Java tutorial
package org.bouncycastle.mail.smime; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.security.AccessController; import java.security.PrivilegedAction; import javax.activation.CommandMap; import javax.activation.MailcapCommandMap; import javax.mail.MessagingException; import javax.mail.Part; import javax.mail.Session; import javax.mail.internet.MimeBodyPart; import javax.mail.internet.MimeMessage; import javax.mail.internet.MimeMultipart; import javax.mail.internet.MimePart; import org.bouncycastle.cms.CMSException; import org.bouncycastle.cms.CMSProcessable; import org.bouncycastle.cms.CMSSignedData; /** * general class for handling a pkcs7-signature message. * <p> * A simple example of usage - note, in the example below the validity of * the certificate isn't verified, just the fact that one of the certs * matches the given signer... * <p> * <pre> * CertStore certs = s.getCertificates("Collection", "BC"); * SignerInformationStore signers = s.getSignerInfos(); * Collection c = signers.getSigners(); * Iterator it = c.iterator(); * * while (it.hasNext()) * { * SignerInformation signer = (SignerInformation)it.next(); * Collection certCollection = certs.getCertificates(signer.getSID()); * * Iterator certIt = certCollection.iterator(); * X509Certificate cert = (X509Certificate)certIt.next(); * * if (signer.verify(cert.getPublicKey())) * { * verified++; * } * } * </pre> * <p> * Note: if you are using this class with AS2 or some other protocol * that does not use 7bit as the default content transfer encoding you * will need to use the constructor that allows you to specify the default * content transfer encoding, such as "binary". * </p> */ public class SMIMESigned extends CMSSignedData { Object message; MimeBodyPart content; private static InputStream getInputStream(Part bodyPart) throws MessagingException { try { if (bodyPart.isMimeType("multipart/signed")) { throw new MessagingException( "attempt to create signed data object from multipart content - use MimeMultipart constructor."); } return bodyPart.getInputStream(); } catch (IOException e) { throw new MessagingException("can't extract input stream: " + e); } } static { final MailcapCommandMap mc = (MailcapCommandMap) CommandMap.getDefaultCommandMap(); mc.addMailcap( "application/pkcs7-signature;; x-java-content-handler=org.bouncycastle.mail.smime.handlers.pkcs7_signature"); mc.addMailcap( "application/pkcs7-mime;; x-java-content-handler=org.bouncycastle.mail.smime.handlers.pkcs7_mime"); mc.addMailcap( "application/x-pkcs7-signature;; x-java-content-handler=org.bouncycastle.mail.smime.handlers.x_pkcs7_signature"); mc.addMailcap( "application/x-pkcs7-mime;; x-java-content-handler=org.bouncycastle.mail.smime.handlers.x_pkcs7_mime"); mc.addMailcap( "multipart/signed;; x-java-content-handler=org.bouncycastle.mail.smime.handlers.multipart_signed"); AccessController.doPrivileged(new PrivilegedAction() { public Object run() { CommandMap.setDefaultCommandMap(mc); return null; } }); } /** * base constructor using a defaultContentTransferEncoding of 7bit * * @exception MessagingException on an error extracting the signature or * otherwise processing the message. * @exception CMSException if some other problem occurs. */ public SMIMESigned(MimeMultipart message) throws MessagingException, CMSException { super(new CMSProcessableBodyPartInbound(message.getBodyPart(0)), getInputStream(message.getBodyPart(1))); this.message = message; this.content = (MimeBodyPart) message.getBodyPart(0); } /** * base constructor with settable contentTransferEncoding * * @param message the signed message * @param defaultContentTransferEncoding new default to use * @exception MessagingException on an error extracting the signature or * otherwise processing the message. * @exception CMSException if some other problem occurs. */ public SMIMESigned(MimeMultipart message, String defaultContentTransferEncoding) throws MessagingException, CMSException { super(new CMSProcessableBodyPartInbound(message.getBodyPart(0), defaultContentTransferEncoding), getInputStream(message.getBodyPart(1))); this.message = message; this.content = (MimeBodyPart) message.getBodyPart(0); } /** * base constructor for a signed message with encapsulated content. * * @exception MessagingException on an error extracting the signature or * otherwise processing the message. * @exception SMIMEException if the body part encapsulated in the message cannot be extracted. * @exception CMSException if some other problem occurs. */ public SMIMESigned(Part message) throws MessagingException, CMSException, SMIMEException { super(getInputStream(message)); this.message = message; CMSProcessable cont = this.getSignedContent(); if (cont != null) { byte[] contBytes = (byte[]) cont.getContent(); this.content = SMIMEUtil.toMimeBodyPart(contBytes); } } /** * return the content that was signed. */ public MimeBodyPart getContent() { return content; } /** * Return the content that was signed as a mime message. * * @param session * @return a MimeMessage holding the content. * @throws MessagingException */ public MimeMessage getContentAsMimeMessage(Session session) throws MessagingException, IOException { Object content = getSignedContent().getContent(); byte[] contentBytes = null; if (content instanceof byte[]) { contentBytes = (byte[]) content; } else if (content instanceof MimePart) { MimePart part = (MimePart) content; ByteArrayOutputStream out; if (part.getSize() > 0) { out = new ByteArrayOutputStream(part.getSize()); } else { out = new ByteArrayOutputStream(); } part.writeTo(out); contentBytes = out.toByteArray(); } else { String type = "<null>"; if (content != null) { type = content.getClass().getName(); } throw new MessagingException("Could not transfrom content of type " + type + " into MimeMessage."); } if (contentBytes != null) { ByteArrayInputStream in = new ByteArrayInputStream(contentBytes); return new MimeMessage(session, in); } return null; } /** * return the content that was signed - depending on whether this was * unencapsulated or not it will return a MimeMultipart or a MimeBodyPart */ public Object getContentWithSignature() { return message; } }