Package org.apache.poi.poifs.crypt.dsig

Class SignatureInfo

  • All Implemented Interfaces:
    SignatureConfig.SignatureConfigurable
    public class SignatureInfo
extends Object
implements SignatureConfig.SignatureConfigurable

    This class is the default entry point for XML signatures and can be used for validating an existing signed office document and signing a office document.

    Validating a signed office document

     OPCPackage pkg = OPCPackage.open(..., PackageAccess.READ);
 SignatureConfig sic = new SignatureConfig();
 sic.setOpcPackage(pkg);
 SignatureInfo si = new SignatureInfo();
 si.setSignatureConfig(sic);
 boolean isValid = si.validate();
 ...

    Signing an office document

     // loading the keystore - pkcs12 is used here, but of course jks & co are also valid
 // the keystore needs to contain a private key and it's certificate having a
 // 'digitalSignature' key usage
 char password[] = "test".toCharArray();
 File file = new File("test.pfx");
 KeyStore keystore = KeyStore.getInstance("PKCS12");
 FileInputStream fis = new FileInputStream(file);
 keystore.load(fis, password);
 fis.close();

 // extracting private key and certificate
 String alias = "xyz"; // alias of the keystore entry
 Key key = keystore.getKey(alias, password);
 X509Certificate x509 = (X509Certificate)keystore.getCertificate(alias);

 // filling the SignatureConfig entries (minimum fields, more options are available ...)
 SignatureConfig signatureConfig = new SignatureConfig();
 signatureConfig.setKey(keyPair.getPrivate());
 signatureConfig.setSigningCertificateChain(Collections.singletonList(x509));
 OPCPackage pkg = OPCPackage.open(..., PackageAccess.READ_WRITE);
 signatureConfig.setOpcPackage(pkg);

 // adding the signature document to the package
 SignatureInfo si = new SignatureInfo();
 si.setSignatureConfig(signatureConfig);
 si.confirmSignature();
 // optionally verify the generated signature
 boolean b = si.verifySignature();
 assert (b);
 // write the changes back to disc
 pkg.close();

    Implementation notes:

    Although there's a XML signature implementation in the Oracle JDKs 6 and higher, compatibility with IBM JDKs is also in focus (... but maybe not thoroughly tested ...). Therefore we are using the Apache Santuario libs (xmlsec) instead of the built-in classes, as the compatibility seems to be provided there.

    To use SignatureInfo and its sibling classes, you'll need to have the following libs in the classpath:

    • BouncyCastle bcpkix and bcprov (tested against 1.60)
    • Apache Santuario "xmlsec" (tested against 2.1.0)
    • and slf4j-api (tested against 1.7.25)

    • Constructor Detail

      • SignatureInfo

        public SignatureInfo()
        Constructor initializes xml signature environment, if it hasn't been initialized before