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crypto / x509

Package x509

go1.15.2
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The latest major version is .

Published: Sep 9, 2020 | License: BSD-3-Clause | Standard library

Overview

Package x509 parses X.509-encoded keys and certificates.

Index

Examples

Variables

var ErrUnsupportedAlgorithm = errors.New("x509: cannot verify signature: algorithm unimplemented")

ErrUnsupportedAlgorithm results from attempting to perform an operation that involves algorithms that are not currently implemented.

var IncorrectPasswordError = errors.New("x509: decryption password incorrect")

IncorrectPasswordError is returned when an incorrect password is detected.

func CreateCertificate

func CreateCertificate(rand io.Reader, template, parent *Certificate, pub, priv interface{}) (cert []byte, err error)

CreateCertificate creates a new X.509v3 certificate based on a template. The following members of template are used:

- AuthorityKeyId
- BasicConstraintsValid
- CRLDistributionPoints
- DNSNames
- EmailAddresses
- ExcludedDNSDomains
- ExcludedEmailAddresses
- ExcludedIPRanges
- ExcludedURIDomains
- ExtKeyUsage
- ExtraExtensions
- IPAddresses
- IsCA
- IssuingCertificateURL
- KeyUsage
- MaxPathLen
- MaxPathLenZero
- NotAfter
- NotBefore
- OCSPServer
- PermittedDNSDomains
- PermittedDNSDomainsCritical
- PermittedEmailAddresses
- PermittedIPRanges
- PermittedURIDomains
- PolicyIdentifiers
- SerialNumber
- SignatureAlgorithm
- Subject
- SubjectKeyId
- URIs
- UnknownExtKeyUsage

The certificate is signed by parent. If parent is equal to template then the certificate is self-signed. The parameter pub is the public key of the signee and priv is the private key of the signer.

The returned slice is the certificate in DER encoding.

The currently supported key types are *rsa.PublicKey, *ecdsa.PublicKey and ed25519.PublicKey. pub must be a supported key type, and priv must be a crypto.Signer with a supported public key.

The AuthorityKeyId will be taken from the SubjectKeyId of parent, if any, unless the resulting certificate is self-signed. Otherwise the value from template will be used.

If SubjectKeyId from template is empty and the template is a CA, SubjectKeyId will be generated from the hash of the public key.

func CreateCertificateRequest

func CreateCertificateRequest(rand io.Reader, template *CertificateRequest, priv interface{}) (csr []byte, err error)

CreateCertificateRequest creates a new certificate request based on a template. The following members of template are used:

- SignatureAlgorithm
- Subject
- DNSNames
- EmailAddresses
- IPAddresses
- URIs
- ExtraExtensions
- Attributes (deprecated)

priv is the private key to sign the CSR with, and the corresponding public key will be included in the CSR. It must implement crypto.Signer and its Public() method must return a *rsa.PublicKey or a *ecdsa.PublicKey or a ed25519.PublicKey. (A *rsa.PrivateKey, *ecdsa.PrivateKey or ed25519.PrivateKey satisfies this.)

The returned slice is the certificate request in DER encoding.

func CreateRevocationList

func CreateRevocationList(rand io.Reader, template *RevocationList, issuer *Certificate, priv crypto.Signer) ([]byte, error)

CreateRevocationList creates a new X.509 v2 Certificate Revocation List, according to RFC 5280, based on template.

The CRL is signed by priv which should be the private key associated with the public key in the issuer certificate.

The issuer may not be nil, and the crlSign bit must be set in KeyUsage in order to use it as a CRL issuer.

The issuer distinguished name CRL field and authority key identifier extension are populated using the issuer certificate. issuer must have SubjectKeyId set.

func DecryptPEMBlock

func DecryptPEMBlock(b *pem.Block, password []byte) ([]byte, error)

DecryptPEMBlock takes a password encrypted PEM block and the password used to encrypt it and returns a slice of decrypted DER encoded bytes. It inspects the DEK-Info header to determine the algorithm used for decryption. If no DEK-Info header is present, an error is returned. If an incorrect password is detected an IncorrectPasswordError is returned. Because of deficiencies in the encrypted-PEM format, it's not always possible to detect an incorrect password. In these cases no error will be returned but the decrypted DER bytes will be random noise.

func EncryptPEMBlock

func EncryptPEMBlock(rand io.Reader, blockType string, data, password []byte, alg PEMCipher) (*pem.Block, error)

EncryptPEMBlock returns a PEM block of the specified type holding the given DER-encoded data encrypted with the specified algorithm and password.

func IsEncryptedPEMBlock

func IsEncryptedPEMBlock(b *pem.Block) bool

IsEncryptedPEMBlock returns if the PEM block is password encrypted.

func MarshalECPrivateKey

func MarshalECPrivateKey(key *ecdsa.PrivateKey) ([]byte, error)

MarshalECPrivateKey converts an EC private key to SEC 1, ASN.1 DER form.

This kind of key is commonly encoded in PEM blocks of type "EC PRIVATE KEY". For a more flexible key format which is not EC specific, use MarshalPKCS8PrivateKey.

func MarshalPKCS1PrivateKey

func MarshalPKCS1PrivateKey(key *rsa.PrivateKey) []byte

MarshalPKCS1PrivateKey converts an RSA private key to PKCS #1, ASN.1 DER form.

This kind of key is commonly encoded in PEM blocks of type "RSA PRIVATE KEY". For a more flexible key format which is not RSA specific, use MarshalPKCS8PrivateKey.

func MarshalPKCS1PublicKey

func MarshalPKCS1PublicKey(key *rsa.PublicKey) []byte

MarshalPKCS1PublicKey converts an RSA public key to PKCS #1, ASN.1 DER form.

This kind of key is commonly encoded in PEM blocks of type "RSA PUBLIC KEY".

func MarshalPKCS8PrivateKey

func MarshalPKCS8PrivateKey(key interface{}) ([]byte, error)

MarshalPKCS8PrivateKey converts a private key to PKCS #8, ASN.1 DER form.

The following key types are currently supported: *rsa.PrivateKey, *ecdsa.PrivateKey and ed25519.PrivateKey. Unsupported key types result in an error.

This kind of key is commonly encoded in PEM blocks of type "PRIVATE KEY".

func MarshalPKIXPublicKey

func MarshalPKIXPublicKey(pub interface{}) ([]byte, error)

MarshalPKIXPublicKey converts a public key to PKIX, ASN.1 DER form. The encoded public key is a SubjectPublicKeyInfo structure (see RFC 5280, Section 4.1).

The following key types are currently supported: *rsa.PublicKey, *ecdsa.PublicKey and ed25519.PublicKey. Unsupported key types result in an error.

This kind of key is commonly encoded in PEM blocks of type "PUBLIC KEY".

func ParseCRL

func ParseCRL(crlBytes []byte) (*pkix.CertificateList, error)

ParseCRL parses a CRL from the given bytes. It's often the case that PEM encoded CRLs will appear where they should be DER encoded, so this function will transparently handle PEM encoding as long as there isn't any leading garbage.

func ParseDERCRL

func ParseDERCRL(derBytes []byte) (*pkix.CertificateList, error)

ParseDERCRL parses a DER encoded CRL from the given bytes.

func ParseECPrivateKey

func ParseECPrivateKey(der []byte) (*ecdsa.PrivateKey, error)

ParseECPrivateKey parses an EC private key in SEC 1, ASN.1 DER form.

This kind of key is commonly encoded in PEM blocks of type "EC PRIVATE KEY".

func ParsePKCS1PrivateKey

func ParsePKCS1PrivateKey(der []byte) (*rsa.PrivateKey, error)

ParsePKCS1PrivateKey parses an RSA private key in PKCS #1, ASN.1 DER form.

This kind of key is commonly encoded in PEM blocks of type "RSA PRIVATE KEY".

func ParsePKCS1PublicKey

func ParsePKCS1PublicKey(der []byte) (*rsa.PublicKey, error)

ParsePKCS1PublicKey parses an RSA public key in PKCS #1, ASN.1 DER form.

This kind of key is commonly encoded in PEM blocks of type "RSA PUBLIC KEY".

func ParsePKCS8PrivateKey

func ParsePKCS8PrivateKey(der []byte) (key interface{}, err error)

ParsePKCS8PrivateKey parses an unencrypted private key in PKCS #8, ASN.1 DER form.

It returns a *rsa.PrivateKey, a *ecdsa.PrivateKey, or a ed25519.PrivateKey. More types might be supported in the future.

This kind of key is commonly encoded in PEM blocks of type "PRIVATE KEY".

func ParsePKIXPublicKey

func ParsePKIXPublicKey(derBytes []byte) (pub interface{}, err error)

ParsePKIXPublicKey parses a public key in PKIX, ASN.1 DER form. The encoded public key is a SubjectPublicKeyInfo structure (see RFC 5280, Section 4.1).

It returns a *rsa.PublicKey, *dsa.PublicKey, *ecdsa.PublicKey, or ed25519.PublicKey. More types might be supported in the future.

This kind of key is commonly encoded in PEM blocks of type "PUBLIC KEY".

Example

Code:

package main

import (
	"crypto/dsa"
	"crypto/ecdsa"
	"crypto/ed25519"
	"crypto/rsa"
	"crypto/x509"
	"encoding/pem"
	"fmt"
)

func main() {
	const pubPEM = `
-----BEGIN PUBLIC KEY-----
MIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEAlRuRnThUjU8/prwYxbty
WPT9pURI3lbsKMiB6Fn/VHOKE13p4D8xgOCADpdRagdT6n4etr9atzDKUSvpMtR3
CP5noNc97WiNCggBjVWhs7szEe8ugyqF23XwpHQ6uV1LKH50m92MbOWfCtjU9p/x
qhNpQQ1AZhqNy5Gevap5k8XzRmjSldNAFZMY7Yv3Gi+nyCwGwpVtBUwhuLzgNFK/
yDtw2WcWmUU7NuC8Q6MWvPebxVtCfVp/iQU6q60yyt6aGOBkhAX0LpKAEhKidixY
nP9PNVBvxgu3XZ4P36gZV6+ummKdBVnc3NqwBLu5+CcdRdusmHPHd5pHf4/38Z3/
6qU2a/fPvWzceVTEgZ47QjFMTCTmCwNt29cvi7zZeQzjtwQgn4ipN9NibRH/Ax/q
TbIzHfrJ1xa2RteWSdFjwtxi9C20HUkjXSeI4YlzQMH0fPX6KCE7aVePTOnB69I/
a9/q96DiXZajwlpq3wFctrs1oXqBp5DVrCIj8hU2wNgB7LtQ1mCtsYz//heai0K9
PhE4X6hiE0YmeAZjR0uHl8M/5aW9xCoJ72+12kKpWAa0SFRWLy6FejNYCYpkupVJ
yecLk/4L1W0l6jQQZnWErXZYe0PNFcmwGXy1Rep83kfBRNKRy5tvocalLlwXLdUk
AIU+2GKjyT3iMuzZxxFxPFMCAwEAAQ==
-----END PUBLIC KEY-----`

	block, _ := pem.Decode([]byte(pubPEM))
	if block == nil {
		panic("failed to parse PEM block containing the public key")
	}

	pub, err := x509.ParsePKIXPublicKey(block.Bytes)
	if err != nil {
		panic("failed to parse DER encoded public key: " + err.Error())
	}

	switch pub := pub.(type) {
	case *rsa.PublicKey:
		fmt.Println("pub is of type RSA:", pub)
	case *dsa.PublicKey:
		fmt.Println("pub is of type DSA:", pub)
	case *ecdsa.PublicKey:
		fmt.Println("pub is of type ECDSA:", pub)
	case ed25519.PublicKey:
		fmt.Println("pub is of type Ed25519:", pub)
	default:
		panic("unknown type of public key")
	}
}

type CertPool

type CertPool struct {
	// contains filtered or unexported fields
}

CertPool is a set of certificates.

func NewCertPool

func NewCertPool() *CertPool

NewCertPool returns a new, empty CertPool.

func SystemCertPool

func SystemCertPool() (*CertPool, error)

SystemCertPool returns a copy of the system cert pool.

On Unix systems other than macOS the environment variables SSL_CERT_FILE and SSL_CERT_DIR can be used to override the system default locations for the SSL certificate file and SSL certificate files directory, respectively. The latter can be a colon-separated list.

Any mutations to the returned pool are not written to disk and do not affect any other pool returned by SystemCertPool.

New changes in the system cert pool might not be reflected in subsequent calls.

func (*CertPool) AddCert

func (s *CertPool) AddCert(cert *Certificate)

AddCert adds a certificate to a pool.

func (*CertPool) AppendCertsFromPEM

func (s *CertPool) AppendCertsFromPEM(pemCerts []byte) (ok bool)

AppendCertsFromPEM attempts to parse a series of PEM encoded certificates. It appends any certificates found to s and reports whether any certificates were successfully parsed.

On many Linux systems, /etc/ssl/cert.pem will contain the system wide set of root CAs in a format suitable for this function.

func (*CertPool) Subjects

func (s *CertPool) Subjects() [][]byte

Subjects returns a list of the DER-encoded subjects of all of the certificates in the pool.

type Certificate

type Certificate struct {
	Raw                     []byte // Complete ASN.1 DER content (certificate, signature algorithm and signature).
	RawTBSCertificate       []byte // Certificate part of raw ASN.1 DER content.
	RawSubjectPublicKeyInfo []byte // DER encoded SubjectPublicKeyInfo.
	RawSubject              []byte // DER encoded Subject
	RawIssuer               []byte // DER encoded Issuer

	Signature          []byte
	SignatureAlgorithm SignatureAlgorithm

	PublicKeyAlgorithm PublicKeyAlgorithm
	PublicKey          interface{}

	Version             int
	SerialNumber        *big.Int
	Issuer              pkix.Name
	Subject             pkix.Name
	NotBefore, NotAfter time.Time // Validity bounds.
	KeyUsage            KeyUsage

	// Extensions contains raw X.509 extensions. When parsing certificates,
	// this can be used to extract non-critical extensions that are not
	// parsed by this package. When marshaling certificates, the Extensions
	// field is ignored, see ExtraExtensions.
	Extensions []pkix.Extension

	// ExtraExtensions contains extensions to be copied, raw, into any
	// marshaled certificates. Values override any extensions that would
	// otherwise be produced based on the other fields. The ExtraExtensions
	// field is not populated when parsing certificates, see Extensions.
	ExtraExtensions []pkix.Extension

	// UnhandledCriticalExtensions contains a list of extension IDs that
	// were not (fully) processed when parsing. Verify will fail if this
	// slice is non-empty, unless verification is delegated to an OS
	// library which understands all the critical extensions.
	//
	// Users can access these extensions using Extensions and can remove
	// elements from this slice if they believe that they have been
	// handled.
	UnhandledCriticalExtensions []asn1.ObjectIdentifier

	ExtKeyUsage        []ExtKeyUsage           // Sequence of extended key usages.
	UnknownExtKeyUsage []asn1.ObjectIdentifier // Encountered extended key usages unknown to this package.

	// BasicConstraintsValid indicates whether IsCA, MaxPathLen,
	// and MaxPathLenZero are valid.
	BasicConstraintsValid bool
	IsCA                  bool

	// MaxPathLen and MaxPathLenZero indicate the presence and
	// value of the BasicConstraints' "pathLenConstraint".
	//
	// When parsing a certificate, a positive non-zero MaxPathLen
	// means that the field was specified, -1 means it was unset,
	// and MaxPathLenZero being true mean that the field was
	// explicitly set to zero. The case of MaxPathLen==0 with MaxPathLenZero==false
	// should be treated equivalent to -1 (unset).
	//
	// When generating a certificate, an unset pathLenConstraint
	// can be requested with either MaxPathLen == -1 or using the
	// zero value for both MaxPathLen and MaxPathLenZero.
	MaxPathLen int
	// MaxPathLenZero indicates that BasicConstraintsValid==true
	// and MaxPathLen==0 should be interpreted as an actual
	// maximum path length of zero. Otherwise, that combination is
	// interpreted as MaxPathLen not being set.
	MaxPathLenZero bool

	SubjectKeyId   []byte
	AuthorityKeyId []byte

	// RFC 5280, 4.2.2.1 (Authority Information Access)
	OCSPServer            []string
	IssuingCertificateURL []string

	// Subject Alternate Name values. (Note that these values may not be valid
	// if invalid values were contained within a parsed certificate. For
	// example, an element of DNSNames may not be a valid DNS domain name.)
	DNSNames       []string
	EmailAddresses []string
	IPAddresses    []net.IP
	URIs           []*url.URL

	// Name constraints
	PermittedDNSDomainsCritical bool // if true then the name constraints are marked critical.
	PermittedDNSDomains         []string
	ExcludedDNSDomains          []string
	PermittedIPRanges           []*net.IPNet
	ExcludedIPRanges            []*net.IPNet
	PermittedEmailAddresses     []string
	ExcludedEmailAddresses      []string
	PermittedURIDomains         []string
	ExcludedURIDomains          []string

	// CRL Distribution Points
	CRLDistributionPoints []string

	PolicyIdentifiers []asn1.ObjectIdentifier
}

A Certificate represents an X.509 certificate.

func ParseCertificate

func ParseCertificate(asn1Data []byte) (*Certificate, error)

ParseCertificate parses a single certificate from the given ASN.1 DER data.

func ParseCertificates

func ParseCertificates(asn1Data []byte) ([]*Certificate, error)

ParseCertificates parses one or more certificates from the given ASN.1 DER data. The certificates must be concatenated with no intermediate padding.

func (*Certificate) CheckCRLSignature

func (c *Certificate) CheckCRLSignature(crl *pkix.CertificateList) error

CheckCRLSignature checks that the signature in crl is from c.

func (*Certificate) CheckSignature

func (c *Certificate) CheckSignature(algo SignatureAlgorithm, signed, signature []byte) error

CheckSignature verifies that signature is a valid signature over signed from c's public key.

func (*Certificate) CheckSignatureFrom

func (c *Certificate) CheckSignatureFrom(parent *Certificate) error

CheckSignatureFrom verifies that the signature on c is a valid signature from parent.

func (*Certificate) CreateCRL

func (c *Certificate) CreateCRL(rand io.Reader, priv interface{}, revokedCerts []pkix.RevokedCertificate, now, expiry time.Time) (crlBytes []byte, err error)

CreateCRL returns a DER encoded CRL, signed by this Certificate, that contains the given list of revoked certificates.

Note: this method does not generate an RFC 5280 conformant X.509 v2 CRL. To generate a standards compliant CRL, use CreateRevocationList instead.

func (*Certificate) Equal

func (c *Certificate) Equal(other *Certificate) bool

func (*Certificate) Verify

func (c *Certificate) Verify(opts VerifyOptions) (chains [][]*Certificate, err error)

Verify attempts to verify c by building one or more chains from c to a certificate in opts.Roots, using certificates in opts.Intermediates if needed. If successful, it returns one or more chains where the first element of the chain is c and the last element is from opts.Roots.

If opts.Roots is nil, the platform verifier might be used, and verification details might differ from what is described below. If system roots are unavailable the returned error will be of type SystemRootsError.

Name constraints in the intermediates will be applied to all names claimed in the chain, not just opts.DNSName. Thus it is invalid for a leaf to claim example.com if an intermediate doesn't permit it, even if example.com is not the name being validated. Note that DirectoryName constraints are not supported.

Name constraint validation follows the rules from RFC 5280, with the addition that DNS name constraints may use the leading period format defined for emails and URIs. When a constraint has a leading period it indicates that at least one additional label must be prepended to the constrained name to be considered valid.

Extended Key Usage values are enforced nested down a chain, so an intermediate or root that enumerates EKUs prevents a leaf from asserting an EKU not in that list. (While this is not specified, it is common practice in order to limit the types of certificates a CA can issue.)

WARNING: this function doesn't do any revocation checking.

Example

Code:

package main

import (
	"crypto/x509"
	"encoding/pem"
)

func main() {
	// Verifying with a custom list of root certificates.

	const rootPEM = `
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----`

	const certPEM = `
-----BEGIN CERTIFICATE-----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==
-----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")
	}

	block, _ := pem.Decode([]byte(certPEM))
	if block == nil {
		panic("failed to parse certificate PEM")
	}
	cert, err := x509.ParseCertificate(block.Bytes)
	if err != nil {
		panic("failed to parse certificate: " + err.Error())
	}

	opts := x509.VerifyOptions{
		DNSName: "mail.google.com",
		Roots:   roots,
	}

	if _, err := cert.Verify(opts); err != nil {
		panic("failed to verify certificate: " + err.Error())
	}
}

func (*Certificate) VerifyHostname

func (c *Certificate) VerifyHostname(h string) error

VerifyHostname returns nil if c is a valid certificate for the named host. Otherwise it returns an error describing the mismatch.

IP addresses can be optionally enclosed in square brackets and are checked against the IPAddresses field. Other names are checked case insensitively against the DNSNames field. If the names are valid hostnames, the certificate fields can have a wildcard as the left-most label.

The legacy Common Name field is ignored unless it's a valid hostname, the certificate doesn't have any Subject Alternative Names, and the GODEBUG environment variable is set to "x509ignoreCN=0". Support for Common Name is deprecated will be entirely removed in the future.

type CertificateInvalidError

type CertificateInvalidError struct {
	Cert   *Certificate
	Reason InvalidReason
	Detail string
}

CertificateInvalidError results when an odd error occurs. Users of this library probably want to handle all these errors uniformly.

func (CertificateInvalidError) Error

func (e CertificateInvalidError) Error() string

type CertificateRequest

type CertificateRequest struct {
	Raw                      []byte // Complete ASN.1 DER content (CSR, signature algorithm and signature).
	RawTBSCertificateRequest []byte // Certificate request info part of raw ASN.1 DER content.
	RawSubjectPublicKeyInfo  []byte // DER encoded SubjectPublicKeyInfo.
	RawSubject               []byte // DER encoded Subject.

	Version            int
	Signature          []byte
	SignatureAlgorithm SignatureAlgorithm

	PublicKeyAlgorithm PublicKeyAlgorithm
	PublicKey          interface{}

	Subject pkix.Name

	// Attributes contains the CSR attributes that can parse as
	// pkix.AttributeTypeAndValueSET.
	//
	// Deprecated: Use Extensions and ExtraExtensions instead for parsing and
	// generating the requestedExtensions attribute.
	Attributes []pkix.AttributeTypeAndValueSET

	// Extensions contains all requested extensions, in raw form. When parsing
	// CSRs, this can be used to extract extensions that are not parsed by this
	// package.
	Extensions []pkix.Extension

	// ExtraExtensions contains extensions to be copied, raw, into any CSR
	// marshaled by CreateCertificateRequest. Values override any extensions
	// that would otherwise be produced based on the other fields but are
	// overridden by any extensions specified in Attributes.
	//
	// The ExtraExtensions field is not populated by ParseCertificateRequest,
	// see Extensions instead.
	ExtraExtensions []pkix.Extension

	// Subject Alternate Name values.
	DNSNames       []string
	EmailAddresses []string
	IPAddresses    []net.IP
	URIs           []*url.URL
}

CertificateRequest represents a PKCS #10, certificate signature request.

func ParseCertificateRequest

func ParseCertificateRequest(asn1Data []byte) (*CertificateRequest, error)

ParseCertificateRequest parses a single certificate request from the given ASN.1 DER data.

func (*CertificateRequest) CheckSignature

func (c *CertificateRequest) CheckSignature() error

CheckSignature reports whether the signature on c is valid.

type ConstraintViolationError

type ConstraintViolationError struct{}

ConstraintViolationError results when a requested usage is not permitted by a certificate. For example: checking a signature when the public key isn't a certificate signing key.

func (ConstraintViolationError) Error

func (ConstraintViolationError) Error() string

type ExtKeyUsage

type ExtKeyUsage int

ExtKeyUsage represents an extended set of actions that are valid for a given key. Each of the ExtKeyUsage* constants define a unique action.

const (
	ExtKeyUsageAny ExtKeyUsage = iota
	ExtKeyUsageServerAuth
	ExtKeyUsageClientAuth
	ExtKeyUsageCodeSigning
	ExtKeyUsageEmailProtection
	ExtKeyUsageIPSECEndSystem
	ExtKeyUsageIPSECTunnel
	ExtKeyUsageIPSECUser
	ExtKeyUsageTimeStamping
	ExtKeyUsageOCSPSigning
	ExtKeyUsageMicrosoftServerGatedCrypto
	ExtKeyUsageNetscapeServerGatedCrypto
	ExtKeyUsageMicrosoftCommercialCodeSigning
	ExtKeyUsageMicrosoftKernelCodeSigning
)

type HostnameError

type HostnameError struct {
	Certificate *Certificate
	Host        string
}

HostnameError results when the set of authorized names doesn't match the requested name.

func (HostnameError) Error

func (h HostnameError) Error() string

type InsecureAlgorithmError

type InsecureAlgorithmError SignatureAlgorithm

An InsecureAlgorithmError

func (InsecureAlgorithmError) Error

func (e InsecureAlgorithmError) Error() string

type InvalidReason

type InvalidReason int
const (
	// NotAuthorizedToSign results when a certificate is signed by another
	// which isn't marked as a CA certificate.
	NotAuthorizedToSign InvalidReason = iota
	// Expired results when a certificate has expired, based on the time
	// given in the VerifyOptions.
	Expired
	// CANotAuthorizedForThisName results when an intermediate or root
	// certificate has a name constraint which doesn't permit a DNS or
	// other name (including IP address) in the leaf certificate.
	CANotAuthorizedForThisName
	// TooManyIntermediates results when a path length constraint is
	// violated.
	TooManyIntermediates
	// IncompatibleUsage results when the certificate's key usage indicates
	// that it may only be used for a different purpose.
	IncompatibleUsage
	// NameMismatch results when the subject name of a parent certificate
	// does not match the issuer name in the child.
	NameMismatch
	// NameConstraintsWithoutSANs results when a leaf certificate doesn't
	// contain a Subject Alternative Name extension, but a CA certificate
	// contains name constraints, and the Common Name can be interpreted as
	// a hostname.
	//
	// This error is only returned when legacy Common Name matching is enabled
	// by setting the GODEBUG environment variable to "x509ignoreCN=1". This
	// setting might be removed in the future.
	NameConstraintsWithoutSANs
	// UnconstrainedName results when a CA certificate contains permitted
	// name constraints, but leaf certificate contains a name of an
	// unsupported or unconstrained type.
	UnconstrainedName
	// TooManyConstraints results when the number of comparison operations
	// needed to check a certificate exceeds the limit set by
	// VerifyOptions.MaxConstraintComparisions. This limit exists to
	// prevent pathological certificates can consuming excessive amounts of
	// CPU time to verify.
	TooManyConstraints
	// CANotAuthorizedForExtKeyUsage results when an intermediate or root
	// certificate does not permit a requested extended key usage.
	CANotAuthorizedForExtKeyUsage
)

type KeyUsage

type KeyUsage int

KeyUsage represents the set of actions that are valid for a given key. It's a bitmap of the KeyUsage* constants.

const (
	KeyUsageDigitalSignature KeyUsage = 1 << iota
	KeyUsageContentCommitment
	KeyUsageKeyEncipherment
	KeyUsageDataEncipherment
	KeyUsageKeyAgreement
	KeyUsageCertSign
	KeyUsageCRLSign
	KeyUsageEncipherOnly
	KeyUsageDecipherOnly
)

type PEMCipher

type PEMCipher int
const (
	PEMCipherDES PEMCipher
	PEMCipher3DES
	PEMCipherAES128
	PEMCipherAES192
	PEMCipherAES256
)

Possible values for the EncryptPEMBlock encryption algorithm.

type PublicKeyAlgorithm

type PublicKeyAlgorithm int
const (
	UnknownPublicKeyAlgorithm PublicKeyAlgorithm = iota
	RSA
	DSA
	ECDSA
	Ed25519
)

func (PublicKeyAlgorithm) String

func (algo PublicKeyAlgorithm) String() string

type RevocationList

type RevocationList struct {
	// SignatureAlgorithm is used to determine the signature algorithm to be
	// used when signing the CRL. If 0 the default algorithm for the signing
	// key will be used.
	SignatureAlgorithm SignatureAlgorithm

	// RevokedCertificates is used to populate the revokedCertificates
	// sequence in the CRL, it may be empty. RevokedCertificates may be nil,
	// in which case an empty CRL will be created.
	RevokedCertificates []pkix.RevokedCertificate

	// Number is used to populate the X.509 v2 cRLNumber extension in the CRL,
	// which should be a monotonically increasing sequence number for a given
	// CRL scope and CRL issuer.
	Number *big.Int
	// ThisUpdate is used to populate the thisUpdate field in the CRL, which
	// indicates the issuance date of the CRL.
	ThisUpdate time.Time
	// NextUpdate is used to populate the nextUpdate field in the CRL, which
	// indicates the date by which the next CRL will be issued. NextUpdate
	// must be greater than ThisUpdate.
	NextUpdate time.Time
	// ExtraExtensions contains any additional extensions to add directly to
	// the CRL.
	ExtraExtensions []pkix.Extension
}

RevocationList contains the fields used to create an X.509 v2 Certificate Revocation list with CreateRevocationList.

type SignatureAlgorithm

type SignatureAlgorithm int
const (
	UnknownSignatureAlgorithm SignatureAlgorithm = iota
	MD2WithRSA
	MD5WithRSA
	SHA1WithRSA
	SHA256WithRSA
	SHA384WithRSA
	SHA512WithRSA
	DSAWithSHA1
	DSAWithSHA256
	ECDSAWithSHA1
	ECDSAWithSHA256
	ECDSAWithSHA384
	ECDSAWithSHA512
	SHA256WithRSAPSS
	SHA384WithRSAPSS
	SHA512WithRSAPSS
	PureEd25519
)

func (SignatureAlgorithm) String

func (algo SignatureAlgorithm) String() string

type SystemRootsError

type SystemRootsError struct {
	Err error
}

SystemRootsError results when we fail to load the system root certificates.

func (SystemRootsError) Error

func (se SystemRootsError) Error() string

type UnhandledCriticalExtension

type UnhandledCriticalExtension struct{}

func (UnhandledCriticalExtension) Error

func (h UnhandledCriticalExtension) Error() string

type UnknownAuthorityError

type UnknownAuthorityError struct {
	Cert *Certificate
	// contains filtered or unexported fields
}

UnknownAuthorityError results when the certificate issuer is unknown

func (UnknownAuthorityError) Error

func (e UnknownAuthorityError) Error() string

type VerifyOptions

type VerifyOptions struct {
	// DNSName, if set, is checked against the leaf certificate with
	// Certificate.VerifyHostname or the platform verifier.
	DNSName string

	// Intermediates is an optional pool of certificates that are not trust
	// anchors, but can be used to form a chain from the leaf certificate to a
	// root certificate.
	Intermediates *CertPool
	// Roots is the set of trusted root certificates the leaf certificate needs
	// to chain up to. If nil, the system roots or the platform verifier are used.
	Roots *CertPool

	// CurrentTime is used to check the validity of all certificates in the
	// chain. If zero, the current time is used.
	CurrentTime time.Time

	// KeyUsages specifies which Extended Key Usage values are acceptable. A
	// chain is accepted if it allows any of the listed values. An empty list
	// means ExtKeyUsageServerAuth. To accept any key usage, include ExtKeyUsageAny.
	KeyUsages []ExtKeyUsage

	// MaxConstraintComparisions is the maximum number of comparisons to
	// perform when checking a given certificate's name constraints. If
	// zero, a sensible default is used. This limit prevents pathological
	// certificates from consuming excessive amounts of CPU time when
	// validating. It does not apply to the platform verifier.
	MaxConstraintComparisions int
}

VerifyOptions contains parameters for Certificate.Verify.

Package Files

Documentation was rendered with GOOS=linux and GOARCH=amd64.

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