package tls

Import Path
	crypto/tls (on golang.org and go.dev)

Dependency Relation
	imports 40 packages, and imported by 5 packages


Code Examples package main import ( "crypto/tls" "log" "net/http" "net/http/httptest" "os" ) // zeroSource is an io.Reader that returns an unlimited number of zero bytes. type zeroSource struct{} func (zeroSource) Read(b []byte) (n int, err error) { for i := range b { b[i] = 0 } return len(b), nil } func main() { // Debugging TLS applications by decrypting a network traffic capture. // WARNING: Use of KeyLogWriter compromises security and should only be // used for debugging. // Dummy test HTTP server for the example with insecure random so output is // reproducible. server := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {})) server.TLS = &tls.Config{ Rand: zeroSource{}, // for example only; don't do this. } server.StartTLS() defer server.Close() // Typically the log would go to an open file: // w, err := os.OpenFile("tls-secrets.txt", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600) w := os.Stdout client := &http.Client{ Transport: &http.Transport{ TLSClientConfig: &tls.Config{ KeyLogWriter: w, Rand: zeroSource{}, // for reproducible output; don't do this. InsecureSkipVerify: true, // test server certificate is not trusted. }, }, } resp, err := client.Get(server.URL) if err != nil { log.Fatalf("Failed to get URL: %v", err) } resp.Body.Close() // The resulting file can be used with Wireshark to decrypt the TLS // connection by setting (Pre)-Master-Secret log filename in SSL Protocol // preferences. } package main import ( "crypto/tls" "crypto/x509" ) func main() { // VerifyConnection can be used to replace and customize connection // verification. This example shows a VerifyConnection implementation that // will be approximately equivalent to what crypto/tls does normally to // verify the peer's certificate. // Client side configuration. _ = &tls.Config{ // Set InsecureSkipVerify to skip the default validation we are // replacing. This will not disable VerifyConnection. InsecureSkipVerify: true, VerifyConnection: func(cs tls.ConnectionState) error { opts := x509.VerifyOptions{ DNSName: cs.ServerName, Intermediates: x509.NewCertPool(), } for _, cert := range cs.PeerCertificates[1:] { opts.Intermediates.AddCert(cert) } _, err := cs.PeerCertificates[0].Verify(opts) return err }, } // Server side configuration. _ = &tls.Config{ // Require client certificates (or VerifyConnection will run anyway and // panic accessing cs.PeerCertificates[0]) but don't verify them with the // default verifier. This will not disable VerifyConnection. ClientAuth: tls.RequireAnyClientCert, VerifyConnection: func(cs tls.ConnectionState) error { opts := x509.VerifyOptions{ DNSName: cs.ServerName, Intermediates: x509.NewCertPool(), KeyUsages: []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth}, } for _, cert := range cs.PeerCertificates[1:] { opts.Intermediates.AddCert(cert) } _, err := cs.PeerCertificates[0].Verify(opts) return err }, } // Note that when certificates are not handled by the default verifier // ConnectionState.VerifiedChains will be nil. } package main import ( "crypto/tls" "crypto/x509" ) func main() { // Connecting with a custom root-certificate set. const rootPEM = ` -- GlobalSign Root R2, valid until Dec 15, 2021 -----BEGIN CERTIFICATE----- MIIDujCCAqKgAwIBAgILBAAAAAABD4Ym5g0wDQYJKoZIhvcNAQEFBQAwTDEgMB4G A1UECxMXR2xvYmFsU2lnbiBSb290IENBIC0gUjIxEzARBgNVBAoTCkdsb2JhbFNp Z24xEzARBgNVBAMTCkdsb2JhbFNpZ24wHhcNMDYxMjE1MDgwMDAwWhcNMjExMjE1 MDgwMDAwWjBMMSAwHgYDVQQLExdHbG9iYWxTaWduIFJvb3QgQ0EgLSBSMjETMBEG A1UEChMKR2xvYmFsU2lnbjETMBEGA1UEAxMKR2xvYmFsU2lnbjCCASIwDQYJKoZI hvcNAQEBBQADggEPADCCAQoCggEBAKbPJA6+Lm8omUVCxKs+IVSbC9N/hHD6ErPL v4dfxn+G07IwXNb9rfF73OX4YJYJkhD10FPe+3t+c4isUoh7SqbKSaZeqKeMWhG8 eoLrvozps6yWJQeXSpkqBy+0Hne/ig+1AnwblrjFuTosvNYSuetZfeLQBoZfXklq tTleiDTsvHgMCJiEbKjNS7SgfQx5TfC4LcshytVsW33hoCmEofnTlEnLJGKRILzd C9XZzPnqJworc5HGnRusyMvo4KD0L5CLTfuwNhv2GXqF4G3yYROIXJ/gkwpRl4pa zq+r1feqCapgvdzZX99yqWATXgAByUr6P6TqBwMhAo6CygPCm48CAwEAAaOBnDCB mTAOBgNVHQ8BAf8EBAMCAQYwDwYDVR0TAQH/BAUwAwEB/zAdBgNVHQ4EFgQUm+IH V2ccHsBqBt5ZtJot39wZhi4wNgYDVR0fBC8wLTAroCmgJ4YlaHR0cDovL2NybC5n bG9iYWxzaWduLm5ldC9yb290LXIyLmNybDAfBgNVHSMEGDAWgBSb4gdXZxwewGoG 3lm0mi3f3BmGLjANBgkqhkiG9w0BAQUFAAOCAQEAmYFThxxol4aR7OBKuEQLq4Gs J0/WwbgcQ3izDJr86iw8bmEbTUsp9Z8FHSbBuOmDAGJFtqkIk7mpM0sYmsL4h4hO 291xNBrBVNpGP+DTKqttVCL1OmLNIG+6KYnX3ZHu01yiPqFbQfXf5WRDLenVOavS ot+3i9DAgBkcRcAtjOj4LaR0VknFBbVPFd5uRHg5h6h+u/N5GJG79G+dwfCMNYxd AfvDbbnvRG15RjF+Cv6pgsH/76tuIMRQyV+dTZsXjAzlAcmgQWpzU/qlULRuJQ/7 TBj0/VLZjmmx6BEP3ojY+x1J96relc8geMJgEtslQIxq/H5COEBkEveegeGTLg== -----END CERTIFICATE-----` // First, create the set of root certificates. For this example we only // have one. It's also possible to omit this in order to use the // default root set of the current operating system. roots := x509.NewCertPool() ok := roots.AppendCertsFromPEM([]byte(rootPEM)) if !ok { panic("failed to parse root certificate") } conn, err := tls.Dial("tcp", "mail.google.com:443", &tls.Config{ RootCAs: roots, }) if err != nil { panic("failed to connect: " + err.Error()) } conn.Close() } package main import ( "crypto/tls" "log" ) func main() { cert, err := tls.LoadX509KeyPair("testdata/example-cert.pem", "testdata/example-key.pem") if err != nil { log.Fatal(err) } cfg := &tls.Config{Certificates: []tls.Certificate{cert}} listener, err := tls.Listen("tcp", ":2000", cfg) if err != nil { log.Fatal(err) } _ = listener } package main import ( "crypto/tls" "log" ) func main() { certPem := []byte(`-----BEGIN CERTIFICATE----- MIIBhTCCASugAwIBAgIQIRi6zePL6mKjOipn+dNuaTAKBggqhkjOPQQDAjASMRAw DgYDVQQKEwdBY21lIENvMB4XDTE3MTAyMDE5NDMwNloXDTE4MTAyMDE5NDMwNlow EjEQMA4GA1UEChMHQWNtZSBDbzBZMBMGByqGSM49AgEGCCqGSM49AwEHA0IABD0d 7VNhbWvZLWPuj/RtHFjvtJBEwOkhbN/BnnE8rnZR8+sbwnc/KhCk3FhnpHZnQz7B 5aETbbIgmuvewdjvSBSjYzBhMA4GA1UdDwEB/wQEAwICpDATBgNVHSUEDDAKBggr BgEFBQcDATAPBgNVHRMBAf8EBTADAQH/MCkGA1UdEQQiMCCCDmxvY2FsaG9zdDo1 NDUzgg4xMjcuMC4wLjE6NTQ1MzAKBggqhkjOPQQDAgNIADBFAiEA2zpJEPQyz6/l Wf86aX6PepsntZv2GYlA5UpabfT2EZICICpJ5h/iI+i341gBmLiAFQOyTDT+/wQc 6MF9+Yw1Yy0t -----END CERTIFICATE-----`) keyPem := []byte(`-----BEGIN EC PRIVATE KEY----- MHcCAQEEIIrYSSNQFaA2Hwf1duRSxKtLYX5CB04fSeQ6tF1aY/PuoAoGCCqGSM49 AwEHoUQDQgAEPR3tU2Fta9ktY+6P9G0cWO+0kETA6SFs38GecTyudlHz6xvCdz8q EKTcWGekdmdDPsHloRNtsiCa697B2O9IFA== -----END EC PRIVATE KEY-----`) cert, err := tls.X509KeyPair(certPem, keyPem) if err != nil { log.Fatal(err) } cfg := &tls.Config{Certificates: []tls.Certificate{cert}} listener, err := tls.Listen("tcp", ":2000", cfg) if err != nil { log.Fatal(err) } _ = listener } package main import ( "crypto/tls" "log" "net/http" "time" ) func main() { certPem := []byte(`-----BEGIN CERTIFICATE----- MIIBhTCCASugAwIBAgIQIRi6zePL6mKjOipn+dNuaTAKBggqhkjOPQQDAjASMRAw DgYDVQQKEwdBY21lIENvMB4XDTE3MTAyMDE5NDMwNloXDTE4MTAyMDE5NDMwNlow EjEQMA4GA1UEChMHQWNtZSBDbzBZMBMGByqGSM49AgEGCCqGSM49AwEHA0IABD0d 7VNhbWvZLWPuj/RtHFjvtJBEwOkhbN/BnnE8rnZR8+sbwnc/KhCk3FhnpHZnQz7B 5aETbbIgmuvewdjvSBSjYzBhMA4GA1UdDwEB/wQEAwICpDATBgNVHSUEDDAKBggr BgEFBQcDATAPBgNVHRMBAf8EBTADAQH/MCkGA1UdEQQiMCCCDmxvY2FsaG9zdDo1 NDUzgg4xMjcuMC4wLjE6NTQ1MzAKBggqhkjOPQQDAgNIADBFAiEA2zpJEPQyz6/l Wf86aX6PepsntZv2GYlA5UpabfT2EZICICpJ5h/iI+i341gBmLiAFQOyTDT+/wQc 6MF9+Yw1Yy0t -----END CERTIFICATE-----`) keyPem := []byte(`-----BEGIN EC PRIVATE KEY----- MHcCAQEEIIrYSSNQFaA2Hwf1duRSxKtLYX5CB04fSeQ6tF1aY/PuoAoGCCqGSM49 AwEHoUQDQgAEPR3tU2Fta9ktY+6P9G0cWO+0kETA6SFs38GecTyudlHz6xvCdz8q EKTcWGekdmdDPsHloRNtsiCa697B2O9IFA== -----END EC PRIVATE KEY-----`) cert, err := tls.X509KeyPair(certPem, keyPem) if err != nil { log.Fatal(err) } cfg := &tls.Config{Certificates: []tls.Certificate{cert}} srv := &http.Server{ TLSConfig: cfg, ReadTimeout: time.Minute, WriteTimeout: time.Minute, } log.Fatal(srv.ListenAndServeTLS("", "")) }
Package-Level Type Names (total 15)
/* sort by: | */
A Certificate is a chain of one or more certificates, leaf first. Certificate [][]byte Leaf is the parsed form of the leaf certificate, which may be initialized using x509.ParseCertificate to reduce per-handshake processing. If nil, the leaf certificate will be parsed as needed. OCSPStaple contains an optional OCSP response which will be served to clients that request it. PrivateKey contains the private key corresponding to the public key in Leaf. This must implement crypto.Signer with an RSA, ECDSA or Ed25519 PublicKey. For a server up to TLS 1.2, it can also implement crypto.Decrypter with an RSA PublicKey. SignedCertificateTimestamps contains an optional list of Signed Certificate Timestamps which will be served to clients that request it. SupportedSignatureAlgorithms is an optional list restricting what signature algorithms the PrivateKey can be used for. func LoadX509KeyPair(certFile, keyFile string) (Certificate, error) func X509KeyPair(certPEMBlock, keyPEMBlock []byte) (Certificate, error) func (*CertificateRequestInfo).SupportsCertificate(c *Certificate) error func (*ClientHelloInfo).SupportsCertificate(c *Certificate) error
CertificateRequestInfo contains information from a server's CertificateRequest message, which is used to demand a certificate and proof of control from a client. AcceptableCAs contains zero or more, DER-encoded, X.501 Distinguished Names. These are the names of root or intermediate CAs that the server wishes the returned certificate to be signed by. An empty slice indicates that the server has no preference. SignatureSchemes lists the signature schemes that the server is willing to verify. Version is the TLS version that was negotiated for this connection. SupportsCertificate returns nil if the provided certificate is supported by the server that sent the CertificateRequest. Otherwise, it returns an error describing the reason for the incompatibility.
CipherSuite is a TLS cipher suite. Note that most functions in this package accept and expose cipher suite IDs instead of this type. ID uint16 Insecure is true if the cipher suite has known security issues due to its primitives, design, or implementation. Name string Supported versions is the list of TLS protocol versions that can negotiate this cipher suite. func CipherSuites() []*CipherSuite func InsecureCipherSuites() []*CipherSuite
ClientAuthType declares the policy the server will follow for TLS Client Authentication. ( T) String() string T : expvar.Var T : fmt.Stringer const NoClientCert const RequestClientCert const RequireAndVerifyClientCert const RequireAnyClientCert const VerifyClientCertIfGiven
ClientHelloInfo contains information from a ClientHello message in order to guide application logic in the GetCertificate and GetConfigForClient callbacks. CipherSuites lists the CipherSuites supported by the client (e.g. TLS_AES_128_GCM_SHA256, TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256). Conn is the underlying net.Conn for the connection. Do not read from, or write to, this connection; that will cause the TLS connection to fail. ServerName indicates the name of the server requested by the client in order to support virtual hosting. ServerName is only set if the client is using SNI (see RFC 4366, Section 3.1). SignatureSchemes lists the signature and hash schemes that the client is willing to verify. SignatureSchemes is set only if the Signature Algorithms Extension is being used (see RFC 5246, Section 7.4.1.4.1). SupportedCurves lists the elliptic curves supported by the client. SupportedCurves is set only if the Supported Elliptic Curves Extension is being used (see RFC 4492, Section 5.1.1). SupportedPoints lists the point formats supported by the client. SupportedPoints is set only if the Supported Point Formats Extension is being used (see RFC 4492, Section 5.1.2). SupportedProtos lists the application protocols supported by the client. SupportedProtos is set only if the Application-Layer Protocol Negotiation Extension is being used (see RFC 7301, Section 3.1). Servers can select a protocol by setting Config.NextProtos in a GetConfigForClient return value. SupportedVersions lists the TLS versions supported by the client. For TLS versions less than 1.3, this is extrapolated from the max version advertised by the client, so values other than the greatest might be rejected if used. SupportsCertificate returns nil if the provided certificate is supported by the client that sent the ClientHello. Otherwise, it returns an error describing the reason for the incompatibility. If this ClientHelloInfo was passed to a GetConfigForClient or GetCertificate callback, this method will take into account the associated Config. Note that if GetConfigForClient returns a different Config, the change can't be accounted for by this method. This function will call x509.ParseCertificate unless c.Leaf is set, which can incur a significant performance cost.
ClientSessionCache is a cache of ClientSessionState objects that can be used by a client to resume a TLS session with a given server. ClientSessionCache implementations should expect to be called concurrently from different goroutines. Up to TLS 1.2, only ticket-based resumption is supported, not SessionID-based resumption. In TLS 1.3 they were merged into PSK modes, which are supported via this interface. Get searches for a ClientSessionState associated with the given key. On return, ok is true if one was found. Put adds the ClientSessionState to the cache with the given key. It might get called multiple times in a connection if a TLS 1.3 server provides more than one session ticket. If called with a nil *ClientSessionState, it should remove the cache entry. func NewLRUClientSessionCache(capacity int) ClientSessionCache
ClientSessionState contains the state needed by clients to resume TLS sessions. func ClientSessionCache.Get(sessionKey string) (session *ClientSessionState, ok bool) func ClientSessionCache.Put(sessionKey string, cs *ClientSessionState)
A Config structure is used to configure a TLS client or server. After one has been passed to a TLS function it must not be modified. A Config may be reused; the tls package will also not modify it. Certificates contains one or more certificate chains to present to the other side of the connection. The first certificate compatible with the peer's requirements is selected automatically. Server configurations must set one of Certificates, GetCertificate or GetConfigForClient. Clients doing client-authentication may set either Certificates or GetClientCertificate. Note: if there are multiple Certificates, and they don't have the optional field Leaf set, certificate selection will incur a significant per-handshake performance cost. CipherSuites is a list of supported cipher suites for TLS versions up to TLS 1.2. If CipherSuites is nil, a default list of secure cipher suites is used, with a preference order based on hardware performance. The default cipher suites might change over Go versions. Note that TLS 1.3 ciphersuites are not configurable. ClientAuth determines the server's policy for TLS Client Authentication. The default is NoClientCert. ClientCAs defines the set of root certificate authorities that servers use if required to verify a client certificate by the policy in ClientAuth. ClientSessionCache is a cache of ClientSessionState entries for TLS session resumption. It is only used by clients. CurvePreferences contains the elliptic curves that will be used in an ECDHE handshake, in preference order. If empty, the default will be used. The client will use the first preference as the type for its key share in TLS 1.3. This may change in the future. DynamicRecordSizingDisabled disables adaptive sizing of TLS records. When true, the largest possible TLS record size is always used. When false, the size of TLS records may be adjusted in an attempt to improve latency. GetCertificate returns a Certificate based on the given ClientHelloInfo. It will only be called if the client supplies SNI information or if Certificates is empty. If GetCertificate is nil or returns nil, then the certificate is retrieved from NameToCertificate. If NameToCertificate is nil, the best element of Certificates will be used. GetClientCertificate, if not nil, is called when a server requests a certificate from a client. If set, the contents of Certificates will be ignored. If GetClientCertificate returns an error, the handshake will be aborted and that error will be returned. Otherwise GetClientCertificate must return a non-nil Certificate. If Certificate.Certificate is empty then no certificate will be sent to the server. If this is unacceptable to the server then it may abort the handshake. GetClientCertificate may be called multiple times for the same connection if renegotiation occurs or if TLS 1.3 is in use. GetConfigForClient, if not nil, is called after a ClientHello is received from a client. It may return a non-nil Config in order to change the Config that will be used to handle this connection. If the returned Config is nil, the original Config will be used. The Config returned by this callback may not be subsequently modified. If GetConfigForClient is nil, the Config passed to Server() will be used for all connections. If SessionTicketKey was explicitly set on the returned Config, or if SetSessionTicketKeys was called on the returned Config, those keys will be used. Otherwise, the original Config keys will be used (and possibly rotated if they are automatically managed). InsecureSkipVerify controls whether a client verifies the server's certificate chain and host name. If InsecureSkipVerify is true, crypto/tls accepts any certificate presented by the server and any host name in that certificate. In this mode, TLS is susceptible to machine-in-the-middle attacks unless custom verification is used. This should be used only for testing or in combination with VerifyConnection or VerifyPeerCertificate. KeyLogWriter optionally specifies a destination for TLS master secrets in NSS key log format that can be used to allow external programs such as Wireshark to decrypt TLS connections. See https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/Key_Log_Format. Use of KeyLogWriter compromises security and should only be used for debugging. MaxVersion contains the maximum TLS version that is acceptable. If zero, the maximum version supported by this package is used, which is currently TLS 1.3. MinVersion contains the minimum TLS version that is acceptable. If zero, TLS 1.0 is currently taken as the minimum. NameToCertificate maps from a certificate name to an element of Certificates. Note that a certificate name can be of the form '*.example.com' and so doesn't have to be a domain name as such. Deprecated: NameToCertificate only allows associating a single certificate with a given name. Leave this field nil to let the library select the first compatible chain from Certificates. NextProtos is a list of supported application level protocols, in order of preference. PreferServerCipherSuites controls whether the server selects the client's most preferred ciphersuite, or the server's most preferred ciphersuite. If true then the server's preference, as expressed in the order of elements in CipherSuites, is used. Rand provides the source of entropy for nonces and RSA blinding. If Rand is nil, TLS uses the cryptographic random reader in package crypto/rand. The Reader must be safe for use by multiple goroutines. Renegotiation controls what types of renegotiation are supported. The default, none, is correct for the vast majority of applications. RootCAs defines the set of root certificate authorities that clients use when verifying server certificates. If RootCAs is nil, TLS uses the host's root CA set. ServerName is used to verify the hostname on the returned certificates unless InsecureSkipVerify is given. It is also included in the client's handshake to support virtual hosting unless it is an IP address. SessionTicketKey is used by TLS servers to provide session resumption. See RFC 5077 and the PSK mode of RFC 8446. If zero, it will be filled with random data before the first server handshake. Deprecated: if this field is left at zero, session ticket keys will be automatically rotated every day and dropped after seven days. For customizing the rotation schedule or synchronizing servers that are terminating connections for the same host, use SetSessionTicketKeys. SessionTicketsDisabled may be set to true to disable session ticket and PSK (resumption) support. Note that on clients, session ticket support is also disabled if ClientSessionCache is nil. Time returns the current time as the number of seconds since the epoch. If Time is nil, TLS uses time.Now. VerifyConnection, if not nil, is called after normal certificate verification and after VerifyPeerCertificate by either a TLS client or server. If it returns a non-nil error, the handshake is aborted and that error results. If normal verification fails then the handshake will abort before considering this callback. This callback will run for all connections regardless of InsecureSkipVerify or ClientAuth settings. VerifyPeerCertificate, if not nil, is called after normal certificate verification by either a TLS client or server. It receives the raw ASN.1 certificates provided by the peer and also any verified chains that normal processing found. If it returns a non-nil error, the handshake is aborted and that error results. If normal verification fails then the handshake will abort before considering this callback. If normal verification is disabled by setting InsecureSkipVerify, or (for a server) when ClientAuth is RequestClientCert or RequireAnyClientCert, then this callback will be considered but the verifiedChains argument will always be nil. BuildNameToCertificate parses c.Certificates and builds c.NameToCertificate from the CommonName and SubjectAlternateName fields of each of the leaf certificates. Deprecated: NameToCertificate only allows associating a single certificate with a given name. Leave that field nil to let the library select the first compatible chain from Certificates. Clone returns a shallow clone of c or nil if c is nil. It is safe to clone a Config that is being used concurrently by a TLS client or server. SetSessionTicketKeys updates the session ticket keys for a server. The first key will be used when creating new tickets, while all keys can be used for decrypting tickets. It is safe to call this function while the server is running in order to rotate the session ticket keys. The function will panic if keys is empty. Calling this function will turn off automatic session ticket key rotation. If multiple servers are terminating connections for the same host they should all have the same session ticket keys. If the session ticket keys leaks, previously recorded and future TLS connections using those keys might be compromised. func (*Config).Clone() *Config func Client(conn net.Conn, config *Config) *Conn func Dial(network, addr string, config *Config) (*Conn, error) func DialWithDialer(dialer *net.Dialer, network, addr string, config *Config) (*Conn, error) func Listen(network, laddr string, config *Config) (net.Listener, error) func NewListener(inner net.Listener, config *Config) net.Listener func Server(conn net.Conn, config *Config) *Conn func net/smtp.(*Client).StartTLS(config *Config) error
A Conn represents a secured connection. It implements the net.Conn interface. Close closes the connection. CloseWrite shuts down the writing side of the connection. It should only be called once the handshake has completed and does not call CloseWrite on the underlying connection. Most callers should just use Close. ConnectionState returns basic TLS details about the connection. Handshake runs the client or server handshake protocol if it has not yet been run. Most uses of this package need not call Handshake explicitly: the first Read or Write will call it automatically. For control over canceling or setting a timeout on a handshake, use the Dialer's DialContext method. LocalAddr returns the local network address. OCSPResponse returns the stapled OCSP response from the TLS server, if any. (Only valid for client connections.) Read reads data from the connection. As Read calls Handshake, in order to prevent indefinite blocking a deadline must be set for both Read and Write before Read is called when the handshake has not yet completed. See SetDeadline, SetReadDeadline, and SetWriteDeadline. RemoteAddr returns the remote network address. SetDeadline sets the read and write deadlines associated with the connection. A zero value for t means Read and Write will not time out. After a Write has timed out, the TLS state is corrupt and all future writes will return the same error. SetReadDeadline sets the read deadline on the underlying connection. A zero value for t means Read will not time out. SetWriteDeadline sets the write deadline on the underlying connection. A zero value for t means Write will not time out. After a Write has timed out, the TLS state is corrupt and all future writes will return the same error. VerifyHostname checks that the peer certificate chain is valid for connecting to host. If so, it returns nil; if not, it returns an error describing the problem. Write writes data to the connection. As Write calls Handshake, in order to prevent indefinite blocking a deadline must be set for both Read and Write before Write is called when the handshake has not yet completed. See SetDeadline, SetReadDeadline, and SetWriteDeadline. *T : io.Closer *T : io.ReadCloser *T : io.Reader *T : io.ReadWriteCloser *T : io.ReadWriter *T : io.WriteCloser *T : io.Writer *T : net.Conn func Client(conn net.Conn, config *Config) *Conn func Dial(network, addr string, config *Config) (*Conn, error) func DialWithDialer(dialer *net.Dialer, network, addr string, config *Config) (*Conn, error) func Server(conn net.Conn, config *Config) *Conn
ConnectionState records basic TLS details about the connection. CipherSuite is the cipher suite negotiated for the connection (e.g. TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256, TLS_AES_128_GCM_SHA256). DidResume is true if this connection was successfully resumed from a previous session with a session ticket or similar mechanism. HandshakeComplete is true if the handshake has concluded. NegotiatedProtocol is the application protocol negotiated with ALPN. NegotiatedProtocolIsMutual used to indicate a mutual NPN negotiation. Deprecated: this value is always true. OCSPResponse is a stapled Online Certificate Status Protocol (OCSP) response provided by the peer for the leaf certificate, if any. PeerCertificates are the parsed certificates sent by the peer, in the order in which they were sent. The first element is the leaf certificate that the connection is verified against. On the client side, it can't be empty. On the server side, it can be empty if Config.ClientAuth is not RequireAnyClientCert or RequireAndVerifyClientCert. ServerName is the value of the Server Name Indication extension sent by the client. It's available both on the server and on the client side. SignedCertificateTimestamps is a list of SCTs provided by the peer through the TLS handshake for the leaf certificate, if any. TLSUnique contains the "tls-unique" channel binding value (see RFC 5929, Section 3). This value will be nil for TLS 1.3 connections and for all resumed connections. Deprecated: there are conditions in which this value might not be unique to a connection. See the Security Considerations sections of RFC 5705 and RFC 7627, and https://mitls.org/pages/attacks/3SHAKE#channelbindings. VerifiedChains is a list of one or more chains where the first element is PeerCertificates[0] and the last element is from Config.RootCAs (on the client side) or Config.ClientCAs (on the server side). On the client side, it's set if Config.InsecureSkipVerify is false. On the server side, it's set if Config.ClientAuth is VerifyClientCertIfGiven (and the peer provided a certificate) or RequireAndVerifyClientCert. Version is the TLS version used by the connection (e.g. VersionTLS12). ExportKeyingMaterial returns length bytes of exported key material in a new slice as defined in RFC 5705. If context is nil, it is not used as part of the seed. If the connection was set to allow renegotiation via Config.Renegotiation, this function will return an error. func (*Conn).ConnectionState() ConnectionState func net/smtp.(*Client).TLSConnectionState() (state ConnectionState, ok bool)
CurveID is the type of a TLS identifier for an elliptic curve. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml#tls-parameters-8. In TLS 1.3, this type is called NamedGroup, but at this time this library only supports Elliptic Curve based groups. See RFC 8446, Section 4.2.7. ( T) String() string T : expvar.Var T : fmt.Stringer const CurveP256 const CurveP384 const CurveP521 const X25519
Dialer dials TLS connections given a configuration and a Dialer for the underlying connection. Config is the TLS configuration to use for new connections. A nil configuration is equivalent to the zero configuration; see the documentation of Config for the defaults. NetDialer is the optional dialer to use for the TLS connections' underlying TCP connections. A nil NetDialer is equivalent to the net.Dialer zero value. Dial connects to the given network address and initiates a TLS handshake, returning the resulting TLS connection. The returned Conn, if any, will always be of type *Conn. DialContext connects to the given network address and initiates a TLS handshake, returning the resulting TLS connection. The provided Context must be non-nil. If the context expires before the connection is complete, an error is returned. Once successfully connected, any expiration of the context will not affect the connection. The returned Conn, if any, will always be of type *Conn.
RecordHeaderError is returned when a TLS record header is invalid. Conn provides the underlying net.Conn in the case that a client sent an initial handshake that didn't look like TLS. It is nil if there's already been a handshake or a TLS alert has been written to the connection. Msg contains a human readable string that describes the error. RecordHeader contains the five bytes of TLS record header that triggered the error. ( T) Error() string T : error
RenegotiationSupport enumerates the different levels of support for TLS renegotiation. TLS renegotiation is the act of performing subsequent handshakes on a connection after the first. This significantly complicates the state machine and has been the source of numerous, subtle security issues. Initiating a renegotiation is not supported, but support for accepting renegotiation requests may be enabled. Even when enabled, the server may not change its identity between handshakes (i.e. the leaf certificate must be the same). Additionally, concurrent handshake and application data flow is not permitted so renegotiation can only be used with protocols that synchronise with the renegotiation, such as HTTPS. Renegotiation is not defined in TLS 1.3. const RenegotiateFreelyAsClient const RenegotiateNever const RenegotiateOnceAsClient
SignatureScheme identifies a signature algorithm supported by TLS. See RFC 8446, Section 4.2.3. ( T) String() string T : expvar.Var T : fmt.Stringer const ECDSAWithP256AndSHA256 const ECDSAWithP384AndSHA384 const ECDSAWithP521AndSHA512 const ECDSAWithSHA1 const Ed25519 const PKCS1WithSHA1 const PKCS1WithSHA256 const PKCS1WithSHA384 const PKCS1WithSHA512 const PSSWithSHA256 const PSSWithSHA384 const PSSWithSHA512
Package-Level Functions (total 12)
CipherSuiteName returns the standard name for the passed cipher suite ID (e.g. "TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256"), or a fallback representation of the ID value if the cipher suite is not implemented by this package.
CipherSuites returns a list of cipher suites currently implemented by this package, excluding those with security issues, which are returned by InsecureCipherSuites. The list is sorted by ID. Note that the default cipher suites selected by this package might depend on logic that can't be captured by a static list.
Client returns a new TLS client side connection using conn as the underlying transport. The config cannot be nil: users must set either ServerName or InsecureSkipVerify in the config.
Dial connects to the given network address using net.Dial and then initiates a TLS handshake, returning the resulting TLS connection. Dial interprets a nil configuration as equivalent to the zero configuration; see the documentation of Config for the defaults.
DialWithDialer connects to the given network address using dialer.Dial and then initiates a TLS handshake, returning the resulting TLS connection. Any timeout or deadline given in the dialer apply to connection and TLS handshake as a whole. DialWithDialer interprets a nil configuration as equivalent to the zero configuration; see the documentation of Config for the defaults.
InsecureCipherSuites returns a list of cipher suites currently implemented by this package and which have security issues. Most applications should not use the cipher suites in this list, and should only use those returned by CipherSuites.
Listen creates a TLS listener accepting connections on the given network address using net.Listen. The configuration config must be non-nil and must include at least one certificate or else set GetCertificate.
LoadX509KeyPair reads and parses a public/private key pair from a pair of files. The files must contain PEM encoded data. The certificate file may contain intermediate certificates following the leaf certificate to form a certificate chain. On successful return, Certificate.Leaf will be nil because the parsed form of the certificate is not retained.
NewListener creates a Listener which accepts connections from an inner Listener and wraps each connection with Server. The configuration config must be non-nil and must include at least one certificate or else set GetCertificate.
NewLRUClientSessionCache returns a ClientSessionCache with the given capacity that uses an LRU strategy. If capacity is < 1, a default capacity is used instead.
Server returns a new TLS server side connection using conn as the underlying transport. The configuration config must be non-nil and must include at least one certificate or else set GetCertificate.
X509KeyPair parses a public/private key pair from a pair of PEM encoded data. On successful return, Certificate.Leaf will be nil because the parsed form of the certificate is not retained.
Package-Level Constants (total 57)
const CurveP256 CurveID = 23
const CurveP384 CurveID = 24
const CurveP521 CurveID = 25
ECDSA algorithms. Only constrained to a specific curve in TLS 1.3.
EdDSA algorithms.
NoClientCert indicates that no client certificate should be requested during the handshake, and if any certificates are sent they will not be verified.
Legacy signature and hash algorithms for TLS 1.2.
RSASSA-PKCS1-v1_5 algorithms.
RSASSA-PSS algorithms with public key OID rsaEncryption.
RenegotiateFreelyAsClient allows a remote server to repeatedly request renegotiation.
RenegotiateNever disables renegotiation.
RenegotiateOnceAsClient allows a remote server to request renegotiation once per connection.
RequestClientCert indicates that a client certificate should be requested during the handshake, but does not require that the client send any certificates.
RequireAndVerifyClientCert indicates that a client certificate should be requested during the handshake, and that at least one valid certificate is required to be sent by the client.
RequireAnyClientCert indicates that a client certificate should be requested during the handshake, and that at least one certificate is required to be sent by the client, but that certificate is not required to be valid.
TLS 1.3 cipher suites.
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
Legacy names for the corresponding cipher suites with the correct _SHA256 suffix, retained for backward compatibility.
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
TLS_FALLBACK_SCSV isn't a standard cipher suite but an indicator that the client is doing version fallback. See RFC 7507.
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
A list of cipher suite IDs that are, or have been, implemented by this package. See https://www.iana.org/assignments/tls-parameters/tls-parameters.xml
TLS 1.0 - 1.2 cipher suites.
VerifyClientCertIfGiven indicates that a client certificate should be requested during the handshake, but does not require that the client sends a certificate. If the client does send a certificate it is required to be valid.
Deprecated: SSLv3 is cryptographically broken, and is no longer supported by this package. See golang.org/issue/32716.
const VersionTLS10 = 769
const VersionTLS11 = 770
const VersionTLS12 = 771
const VersionTLS13 = 772
const X25519 CurveID = 29