使用Java Mail驗證帶有Outlook 2013簽名的電子郵件

Question

我發送一封帶有簽名的電子郵件到我的收件箱。 然后我使用Java Mail接收郵件並驗證簽名。 但總是有一條錯誤消息' message-digest屬性值與計算值不匹配 '。

org.bouncycastle.cms.CMSSignerDigestMismatchException: message-digest attribute value does not match calculated value
at org.bouncycastle.cms.SignerInformation.doVerify(SignerInformation.java:517)
at org.bouncycastle.cms.SignerInformation.verify(SignerInformation.java:601)

我用maven

  <dependency> <groupId>javax.mail</groupId> <artifactId>mail</artifactId> <version>1.4.5</version> </dependency> <!-- Bouncy Castle Provider --> <dependency> <groupId>org.bouncycastle</groupId> <artifactId>bcprov-jdk15on</artifactId> <version>1.54</version> </dependency> <!-- BC Mail --> <dependency> <groupId>org.bouncycastle</groupId> <artifactId>bcmail-jdk15on</artifactId> <version>1.54</version> </dependency> 

這條線我得到了一個例外：

 verify = signer.verify(new JcaSimpleSignerInfoVerifierBuilder().setProvider("BC").build(certificate));

這是我的代碼：

    public static void receiveSignedMail(Message msg) throws MessagingException {
    try {
        SMIMESigned signed = new SMIMESigned((MimeMultipart) msg.getContent());
        if (isValid(signed)) {
            System.out.println("verification succeeded");
        } else {
            System.out.println("verification failed");
        }
        signed = new SMIMESigned((MimeMultipart) msg.getContent());
         MimeBodyPart content = signed.getContent();
         System.out.println("Content: " + content.getContent());
    } catch (Exception e) {
        e.printStackTrace(System.out);
    }
}

public static boolean isValid(CMSSignedData signedData) {
    try {
        SignerInformationStore signers = signedData.getSignerInfos();
        Iterator<SignerInformation> it = signers.getSigners().iterator();
        boolean verify = false;
        while (it.hasNext()) {
            SignerInformation signer = it.next();
            org.bouncycastle.util.Store store = (org.bouncycastle.util.Store) signedData.getCertificates();
            Collection certCollection = ((org.bouncycastle.util.Store) store).getMatches(signer.getSID());
            Iterator certIt = certCollection.iterator();
            X509CertificateHolder certHolder = (X509CertificateHolder) certIt.next();
            X509Certificate certificate = new JcaX509CertificateConverter().setProvider("BC").getCertificate(certHolder);
            verify = signer.verify(new JcaSimpleSignerInfoVerifierBuilder().setProvider("BC").build(certificate));
        }
        return verify;
    } catch (Exception e) {
        e.printStackTrace(System.out);
        return false;
    }
}

public static Folder getFolder(String folderName) {
    try {
        String host = "your mail server";
        boolean auth = true;
        /* You must use SSL for incoming mail, SSL ports are 993 for IMAP and 995 for POP3 */
        /* To support SSL, using protocl 'pop3s' or 'imaps' */
        String port = "993";
        String receivingProtocol = "imaps";
        String username = "your email address";
        String password = "your email password";

        Properties props = System.getProperties();
        props.put("mail.smtp.host", host);
        props.put("mail.smtp.port", port);
        props.put("mail.smtp.auth", auth);
        props.put("mail.store.protocol", receivingProtocol);
        Session session = Session.getDefaultInstance(props, null);
        Store store = session.getStore(receivingProtocol);
        store.connect(host, username, password);
        Folder folder = store.getFolder(folderName);
        folder.open(Folder.READ_WRITE);
        return folder;
    } catch (Exception e) {
        e.printStackTrace(System.out);
        return null;
    }
}

以及運行它的主要方法

public static void main(String args[]) {
    Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
    try {
        String inbox = "Your Inbox";
        Folder folder = getFolder(inbox);
        SearchTerm st = new OrTerm(new FromStringTerm("search condition"), new SubjectTerm("search condition"));
        Message[] messages = folder.search(st);
        int mailCounts = messages.length;
        System.out.println("Found: " + mailCounts + " mails matched with the condition.");

        if (messages.length == 0) {
            System.out.println("No Message!");
        }
        for (int i = 0; i < messages.length; i++) {
            System.out.println("the " + (i + 1) + " mail" + "------------------------------------------------");
            MimeMessage mail = (MimeMessage) messages[i];
            String out_from = ((InternetAddress) messages[i].getFrom()[0]).getAddress();
            System.out.println("From:" + out_from);
            System.out.println("Subject:" + messages[i].getSubject());
            System.out.println("Type: " + mail.getContentType());
            if (mail.isMimeType("multipart/signed")) {
                System.out.println("a signed mail");
                receiveSignedMail(mail);
            }
        }
        folder.close(true);
    } catch (Exception e) {
        e.printStackTrace(System.out);
    }
}

Answer 1

我和所有其他電子郵件客戶端（Thunderbird，Outlook等等）有同樣的問題，但我能夠解決它。 我認為這個問題是由javax.mail庫中的錯誤引起的。

我使用以下Maven依賴項：

<dependency>
    <groupId>com.sun.mail</groupId>
    <artifactId>javax.mail</artifactId>
    <version>1.6.2</version>
</dependency>

<dependency>
     <groupId>org.bouncycastle</groupId>
     <artifactId>bcprov-jdk15on</artifactId>
     <version>1.62</version>
</dependency>

<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcmail-jdk15on</artifactId>
    <version>1.62</version>
</dependency>

解：

通過IMAP輪詢來自電子郵件服務器的電子郵件時，您將其作為Message對象數組接收：

Message[] messages = pollFolder.getMessages();

現在，您將迭代此數組並分別處理每個消息。 這意味着，您正在直接使用Message對象。

但是如果你想用Bouncy Castle驗證郵件的簽名，你需要使用MimeMessage對象（參見Bouncy Castle的官方示例代碼;代碼行93）

要將Message轉換為MimeMessage ，通常需要以這種方式轉換對象：

MimeMessage mimeMsg = (MimeMessage) message;

但由於某種原因，這無法正常工作，所以稍后我在使用Bouncy Castle驗證電子郵件簽名時遇到以下異常： org.bouncycastle.cms.CMSSignerDigestMismatchException: message-digest attribute value does not match calculated value

我作為一種解決方法所做的是，使用MimeMessage構造函數復制已經轉換的MimeMessage對象！

所以這解決了我的問題 ：

MimeMessage mimeMsg = new MimeMessage((MimeMessage) message);

這是完整的工作代碼 ：

Message message = // get Message from folder...
MimeMessage mimeMsg = new MimeMessage((MimeMessage) message);
boolean emailSignatureValid = verifySignature(mimeMsg);

 // code from Bouncy Castle
 public boolean verifySignature(MimeMessage signedMimeMessage) {
    try {
        if (signedMimeMessage.isMimeType("multipart/signed")) {
            SMIMESignedParser s = new SMIMESignedParser(new JcaDigestCalculatorProviderBuilder().build(), (MimeMultipart) signedMimeMessage.getContent());
            return verify(s);
        } else if (signedMimeMessage.isMimeType("application/pkcs7-mime")) {
            SMIMESignedParser s = new SMIMESignedParser(new JcaDigestCalculatorProviderBuilder().build(), signedMimeMessage);
            return verify(s);
        } else {
            throw new IllegalArgumentException("This mimeMessage is not signed: " + EmailPrinter.printMessage(signedMimeMessage));
        }
    } catch (Exception e) {
        log.error("Could not verify signature of mimeMessage", e);
        return false;
    }
}

 // code from Bouncy Castle
 private static boolean verify(SMIMESignedParser s) throws Exception {

    Store certs = s.getCertificates();
    SignerInformationStore signers = s.getSignerInfos();
    Collection c = signers.getSigners();
    Iterator it = c.iterator();
    while (it.hasNext()) {
        SignerInformation signer = (SignerInformation) it.next();
        Collection certCollection = certs.getMatches(signer.getSID());
        Iterator certIt = certCollection.iterator();
        X509Certificate cert = new JcaX509CertificateConverter().setProvider(BC).getCertificate((X509CertificateHolder) certIt.next());
        try {
            return signer.verify(new JcaSimpleSignerInfoVerifierBuilder().setProvider(BC).build(cert));
        } catch (Exception e) {
            log.error("Error occured during verification",e);
        }
    }

    return false;
}

我知道這是一個奇怪的解決方法，但這是唯一的方法，我可以解決問題。 我希望你也覺得它很有用。

干杯！

BEEveloper