package x509
Import Path
crypto/x509 (on go.dev)
Dependency Relation
imports 47 packages, and imported by 2 packages
Involved Source Files
cert_pool.go
oid.go
parser.go
pem_decrypt.go
pkcs1.go
pkcs8.go
root.go
root_linux.go
root_unix.go
sec1.go
verify.go
Package x509 implements a subset of the X.509 standard.
It allows parsing and generating certificates, certificate signing
requests, certificate revocation lists, and encoded public and private keys.
It provides a certificate verifier, complete with a chain builder.
The package targets the X.509 technical profile defined by the IETF (RFC
2459/3280/5280), and as further restricted by the CA/Browser Forum Baseline
Requirements. There is minimal support for features outside of these
profiles, as the primary goal of the package is to provide compatibility
with the publicly trusted TLS certificate ecosystem and its policies and
constraints.
On macOS and Windows, certificate verification is handled by system APIs, but
the package aims to apply consistent validation rules across operating
systems.
Code Examples
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())
}
}
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")
}
}
Package-Level Type Names (total 21)
A Certificate represents an X.509 certificate.
AuthorityKeyId []byte
BasicConstraintsValid indicates whether IsCA, MaxPathLen,
and MaxPathLenZero are valid.
CRL Distribution Points
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.)
EmailAddresses []string
ExcludedDNSDomains []string
ExcludedEmailAddresses []string
ExcludedIPRanges []*net.IPNet
ExcludedURIDomains []string
// Sequence of extended key usages.
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.
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.
IPAddresses []net.IP
InhibitAnyPolicy and InhibitAnyPolicyZero indicate the presence and value
of the inhibitAnyPolicy extension.
The value of InhibitAnyPolicy indicates the number of additional
certificates in the path after this certificate that may use the
anyPolicy policy OID to indicate a match with any other policy.
When parsing a certificate, a positive non-zero InhibitAnyPolicy means
that the field was specified, -1 means it was unset, and
InhibitAnyPolicyZero being true mean that the field was explicitly set to
zero. The case of InhibitAnyPolicy==0 with InhibitAnyPolicyZero==false
should be treated equivalent to -1 (unset).
InhibitAnyPolicyZero indicates that InhibitAnyPolicy==0 should be
interpreted as an actual maximum path length of zero. Otherwise, that
combination is interpreted as InhibitAnyPolicy not being set.
InhibitPolicyMapping and InhibitPolicyMappingZero indicate the presence
and value of the inhibitPolicyMapping field of the policyConstraints
extension.
The value of InhibitPolicyMapping indicates the number of additional
certificates in the path after this certificate that may use policy
mapping.
When parsing a certificate, a positive non-zero InhibitPolicyMapping
means that the field was specified, -1 means it was unset, and
InhibitPolicyMappingZero being true mean that the field was explicitly
set to zero. The case of InhibitPolicyMapping==0 with
InhibitPolicyMappingZero==false should be treated equivalent to -1
(unset).
InhibitPolicyMappingZero indicates that InhibitPolicyMapping==0 should be
interpreted as an actual maximum path length of zero. Otherwise, that
combination is interpreted as InhibitAnyPolicy not being set.
IsCA bool
Issuer pkix.Name
IssuingCertificateURL []string
KeyUsage KeyUsage
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.
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.
// Validity bounds.
// Validity bounds.
RFC 5280, 4.2.2.1 (Authority Information Access)
PermittedDNSDomains []string
Name constraints
// if true then the name constraints are marked critical.
PermittedEmailAddresses []string
PermittedIPRanges []*net.IPNet
PermittedURIDomains []string
Policies contains all policy identifiers included in the certificate.
See CreateCertificate for context about how this field and the PolicyIdentifiers field
interact.
In Go 1.22, encoding/gob cannot handle and ignores this field.
PolicyIdentifiers contains asn1.ObjectIdentifiers, the components
of which are limited to int32. If a certificate contains a policy which
cannot be represented by asn1.ObjectIdentifier, it will not be included in
PolicyIdentifiers, but will be present in Policies, which contains all parsed
policy OIDs.
See CreateCertificate for context about how this field and the Policies field
interact.
PolicyMappings contains a list of policy mappings included in the certificate.
PublicKey any
PublicKeyAlgorithm PublicKeyAlgorithm
// Complete ASN.1 DER content (certificate, signature algorithm and signature).
// DER encoded Issuer
// DER encoded Subject
// DER encoded SubjectPublicKeyInfo.
// Certificate part of raw ASN.1 DER content.
RequireExplicitPolicy and RequireExplicitPolicyZero indicate the presence
and value of the requireExplicitPolicy field of the policyConstraints
extension.
The value of RequireExplicitPolicy indicates the number of additional
certificates in the path after this certificate before an explicit policy
is required for the rest of the path. When an explicit policy is required,
each subsequent certificate in the path must contain a required policy OID,
or a policy OID which has been declared as equivalent through the policy
mapping extension.
When parsing a certificate, a positive non-zero RequireExplicitPolicy
means that the field was specified, -1 means it was unset, and
RequireExplicitPolicyZero being true mean that the field was explicitly
set to zero. The case of RequireExplicitPolicy==0 with
RequireExplicitPolicyZero==false should be treated equivalent to -1
(unset).
RequireExplicitPolicyZero indicates that RequireExplicitPolicy==0 should be
interpreted as an actual maximum path length of zero. Otherwise, that
combination is interpreted as InhibitAnyPolicy not being set.
SerialNumber *big.Int
Signature []byte
SignatureAlgorithm SignatureAlgorithm
Subject pkix.Name
SubjectKeyId []byte
URIs []*url.URL
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.
// Encountered extended key usages unknown to this package.
Version int
CheckCRLSignature checks that the signature in crl is from c.
Deprecated: Use [RevocationList.CheckSignatureFrom] instead.
CheckSignature verifies that signature is a valid signature over signed from
c's public key.
This is a low-level API that performs no validity checks on the certificate.
[MD5WithRSA] signatures are rejected, while [SHA1WithRSA] and [ECDSAWithSHA1]
signatures are currently accepted.
CheckSignatureFrom verifies that the signature on c is a valid signature from parent.
This is a low-level API that performs very limited checks, and not a full
path verifier. Most users should use [Certificate.Verify] instead.
CreateCRL returns a DER encoded CRL, signed by this Certificate, that
contains the given list of revoked certificates.
Deprecated: this method does not generate an RFC 5280 conformant X.509 v2 CRL.
To generate a standards compliant CRL, use [CreateRevocationList] instead.
(*Certificate) Equal(other *Certificate) bool
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.)
Certificates that use SHA1WithRSA and ECDSAWithSHA1 signatures are not supported,
and will not be used to build chains.
Certificates other than c in the returned chains should not be modified.
WARNING: this function doesn't do any revocation checking.
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 complete left-most label (e.g. *.example.com).
Note that the legacy Common Name field is ignored.
func ParseCertificate(der []byte) (*Certificate, error)
func ParseCertificates(der []byte) ([]*Certificate, error)
func (*Certificate).Verify(opts VerifyOptions) (chains [][]*Certificate, err error)
func net/http/httptest.(*Server).Certificate() *Certificate
func CreateCertificate(rand io.Reader, template, parent *Certificate, pub, priv any) ([]byte, error)
func CreateRevocationList(rand io.Reader, template *RevocationList, issuer *Certificate, priv crypto.Signer) ([]byte, error)
func (*Certificate).CheckSignatureFrom(parent *Certificate) error
func (*Certificate).Equal(other *Certificate) bool
func (*CertPool).AddCert(cert *Certificate)
func (*CertPool).AddCertWithConstraint(cert *Certificate, constraint func([]*Certificate) error)
func (*RevocationList).CheckSignatureFrom(parent *Certificate) error
CertificateInvalidError results when an odd error occurs. Users of this
library probably want to handle all these errors uniformly.
Cert *Certificate
Detail string
Reason InvalidReason
( CertificateInvalidError) Error() string
CertificateInvalidError : error
CertificateRequest represents a PKCS #10, certificate signature request.
Attributes contains the CSR attributes that can parse as
pkix.AttributeTypeAndValueSET.
Deprecated: Use Extensions and ExtraExtensions instead for parsing and
generating the requestedExtensions attribute.
Subject Alternate Name values.
EmailAddresses []string
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.
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.
IPAddresses []net.IP
PublicKey any
PublicKeyAlgorithm PublicKeyAlgorithm
// Complete ASN.1 DER content (CSR, signature algorithm and signature).
// DER encoded Subject.
// DER encoded SubjectPublicKeyInfo.
// Certificate request info part of raw ASN.1 DER content.
Signature []byte
SignatureAlgorithm SignatureAlgorithm
Subject pkix.Name
URIs []*url.URL
Version int
CheckSignature reports whether the signature on c is valid.
func ParseCertificateRequest(asn1Data []byte) (*CertificateRequest, error)
func CreateCertificateRequest(rand io.Reader, template *CertificateRequest, priv any) (csr []byte, err error)
CertPool is a set of certificates.
AddCert adds a certificate to a pool.
AddCertWithConstraint adds a certificate to the pool with the additional
constraint. When Certificate.Verify builds a chain which is rooted by cert,
it will additionally pass the whole chain to constraint to determine its
validity. If constraint returns a non-nil error, the chain will be discarded.
constraint may be called concurrently from multiple goroutines.
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.
Clone returns a copy of s.
Equal reports whether s and other are equal.
Subjects returns a list of the DER-encoded subjects of
all of the certificates in the pool.
Deprecated: if s was returned by [SystemCertPool], Subjects
will not include the system roots.
func NewCertPool() *CertPool
func SystemCertPool() (*CertPool, error)
func (*CertPool).Clone() *CertPool
func SetFallbackRoots(roots *CertPool)
func (*CertPool).Equal(other *CertPool) bool
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.
( ConstraintViolationError) Error() string
ConstraintViolationError : error
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
const ExtKeyUsageClientAuth
const ExtKeyUsageCodeSigning
const ExtKeyUsageEmailProtection
const ExtKeyUsageIPSECEndSystem
const ExtKeyUsageIPSECTunnel
const ExtKeyUsageIPSECUser
const ExtKeyUsageMicrosoftCommercialCodeSigning
const ExtKeyUsageMicrosoftKernelCodeSigning
const ExtKeyUsageMicrosoftServerGatedCrypto
const ExtKeyUsageNetscapeServerGatedCrypto
const ExtKeyUsageOCSPSigning
const ExtKeyUsageServerAuth
const ExtKeyUsageTimeStamping
HostnameError results when the set of authorized names doesn't match the
requested name.
Certificate *Certificate
Host string
( HostnameError) Error() string
HostnameError : error
An InsecureAlgorithmError indicates that the [SignatureAlgorithm] used to
generate the signature is not secure, and the signature has been rejected.
( InsecureAlgorithmError) Error() string
InsecureAlgorithmError : error
const CANotAuthorizedForExtKeyUsage
const CANotAuthorizedForThisName
const Expired
const IncompatibleUsage
const NameConstraintsWithoutSANs
const NameMismatch
const NotAuthorizedToSign
const NoValidChains
const TooManyConstraints
const TooManyIntermediates
const UnconstrainedName
KeyUsage represents the set of actions that are valid for a given key. It's
a bitmap of the KeyUsage* constants.
const KeyUsageCertSign
const KeyUsageContentCommitment
const KeyUsageCRLSign
const KeyUsageDataEncipherment
const KeyUsageDecipherOnly
const KeyUsageDigitalSignature
const KeyUsageEncipherOnly
const KeyUsageKeyAgreement
const KeyUsageKeyEncipherment
An OID represents an ASN.1 OBJECT IDENTIFIER.
AppendBinary implements [encoding.BinaryAppender]
AppendText implements [encoding.TextAppender]
Equal returns true when oid and other represents the same Object Identifier.
EqualASN1OID returns whether an OID equals an asn1.ObjectIdentifier. If
asn1.ObjectIdentifier cannot represent the OID specified by oid, because
a component of OID requires more than 31 bits, it returns false.
MarshalBinary implements [encoding.BinaryMarshaler]
MarshalText implements [encoding.TextMarshaler]
Strings returns the string representation of the Object Identifier.
UnmarshalBinary implements [encoding.BinaryUnmarshaler]
UnmarshalText implements [encoding.TextUnmarshaler]
OID : encoding.BinaryAppender
OID : encoding.BinaryMarshaler
*OID : encoding.BinaryUnmarshaler
OID : encoding.TextAppender
OID : encoding.TextMarshaler
*OID : encoding.TextUnmarshaler
OID : expvar.Var
OID : fmt.Stringer
func OIDFromInts(oid []uint64) (OID, error)
func ParseOID(oid string) (OID, error)
func OID.Equal(other OID) bool
func EncryptPEMBlock(rand io.Reader, blockType string, data, password []byte, alg PEMCipher) (*pem.Block, error)
const PEMCipher3DES
const PEMCipherAES128
const PEMCipherAES192
const PEMCipherAES256
const PEMCipherDES
PolicyMapping represents a policy mapping entry in the policyMappings extension.
IssuerDomainPolicy contains a policy OID the issuing certificate considers
equivalent to SubjectDomainPolicy in the subject certificate.
SubjectDomainPolicy contains a OID the issuing certificate considers
equivalent to IssuerDomainPolicy in the subject certificate.
( PublicKeyAlgorithm) String() string
PublicKeyAlgorithm : expvar.Var
PublicKeyAlgorithm : fmt.Stringer
const DSA
const ECDSA
const Ed25519
const RSA
const UnknownPublicKeyAlgorithm
RevocationList represents a [Certificate] Revocation List (CRL) as specified
by RFC 5280.
AuthorityKeyId is used to identify the public key associated with the
issuing certificate. It is populated from the authorityKeyIdentifier
extension when parsing a CRL. It is ignored when creating a CRL; the
extension is populated from the issuing certificate itself.
Extensions contains raw X.509 extensions. When creating a CRL,
the Extensions field is ignored, see ExtraExtensions.
ExtraExtensions contains any additional extensions to add directly to
the CRL.
Issuer contains the DN of the issuing certificate.
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.
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. It is also populated from the cRLNumber
extension when parsing a CRL.
Raw contains the complete ASN.1 DER content of the CRL (tbsCertList,
signatureAlgorithm, and signatureValue.)
RawIssuer contains the DER encoded Issuer.
RawTBSRevocationList contains just the tbsCertList portion of the ASN.1
DER.
RevokedCertificateEntries represents the revokedCertificates sequence in
the CRL. It is used when creating a CRL and also populated when parsing a
CRL. When creating a CRL, it may be empty or nil, in which case the
revokedCertificates ASN.1 sequence will be omitted from the CRL entirely.
RevokedCertificates is used to populate the revokedCertificates
sequence in the CRL if RevokedCertificateEntries is empty. It may be empty
or nil, in which case an empty CRL will be created.
Deprecated: Use RevokedCertificateEntries instead.
Signature []byte
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.
ThisUpdate is used to populate the thisUpdate field in the CRL, which
indicates the issuance date of the CRL.
CheckSignatureFrom verifies that the signature on rl is a valid signature
from issuer.
func ParseRevocationList(der []byte) (*RevocationList, error)
func CreateRevocationList(rand io.Reader, template *RevocationList, issuer *Certificate, priv crypto.Signer) ([]byte, error)
RevocationListEntry represents an entry in the revokedCertificates
sequence of a CRL.
Extensions contains raw X.509 extensions. When parsing CRL entries,
this can be used to extract non-critical extensions that are not
parsed by this package. When marshaling CRL entries, the Extensions
field is ignored, see ExtraExtensions.
ExtraExtensions contains extensions to be copied, raw, into any
marshaled CRL entries. Values override any extensions that would
otherwise be produced based on the other fields. The ExtraExtensions
field is not populated when parsing CRL entries, see Extensions.
Raw contains the raw bytes of the revokedCertificates entry. It is set when
parsing a CRL; it is ignored when generating a CRL.
ReasonCode represents the reason for revocation, using the integer enum
values specified in RFC 5280 Section 5.3.1. When creating a CRL, the zero
value will result in the reasonCode extension being omitted. When parsing a
CRL, the zero value may represent either the reasonCode extension being
absent (which implies the default revocation reason of 0/Unspecified), or
it may represent the reasonCode extension being present and explicitly
containing a value of 0/Unspecified (which should not happen according to
the DER encoding rules, but can and does happen anyway).
RevocationTime represents the time at which the certificate was revoked. It
is both used when creating a CRL and populated when parsing a CRL. It must
not be the zero time.
SerialNumber represents the serial number of a revoked certificate. It is
both used when creating a CRL and populated when parsing a CRL. It must not
be nil.
( SignatureAlgorithm) String() string
SignatureAlgorithm : expvar.Var
SignatureAlgorithm : fmt.Stringer
func (*Certificate).CheckSignature(algo SignatureAlgorithm, signed, signature []byte) error
const DSAWithSHA1
const DSAWithSHA256
const ECDSAWithSHA1
const ECDSAWithSHA256
const ECDSAWithSHA384
const ECDSAWithSHA512
const MD2WithRSA
const MD5WithRSA
const PureEd25519
const SHA1WithRSA
const SHA256WithRSA
const SHA256WithRSAPSS
const SHA384WithRSA
const SHA384WithRSAPSS
const SHA512WithRSA
const SHA512WithRSAPSS
const UnknownSignatureAlgorithm
SystemRootsError results when we fail to load the system root certificates.
Err error
( SystemRootsError) Error() string
( SystemRootsError) Unwrap() error
SystemRootsError : error
UnknownAuthorityError results when the certificate issuer is unknown
Cert *Certificate
( UnknownAuthorityError) Error() string
UnknownAuthorityError : error
VerifyOptions contains parameters for Certificate.Verify.
CertificatePolicies specifies which certificate policy OIDs are
acceptable during policy validation. An empty CertificatePolices
field implies any valid policy is acceptable.
CurrentTime is used to check the validity of all certificates in the
chain. If zero, the current time is used.
DNSName, if set, is checked against the leaf certificate with
Certificate.VerifyHostname or the platform verifier.
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.
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.
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.
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.
func (*Certificate).Verify(opts VerifyOptions) (chains [][]*Certificate, err error)
Package-Level Functions (total 27)
CreateCertificate creates a new X.509 v3 certificate based on a template.
The following members of template are currently 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 (see note below)
- Policies (see note below)
- 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
certificate to be generated 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 or crypto.MessageSigner 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.
If template.SerialNumber is nil, a serial number will be generated which
conforms to RFC 5280, Section 4.1.2.2 using entropy from rand.
The PolicyIdentifier and Policies fields can both be used to marshal certificate
policy OIDs. By default, only the Policies is marshaled, but if the
GODEBUG setting "x509usepolicies" has the value "0", the PolicyIdentifiers field will
be marshaled instead of the Policies field. This changed in Go 1.24. The Policies field can
be used to marshal policy OIDs which have components that are larger than 31
bits.
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 or
crypto.MessageSigner 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.
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 a crypto.Signer or
crypto.MessageSigner 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.
DecryptPEMBlock takes a PEM block encrypted according to RFC 1423 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 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.
Deprecated: Legacy PEM encryption as specified in RFC 1423 is insecure by
design. Since it does not authenticate the ciphertext, it is vulnerable to
padding oracle attacks that can let an attacker recover the plaintext.
EncryptPEMBlock returns a PEM block of the specified type holding the
given DER encoded data encrypted with the specified algorithm and
password according to RFC 1423.
Deprecated: Legacy PEM encryption as specified in RFC 1423 is insecure by
design. Since it does not authenticate the ciphertext, it is vulnerable to
padding oracle attacks that can let an attacker recover the plaintext.
IsEncryptedPEMBlock returns whether the PEM block is password encrypted
according to RFC 1423.
Deprecated: Legacy PEM encryption as specified in RFC 1423 is insecure by
design. Since it does not authenticate the ciphertext, it is vulnerable to
padding oracle attacks that can let an attacker recover the plaintext.
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].
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].
The key must have passed validation by calling [rsa.PrivateKey.Validate]
first. MarshalPKCS1PrivateKey calls [rsa.PrivateKey.Precompute], which may
modify the key if not already precomputed.
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".
MarshalPKCS8PrivateKey converts a private key to PKCS #8, ASN.1 DER form.
The following key types are currently supported: *[rsa.PrivateKey],
*[ecdsa.PrivateKey], [ed25519.PrivateKey] (not a pointer), and *[ecdh.PrivateKey].
Unsupported key types result in an error.
This kind of key is commonly encoded in PEM blocks of type "PRIVATE KEY".
MarshalPKCS8PrivateKey runs [rsa.PrivateKey.Precompute] on RSA keys.
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], [ed25519.PublicKey] (not a pointer), and *[ecdh.PublicKey].
Unsupported key types result in an error.
This kind of key is commonly encoded in PEM blocks of type "PUBLIC KEY".
NewCertPool returns a new, empty CertPool.
OIDFromInts creates a new OID using ints, each integer is a separate component.
ParseCertificate parses a single certificate from the given ASN.1 DER data.
Before Go 1.23, ParseCertificate accepted certificates with negative serial
numbers. This behavior can be restored by including "x509negativeserial=1" in
the GODEBUG environment variable.
ParseCertificateRequest parses a single certificate request from the
given ASN.1 DER data.
ParseCertificates parses one or more certificates from the given ASN.1 DER
data. The certificates must be concatenated with no intermediate padding.
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.
Deprecated: Use [ParseRevocationList] instead.
ParseDERCRL parses a DER encoded CRL from the given bytes.
Deprecated: Use [ParseRevocationList] instead.
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".
ParseOID parses a Object Identifier string, represented by ASCII numbers separated by dots.
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".
Before Go 1.24, the CRT parameters were ignored and recomputed. To restore
the old behavior, use the GODEBUG=x509rsacrt=0 environment variable.
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".
ParsePKCS8PrivateKey parses an unencrypted private key in PKCS #8, ASN.1 DER form.
It returns a *[rsa.PrivateKey], an *[ecdsa.PrivateKey], an [ed25519.PrivateKey] (not
a pointer), or an *[ecdh.PrivateKey] (for X25519). More types might be supported
in the future.
This kind of key is commonly encoded in PEM blocks of type "PRIVATE KEY".
Before Go 1.24, the CRT parameters of RSA keys were ignored and recomputed.
To restore the old behavior, use the GODEBUG=x509rsacrt=0 environment variable.
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],
[ed25519.PublicKey] (not a pointer), or *[ecdh.PublicKey] (for X25519).
More types might be supported in the future.
This kind of key is commonly encoded in PEM blocks of type "PUBLIC KEY".
ParseRevocationList parses a X509 v2 [Certificate] Revocation List from the given
ASN.1 DER data.
SetFallbackRoots sets the roots to use during certificate verification, if no
custom roots are specified and a platform verifier or a system certificate
pool is not available (for instance in a container which does not have a root
certificate bundle). SetFallbackRoots will panic if roots is nil.
SetFallbackRoots may only be called once, if called multiple times it will
panic.
The fallback behavior can be forced on all platforms, even when there is a
system certificate pool, by setting GODEBUG=x509usefallbackroots=1 (note that
on Windows and macOS this will disable usage of the platform verification
APIs and cause the pure Go verifier to be used). Setting
x509usefallbackroots=1 without calling SetFallbackRoots has no effect.
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.
Package-Level Variables (total 2)
ErrUnsupportedAlgorithm results from attempting to perform an operation that
involves algorithms that are not currently implemented.
IncorrectPasswordError is returned when an incorrect password is detected.
Package-Level Constants (total 61)
CANotAuthorizedForExtKeyUsage results when an intermediate or root
certificate does not permit a requested extended key usage.
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.
const DSA PublicKeyAlgorithm = 2 // Only supported for parsing. const DSAWithSHA1 SignatureAlgorithm = 7 // Unsupported. const DSAWithSHA256 SignatureAlgorithm = 8 // Unsupported. const ECDSA PublicKeyAlgorithm = 3 const ECDSAWithSHA1 SignatureAlgorithm = 9 // Only supported for signing, and verification of CRLs, CSRs, and OCSP responses. const ECDSAWithSHA256 SignatureAlgorithm = 10 const ECDSAWithSHA384 SignatureAlgorithm = 11 const ECDSAWithSHA512 SignatureAlgorithm = 12 const Ed25519 PublicKeyAlgorithm = 4
Expired results when a certificate has expired, based on the time
given in the VerifyOptions.
const ExtKeyUsageAny ExtKeyUsage = 0 const ExtKeyUsageClientAuth ExtKeyUsage = 2 const ExtKeyUsageCodeSigning ExtKeyUsage = 3 const ExtKeyUsageEmailProtection ExtKeyUsage = 4 const ExtKeyUsageIPSECEndSystem ExtKeyUsage = 5 const ExtKeyUsageIPSECTunnel ExtKeyUsage = 6 const ExtKeyUsageIPSECUser ExtKeyUsage = 7 const ExtKeyUsageMicrosoftKernelCodeSigning ExtKeyUsage = 13 const ExtKeyUsageMicrosoftServerGatedCrypto ExtKeyUsage = 10 const ExtKeyUsageNetscapeServerGatedCrypto ExtKeyUsage = 11 const ExtKeyUsageOCSPSigning ExtKeyUsage = 9 const ExtKeyUsageServerAuth ExtKeyUsage = 1 const ExtKeyUsageTimeStamping ExtKeyUsage = 8
IncompatibleUsage results when the certificate's key usage indicates
that it may only be used for a different purpose.
const KeyUsageCertSign KeyUsage = 32 const KeyUsageContentCommitment KeyUsage = 2 const KeyUsageCRLSign KeyUsage = 64 const KeyUsageDataEncipherment KeyUsage = 8 const KeyUsageDecipherOnly KeyUsage = 256 const KeyUsageDigitalSignature KeyUsage = 1 const KeyUsageEncipherOnly KeyUsage = 128 const KeyUsageKeyAgreement KeyUsage = 16 const KeyUsageKeyEncipherment KeyUsage = 4 const MD2WithRSA SignatureAlgorithm = 1 // Unsupported. const MD5WithRSA SignatureAlgorithm = 2 // Only supported for signing, not verification.
NameConstraintsWithoutSANs is a legacy error and is no longer returned.
NameMismatch results when the subject name of a parent certificate
does not match the issuer name in the child.
NotAuthorizedToSign results when a certificate is signed by another
which isn't marked as a CA certificate.
NoValidChains results when there are no valid chains to return.
Possible values for the EncryptPEMBlock encryption algorithm.
Possible values for the EncryptPEMBlock encryption algorithm.
Possible values for the EncryptPEMBlock encryption algorithm.
Possible values for the EncryptPEMBlock encryption algorithm.
Possible values for the EncryptPEMBlock encryption algorithm.
const PureEd25519 SignatureAlgorithm = 16 const RSA PublicKeyAlgorithm = 1 const SHA1WithRSA SignatureAlgorithm = 3 // Only supported for signing, and verification of CRLs, CSRs, and OCSP responses. const SHA256WithRSA SignatureAlgorithm = 4 const SHA256WithRSAPSS SignatureAlgorithm = 13 const SHA384WithRSA SignatureAlgorithm = 5 const SHA384WithRSAPSS SignatureAlgorithm = 14 const SHA512WithRSA SignatureAlgorithm = 6 const SHA512WithRSAPSS SignatureAlgorithm = 15
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.
TooManyIntermediates results when a path length constraint is
violated.
UnconstrainedName results when a CA certificate contains permitted
name constraints, but leaf certificate contains a name of an
unsupported or unconstrained type.
const UnknownPublicKeyAlgorithm PublicKeyAlgorithm = 0 const UnknownSignatureAlgorithm SignatureAlgorithm = 0 |
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