/* * Copyright (C) 2016 Nikita Mikhailov * Copyright (C) 2013-2015 Dominik Schürmann * Copyright (C) 2015 Vincent Breitmoser * Copyright (C) 2013-2014 Signe Rüsch * Copyright (C) 2013-2014 Philipp Jakubeit * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ package org.sufficientlysecure.keychain.securitytoken; import android.support.annotation.NonNull; import org.bouncycastle.bcpg.HashAlgorithmTags; import org.bouncycastle.util.Arrays; import org.bouncycastle.util.encoders.Hex; import org.sufficientlysecure.keychain.Constants; import org.sufficientlysecure.keychain.pgp.CanonicalizedSecretKey; import org.sufficientlysecure.keychain.pgp.exception.PgpGeneralException; import org.sufficientlysecure.keychain.util.Iso7816TLV; import org.sufficientlysecure.keychain.util.Log; import org.sufficientlysecure.keychain.util.Passphrase; import java.io.IOException; import java.math.BigInteger; import java.nio.ByteBuffer; import java.security.interfaces.RSAPrivateCrtKey; import nordpol.Apdu; /** * This class provides a communication interface to OpenPGP applications on ISO SmartCard compliant * devices. * For the full specs, see http://g10code.com/docs/openpgp-card-2.0.pdf */ public class SecurityTokenHelper { private static final int MAX_APDU_DATAFIELD_SIZE = 254; // Fidesmo constants private static final String FIDESMO_APPS_AID_PREFIX = "A000000617"; private static final byte[] BLANK_FINGERPRINT = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}; private Transport mTransport; private Passphrase mPin; private Passphrase mAdminPin; private boolean mPw1ValidForMultipleSignatures; private boolean mPw1ValidatedForSignature; private boolean mPw1ValidatedForDecrypt; // Mode 82 does other things; consider renaming? private boolean mPw3Validated; protected SecurityTokenHelper() { } public static SecurityTokenHelper getInstance() { return LazyHolder.SECURITY_TOKEN_HELPER; } private static String getHex(byte[] raw) { return new String(Hex.encode(raw)); } private String getHolderName(String name) { try { String slength; int ilength; name = name.substring(6); slength = name.substring(0, 2); ilength = Integer.parseInt(slength, 16) * 2; name = name.substring(2, ilength + 2); name = (new String(Hex.decode(name))).replace('<', ' '); return name; } catch (IndexOutOfBoundsException e) { // try-catch for https://github.com/FluffyKaon/OpenPGP-Card // Note: This should not happen, but happens with // https://github.com/FluffyKaon/OpenPGP-Card, thus return an empty string for now! Log.e(Constants.TAG, "Couldn't get holder name, returning empty string!", e); return ""; } } public Passphrase getPin() { return mPin; } public void setPin(final Passphrase pin) { this.mPin = pin; } public Passphrase getAdminPin() { return mAdminPin; } public void setAdminPin(final Passphrase adminPin) { this.mAdminPin = adminPin; } public void changeKey(CanonicalizedSecretKey secretKey, Passphrase passphrase) throws IOException { long keyGenerationTimestamp = secretKey.getCreationTime().getTime() / 1000; byte[] timestampBytes = ByteBuffer.allocate(4).putInt((int) keyGenerationTimestamp).array(); KeyType keyType = KeyType.from(secretKey); if (keyType == null) { throw new IOException("Inappropriate key flags for smart card key."); } // Slot is empty, or contains this key already. PUT KEY operation is safe boolean canPutKey = isSlotEmpty(keyType) || keyMatchesFingerPrint(keyType, secretKey.getFingerprint()); if (!canPutKey) { throw new IOException(String.format("Key slot occupied; card must be reset to put new %s key.", keyType.toString())); } putKey(keyType.getmSlot(), secretKey, passphrase); putData(keyType.getmFingerprintObjectId(), secretKey.getFingerprint()); putData(keyType.getTimestampObjectId(), timestampBytes); } private boolean isSlotEmpty(KeyType keyType) throws IOException { // Note: special case: This should not happen, but happens with // https://github.com/FluffyKaon/OpenPGP-Card, thus for now assume true if (getKeyFingerprint(keyType) == null) return true; return keyMatchesFingerPrint(keyType, BLANK_FINGERPRINT); } public boolean keyMatchesFingerPrint(KeyType keyType, byte[] fingerprint) throws IOException { return java.util.Arrays.equals(getKeyFingerprint(keyType), fingerprint); } /** * Connect to device and select pgp applet * * @throws IOException */ public void connectToDevice() throws IOException { // Connect on transport layer mTransport.connect(); // Connect on smartcard layer // SW1/2 0x9000 is the generic "ok" response, which we expect most of the time. // See specification, page 51 String accepted = "9000"; // Command APDU (page 51) for SELECT FILE command (page 29) String opening = "00" // CLA + "A4" // INS + "04" // P1 + "00" // P2 + "06" // Lc (number of bytes) + "D27600012401" // Data (6 bytes) + "00"; // Le String response = communicate(opening); // activate connection if (!response.endsWith(accepted)) { throw new CardException("Initialization failed!", parseCardStatus(response)); } byte[] pwStatusBytes = getPwStatusBytes(); mPw1ValidForMultipleSignatures = (pwStatusBytes[0] == 1); mPw1ValidatedForSignature = false; mPw1ValidatedForDecrypt = false; mPw3Validated = false; } /** * Parses out the status word from a JavaCard response string. * * @param response A hex string with the response from the card * @return A short indicating the SW1/SW2, or 0 if a status could not be determined. */ private short parseCardStatus(String response) { if (response.length() < 4) { return 0; // invalid input } try { return Short.parseShort(response.substring(response.length() - 4), 16); } catch (NumberFormatException e) { return 0; } } /** * Modifies the user's PW1 or PW3. Before sending, the new PIN will be validated for * conformance to the token's requirements for key length. * * @param pw For PW1, this is 0x81. For PW3 (Admin PIN), mode is 0x83. * @param newPin The new PW1 or PW3. */ public void modifyPin(int pw, byte[] newPin) throws IOException { final int MAX_PW1_LENGTH_INDEX = 1; final int MAX_PW3_LENGTH_INDEX = 3; byte[] pwStatusBytes = getPwStatusBytes(); if (pw == 0x81) { if (newPin.length < 6 || newPin.length > pwStatusBytes[MAX_PW1_LENGTH_INDEX]) { throw new IOException("Invalid PIN length"); } } else if (pw == 0x83) { if (newPin.length < 8 || newPin.length > pwStatusBytes[MAX_PW3_LENGTH_INDEX]) { throw new IOException("Invalid PIN length"); } } else { throw new IOException("Invalid PW index for modify PIN operation"); } byte[] pin; if (pw == 0x83) { pin = mAdminPin.toStringUnsafe().getBytes(); } else { pin = mPin.toStringUnsafe().getBytes(); } // Command APDU for CHANGE REFERENCE DATA command (page 32) String changeReferenceDataApdu = "00" // CLA + "24" // INS + "00" // P1 + String.format("%02x", pw) // P2 + String.format("%02x", pin.length + newPin.length) // Lc + getHex(pin) + getHex(newPin); String response = communicate(changeReferenceDataApdu); // change PIN if (!response.equals("9000")) { throw new CardException("Failed to change PIN", parseCardStatus(response)); } } /** * Call DECIPHER command * * @param encryptedSessionKey the encoded session key * @return the decoded session key */ public byte[] decryptSessionKey(@NonNull byte[] encryptedSessionKey) throws IOException { if (!mPw1ValidatedForDecrypt) { verifyPin(0x82); // (Verify PW1 with mode 82 for decryption) } int offset = 1; // Skip first byte String response = "", status = ""; // Transmit while (offset < encryptedSessionKey.length) { boolean isLastCommand = offset + MAX_APDU_DATAFIELD_SIZE < encryptedSessionKey.length; String cla = isLastCommand ? "10" : "00"; int len = Math.min(MAX_APDU_DATAFIELD_SIZE, encryptedSessionKey.length - offset); response = communicate(cla + "2a8086" + Hex.toHexString(new byte[]{(byte) len}) + Hex.toHexString(encryptedSessionKey, offset, len)); status = response.substring(response.length() - 4); if (!isLastCommand && !response.endsWith("9000")) { throw new CardException("Deciphering with Security token failed on transmit", parseCardStatus(response)); } offset += MAX_APDU_DATAFIELD_SIZE; } // Receive String result = getDataField(response); while (response.endsWith("61")) { response = communicate("00C00000" + status.substring(2)); status = response.substring(response.length() - 4); result += getDataField(response); } if (!status.equals("9000")) { throw new CardException("Deciphering with Security token failed on receive", parseCardStatus(response)); } return Hex.decode(result); } /** * Verifies the user's PW1 or PW3 with the appropriate mode. * * @param mode For PW1, this is 0x81 for signing, 0x82 for everything else. * For PW3 (Admin PIN), mode is 0x83. */ private void verifyPin(int mode) throws IOException { if (mPin != null || mode == 0x83) { byte[] pin; if (mode == 0x83) { pin = mAdminPin.toStringUnsafe().getBytes(); } else { pin = mPin.toStringUnsafe().getBytes(); } // SW1/2 0x9000 is the generic "ok" response, which we expect most of the time. // See specification, page 51 String accepted = "9000"; String response = tryPin(mode, pin); // login if (!response.equals(accepted)) { throw new CardException("Bad PIN!", parseCardStatus(response)); } if (mode == 0x81) { mPw1ValidatedForSignature = true; } else if (mode == 0x82) { mPw1ValidatedForDecrypt = true; } else if (mode == 0x83) { mPw3Validated = true; } } } /** * Stores a data object on the token. Automatically validates the proper PIN for the operation. * Supported for all data objects < 255 bytes in length. Only the cardholder certificate * (0x7F21) can exceed this length. * * @param dataObject The data object to be stored. * @param data The data to store in the object */ private void putData(int dataObject, byte[] data) throws IOException { if (data.length > 254) { throw new IOException("Cannot PUT DATA with length > 254"); } if (dataObject == 0x0101 || dataObject == 0x0103) { if (!mPw1ValidatedForDecrypt) { verifyPin(0x82); // (Verify PW1 for non-signing operations) } } else if (!mPw3Validated) { verifyPin(0x83); // (Verify PW3) } String putDataApdu = "00" // CLA + "DA" // INS + String.format("%02x", (dataObject & 0xFF00) >> 8) // P1 + String.format("%02x", dataObject & 0xFF) // P2 + String.format("%02x", data.length) // Lc + getHex(data); String response = communicate(putDataApdu); // put data if (!response.equals("9000")) { throw new CardException("Failed to put data.", parseCardStatus(response)); } } /** * Puts a key on the token in the given slot. * * @param slot The slot on the token where the key should be stored: * 0xB6: Signature Key * 0xB8: Decipherment Key * 0xA4: Authentication Key */ private void putKey(int slot, CanonicalizedSecretKey secretKey, Passphrase passphrase) throws IOException { if (slot != 0xB6 && slot != 0xB8 && slot != 0xA4) { throw new IOException("Invalid key slot"); } RSAPrivateCrtKey crtSecretKey; try { secretKey.unlock(passphrase); crtSecretKey = secretKey.getCrtSecretKey(); } catch (PgpGeneralException e) { throw new IOException(e.getMessage()); } // Shouldn't happen; the UI should block the user from getting an incompatible key this far. if (crtSecretKey.getModulus().bitLength() > 2048) { throw new IOException("Key too large to export to Security Token."); } // Should happen only rarely; all GnuPG keys since 2006 use public exponent 65537. if (!crtSecretKey.getPublicExponent().equals(new BigInteger("65537"))) { throw new IOException("Invalid public exponent for smart Security Token."); } if (!mPw3Validated) { verifyPin(0x83); // (Verify PW3 with mode 83) } byte[] header = Hex.decode( "4D82" + "03A2" // Extended header list 4D82, length of 930 bytes. (page 23) + String.format("%02x", slot) + "00" // CRT to indicate targeted key, no length + "7F48" + "15" // Private key template 0x7F48, length 21 (decimal, 0x15 hex) + "9103" // Public modulus, length 3 + "928180" // Prime P, length 128 + "938180" // Prime Q, length 128 + "948180" // Coefficient (1/q mod p), length 128 + "958180" // Prime exponent P (d mod (p - 1)), length 128 + "968180" // Prime exponent Q (d mod (1 - 1)), length 128 + "97820100" // Modulus, length 256, last item in private key template + "5F48" + "820383");// DO 5F48; 899 bytes of concatenated key data will follow byte[] dataToSend = new byte[934]; byte[] currentKeyObject; int offset = 0; System.arraycopy(header, 0, dataToSend, offset, header.length); offset += header.length; currentKeyObject = crtSecretKey.getPublicExponent().toByteArray(); System.arraycopy(currentKeyObject, 0, dataToSend, offset, 3); offset += 3; // NOTE: For a 2048-bit key, these lengths are fixed. However, bigint includes a leading 0 // in the array to represent sign, so we take care to set the offset to 1 if necessary. currentKeyObject = crtSecretKey.getPrimeP().toByteArray(); System.arraycopy(currentKeyObject, currentKeyObject.length - 128, dataToSend, offset, 128); Arrays.fill(currentKeyObject, (byte) 0); offset += 128; currentKeyObject = crtSecretKey.getPrimeQ().toByteArray(); System.arraycopy(currentKeyObject, currentKeyObject.length - 128, dataToSend, offset, 128); Arrays.fill(currentKeyObject, (byte) 0); offset += 128; currentKeyObject = crtSecretKey.getCrtCoefficient().toByteArray(); System.arraycopy(currentKeyObject, currentKeyObject.length - 128, dataToSend, offset, 128); Arrays.fill(currentKeyObject, (byte) 0); offset += 128; currentKeyObject = crtSecretKey.getPrimeExponentP().toByteArray(); System.arraycopy(currentKeyObject, currentKeyObject.length - 128, dataToSend, offset, 128); Arrays.fill(currentKeyObject, (byte) 0); offset += 128; currentKeyObject = crtSecretKey.getPrimeExponentQ().toByteArray(); System.arraycopy(currentKeyObject, currentKeyObject.length - 128, dataToSend, offset, 128); Arrays.fill(currentKeyObject, (byte) 0); offset += 128; currentKeyObject = crtSecretKey.getModulus().toByteArray(); System.arraycopy(currentKeyObject, currentKeyObject.length - 256, dataToSend, offset, 256); String putKeyCommand = "10DB3FFF"; String lastPutKeyCommand = "00DB3FFF"; // Now we're ready to communicate with the token. offset = 0; String response; while (offset < dataToSend.length) { int dataRemaining = dataToSend.length - offset; if (dataRemaining > 254) { response = communicate( putKeyCommand + "FE" + Hex.toHexString(dataToSend, offset, 254) ); offset += 254; } else { int length = dataToSend.length - offset; response = communicate( lastPutKeyCommand + String.format("%02x", length) + Hex.toHexString(dataToSend, offset, length)); offset += length; } if (!response.endsWith("9000")) { throw new CardException("Key export to Security Token failed", parseCardStatus(response)); } } // Clear array with secret data before we return. Arrays.fill(dataToSend, (byte) 0); } /** * Return fingerprints of all keys from application specific data stored * on tag, or null if data not available. * * @return The fingerprints of all subkeys in a contiguous byte array. */ public byte[] getFingerprints() throws IOException { String data = "00CA006E00"; byte[] buf = mTransport.transceive(Hex.decode(data)); Iso7816TLV tlv = Iso7816TLV.readSingle(buf, true); Log.d(Constants.TAG, "nfcGetFingerprints() Iso7816TLV tlv data:\n" + tlv.prettyPrint()); Iso7816TLV fptlv = Iso7816TLV.findRecursive(tlv, 0xc5); if (fptlv == null) { return null; } return fptlv.mV; } /** * Return the PW Status Bytes from the token. This is a simple DO; no TLV decoding needed. * * @return Seven bytes in fixed format, plus 0x9000 status word at the end. */ private byte[] getPwStatusBytes() throws IOException { String data = "00CA00C400"; return mTransport.transceive(Hex.decode(data)); } public byte[] getAid() throws IOException { String info = "00CA004F00"; return mTransport.transceive(Hex.decode(info)); } public String getUserId() throws IOException { String info = "00CA006500"; return getHolderName(communicate(info)); } /** * Call COMPUTE DIGITAL SIGNATURE command and returns the MPI value * * @param hash the hash for signing * @return a big integer representing the MPI for the given hash */ public byte[] calculateSignature(byte[] hash, int hashAlgo, boolean useAuthKey) throws IOException { if (!mPw1ValidatedForSignature) { // (Verify PW1 with mode 81 for signing) // (Verify PW1 with mode 82 for auth) verifyPin(useAuthKey ? 0x82 : 0x81); } // dsi, including Lc String dsi; Log.i(Constants.TAG, "Hash: " + hashAlgo); switch (hashAlgo) { case HashAlgorithmTags.SHA1: if (hash.length != 20) { throw new IOException("Bad hash length (" + hash.length + ", expected 20!"); } dsi = "23" // Lc + "3021" // Tag/Length of Sequence, the 0x21 includes all following 33 bytes + "3009" // Tag/Length of Sequence, the 0x09 are the following header bytes + "0605" + "2B0E03021A" // OID of SHA1 + "0500" // TLV coding of ZERO + "0414" + getHex(hash); // 0x14 are 20 hash bytes break; case HashAlgorithmTags.RIPEMD160: if (hash.length != 20) { throw new IOException("Bad hash length (" + hash.length + ", expected 20!"); } dsi = "233021300906052B2403020105000414" + getHex(hash); break; case HashAlgorithmTags.SHA224: if (hash.length != 28) { throw new IOException("Bad hash length (" + hash.length + ", expected 28!"); } dsi = "2F302D300D06096086480165030402040500041C" + getHex(hash); break; case HashAlgorithmTags.SHA256: if (hash.length != 32) { throw new IOException("Bad hash length (" + hash.length + ", expected 32!"); } dsi = "333031300D060960864801650304020105000420" + getHex(hash); break; case HashAlgorithmTags.SHA384: if (hash.length != 48) { throw new IOException("Bad hash length (" + hash.length + ", expected 48!"); } dsi = "433041300D060960864801650304020205000430" + getHex(hash); break; case HashAlgorithmTags.SHA512: if (hash.length != 64) { throw new IOException("Bad hash length (" + hash.length + ", expected 64!"); } dsi = "533051300D060960864801650304020305000440" + getHex(hash); break; default: throw new IOException("Not supported hash algo!"); } String apdu; if (!useAuthKey) { // Command APDU for PERFORM SECURITY OPERATION: COMPUTE DIGITAL SIGNATURE (page 37) apdu = "002A9E9A" // CLA, INS, P1, P2 + dsi // digital signature input + "00"; // Le } else { // Command APDU for INTERNAL AUTHENTICATE (page 55) // This command doesn't take / apdu = "00880000" // CLA, INS, P1, P2 + dsi // digital signature input, card does PKCS#1 + "00"; // Le } String response = communicate(apdu); if (response.length() < 4) { throw new CardException("Bad response", (short) 0); } // split up response into signature and status String status = response.substring(response.length() - 4); String signature = response.substring(0, response.length() - 4); // while we are getting 0x61 status codes, retrieve more data while (status.substring(0, 2).equals("61")) { Log.d(Constants.TAG, "requesting more data, status " + status); // Send GET RESPONSE command response = communicate("00C00000" + status.substring(2)); status = response.substring(response.length() - 4); signature += response.substring(0, response.length() - 4); } Log.d(Constants.TAG, "final response:" + status); if (!mPw1ValidForMultipleSignatures) { mPw1ValidatedForSignature = false; } if (!"9000".equals(status)) { throw new CardException("Bad NFC response code: " + status, parseCardStatus(response)); } // Make sure the signature we received is actually the expected number of bytes long! if (signature.length() != 256 && signature.length() != 512 && signature.length() != 768 && signature.length() != 1024) { throw new IOException("Bad signature length! Expected 128/256/384/512 bytes, got " + signature.length() / 2); } return Hex.decode(signature); } /** * Transceive data via NFC encoded as Hex */ private String communicate(String apdu) throws IOException { return getHex(mTransport.transceive(Hex.decode(apdu))); } public Transport getTransport() { return mTransport; } public void setTransport(Transport mTransport) { this.mTransport = mTransport; } public boolean isFidesmoToken() { if (isConnected()) { // Check if we can still talk to the card try { // By trying to select any apps that have the Fidesmo AID prefix we can // see if it is a Fidesmo device or not byte[] mSelectResponse = mTransport.transceive(Apdu.select(FIDESMO_APPS_AID_PREFIX)); // Compare the status returned by our select with the OK status code return Apdu.hasStatus(mSelectResponse, Apdu.OK_APDU); } catch (IOException e) { Log.e(Constants.TAG, "Card communication failed!", e); } } return false; } /** * Generates a key on the card in the given slot. If the slot is 0xB6 (the signature key), * this command also has the effect of resetting the digital signature counter. * NOTE: This does not set the key fingerprint data object! After calling this command, you * must construct a public key packet using the returned public key data objects, compute the * key fingerprint, and store it on the card using: putData(0xC8, key.getFingerprint()) * * @param slot The slot on the card where the key should be generated: * 0xB6: Signature Key * 0xB8: Decipherment Key * 0xA4: Authentication Key * @return the public key data objects, in TLV format. For RSA this will be the public modulus * (0x81) and exponent (0x82). These may come out of order; proper TLV parsing is required. */ public byte[] generateKey(int slot) throws IOException { if (slot != 0xB6 && slot != 0xB8 && slot != 0xA4) { throw new IOException("Invalid key slot"); } if (!mPw3Validated) { verifyPin(0x83); // (Verify PW3 with mode 83) } String generateKeyApdu = "0047800002" + String.format("%02x", slot) + "0000"; String getResponseApdu = "00C00000"; String first = communicate(generateKeyApdu); String second = communicate(getResponseApdu); if (!second.endsWith("9000")) { throw new IOException("On-card key generation failed"); } String publicKeyData = getDataField(first) + getDataField(second); Log.d(Constants.TAG, "Public Key Data Objects: " + publicKeyData); return Hex.decode(publicKeyData); } private String getDataField(String output) { return output.substring(0, output.length() - 4); } private String tryPin(int mode, byte[] pin) throws IOException { // Command APDU for VERIFY command (page 32) String login = "00" // CLA + "20" // INS + "00" // P1 + String.format("%02x", mode) // P2 + String.format("%02x", pin.length) // Lc + Hex.toHexString(pin); return communicate(login); } /** * Resets security token, which deletes all keys and data objects. * This works by entering a wrong PIN and then Admin PIN 4 times respectively. * Afterwards, the token is reactivated. */ public void resetAndWipeToken() throws IOException { String accepted = "9000"; // try wrong PIN 4 times until counter goes to C0 byte[] pin = "XXXXXX".getBytes(); for (int i = 0; i <= 4; i++) { String response = tryPin(0x81, pin); if (response.equals(accepted)) { // Should NOT accept! throw new CardException("Should never happen, XXXXXX has been accepted!", parseCardStatus(response)); } } // try wrong Admin PIN 4 times until counter goes to C0 byte[] adminPin = "XXXXXXXX".getBytes(); for (int i = 0; i <= 4; i++) { String response = tryPin(0x83, adminPin); if (response.equals(accepted)) { // Should NOT accept! throw new CardException("Should never happen, XXXXXXXX has been accepted", parseCardStatus(response)); } } // reactivate token! String reactivate1 = "00" + "e6" + "00" + "00"; String reactivate2 = "00" + "44" + "00" + "00"; String response1 = communicate(reactivate1); String response2 = communicate(reactivate2); if (!response1.equals(accepted) || !response2.equals(accepted)) { throw new CardException("Reactivating failed!", parseCardStatus(response1)); } } /** * Return the fingerprint from application specific data stored on tag, or * null if it doesn't exist. * * @param keyType key type * @return The fingerprint of the requested key, or null if not found. */ public byte[] getKeyFingerprint(@NonNull KeyType keyType) throws IOException { byte[] data = getFingerprints(); if (data == null) { return null; } // return the master key fingerprint ByteBuffer fpbuf = ByteBuffer.wrap(data); byte[] fp = new byte[20]; fpbuf.position(keyType.getIdx() * 20); fpbuf.get(fp, 0, 20); return fp; } public boolean isPersistentConnectionAllowed() { return mTransport != null && mTransport.isPersistentConnectionAllowed(); } public boolean isConnected() { return mTransport != null && mTransport.isConnected(); } private static class LazyHolder { private static final SecurityTokenHelper SECURITY_TOKEN_HELPER = new SecurityTokenHelper(); } }