 encountered. It is also called when a certificate is considered
372 valid by the path validation to allow access to each certificate
373 in the path to the user application. It differentiates between
374 the peer certificate and the CA certificates by using valid_peer
375 or valid as second argument to the verification fun. See the
376 public_key User's Guide for definition of #'OTPCertificate'{}
377 and #'Extension'{}.
378 * If the verify callback fun returns {fail, Reason}, the veri‐
380 fication process is immediately stopped, an alert is sent to
381 the peer, and the TLS/DTLS handshake terminates.
382 * If the verify callback fun returns {valid, UserState}, the
384 verification process continues.
385 * If the verify callback fun always returns {valid, User‐
387 State}, the TLS/DTLS handshake does not terminate regarding
388 verification failures and the connection is established.
389 * If called with an extension unknown to the user application,
391 return value {unknown, UserState} is to be used.
392 Note that if the fun returns unknown for an extension marked
394 as critical, validation will fail.
395 Default option verify_fun in verify_peer mode:
397 {fun(_,{bad_cert, _} = Reason, _) ->
399 {fail, Reason};
400 (_,{extension, _}, UserState) ->
401 {unknown, UserState};
402 (_, valid, UserState) ->
403 {valid, UserState};
404 (_, valid_peer, UserState) ->
405 {valid, UserState}
406 end, []}
407 Default option verify_fun in mode verify_none:
410 {fun(_,{bad_cert, _}, UserState) ->
412 {valid, UserState};
413 (_,{extension, #'Extension'{critical = true}}, UserState) ->
414 {valid, UserState};
415 (_,{extension, _}, UserState) ->
416 {unknown, UserState};
417 (_, valid, UserState) ->
418 {valid, UserState};
419 (_, valid_peer, UserState) ->
420 {valid, UserState}
421 end, []}
422 The possible path validation errors are given on form {bad_cert,
425 Reason} where Reason is:
426 unknown_ca:
428 No trusted CA was found in the trusted store. The trusted CA
429 is normally a so called ROOT CA, which is a self-signed cer‐
430 tificate. Trust can be claimed for an intermediate CA
431 (trusted anchor does not have to be self-signed according to
432 X-509) by using option partial_chain.
433 selfsigned_peer:
435 The chain consisted only of one self-signed certificate.
436 PKIX X-509-path validation error:
438 For possible reasons, see public_key:pkix_path_validation/3
439 crl_check() = boolean() | peer | best_effort
441 Perform CRL (Certificate Revocation List) verification (pub‐
443 lic_key:pkix_crls_validate/3) on all the certificates during the
444 path validation (public_key:pkix_path_validation/3) of the cer‐
445 tificate chain. Defaults to false.
446 peer:
448 check is only performed on the peer certificate.
449 best_effort:
451 if certificate revocation status can not be determined it
452 will be accepted as valid.
453 The CA certificates specified for the connection will be used to
455 construct the certificate chain validating the CRLs.
456 The CRLs will be fetched from a local or external cache. See
458 ssl_crl_cache_api(3).
459 crl_cache_opts() = [term()]
461 Specify how to perform lookup and caching of certificate revoca‐
463 tion lists. Module defaults to ssl_crl_cache with DbHandle
464 being internal and an empty argument list.
465 There are two implementations available:
467 ssl_crl_cache:
469 This module maintains a cache of CRLs. CRLs can be added to
470 the cache using the function ssl_crl_cache:insert/1, and
471 optionally automatically fetched through HTTP if the follow‐
472 ing argument is specified:
473 {http, timeout()}:
475 Enables fetching of CRLs specified as http URIs inX509
476 certificate extensions. Requires the OTP inets applica‐
477 tion.
478 ssl_crl_hash_dir:
480 This module makes use of a directory where CRLs are stored
481 in files named by the hash of the issuer name.
482 The file names consist of eight hexadecimal digits followed
484 by .rN, where N is an integer, e.g. 1a2b3c4d.r0. For the
485 first version of the CRL, N starts at zero, and for each new
486 version, N is incremented by one. The OpenSSL utility
487 c_rehash creates symlinks according to this pattern.
488 For a given hash value, this module finds all consecutive
490 .r* files starting from zero, and those files taken together
491 make up the revocation list. CRL files whose nextUpdate
492 fields are in the past, or that are issued by a different CA
493 that happens to have the same name hash, are excluded.
494 The following argument is required:
496 {dir, string()}:
498 Specifies the directory in which the CRLs can be found.
499 root_fun() = function()
501 fun(Chain::[public_key:der_encoded()]) ->
503 {trusted_ca, DerCert::public_key:der_encoded()} | unknown_ca}
504 Claim an intermediate CA in the chain as trusted. TLS then per‐
507 forms public_key:pkix_path_validation/3 with the selected CA as
508 trusted anchor and the rest of the chain.
509 protocol_versions() = [protocol_version()]
511 TLS protocol versions supported by started clients and servers.
513 This option overrides the application environment option proto‐
514 col_version and dtls_protocol_version. If the environment option
515 is not set, it defaults to all versions, except SSL-3.0, sup‐
516 ported by the SSL application. See also ssl(6).
517 custom_user_lookup() =
519 {Lookupfun :: function(), UserState :: term()}
520 The lookup fun is to defined as follows:
522 fun(psk, PSKIdentity ::string(), UserState :: term()) ->
524 {ok, SharedSecret :: binary()} | error;
525 fun(srp, Username :: string(), UserState :: term()) ->
526 {ok, {SRPParams :: srp_param_type(), Salt :: binary(),
527 DerivedKey :: binary()}} | error.
528 For Pre-Shared Key (PSK) cipher suites, the lookup fun is called
531 by the client and server to determine the shared secret. When
532 called by the client, PSKIdentity is set to the hint presented
533 by the server or to undefined. When called by the server, PSKI‐
534 dentity is the identity presented by the client.
535 For Secure Remote Password (SRP), the fun is only used by the
537 server to obtain parameters that it uses to generate its session
538 keys. DerivedKey is to be derived according to RFC 2945 and
539 RFC 5054: crypto:sha([Salt, crypto:sha([Username, <<$:>>, Pass‐
540 word])])
541 session_id() = binary()
543 Identifies a TLS session.
545 log_alert() = boolean()
547 If set to false, error reports are not displayed.
549 hibernate_after() = timeout()
551 When an integer-value is specified, TLS/DTLS-connection goes
553 into hibernation after the specified number of milliseconds of
554 inactivity, thus reducing its memory footprint. When undefined
555 is specified (this is the default), the process never goes into
556 hibernation.
557 handshake_size() = integer()
559 Integer (24 bits unsigned). Used to limit the size of valid TLS
561 handshake packets to avoid DoS attacks. Defaults to 256*1024.
562 padding_check() = boolean()
564 Affects TLS-1.0 connections only. If set to false, it disables
566 the block cipher padding check to be able to interoperate with
567 legacy software.
568 Warning:
570 Using {padding_check, boolean()} makes TLS vulnerable to the
571 Poodle attack.
572 beast_mitigation() = one_n_minus_one | zero_n | disabled
575 Affects SSL-3.0 and TLS-1.0 connections only. Used to change the
577 BEAST mitigation strategy to interoperate with legacy software.
578 Defaults to one_n_minus_one.
579 one_n_minus_one - Perform 1/n-1 BEAST mitigation.
581 zero_n - Perform 0/n BEAST mitigation.
583 disabled - Disable BEAST mitigation.
585 Warning:
587 Using {beast_mitigation, disabled} makes SSL-3.0 or TLS-1.0 vul‐
588 nerable to the BEAST attack.
589 ssl_imp() = new | old
592 Deprecated since OTP-17, has no affect.
594 TLS/DTLS OPTION DESCRIPTIONS - CLIENT
596 client_option() =
597 {verify, client_verify_type()} |
598 {reuse_session, client_reuse_session()} |
599 {reuse_sessions, client_reuse_sessions()} |
600 {cacerts, client_cacerts()} |
601 {cacertfile, client_cafile()} |
602 {alpn_advertised_protocols, client_alpn()} |
603 {client_preferred_next_protocols,
604 client_preferred_next_protocols()} |
605 {psk_identity, client_psk_identity()} |
606 {srp_identity, client_srp_identity()} |
607 {server_name_indication, sni()} |
608 {customize_hostname_check, customize_hostname_check()} |
609 {signature_algs, client_signature_algs()} |
610 {fallback, fallback()}
611 client_verify_type() = verify_type()
613 In mode verify_none the default behavior is to allow all
615 x509-path validation errors. See also option verify_fun.
616 client_reuse_session() = session_id()
618 Reuses a specific session earlier saved with the option {re‐
620 use_sessions, save} since OTP-21.3
621 client_reuse_sessions() = boolean() | save
623 When save is specified a new connection will be negotiated and
625 saved for later reuse. The session ID can be fetched with con‐
626 nection_information/2 and used with the client option reuse_ses‐
627 sion The boolean value true specifies that if possible, automa‐
628 tized session reuse will be performed. If a new session is cre‐
629 ated, and is unique in regard to previous stored sessions, it
630 will be saved for possible later reuse. Since OTP-21.3
631 client_cacerts() = [public_key:der_encoded()]
633 The DER-encoded trusted certificates. If this option is supplied
635 it overrides option cacertfile.
636 client_cafile() = file:filename()
638 Path to a file containing PEM-encoded CA certificates. The CA
640 certificates are used during server authentication and when
641 building the client certificate chain.
642 client_alpn() = [app_level_protocol()]
644 The list of protocols supported by the client to be sent to the
646 server to be used for an Application-Layer Protocol Negotiation
647 (ALPN). If the server supports ALPN then it will choose a proto‐
648 col from this list; otherwise it will fail the connection with a
649 "no_application_protocol" alert. A server that does not support
650 ALPN will ignore this value.
651 The list of protocols must not contain an empty binary.
653 The negotiated protocol can be retrieved using the negoti‐
655 ated_protocol/1 function.
656 client_preferred_next_protocols() =
658 {Precedence :: server | client,
659 ClientPrefs :: [app_level_protocol()]} |
660 {Precedence :: server | client,
661 ClientPrefs :: [app_level_protocol()],
662 Default :: app_level_protocol()}
663 Indicates that the client is to try to perform Next Protocol
665 Negotiation.
666 If precedence is server, the negotiated protocol is the first
668 protocol to be shown on the server advertised list, which is
669 also on the client preference list.
670 If precedence is client, the negotiated protocol is the first
672 protocol to be shown on the client preference list, which is
673 also on the server advertised list.
674 If the client does not support any of the server advertised pro‐
676 tocols or the server does not advertise any protocols, the
677 client falls back to the first protocol in its list or to the
678 default protocol (if a default is supplied). If the server does
679 not support Next Protocol Negotiation, the connection terminates
680 if no default protocol is supplied.
681 client_psk_identity() = psk_identity()
683 Specifies the identity the client presents to the server. The
685 matching secret is found by calling user_lookup_fun
686 client_srp_identity() = srp_identity()
688 Specifies the username and password to use to authenticate to
690 the server.
691 sni() = hostname() | disable
693 Specify the hostname to be used in TLS Server Name Indication
695 extension. If not specified it will default to the Host argument
696 of connect/[3,4] unless it is of type inet:ipaddress().
697 The HostName will also be used in the hostname verification of
699 the peer certificate using public_key:pkix_verify_hostname/2.
700 The special value disable prevents the Server Name Indication
702 extension from being sent and disables the hostname verification
703 check public_key:pkix_verify_hostname/2
704 customize_hostname_check() = list()
706 Customizes the hostname verification of the peer certificate, as
708 different protocols that use TLS such as HTTP or LDAP may want
709 to do it differently, for possible options see pub‐
710 lic_key:pkix_verify_hostname/3
711 fallback() = boolean()
713 Send special cipher suite TLS_FALLBACK_SCSV to avoid undesired
715 TLS version downgrade. Defaults to false
716 Warning:
718 Note this option is not needed in normal TLS usage and should
719 not be used to implement new clients. But legacy clients that
720 retries connections in the following manner
721 ssl:connect(Host, Port, [...{versions, ['tlsv2', 'tlsv1.1',
723 'tlsv1', 'sslv3']}])
724 ssl:connect(Host, Port, [...{versions, [tlsv1.1', 'tlsv1',
726 'sslv3']}, {fallback, true}])
727 ssl:connect(Host, Port, [...{versions, ['tlsv1', 'sslv3']},
729 {fallback, true}])
730 ssl:connect(Host, Port, [...{versions, ['sslv3']}, {fallback,
732 true}])
733 may use it to avoid undesired TLS version downgrade. Note that
735 TLS_FALLBACK_SCSV must also be supported by the server for the
736 prevention to work.
737 client_signature_algs() = signature_algs()
740 In addition to the algorithms negotiated by the cipher suite
742 used for key exchange, payload encryption, message authentica‐
743 tion and pseudo random calculation, the TLS signature algorithm
744 extension Section 7.4.1.4.1 in RFC 5246 may be used, from TLS
745 1.2, to negotiate which signature algorithm to use during the
746 TLS handshake. If no lower TLS versions than 1.2 are supported,
747 the client will send a TLS signature algorithm extension with
748 the algorithms specified by this option. Defaults to
749 [
751 %% SHA2
752 {sha512, ecdsa},
753 {sha512, rsa},
754 {sha384, ecdsa},
755 {sha384, rsa},
756 {sha256, ecdsa},
757 {sha256, rsa},
758 {sha224, ecdsa},
759 {sha224, rsa},
760 %% SHA
761 {sha, ecdsa},
762 {sha, rsa},
763 {sha, dsa},
764 ]
765 The algorithms should be in the preferred order. Selected signa‐
767 ture algorithm can restrict which hash functions that may be
768 selected. Default support for {md5, rsa} removed in ssl-8.0
769 TLS/DTLS OPTION DESCRIPTIONS - SERVER
771 server_option() =
772 {cacerts, server_cacerts()} |
773 {cacertfile, server_cafile()} |
774 {dh, dh_der()} |
775 {dhfile, dh_file()} |
776 {verify, server_verify_type()} |
777 {fail_if_no_peer_cert, fail_if_no_peer_cert()} |
778 {reuse_sessions, server_reuse_sessions()} |
779 {reuse_session, server_reuse_session()} |
780 {alpn_preferred_protocols, server_alpn()} |
781 {next_protocols_advertised, server_next_protocol()} |
782 {psk_identity, server_psk_identity()} |
783 {honor_cipher_order, boolean()} |
784 {sni_hosts, sni_hosts()} |
785 {sni_fun, sni_fun()} |
786 {honor_cipher_order, honor_cipher_order()} |
787 {honor_ecc_order, honor_ecc_order()} |
788 {client_renegotiation, client_renegotiation()} |
789 {signature_algs, server_signature_algs()}
790 server_cacerts() = [public_key:der_encoded()]
792 The DER-encoded trusted certificates. If this option is supplied
794 it overrides option cacertfile.
795 server_cafile() = file:filename()
797 Path to a file containing PEM-encoded CA certificates. The CA
799 certificates are used to build the server certificate chain and
800 for client authentication. The CAs are also used in the list of
801 acceptable client CAs passed to the client when a certificate is
802 requested. Can be omitted if there is no need to verify the
803 client and if there are no intermediate CAs for the server cer‐
804 tificate.
805 dh_der() = binary()
807 The DER-encoded Diffie-Hellman parameters. If specified, it
809 overrides option dhfile.
810 dh_file() = file:filename()
812 Path to a file containing PEM-encoded Diffie Hellman parameters
814 to be used by the server if a cipher suite using Diffie Hellman
815 key exchange is negotiated. If not specified, default parameters
816 are used.
817 server_verify_type() = verify_type()
819 A server only does x509-path validation in mode verify_peer, as
821 it then sends a certificate request to the client (this message
822 is not sent if the verify option is verify_none). You can then
823 also want to specify option fail_if_no_peer_cert.
824 fail_if_no_peer_cert() = boolean()
826 Used together with {verify, verify_peer} by an TLS/DTLS server.
828 If set to true, the server fails if the client does not have a
829 certificate to send, that is, sends an empty certificate. If set
830 to false, it fails only if the client sends an invalid certifi‐
831 cate (an empty certificate is considered valid). Defaults to
832 false.
833 server_reuse_sessions() = boolean()
835 The boolean value true specifies that the server will agree to
837 reuse sessions. Setting it to false will result in an empty ses‐
838 sion table, that is no sessions will be reused. See also option
839 reuse_session
840 server_reuse_session() = function()
842 Enables the TLS/DTLS server to have a local policy for deciding
844 if a session is to be reused or not. Meaningful only if re‐
845 use_sessions is set to true. SuggestedSessionId is a binary(),
846 PeerCert is a DER-encoded certificate, Compression is an enumer‐
847 ation integer, and CipherSuite is of type ciphersuite().
848 server_alpn() = [app_level_protocol()]
850 Indicates the server will try to perform Application-Layer Pro‐
852 tocol Negotiation (ALPN).
853 The list of protocols is in order of preference. The protocol
855 negotiated will be the first in the list that matches one of the
856 protocols advertised by the client. If no protocol matches, the
857 server will fail the connection with a "no_application_protocol"
858 alert.
859 The negotiated protocol can be retrieved using the negoti‐
861 ated_protocol/1 function.
862 server_next_protocol() = [app_level_protocol()]
864 List of protocols to send to the client if the client indicates
866 that it supports the Next Protocol extension. The client can
867 select a protocol that is not on this list. The list of proto‐
868 cols must not contain an empty binary. If the server negotiates
869 a Next Protocol, it can be accessed using the negoti‐
870 ated_next_protocol/1 method.
871 server_psk_identity() = psk_identity()
873 Specifies the server identity hint, which the server presents to
875 the client.
876 honor_cipher_order() = boolean()
878 If set to true, use the server preference for cipher selection.
880 If set to false (the default), use the client preference.
881 sni_hosts() =
883 [{hostname(), [server_option() | common_option()]}]
884 If the server receives a SNI (Server Name Indication) from the
886 client matching a host listed in the sni_hosts option, the spe‐
887 cific options for that host will override previously specified
888 options. The option sni_fun, and sni_hosts are mutually exclu‐
889 sive.
890 sni_fun() = function()
892 If the server receives a SNI (Server Name Indication) from the
894 client, the given function will be called to retrieve
895 [server_option()] for the indicated server. These options will
896 be merged into predefined [server_option()] list. The function
897 should be defined as: fun(ServerName :: string()) ->
898 [server_option()] and can be specified as a fun or as named fun
899 module:function/1 The option sni_fun, and sni_hosts are mutually
900 exclusive.
901 client_renegotiation() = boolean()
903 In protocols that support client-initiated renegotiation, the
905 cost of resources of such an operation is higher for the server
906 than the client. This can act as a vector for denial of service
907 attacks. The SSL application already takes measures to counter-
908 act such attempts, but client-initiated renegotiation can be
909 strictly disabled by setting this option to false. The default
910 value is true. Note that disabling renegotiation can result in
911 long-lived connections becoming unusable due to limits on the
912 number of messages the underlying cipher suite can encipher.
913 honor_cipher_order() = boolean()
915 If true, use the server's preference for cipher selection. If
917 false (the default), use the client's preference.
918 honor_ecc_order() = boolean()
920 If true, use the server's preference for ECC curve selection. If
922 false (the default), use the client's preference.
923 server_signature_algs() = signature_algs()
925 The algorithms specified by this option will be the ones
927 accepted by the server in a signature algorithm negotiation,
928 introduced in TLS-1.2. The algorithms will also be offered to
929 the client if a client certificate is requested. For more
930 details see the corresponding client option.
931
933 append_cipher_suites(Deferred, Suites) -> ciphers()
934 Types:
936 Deferred = ciphers() | cipher_filters()
938 Suites = ciphers()
939 Make Deferred suites become the least preferred suites, that is
941 put them at the end of the cipher suite list Suites after remov‐
942 ing them from Suites if present. Deferred may be a list of
943 cipher suits or a list of filters in which case the filters are
944 use on Suites to extract the Deferred cipher list.
945 cipher_suites() -> [old_cipher_suite()] | [string()]
947 cipher_suites(Type) -> [old_cipher_suite() | string()]
949 Types:
951 Type = erlang | openssl | all
953 Deprecated in OTP 21, use cipher_suites/2 instead.
955 cipher_suites(Supported, Version) -> ciphers()
957 Types:
959 Supported = default | all | anonymous
961 Version = protocol_version()
962 Returns all default or all supported (except anonymous), or all
964 anonymous cipher suites for a TLS version
965 eccs() -> NamedCurves
967 eccs(Version) -> NamedCurves
969 Types:
971 Version = protocol_version()
973 NamedCurves = [named_curve()]
974 Returns a list of supported ECCs. eccs() is equivalent to call‐
976 ing eccs(Protocol) with all supported protocols and then dedu‐
977 plicating the output.
978 clear_pem_cache() -> ok
980 PEM files, used by ssl API-functions, are cached. The cache is
982 regularly checked to see if any cache entries should be invali‐
983 dated, however this function provides a way to unconditionally
984 clear the whole cache.
985 connect(TCPSocket, TLSOptions) ->
987 {ok, sslsocket()} |
988 {error, reason()} |
989 {option_not_a_key_value_tuple, any()}
990 connect(TCPSocket, TLSOptions, Timeout) ->
992 {ok, sslsocket()} | {error, reason()}
993 Types:
995 TCPSocket = socket()
997 TLSOptions = [tls_client_option()]
998 Timeout = timeout()
999 Upgrades a gen_tcp, or equivalent, connected socket to an TLS
1001 socket, that is, performs the client-side TLS handshake.
1002 Note:
1004 If the option verify is set to verify_peer the option
1005 server_name_indication shall also be specified, if it is not no
1006 Server Name Indication extension will be sent, and pub‐
1007 lic_key:pkix_verify_hostname/2 will be called with the IP-
1008 address of the connection as ReferenceID, which is proably not
1009 what you want.
1010 If the option {handshake, hello} is used the handshake is paused
1013 after receiving the server hello message and the success
1014 response is {ok, SslSocket, Ext} instead of {ok, SslSocket}.
1015 Thereafter the handshake is continued or canceled by calling
1016 handshake_continue/3 or handshake_cancel/1.
1017 If the option active is set to once, true or an integer value,
1019 the process owning the sslsocket will receive messages of type
1020 active_msgs()
1021 connect(Host, Port, TLSOptions) ->
1023 {ok, sslsocket()} |
1024 {ok, sslsocket(), Ext :: protocol_extensions()} |
1025 {error, reason()} |
1026 {option_not_a_key_value_tuple, any()}
1027 connect(Host, Port, TLSOptions, Timeout) ->
1029 {ok, sslsocket()} |
1030 {ok, sslsocket(), Ext :: protocol_extensions()} |
1031 {error, reason()} |
1032 {option_not_a_key_value_tuple, any()}
1033 Types:
1035 Host = host()
1037 Port = inet:port_number()
1038 TLSOptions = [tls_client_option()]
1039 Timeout = timeout()
1040 Opens an TLS/DTLS connection to Host, Port.
1042 When the option verify is set to verify_peer the check pub‐
1044 lic_key:pkix_verify_hostname/2 will be performed in addition to
1045 the usual x509-path validation checks. If the check fails the
1046 error {bad_cert, hostname_check_failed} will be propagated to
1047 the path validation fun verify_fun, where it is possible to do
1048 customized checks by using the full possibilities of the pub‐
1049 lic_key:pkix_verify_hostname/3 API. When the option
1050 server_name_indication is provided, its value (the DNS name)
1051 will be used as ReferenceID to public_key:pkix_verify_host‐
1052 name/2. When no server_name_indication option is given, the Host
1053 argument will be used as Server Name Indication extension. The
1054 Host argument will also be used for the public_key:pkix_ver‐
1055 ify_hostname/2 check and if the Host argument is an
1056 inet:ip_address() the ReferenceID used for the check will be
1057 {ip, Host} otherwise dns_id will be assumed with a fallback to
1058 ip if that fails.
1059 Note:
1061 According to good practices certificates should not use IP-
1062 addresses as "server names". It would be very surprising if this
1063 happen outside a closed network.
1064 If the option {handshake, hello} is used the handshake is paused
1067 after receiving the server hello message and the success
1068 response is {ok, SslSocket, Ext} instead of {ok, SslSocket}.
1069 Thereafter the handshake is continued or canceled by calling
1070 handshake_continue/3 or handshake_cancel/1.
1071 If the option active is set to once, true or an integer value,
1073 the process owning the sslsocket will receive messages of type
1074 active_msgs()
1075 close(SslSocket) -> ok | {error, Reason}
1077 Types:
1079 SslSocket = sslsocket()
1081 Reason = any()
1082 Closes an TLS/DTLS connection.
1084 close(SslSocket, How) -> ok | {ok, port()} | {error, Reason}
1086 Types:
1088 SslSocket = sslsocket()
1090 How = timeout() | {NewController :: pid(), timeout()}
1091 Reason = any()
1092 Closes or downgrades an TLS connection. In the latter case the
1094 transport connection will be handed over to the NewController
1095 process after receiving the TLS close alert from the peer. The
1096 returned transport socket will have the following options set:
1097 [{active, false}, {packet, 0}, {mode, binary}]
1098 controlling_process(SslSocket, NewOwner) -> ok | {error, Reason}
1100 Types:
1102 SslSocket = sslsocket()
1104 NewOwner = pid()
1105 Reason = any()
1106 Assigns a new controlling process to the SSL socket. A control‐
1108 ling process is the owner of an SSL socket, and receives all
1109 messages from the socket.
1110 connection_information(SslSocket) ->
1112 {ok, Result} | {error, reason()}
1113 Types:
1115 SslSocket = sslsocket()
1117 Result = [{OptionName, OptionValue}]
1118 OptionName = atom()
1119 OptionValue = any()
1120 Returns the most relevant information about the connection, ssl
1122 options that are undefined will be filtered out. Note that val‐
1123 ues that affect the security of the connection will only be
1124 returned if explicitly requested by connection_information/2.
1125 Note:
1127 The legacy Item = cipher_suite is still supported and returns
1128 the cipher suite on its (undocumented) legacy format. It should
1129 be replaced by selected_cipher_suite.
1130 connection_information(SslSocket, Items) ->
1133 {ok, Result} | {error, reason()}
1134 Types:
1136 SslSocket = sslsocket()
1138 Items = [OptionName]
1139 Result = [{OptionName, OptionValue}]
1140 OptionName = atom()
1141 OptionValue = any()
1142 Returns the requested information items about the connection, if
1144 they are defined.
1145 Note that client_random, server_random and master_secret are
1147 values that affect the security of connection. Meaningful atoms,
1148 not specified above, are the ssl option names.
1149 Note:
1151 If only undefined options are requested the resulting list can
1152 be empty.
1153 filter_cipher_suites(Suites, Filters) -> Ciphers
1156 Types:
1158 Suites = ciphers()
1160 Filters = cipher_filters()
1161 Ciphers = ciphers()
1162 Removes cipher suites if any of the filter functions returns
1164 false for any part of the cipher suite. This function also calls
1165 default filter functions to make sure the cipher suites are sup‐
1166 ported by crypto. If no filter function is supplied for some
1167 part the default behaviour is fun(Algorithm) -> true.
1168 format_error(Reason :: {error, Reason}) -> string()
1170 Types:
1172 Reason = any()
1174 Presents the error returned by an SSL function as a printable
1176 string.
1177 getopts(SslSocket, OptionNames) ->
1179 {ok, [gen_tcp:option()]} | {error, reason()}
1180 Types:
1182 SslSocket = sslsocket()
1184 OptionNames = [gen_tcp:option_name()]
1185 Gets the values of the specified socket options.
1187 getstat(SslSocket) -> {ok, OptionValues} | {error, inet:posix()}
1189 getstat(SslSocket, Options) ->
1191 {ok, OptionValues} | {error, inet:posix()}
1192 Types:
1194 SslSocket = sslsocket()
1196 Options = [inet:stat_option()]
1197 OptionValues = [{inet:stat_option(), integer()}]
1198 Gets one or more statistic options for the underlying TCP
1200 socket.
1201 See inet:getstat/2 for statistic options description.
1203 handshake(HsSocket) ->
1205 {ok, SslSocket} |
1206 {ok, SslSocket, Ext} |
1207 {error, Reason}
1208 handshake(HsSocket, Timeout) ->
1210 {ok, SslSocket} |
1211 {ok, SslSocket, Ext} |
1212 {error, Reason}
1213 Types:
1215 HsSocket = sslsocket()
1217 Timeout = timeout()
1218 SslSocket = sslsocket()
1219 Ext = protocol_extensions()
1220 Reason = closed | timeout | error_alert()
1221 Performs the SSL/TLS/DTLS server-side handshake.
1223 Returns a new TLS/DTLS socket if the handshake is successful.
1225 If the option active is set to once, true or an integer value,
1227 the process owning the sslsocket will receive messages of type
1228 active_msgs()
1229 handshake(Socket, Options) ->
1231 {ok, SslSocket} |
1232 {ok, SslSocket, Ext} |
1233 {error, Reason}
1234 handshake(Socket, Options, Timeout) ->
1236 {ok, SslSocket} |
1237 {ok, SslSocket, Ext} |
1238 {error, Reason}
1239 Types:
1241 Socket = socket() | sslsocket()
1243 SslSocket = sslsocket()
1244 Options = [server_option()]
1245 Timeout = timeout()
1246 Ext = protocol_extensions()
1247 Reason = closed | timeout | {options, any()} | error_alert()
1248 If Socket is a ordinary socket(): upgrades a gen_tcp, or equiva‐
1250 lent, socket to an SSL socket, that is, performs the SSL/TLS
1251 server-side handshake and returns a TLS socket.
1252 Warning:
1254 The Socket shall be in passive mode ({active, false}) before
1255 calling this function or else the behavior of this function is
1256 undefined.
1257 If Socket is an sslsocket() : provides extra SSL/TLS/DTLS
1260 options to those specified in listen/2 and then performs the
1261 SSL/TLS/DTLS handshake. Returns a new TLS/DTLS socket if the
1262 handshake is successful.
1263 If option {handshake, hello} is specified the handshake is
1265 paused after receiving the client hello message and the success
1266 response is {ok, SslSocket, Ext} instead of {ok, SslSocket}.
1267 Thereafter the handshake is continued or canceled by calling
1268 handshake_continue/3 or handshake_cancel/1.
1269 If the option active is set to once, true or an integer value,
1271 the process owning the sslsocket will receive messages of type
1272 active_msgs()
1273 handshake_cancel(Sslsocket :: #sslsocket{}) -> any()
1275 Cancel the handshake with a fatal USER_CANCELED alert.
1277 handshake_continue(HsSocket, Options) ->
1279 {ok, SslSocket} | {error, Reason}
1280 handshake_continue(HsSocket, Options, Timeout) ->
1282 {ok, SslSocket} | {error, Reason}
1283 Types:
1285 HsSocket = sslsocket()
1287 Options = [tls_client_option() | tls_server_option()]
1288 Timeout = timeout()
1289 SslSocket = sslsocket()
1290 Reason = closed | timeout | error_alert()
1291 Continue the SSL/TLS handshake possiby with new, additional or
1293 changed options.
1294 listen(Port, Options) -> {ok, ListenSocket} | {error, reason()}
1296 Types:
1298 Port = inet:port_number()
1300 Options = [tls_server_option()]
1301 ListenSocket = sslsocket()
1302 Creates an SSL listen socket.
1304 negotiated_protocol(SslSocket) -> {ok, Protocol} | {error, Reason}
1306 Types:
1308 SslSocket = sslsocket()
1310 Protocol = binary()
1311 Reason = protocol_not_negotiated
1312 Returns the protocol negotiated through ALPN or NPN extensions.
1314 peercert(SslSocket) -> {ok, Cert} | {error, reason()}
1316 Types:
1318 SslSocket = sslsocket()
1320 Cert = binary()
1321 The peer certificate is returned as a DER-encoded binary. The
1323 certificate can be decoded with public_key:pkix_decode_cert/2
1324 peername(SslSocket) -> {ok, {Address, Port}} | {error, reason()}
1326 Types:
1328 SslSocket = sslsocket()
1330 Address = inet:ip_address()
1331 Port = inet:port_number()
1332 Returns the address and port number of the peer.
1334 prepend_cipher_suites(Preferred, Suites) -> ciphers()
1336 Types:
1338 Preferred = ciphers() | cipher_filters()
1340 Suites = ciphers()
1341 Make Preferred suites become the most preferred suites that is
1343 put them at the head of the cipher suite list Suites after
1344 removing them from Suites if present. Preferred may be a list of
1345 cipher suits or a list of filters in which case the filters are
1346 use on Suites to extract the preferred cipher list.
1347 prf(SslSocket, Secret, Label, Seed, WantedLength) ->
1349 {ok, binary()} | {error, reason()}
1350 Types:
1352 SslSocket = sslsocket()
1354 Secret = binary() | master_secret
1355 Label = binary()
1356 Seed = [binary() | prf_random()]
1357 WantedLength = integer() >= 0
1358 Uses the Pseudo-Random Function (PRF) of a TLS session to gener‐
1360 ate extra key material. It either takes user-generated values
1361 for Secret and Seed or atoms directing it to use a specific
1362 value from the session security parameters.
1363 Can only be used with TLS/DTLS connections; {error, undefined}
1365 is returned for SSLv3 connections.
1366 recv(SslSocket, Length) -> {ok, Data} | {error, reason()}
1368 recv(SslSocket, Length, Timeout) -> {ok, Data} | {error, reason()}
1370 Types:
1372 SslSocket = sslsocket()
1374 Length = integer()
1375 Data = binary() | list() | HttpPacket
1376 Timeout = timeout()
1377 HttpPacket = any()
1378 See the description of HttpPacket in erlang:decode_packet/3
1379 in ERTS.
1380 Receives a packet from a socket in passive mode. A closed socket
1382 is indicated by return value {error, closed}.
1383 Argument Length is meaningful only when the socket is in mode
1385 raw and denotes the number of bytes to read. If Length = 0, all
1386 available bytes are returned. If Length > 0, exactly Length
1387 bytes are returned, or an error; possibly discarding less than
1388 Length bytes of data when the socket gets closed from the other
1389 side.
1390 Optional argument Timeout specifies a time-out in milliseconds.
1392 The default value is infinity.
1393 renegotiate(SslSocket) -> ok | {error, reason()}
1395 Types:
1397 SslSocket = sslsocket()
1399 Initiates a new handshake. A notable return value is {error,
1401 renegotiation_rejected} indicating that the peer refused to go
1402 through with the renegotiation, but the connection is still
1403 active using the previously negotiated session.
1404 send(SslSocket, Data) -> ok | {error, reason()}
1406 Types:
1408 SslSocket = sslsocket()
1410 Data = iodata()
1411 Writes Data to SslSocket.
1413 A notable return value is {error, closed} indicating that the
1415 socket is closed.
1416 setopts(SslSocket, Options) -> ok | {error, reason()}
1418 Types:
1420 SslSocket = sslsocket()
1422 Options = [gen_tcp:option()]
1423 Sets options according to Options for socket SslSocket.
1425 shutdown(SslSocket, How) -> ok | {error, reason()}
1427 Types:
1429 SslSocket = sslsocket()
1431 How = read | write | read_write
1432 Immediately closes a socket in one or two directions.
1434 How == write means closing the socket for writing, reading from
1436 it is still possible.
1437 To be able to handle that the peer has done a shutdown on the
1439 write side, option {exit_on_close, false} is useful.
1440 ssl_accept(SslSocket) -> ok | {error, Reason}
1442 ssl_accept(Socket, TimeoutOrOptions) ->
1444 ok | {ok, sslsocket()} | {error, Reason}
1445 Types:
1447 Socket = sslsocket() | socket()
1449 TimeoutOrOptions = timeout() | [tls_server_option()]
1450 Reason = timeout | closed | {options, any()} | error_alert()
1451 Deprecated in OTP 21, use handshake/[1,2] instead.
1453 Note:
1455 handshake/[1,2] always returns a new socket.
1456 ssl_accept(Socket, Options, Timeout) ->
1459 ok | {ok, sslsocket()} | {error, Reason}
1460 Types:
1462 Socket = sslsocket() | socket()
1464 Options = [tls_server_option()]
1465 Timeout = timeout()
1466 Reason = timeout | closed | {options, any()} | error_alert()
1467 Deprecated in OTP 21, use handshake/[2,3] instead.
1469 Note:
1471 handshake/[2,3] always returns a new socket.
1472 sockname(SslSocket) -> {ok, {Address, Port}} | {error, reason()}
1475 Types:
1477 SslSocket = sslsocket()
1479 Address = inet:ip_address()
1480 Port = inet:port_number()
1481 Returns the local address and port number of socket SslSocket.
1483 start() -> ok | {error, reason()}
1485 start(Type) -> ok | {error, Reason}
1486 Starts the SSL application. Default type is temporary.
1488 stop() -> ok
1490 Stops the SSL application.
1492 suite_to_str(CipherSuite) -> string()
1494 Types:
1496 CipherSuite = erl_cipher_suite()
1498 Returns the string representation of a cipher suite.
1500 transport_accept(ListenSocket) ->
1502 {ok, SslSocket} | {error, reason()}
1503 transport_accept(ListenSocket, Timeout) ->
1505 {ok, SslSocket} | {error, reason()}
1506 Types:
1508 ListenSocket = sslsocket()
1510 Timeout = timeout()
1511 SslSocket = sslsocket()
1512 Accepts an incoming connection request on a listen socket. Lis‐
1514 tenSocket must be a socket returned from listen/2. The socket
1515 returned is to be passed to handshake/[2,3] to complete hand‐
1516 shaking, that is, establishing the SSL/TLS/DTLS connection.
1517 Warning:
1519 Most API functions require that the TLS/DTLS connection is
1520 established to work as expected.
1521 The accepted socket inherits the options set for ListenSocket in
1524 listen/2.
1525 The default value for Timeout is infinity. If Timeout is speci‐
1527 fied and no connection is accepted within the given time,
1528 {error, timeout} is returned.
1529 versions() -> [VersionInfo]
1531 Types:
1533 VersionInfo =
1535 {ssl_app, string()} |
1536 {supported | available, [tls_version()]} |
1537 {supported_dtls | available_dtls, [dtls_version()]}
1538 Returns version information relevant for the SSL application.
1540 app_vsn:
1542 The application version of the SSL application.
1543 supported:
1545 SSL/TLS versions supported by default. Overridden by a ver‐
1546 sion option on connect/[2,3,4], listen/2, and
1547 ssl_accept/[1,2,3]. For the negotiated SSL/TLS version, see
1548 connection_information/1 .
1549 supported_dtls:
1551 DTLS versions supported by default. Overridden by a version
1552 option on connect/[2,3,4], listen/2, and
1553 ssl_accept/[1,2,3]. For the negotiated DTLS version, see
1554 connection_information/1 .
1555 available:
1557 All SSL/TLS versions supported by the SSL application. TLS
1558 1.2 requires sufficient support from the Crypto application.
1559 available_dtls:
1561 All DTLS versions supported by the SSL application. DTLS 1.2
1562 requires sufficient support from the Crypto application.
1563
1565 inet(3) and gen_tcp(3) gen_udp(3)
1566Ericsson AB ssl 9.2.3.2 ssl(3)