// MANIFEST.MF
            Manifest manifest = addDigestsToManifest(inputJar);
            je = new JarEntry(JarFile.MANIFEST_NAME);
            je.setTime(timestamp);
            outputJar.putNextEntry(je);
            manifest.write(outputJar);

/** Add the SHA1 of every file to the manifest, creating it if necessary. */
    private static Manifest addDigestsToManifest(JarFile jar)
            throws IOException, GeneralSecurityException {
        Manifest input = jar.getManifest();
        Manifest output = new Manifest();
        Attributes main = output.getMainAttributes();
        if (input != null) {
            main.putAll(input.getMainAttributes());
        } else {
            main.putValue("Manifest-Version", "1.0");
            main.putValue("Created-By", "1.0 (Android SignApk)");
        }
<span style="white-space:pre">	</span>......
        for (JarEntry entry: byName.values()) {
            String name = entry.getName();
            if (!entry.isDirectory() && !name.equals(JarFile.MANIFEST_NAME) &&
                !name.equals(CERT_SF_NAME) && !name.equals(CERT_RSA_NAME) &&
                (stripPattern == null ||
                 !stripPattern.matcher(name).matches())) {
                InputStream data = jar.getInputStream(entry);
                while ((num = data.read(buffer)) > 0) {
                    md.update(buffer, 0, num);
                }

                Attributes attr = null;
                if (input != null) attr = input.getAttributes(name);
                attr = attr != null ? new Attributes(attr) : new Attributes();
                attr.putValue("SHA1-Digest", base64.encode(md.digest()));
                output.getEntries().put(name, attr);
            }
        }

        return output;
    }

Name: AndroidManifest.xml
SHA1-Digest: Zovq4AVMcCjFkILZLlHgmeOLvnU=

// CERT.SF
            Signature signature = Signature.getInstance("SHA1withRSA");
            signature.initSign(privateKey);
            je = new JarEntry(CERT_SF_NAME);
            je.setTime(timestamp);
            outputJar.putNextEntry(je);
            writeSignatureFile(manifest,
                    new SignatureOutputStream(outputJar, signature));

/** Write a .SF file with a digest of the specified manifest. */
    private static void writeSignatureFile(Manifest manifest, SignatureOutputStream out)
            throws IOException, GeneralSecurityException {
        Manifest sf = new Manifest();
        Attributes main = sf.getMainAttributes();
        main.putValue("Signature-Version", "1.0");
        main.putValue("Created-By", "1.0 (Android SignApk)");

        BASE64Encoder base64 = new BASE64Encoder();
        MessageDigest md = MessageDigest.getInstance("SHA1");
        PrintStream print = new PrintStream(
                new DigestOutputStream(new ByteArrayOutputStream(), md),
                true, "UTF-8");

        // Digest of the entire manifest
        manifest.write(print);
        print.flush();
        main.putValue("SHA1-Digest-Manifest", base64.encode(md.digest()));

        Map<String, Attributes> entries = manifest.getEntries();
        for (Map.Entry<String, Attributes> entry : entries.entrySet()) {
            // Digest of the manifest stanza for this entry.
            print.print("Name: " + entry.getKey() + "\r\n");
            for (Map.Entry<Object, Object> att : entry.getValue().entrySet()) {
                print.print(att.getKey() + ": " + att.getValue() + "\r\n");
            }
            print.print("\r\n");
            print.flush();

            Attributes sfAttr = new Attributes();
            sfAttr.putValue("SHA1-Digest", base64.encode(md.digest()));
            sf.getEntries().put(entry.getKey(), sfAttr);
        }
<span style="white-space:pre">	</span>//签名信息在上面并没有使用的到
        sf.write(out);

        // A bug in the java.util.jar implementation of Android platforms
        // up to version 1.6 will cause a spurious IOException to be thrown
        // if the length of the signature file is a multiple of 1024 bytes.
        // As a workaround, add an extra CRLF in this case.
        if ((out.size() % 1024) == 0) {
            out.write('\r');
            out.write('\n');
        }
    }

Signature-Version: 1.0
Created-By: 1.0 (Android)
SHA1-Digest-Manifest: nGpBbfOirA4fsY0pn0dBONop5bQ=

Name: AndroidManifest.xml
SHA1-Digest: PJblxooLyYkHHlr/0lKZkk2DkM0=

            // CERT.RSA
            je = new JarEntry(CERT_RSA_NAME);
            je.setTime(timestamp);
            outputJar.putNextEntry(je);
            writeSignatureBlock(signature, publicKey, outputJar);

    /** Write a .RSA file with a digital signature. */
    private static void writeSignatureBlock(
            Signature signature, X509Certificate publicKey, OutputStream out)
            throws IOException, GeneralSecurityException {
        SignerInfo signerInfo = new SignerInfo(
                new X500Name(publicKey.getIssuerX500Principal().getName()),
                publicKey.getSerialNumber(),
                AlgorithmId.get("SHA1"),
                AlgorithmId.get("RSA"),
                signature.sign());

        PKCS7 pkcs7 = new PKCS7(
                new AlgorithmId[] { AlgorithmId.get("SHA1") },
                new ContentInfo(ContentInfo.DATA_OID, null),
                new X509Certificate[] { publicKey },
                new SignerInfo[] { signerInfo });

        pkcs7.encodeSignedData(out);
    }

Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number: 1281971851 (0x4c69568b)
        Signature Algorithm: sha1WithRSAEncryption
        Issuer: CN=Michael Liu
        Validity
            Not Before: Aug 16 15:17:31 2010 GMT
            Not After : Aug 10 15:17:31 2035 GMT
        Subject: CN=Michael Liu
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
            RSA Public Key: (1024 bit)
                Modulus (1024 bit):
                    00:8d:04:84:a2:1e:c6:56:39:f2:cd:a6:f0:48:a5:
                    f7:5e:71:8f:e1:a8:af:a7:dc:66:92:a2:b9:cf:da:
                    0f:32:42:ce:83:fe:bc:e1:4f:0a:fd:d9:a8:b3:73:
                    f4:ff:97:15:17:87:d6:d0:3c:da:01:fc:11:40:7d:
                    04:da:31:cc:cd:da:d0:e7:7b:e3:c1:84:30:9f:21:
                    93:95:20:48:b1:2d:24:02:d2:b9:3c:87:0d:fa:b8:
                    e1:b1:45:f4:8d:90:0a:3b:9d:d8:8a:9a:96:d1:51:
                    23:0e:8e:c4:09:68:7d:95:be:c6:42:e9:54:a1:5c:
                    5d:3f:25:d8:5c:c3:42:73:21
                Exponent: 65537 (0x10001)
    Signature Algorithm: sha1WithRSAEncryption
        78:3c:6b:ef:71:70:55:68:28:80:4d:f8:b5:cd:83:a9:01:21:
        2a:c1:e4:96:ad:bc:5f:67:0c:cd:c3:34:51:6d:63:90:a9:f9:
        d5:5e:c7:ef:34:43:86:7d:68:e1:99:87:92:86:34:91:6d:67:
        6d:b2:22:e9:5e:28:aa:e8:05:52:04:6e:4e:d4:7f:0f:b0:d6:
        28:f5:2b:11:38:d5:15:cb:e3:e4:c9:99:23:c1:84:4f:ce:69:
        e9:b1:59:7b:8e:30:01:1c:e1:92:ee:0d:54:61:29:f5:8e:9e:
        42:72:26:2b:aa:c7:af:d9:c9:d1:85:95:8e:4c:8d:5c:77:c5:
        ce:4e