PAdES B-LT example

go.mod

@@ -16,7 +16,7 @@ require (
 	github.com/unidoc/globalsign-dss v0.0.0-20220330092912-b69d85b63736
 	github.com/unidoc/pkcs7 v0.2.0
 	github.com/unidoc/unichart v0.3.0
-	github.com/unidoc/unipdf/v3 v3.49.0
+	github.com/unidoc/unipdf/v3 v3.50.0
 	github.com/wcharczuk/go-chart/v2 v2.1.0
 	go.opencensus.io v0.24.0 // indirect
 	golang.org/x/crypto v0.0.0-20220722155217-630584e8d5aa

go.sum

@@ -404,8 +404,8 @@ github.com/unidoc/timestamp v0.0.0-20200412005513-91597fd3793a/go.mod h1:j+qMWZV
 github.com/unidoc/unichart v0.1.0/go.mod h1:9sJXeqxIIsU2D07tmhpDMoND0mBFRGfKBJnXZMsJnzk=
 github.com/unidoc/unichart v0.3.0 h1:VX1j5yzhjrR3f2flC03Yat6/WF3h7Z+DLEvJLoTGhoc=
 github.com/unidoc/unichart v0.3.0/go.mod h1:8JnLNKSOl8yQt1jXewNgYFHhFm5M6/ZiaydncFDpakA=
-github.com/unidoc/unipdf/v3 v3.49.0 h1:G6o08ZEpH4s+szlY9PdTt9+2/vHaSmgBFYLExv74Upo=
-github.com/unidoc/unipdf/v3 v3.49.0/go.mod h1:wepYPiDK9JM54sIXGedULFgETtexs8vgqPUp8fQ6vXg=
+github.com/unidoc/unipdf/v3 v3.50.0 h1:+bC4AWZh/8nVLdHY/YoU176OhISryHteT3uQ7g3dlmU=
+github.com/unidoc/unipdf/v3 v3.50.0/go.mod h1:wepYPiDK9JM54sIXGedULFgETtexs8vgqPUp8fQ6vXg=
 github.com/unidoc/unitype v0.2.1 h1:x0jMn7pB/tNrjEVjy3Ukpxo++HOBQaTCXcTYFA6BH3w=
 github.com/unidoc/unitype v0.2.1/go.mod h1:mafyug7zYmDOusqa7G0dJV45qp4b6TDAN+pHN7ZUIBU=
 github.com/wcharczuk/go-chart/v2 v2.1.0 h1:tY2slqVQ6bN+yHSnDYwZebLQFkphK4WNrVwnt7CJZ2I=

signatures/README.md

@@ -12,6 +12,7 @@ Examples for digital signing of PDF files with UniDoc:
 - [pdf_sign_pades_b_b.go](pdf_sign_pades_b_b.go) Example of signing with a PAdES B-B compatible digital signature.
 - [pdf_sign_pades_b_t.go](pdf_sign_pades_b_t.go) Example of signing with a PAdES B-T compatible digital signature.
 - [pdf_sign_validate_pades_b_b.go](pdf_sign_validate_pades_b_b.go) Example of PAdES signature validation.
+- [pdf_sign_pades_b_lt.go](pdf_sign_pades_b_lt.go) Example of signing with a PAdES B-LT compatible digital signature.
 For LTV enabling digital signatures, see the [LTV](ltv) guide and samples.
 
 ## pdf_sign_hsm_pkcs11_cgo.go

signatures/pdf_sign_pades_b_lt.go

@@ -0,0 +1,161 @@
+/*
+ * This example showcases how to create a  PAdES B-LT compatible digital signature for a PDF file.
+ *
+ * $ ./pdf_sign_pades_b_lt <FILE.PFX> <PASSWORD> <FILE.PEM> <INPUT_PDF_PATH> <OUTPUT_PDF_PATH>
+ */
+package main
+
+import (
+	"bytes"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"time"
+
+	"golang.org/x/crypto/pkcs12"
+
+	"github.com/unidoc/unipdf/v3/annotator"
+	"github.com/unidoc/unipdf/v3/common/license"
+	"github.com/unidoc/unipdf/v3/core"
+	"github.com/unidoc/unipdf/v3/model"
+	"github.com/unidoc/unipdf/v3/model/sighandler"
+)
+
+func init() {
+	// Make sure to load your metered License API key prior to using the library.
+	// If you need a key, you can sign up and create a free one at https://cloud.unidoc.io
+	err := license.SetMeteredKey(os.Getenv(`UNIDOC_LICENSE_API_KEY`))
+	if err != nil {
+		panic(err)
+	}
+}
+
+const usagef = "Usage: %s PFX_FILE PASSWORD PEM_FILE INPUT_PDF_PATH OUTPUT_PDF_PATH\n"
+
+func main() {
+	args := os.Args
+	if len(args) < 6 {
+		fmt.Printf(usagef, os.Args[0])
+		return
+	}
+	pfxPath := args[1]
+	password := args[2]
+	pemPath := args[3]
+	inputPath := args[4]
+	outputPath := args[5]
+
+	// Get private key and X509 certificate from the PFX file.
+	pfxData, err := ioutil.ReadFile(pfxPath)
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	priv, cert, err := pkcs12.Decode(pfxData, password)
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	// Get CA Certificate from the PEM file.
+	caCertF, err := ioutil.ReadFile(pemPath)
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	certDERBlock, _ := pem.Decode(caCertF)
+
+	cacert, err := x509.ParseCertificate(certDERBlock.Bytes)
+
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+		return
+	}
+
+	// Create reader.
+	file, err := os.Open(inputPath)
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+	defer file.Close()
+
+	reader, err := model.NewPdfReader(file)
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	// Create appender.
+	appender, err := model.NewPdfAppender(reader)
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	// Set timestamp server.
+	timestampServerURL := "https://freetsa.org/tsr"
+
+	// Create signature handler.
+	handler, err := sighandler.NewEtsiPAdESLevelLT(priv.(*rsa.PrivateKey), cert, cacert, timestampServerURL, appender)
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	// Create signature.
+	signature := model.NewPdfSignature(handler)
+	signature.SetName("PAdES B-LT Signature PDF")
+	signature.SetReason("TestPAdESPDF")
+	signature.SetDate(time.Now(), "")
+
+	if err := signature.Initialize(); err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	// Create signature field and appearance.
+	opts := annotator.NewSignatureFieldOpts()
+	opts.FontSize = 10
+	opts.Rect = []float64{10, 25, 75, 60}
+
+	field, err := annotator.NewSignatureField(
+		signature,
+		[]*annotator.SignatureLine{
+			annotator.NewSignatureLine("Name", "John Doe"),
+			annotator.NewSignatureLine("Date", "2023.05.08"),
+			annotator.NewSignatureLine("Reason", "PAdES signature test"),
+		},
+		opts,
+	)
+	field.T = core.MakeString("Self signed PDF")
+
+	if err = appender.Sign(1, field); err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	// Write output to buffer.
+	buffer := bytes.NewBuffer(nil)
+	err = appender.Write(buffer)
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	// We need the second pass to correctly save DSS/VRI information.
+	pdf2, err := model.NewPdfReader(bytes.NewReader(buffer.Bytes()))
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	appender2, err := model.NewPdfAppender(pdf2)
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	appender2.SetDSS(appender.GetDSS())
+
+	// Write output to the PDF file.
+	err = appender2.WriteToFile(outputPath)
+	if err != nil {
+		log.Fatal("Fail: %v\n", err)
+	}
+
+	log.Printf("PDF file successfully signed. Output path: %s\n", outputPath)
+}