ietf-cms/signed_data.go

84 строки
2.1 KiB
Go

package cms
import (
"crypto/x509"
"encoding/asn1"
"github.com/github/ietf-cms/protocol"
)
// SignedData represents a signed message or detached signature.
type SignedData struct {
psd *protocol.SignedData
}
// NewSignedData creates a new SignedData from the given data.
func NewSignedData(data []byte) (*SignedData, error) {
eci, err := protocol.NewDataEncapsulatedContentInfo(data)
if err != nil {
return nil, err
}
psd, err := protocol.NewSignedData(eci)
if err != nil {
return nil, err
}
return &SignedData{psd}, nil
}
// ParseSignedData parses a SignedData from BER encoded data.
func ParseSignedData(ber []byte) (*SignedData, error) {
ci, err := protocol.ParseContentInfo(ber)
if err != nil {
return nil, err
}
psd, err := ci.SignedDataContent()
if err != nil {
return nil, err
}
return &SignedData{psd}, nil
}
// GetData gets the encapsulated data from the SignedData. Nil will be returned
// if this is a detached signature. A protocol.ErrWrongType will be returned if
// the SignedData encapsulates something other than data (1.2.840.113549.1.7.1).
func (sd *SignedData) GetData() ([]byte, error) {
return sd.psd.EncapContentInfo.DataEContent()
}
// GetCertificates gets all the certificates stored in the SignedData.
func (sd *SignedData) GetCertificates() ([]*x509.Certificate, error) {
return sd.psd.X509Certificates()
}
// SetCertificates replaces the certificates stored in the SignedData with new
// ones.
func (sd *SignedData) SetCertificates(certs []*x509.Certificate) error {
sd.psd.ClearCertificates()
for _, cert := range certs {
if err := sd.psd.AddCertificate(cert); err != nil {
return err
}
}
return nil
}
// Detached removes the data content from this SignedData. No more signatures
// can be added after this method has been called.
func (sd *SignedData) Detached() {
sd.psd.EncapContentInfo.EContent = asn1.RawValue{}
}
// IsDetached checks if this SignedData has data content.
func (sd *SignedData) IsDetached() bool {
return sd.psd.EncapContentInfo.EContent.Bytes == nil
}
// ToDER encodes this SignedData message using DER.
func (sd *SignedData) ToDER() ([]byte, error) {
return sd.psd.ContentInfoDER()
}