--- /dev/null
+package club.wpia.gigi.crypto;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.math.BigInteger;
+import java.security.GeneralSecurityException;
+import java.security.PrivateKey;
+import java.security.Signature;
+import java.security.cert.X509Certificate;
+import java.util.Random;
+
+import club.wpia.gigi.util.PEM;
+import sun.security.pkcs.ContentInfo;
+import sun.security.pkcs.PKCS7;
+import sun.security.pkcs.SignerInfo;
+import sun.security.util.DerOutputStream;
+import sun.security.x509.AlgorithmId;
+import sun.security.x509.X500Name;
+
+public class SMIME {
+
+ public static String doAlternatives(String plain, String html) {
+
+ plain = "Content-type: text/plain\r\n\r\n" + plain;
+ html = "Content-type: text/html\r\n\r\n" + html;
+ String boundary = generateBoundary(plain, html);
+ StringBuffer content = new StringBuffer("Content-Type: multipart/alternative; boundary=\"");
+ content.append(boundary);
+ content.append("\"\r\n\r\n");
+ content.append("--");
+ content.append(boundary);
+ content.append("\r\n");
+ content.append(plain);
+ content.append("\r\n--");
+ content.append(boundary);
+ content.append("\r\n");
+ content.append(html);
+ content.append("\r\n--");
+ content.append(boundary);
+ content.append("--\r\n");
+ return content.toString();
+
+ }
+
+ public static void smime(String contents, PrivateKey pKey, X509Certificate c, PrintWriter to) throws IOException, GeneralSecurityException {
+ contents = normalizeNewlinesToCRLF(contents);
+
+ Signature signature = Signature.getInstance("SHA1WithRSA");
+ signature.initSign(pKey);
+ signature.update(contents.getBytes("UTF-8"));
+ byte[] signedData = signature.sign();
+
+ // "IssuerAndSerialNumber"
+ X500Name xName = X500Name.asX500Name(c.getIssuerX500Principal());
+ BigInteger serial = c.getSerialNumber();
+
+ SignerInfo sInfo = new SignerInfo(xName, serial, new AlgorithmId(AlgorithmId.SHA_oid), null, new AlgorithmId(AlgorithmId.RSAEncryption_oid), signedData, null);
+
+ // Content is outside so content here is null.
+ ContentInfo cInfo = new ContentInfo(ContentInfo.DATA_OID, null);
+
+ // Create PKCS7 Signed data
+ PKCS7 p7 = new PKCS7(new AlgorithmId[] {
+ new AlgorithmId(AlgorithmId.SHA_oid)
+ }, cInfo, new java.security.cert.X509Certificate[] {
+ c
+ }, new SignerInfo[] {
+ sInfo
+ });
+
+ ByteArrayOutputStream bOut = new DerOutputStream();
+ p7.encodeSignedData(bOut);
+
+ mimeEncode(contents, PEM.formatBase64(bOut.toByteArray()), to);
+ }
+
+ private static String normalizeNewlinesToCRLF(String contents) {
+ return contents.replace("\r\n", "\r").replace("\r", "\n").replace("\n", "\r\n");
+ }
+
+ private static Random r = new Random();
+
+ private static void mimeEncode(String contents, String signature, PrintWriter to) {
+ String boundary = generateBoundary(contents, null);
+ to.print("MIME-Version: 1.0\r\n");
+ to.print("Content-Type: multipart/signed; protocol=\"application/x-pkcs7-signature\"; micalg=\"sha1\"; boundary=\"" + boundary + "\"\r\n");
+ to.print("\r\n");
+ to.print("This is an S/MIME signed message\r\n");
+ to.print("\r\n");
+ to.print("--" + boundary + "\r\n");
+ to.print(contents + "\r\n");
+ to.print("--" + boundary + "\r\n");
+ to.print("Content-Type: application/x-pkcs7-signature; name=\"smime.p7s\"\r\n");
+ to.print("Content-Transfer-Encoding: base64\r\n");
+ to.print("Content-Disposition: attachment; filename=\"smime.p7s\"\r\n");
+ to.print("\r\n");
+ to.print(signature + "\r\n");
+ to.print("\r\n");
+ to.print("--" + boundary + "--\r\n");
+ }
+
+ private static String generateBoundary(String contents, String contents2) {
+ String boundary = "";
+ while (contents.contains(boundary) || (contents2 != null && contents2.contains(boundary))) {
+ boundary = "--" + new BigInteger(16 * 8, r).toString(16).toUpperCase();
+ }
+ return boundary;
+ }
+}