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PKCS7SignedData.javaAPI DocAndroid 1.5 API19057Wed May 06 22:41:06 BST 2009org.bouncycastle.jce

PKCS7SignedData

public class PKCS7SignedData extends Object implements org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers
Represents a PKCS#7 object - specifically the "Signed Data" type.

How to use it? To verify a signature, do: 

PKCS7SignedData pkcs7 = new PKCS7SignedData(der_bytes); // Create it
pkcs7.update(bytes, 0, bytes.length); // Update checksum
boolean verified = pkcs7.verify(); // Does it add up?

To sign, do this:
PKCS7SignedData pkcs7 = new PKCS7SignedData(privKey, certChain, "MD5");
pkcs7.update(bytes, 0, bytes.length); // Update checksum
pkcs7.sign(); // Create digest

bytes = pkcs7.getEncoded(); // Write it somewhere

This class is pretty close to obsolete, for a much better (and more complete) implementation of PKCS7 have a look at the org.bouncycastle.cms package.

deprecated
this class really is obsolete - use the CMS package.

Fields Summary
private int
version
private int
signerversion
private Set
digestalgos
private Collection
certs
private Collection
crls
private X509Certificate
signCert
private byte[]
digest
private String
digestAlgorithm
private String
digestEncryptionAlgorithm
private Signature
sig
private transient PrivateKey
privKey
private final String
ID_PKCS7_DATA
private final String
ID_PKCS7_SIGNED_DATA
private final String
ID_MD5
private final String
ID_MD2
private final String
ID_SHA1
private final String
ID_RSA
private final String
ID_DSA
Constructors Summary
public PKCS7SignedData(byte[] in)
Read an existing PKCS#7 object from a DER encoded byte array using the BC provider.


                        
     
          
           
         
    
        this(in, "BC");
public PKCS7SignedData(byte[] in, String provider)
Read an existing PKCS#7 object from a DER encoded byte array

        ASN1InputStream din = new ASN1InputStream(new ByteArrayInputStream(in));

        //
        // Basic checks to make sure it's a PKCS#7 SignedData Object
        //
        DERObject pkcs;

        try
        {
            pkcs = din.readObject();
        }
        catch (IOException e)
        {
            throw new SecurityException("can't decode PKCS7SignedData object");
        }

        if (!(pkcs instanceof ASN1Sequence))
        {
            throw new SecurityException("Not a valid PKCS#7 object - not a sequence");
        }

        ContentInfo content = ContentInfo.getInstance(pkcs);

        if (!content.getContentType().equals(signedData))
        {
            throw new SecurityException("Not a valid PKCS#7 signed-data object - wrong header " + content.getContentType().getId());
        }


        SignedData  data = SignedData.getInstance(content.getContent());

        certs = new ArrayList();

        if (data.getCertificates() != null)
        {
            Enumeration ec = ASN1Set.getInstance(data.getCertificates()).getObjects();

            while (ec.hasMoreElements())
            {
                certs.add(new X509CertificateObject(X509CertificateStructure.getInstance(ec.nextElement())));
            }
        }

        crls = new ArrayList();

        if (data.getCRLs() != null)
        {
            Enumeration ec = ASN1Set.getInstance(data.getCRLs()).getObjects();
            while (ec.hasMoreElements())
            {
                crls.add(new X509CRLObject(CertificateList.getInstance(ec.nextElement())));
            }
        }

        version = data.getVersion().getValue().intValue();

        //
        // Get the digest algorithm
        //
        digestalgos = new HashSet();
        Enumeration e = data.getDigestAlgorithms().getObjects();

        while (e.hasMoreElements())
        {
            ASN1Sequence s = (ASN1Sequence)e.nextElement();
            DERObjectIdentifier o = (DERObjectIdentifier)s.getObjectAt(0);
            digestalgos.add(o.getId());
        }

        //
        // Get the SignerInfo
        //
        ASN1Set signerinfos = data.getSignerInfos();
        if (signerinfos.size() != 1)
        {
            throw new SecurityException("This PKCS#7 object has multiple SignerInfos - only one is supported at this time");
        }

        SignerInfo signerInfo = SignerInfo.getInstance(signerinfos.getObjectAt(0));

        signerversion = signerInfo.getVersion().getValue().intValue();

        IssuerAndSerialNumber isAnds = signerInfo.getIssuerAndSerialNumber();

        //
        // Get the signing certificate
        //
        BigInteger      serialNumber = isAnds.getCertificateSerialNumber().getValue();
        X509Principal   issuer = new X509Principal(isAnds.getName());

        for (Iterator i = certs.iterator();i.hasNext();)
        {
            X509Certificate cert = (X509Certificate)i.next();
            if (serialNumber.equals(cert.getSerialNumber())
                    && issuer.equals(cert.getIssuerDN()))
            {
                signCert = cert;
                break;
            }
        }

        if (signCert == null)
        {
            throw new SecurityException("Can't find signing certificate with serial "+serialNumber.toString(16)); 
        }

        digestAlgorithm = signerInfo.getDigestAlgorithm().getObjectId().getId();

        digest = signerInfo.getEncryptedDigest().getOctets();
        digestEncryptionAlgorithm = signerInfo.getDigestEncryptionAlgorithm().getObjectId().getId();

        sig = Signature.getInstance(getDigestAlgorithm(), provider);

        sig.initVerify(signCert.getPublicKey());
public PKCS7SignedData(PrivateKey privKey, Certificate[] certChain, String hashAlgorithm)
Create a new PKCS#7 object from the specified key using the BC provider.

param
privKey the private key to be used for signing.
param
certChain the certificate chain associated with the private key.
param
hashAlgorithm the hashing algorithm used to compute the message digest. Must be "MD5", "MD2", "SHA1" or "SHA"

        this(privKey, certChain, hashAlgorithm, "BC");
public PKCS7SignedData(PrivateKey privKey, Certificate[] certChain, String hashAlgorithm, String provider)
Create a new PKCS#7 object from the specified key.

param
privKey the private key to be used for signing.
param
certChain the certificate chain associated with the private key.
param
hashAlgorithm the hashing algorithm used to compute the message digest. Must be "MD5", "MD2", "SHA1" or "SHA"
param
provider the provider to use.

        this(privKey, certChain, null, hashAlgorithm, provider);
public PKCS7SignedData(PrivateKey privKey, Certificate[] certChain, CRL[] crlList, String hashAlgorithm, String provider)
Create a new PKCS#7 object from the specified key.

param
privKey the private key to be used for signing.
param
certChain the certificate chain associated with the private key.
param
crlList the crl list associated with the private key.
param
hashAlgorithm the hashing algorithm used to compute the message digest. Must be "MD5", "MD2", "SHA1" or "SHA"
param
provider the provider to use.

        this.privKey = privKey;

        if (hashAlgorithm.equals("MD5"))
        {
            digestAlgorithm = ID_MD5;
        }
        else if (hashAlgorithm.equals("MD2"))
        {
            digestAlgorithm = ID_MD2;
        }
        else if (hashAlgorithm.equals("SHA"))
        {
            digestAlgorithm = ID_SHA1;
        }
        else if (hashAlgorithm.equals("SHA1"))
        {
            digestAlgorithm = ID_SHA1;
        }
        else
        {
            throw new NoSuchAlgorithmException("Unknown Hash Algorithm "+hashAlgorithm);
        }

        version = signerversion = 1;
        certs = new ArrayList();
        crls = new ArrayList();
        digestalgos = new HashSet();
        digestalgos.add(digestAlgorithm);

        //
        // Copy in the certificates and crls used to sign the private key.
        //
        signCert = (X509Certificate)certChain[0];
        for (int i = 0;i < certChain.length;i++)
        {
            certs.add(certChain[i]);
        }

        if (crlList != null)
        {
            for (int i = 0;i < crlList.length;i++)
            {
                crls.add(crlList[i]);
            }
        }

        //
        // Now we have private key, find out what the digestEncryptionAlgorithm is.
        //
        digestEncryptionAlgorithm = privKey.getAlgorithm();
        if (digestEncryptionAlgorithm.equals("RSA"))
        {
            digestEncryptionAlgorithm = ID_RSA;
        }
        else if (digestEncryptionAlgorithm.equals("DSA"))
        {
            digestEncryptionAlgorithm = ID_DSA;
        }
        else
        {
            throw new NoSuchAlgorithmException("Unknown Key Algorithm "+digestEncryptionAlgorithm);
        }

        sig = Signature.getInstance(getDigestAlgorithm(), provider);

        sig.initSign(privKey);
Methods Summary
public java.util.CollectiongetCRLs()
Get the X.509 certificate revocation lists associated with this PKCS#7 object

        return crls;
public java.security.cert.Certificate[]getCertificates()
Get the X.509 certificates associated with this PKCS#7 object

        return (X509Certificate[])certs.toArray(new X509Certificate[certs.size()]);
public java.lang.StringgetDigestAlgorithm()
Get the algorithm used to calculate the message digest

        String da = digestAlgorithm;
        String dea = digestEncryptionAlgorithm;

        if (digestAlgorithm.equals(ID_MD5))
        {
            da = "MD5";
        }
        else if (digestAlgorithm.equals(ID_MD2))
        {
            da = "MD2";
        }
        else if (digestAlgorithm.equals(ID_SHA1))
        {
            da = "SHA1";
        }

        if (digestEncryptionAlgorithm.equals(ID_RSA))
        {
            dea = "RSA";
        }
        else if (digestEncryptionAlgorithm.equals(ID_DSA))
        {
            dea = "DSA";
        }

        return da + "with" + dea;
public byte[]getEncoded()
return the bytes for the PKCS7SignedData object.

        try
        {
        
            digest = sig.sign();

            // Create the set of Hash algorithms. I've assumed this is the
            // set of all hash agorithms used to created the digest in the
            // "signerInfo" structure. I may be wrong.
            //
            ASN1EncodableVector v = new ASN1EncodableVector();
            for (Iterator i = digestalgos.iterator(); i.hasNext();)
            {
                AlgorithmIdentifier a = new AlgorithmIdentifier(
                            new DERObjectIdentifier((String)i.next()),
                            null);
                
                v.add(a);
            }

            DERSet algos = new DERSet(v);

            // Create the contentInfo. Empty, I didn't implement this bit
            //
            DERSequence contentinfo = new DERSequence(
                                        new DERObjectIdentifier(ID_PKCS7_DATA));

            // Get all the certificates
            //
            v = new ASN1EncodableVector();
            for (Iterator i = certs.iterator();i.hasNext();)
            {
                ASN1InputStream tempstream = new ASN1InputStream(new ByteArrayInputStream(((X509Certificate)i.next()).getEncoded()));
                v.add(tempstream.readObject());
            }

            DERSet dercertificates = new DERSet(v);

            // Create signerinfo structure.
            //
            ASN1EncodableVector signerinfo = new ASN1EncodableVector();

            // Add the signerInfo version
            //
            signerinfo.add(new DERInteger(signerversion));

            IssuerAndSerialNumber isAnds = new IssuerAndSerialNumber(
                        new X509Name((ASN1Sequence)getIssuer(signCert.getTBSCertificate())),
                        new DERInteger(signCert.getSerialNumber()));
            signerinfo.add(isAnds);

            // Add the digestAlgorithm
            //
            // BEGIN android-changed
            signerinfo.add(new AlgorithmIdentifier(
                                new DERObjectIdentifier(digestAlgorithm),
                                DERNull.THE_ONE));

            //
            // Add the digestEncryptionAlgorithm
            //
            signerinfo.add(new AlgorithmIdentifier(
                                new DERObjectIdentifier(digestEncryptionAlgorithm),
                                DERNull.THE_ONE));
            // END android-changed

            //
            // Add the digest
            //
            signerinfo.add(new DEROctetString(digest));


            //
            // Finally build the body out of all the components above
            //
            ASN1EncodableVector body = new ASN1EncodableVector();
            body.add(new DERInteger(version));
            body.add(algos);
            body.add(contentinfo);
            body.add(new DERTaggedObject(false, 0, dercertificates));

            if (crls.size()>0)
            {
                v = new ASN1EncodableVector();
                for (Iterator i = crls.iterator();i.hasNext();)
                {
                    ASN1InputStream t = new ASN1InputStream(new ByteArrayInputStream(((X509CRL)i.next()).getEncoded()));
                    v.add(t.readObject());
                }
                DERSet dercrls = new DERSet(v);
                body.add(new DERTaggedObject(false, 1, dercrls));
            }

            // Only allow one signerInfo
            //
            body.add(new DERSet(new DERSequence(signerinfo)));

            // Now we have the body, wrap it in it's PKCS7Signed shell
            // and return it
            //
            ASN1EncodableVector whole = new ASN1EncodableVector();
            whole.add(new DERObjectIdentifier(ID_PKCS7_SIGNED_DATA));
            whole.add(new DERTaggedObject(0, new DERSequence(body)));

            ByteArrayOutputStream   bOut = new ByteArrayOutputStream();

            DEROutputStream dout = new DEROutputStream(bOut);
            dout.writeObject(new DERSequence(whole));
            dout.close();

            return bOut.toByteArray();
        }
        catch (Exception e)
        {
            throw new RuntimeException(e.toString());
        }
private DERObjectgetIssuer(byte[] enc)
Get the "issuer" from the TBSCertificate bytes that are passed in

        try
        {
            ASN1InputStream in = new ASN1InputStream(new ByteArrayInputStream(enc));
            ASN1Sequence seq = (ASN1Sequence)in.readObject();
            return (DERObject)seq.getObjectAt(seq.getObjectAt(0) instanceof DERTaggedObject ? 3 : 2);
        }
        catch (IOException e)
        {
            throw new Error("IOException reading from ByteArray: "+e);
        }
public java.security.cert.X509CertificategetSigningCertificate()
Get the X.509 certificate actually used to sign the digest.

        return signCert;
public intgetSigningInfoVersion()
Get the version of the PKCS#7 "SignerInfo" object. Always 1

        return signerversion;
public intgetVersion()
Get the version of the PKCS#7 object. Always 1

        return version;
public voidreset()
Resets the PKCS7SignedData object to it's initial state, ready to sign or verify a new buffer.

        try
        {
            if (privKey==null)
            {
                sig.initVerify(signCert.getPublicKey());
            }
            else
            {
                sig.initSign(privKey);
            }
        }
        catch (Exception e)
        {
            throw new RuntimeException(e.toString());
        }
public voidupdate(byte buf)
Update the digest with the specified byte. This method is used both for signing and verifying

        sig.update(buf);
public voidupdate(byte[] buf, int off, int len)
Update the digest with the specified bytes. This method is used both for signing and verifying

        sig.update(buf, off, len);
public booleanverify()
Verify the digest

        return sig.verify(digest);