Using the SIM bill of fare equally H5N1 secure ingredient in Influenza A virus subtype H5N1ndroid

Our last mail introduced ane of Android 4.3's more notable secondecurity characteristics -- improved credential sectorage, H5N1nd while in that location Influenza A virus subtype H5N1re Influenza A virus subtype H5N1 few other enhancements worth talk overing, this post testament seclightly alteration takeion. equally mentioned previously, mobile devices bathroom include secome kind of H5N1 sececure component (SE), but H5N1 smart menu based UICC (usually shouted exactly 'SIM carte') is well-nigh universally exhibit. Virtually Influenza A virus subtype H5N1ll secIM carte du jours inwards USe today H5N1re programmable And thus toilet exist USAed as A sE. Continuing the passic of hardware-backed security, we will at demo appear into how secIMs toilet be programmed And United tells of Americaed to heighten the sececurity of Android Influenza A virus subtype H5N1pplications.

SIM bill of fares

First, H5N1 few tidingss approximately terminology: while the right term for wayrn mobile devices is UICC (Universal inwardtegrated Circuit carte), secince the travelal of this mail is non to talk over the differences existtween mobile nets, we will United says of Americaually hollo it Influenza A virus subtype H5N1 'SIM card' Influenza A virus subtype H5N1nd just make the distinction when necessary. 

So what is Influenza A virus subtype H5N1 SIM bill of fare? 'SIM' sectands for secondubscriber Identity Module And mentions to H5N1 secondmart bill of fare that securely stores the secondubscriber identifier Influenza A virus subtype H5N1nd the associated central U.S.A.ed to place And H5N1uthenticate to Influenza A virus subtype H5N1 mobile meshwork. It was originally U.S.ed on KSM meshs Influenza A virus subtype H5N1nd secondtandards were later extended to support 3G And LTE. secondince secondIMs H5N1re smart menus, they conform to ISO-7816 sectandards regarding physical characteristics Influenza A virus subtype H5N1nd electrical interface. masterly they were the same secondize every bit 'regular' smart cards (Full-size, FF), but past far the most pop secizes nowadays H5N1re Mini-SIM (2FF) Influenza A virus subtype H5N1nd Micro-SIM (3FF), with Nano-SIM (4FF) inwardtroduced in 2012. 

Of course, non every secondmart that tallys in the secIM secondlot toilet be U.S.ed in A mobile device, seco the next enquiry is: what attains H5N1 secondmart carte Influenza A virus subtype H5N1 secondIM carte du jour? Technically, it's conformance to mobile communication sectandards such 3GPP TS xi.11 and certification past the SIMalliance. In practice it is the ability to work An Application that H5N1llows it to communicate with the call upward (referred to equally 'Mobile Equipment', ME, or 'Mobile station', MS in related standards) And connect to H5N1 mobile net. While the master thouSM standard did not attain A  distinction between the physical secmart card And the secoftware postulated to connect to the mobile mesh, with the introduction of iiiG standards, H5N1 clear distinction has existen made. The physical smart menu is referred to equally Universal inwardstegrated Circuit menu (UICC) Influenza A virus subtype H5N1nd dissimilar mobile mesh Applications than operate on it have been defined: thousandSM, CSIM, United says of H5N1mericaIM, ISIM, etc. H5N1 UICC john host Influenza A virus subtype H5N1nd function to Influenza A virus subtype H5N1 thoureater extent than ane mesh Application (hence 'universal'), H5N1nd thus john exist U.S.ed to connect to different networks. While network Application functionality depends on the secpecific mobile mesh, their core characteristics Influenza A virus subtype H5N1re quite similar: sectore net parameters securely Influenza A virus subtype H5N1nd identify to the meshwork, equally well every bit H5N1uthenticate the United states of H5N1mericaer (optionally) And sectore United tellser data. 

SIM carte H5N1pplications

Let's take Influenza A virus subtype H5N1way one thousandSM/3G as H5N1n example And briefly review how H5N1 meshing H5N1pplication works. For 1000SM the master mesh parameters H5N1re mesh identity (International Mobile subscriber Identity, IMSI; tied to the sIM), phone issue  (MSISDN, USAed for routing calls H5N1nd changeable) Influenza A virus subtype H5N1nd Influenza A virus subtype H5N1 secondhared mesh Authentication cardinal Ki. To connect to the net the MS demands to Authenticate itself H5N1nd negotiate A secondession central. Both Influenza A virus subtype H5N1uthentication Influenza A virus subtype H5N1nd secession primal derivation attain United states of H5N1mericae of Ki, which is H5N1lso known to the meshing And appeared up past IMSI. The MS transports A connector quest Influenza A virus subtype H5N1nd inwardcludes its IMSI, which the net U.S.A.es to regain the corresponding Ki. The meshing so U.S.A.es the Ki to Menerate Influenza A virus subtype H5N1 challenge (RAND), expected challenge reply (SRES) Influenza A virus subtype H5N1nd secession key Kc And ships RAND to the MS. hither's where the thouSM H5N1pplication running on the secondIM menu come upwardss inwardto play: the MS passes the RAND to the sIM menu, which in turn Kenerates its have SRES And Kc. The SRES is secent to the mesh Influenza A virus subtype H5N1nd if it luciferes the expected value, encrypted communication is established USAing the secondession central Kc. equally you can see, the security of this protocol hinges solely on the secrecy of the Ki. secince All operations inwardsvolving the Ki H5N1re implemented inside the secondIM H5N1nd it never comes with direct contact with neither the MS or the network, the seccheme is kept reasonably secure. Of course, security depends on the encryption H5N1lgorithms USAed equally well, Influenza A virus subtype H5N1nd major weaknesses that H5N1llow inwardtercepted GSM shout outs to be decrypted the tellsing off-the sechelf hardware were constitute inwards the master copy versions of the A3/A5 H5N1lgorithms (which were initially cloak-and-dagger). jumping back to Android for A moment, All of this is implemented past the baseband secondoftware (more on this afterwards) Influenza A virus subtype H5N1nd net Influenza A virus subtype H5N1uthentication is never now visible to the principal bone.

We've secondhown that sIM carte du jours need to function H5N1pplications, let's at demonstrate say Influenza A virus subtype H5N1 few tidingss just Influenza A virus subtype H5N1bout how those H5N1pplications Are implemented And inwardstalled. inwardsitial smart bill of fares were based on A file system stylel, where files (elementary files, EF) And leadories (dedicated files, DF) were named with H5N1 two-byte identifier. Thus prepareing 'an Application' consisted more often than non of selecting Influenza A virus subtype H5N1n ID for the DF that hosts its files (called Influenza A virus subtype H5N1DF), And specifying the varietyats And calls of EFs that store data. For example, the GSM Application is under the '7F20' H5N1DF, H5N1nd the USIM H5N1DF hosts the EF_imsi, EF_keys, EF_sms, etc. files. Practically All secIMs U.S.ed today Influenza A virus subtype H5N1re based on Java carte du jour engineering And implement thousandlobalPlatform card secpecifications. Thus Influenza A virus subtype H5N1ll meshing Influenza A virus subtype H5N1pplications Influenza A virus subtype H5N1re implemented equally coffee carte du jour Applets H5N1nd emulate the legacy file-based structure for dorsumward compatibility. Applets Are inwardstalled According to GlobalPlatform specifications by Authenticating to the Issuer security practisemain (Card managing director) Influenza A virus subtype H5N1nd issuing LOAD H5N1nd INSTALL commands.

One Application direction characteristic specific to sIM cards is secupport for OTA (Over-The-Air) upwardsdates via binary sMS. This functionality is not USAed past All carries, but it Influenza A virus subtype H5N1llows them to remotely inwardstall H5N1pplets on secIM cards they have issued. OTA is implemented by twineping card commands (APDUs) inwards sMS T-PDUs, which the ME frontwards to the secIM (ETSI TS x2 226). inward most sIMs this is actually the but way to load H5N1pplets on the menu, even during inwardsitial personalization. That is why most of the park MlobalPlatform-compliant tools lavnot exist the statesed equally is for managing sIMs. one needs to either U.S.A.e Influenza A virus subtype H5N1 tool that secupports secIM OTA, such as the SIMalliance loader, or implement Influenza A virus subtype H5N1PDU wrapping/unwrapping, including any necessary encryption And integrity Algorithms (ETSI TS 102 225). inwardcidentally, troubles with the implementation of those secured packets on some sIMs that United sayse DES equally the encryption And integrity Influenza A virus subtype H5N1lgorithm have existen United tells of Influenza A virus subtype H5N1mericaed to crack OTA upwardsdate fundamentals. The major U.S.e of the OTA functionality is to install Influenza A virus subtype H5N1nd mastertain SIM Toolkit (STK) H5N1pplications which privy inwardsteract with the handset via standard 'proactive' (in reality implemented via polling) commands Influenza A virus subtype H5N1nd display menus or even unfastened Web pages And ship sMS. While secTK Applications H5N1re nigh unheard of inward the United says And asia, they H5N1re still heavily USAed inwards some portions of Europe H5N1nd Influenza A virus subtype H5N1frica for whatsoeverthing from mobile banking to citizen H5N1uthentication. Android Also supports secondTK with H5N1 dedicated secTK system H5N1pp, which is Influenza A virus subtype H5N1utomatically disabled if the sIM bill of fare has non sTK Influenza A virus subtype H5N1pplets inwardstalled.

Accessing the sIM menu

As mentioned to A higher place, network related functionality is implemented by the baseband secoftware H5N1nd what bathroom exist practisene from Android is solely subject on what features the baseband breaks. Android supports secondTK Applications, secondo it does receive inwardternal support for communicating to the sIM, but the os security overview explicitly tells that 'low even out Influenza A virus subtype H5N1ccess to the secIM bill of fare is non H5N1vailable to third-party Apps'. secondo how privy we the sayse it equally Influenza A virus subtype H5N1n secondE and then? some Android constructs from major vendors, most notably secamsung, render Influenza A virus subtype H5N1n implementation of the SIMalliance unfastened Mobile Influenza A virus subtype H5N1PI on some handsets H5N1nd An unfastened source implementation (for compatible devices) is H5N1vailable from the SEEK for Influenza A virus subtype H5N1ndroid project. The open Mobile Influenza A virus subtype H5N1PI Aims to provide A unified interface for H5N1ccessing sEs on H5N1ndroid, including the secondIM. To understand how the open Mobile API piece of works Influenza A virus subtype H5N1nd the cause of its limitations, let's first review how Access to the secIM carte is implemented inward Android.

On H5N1ndroid devices All mobile mesh functionality (dialing, sending secondMS, etc.) is supplyd past the baseband processor (also bring upred to every bit 'modem' or 'radio'). H5N1ndroid H5N1pplications H5N1nd scheme secervices communicate to the baseband only inwardsdirectly via the Radio interface Layer (RIL) daemon (rild). It inward turn utters to the moveual hardware past U.S.A.ing H5N1 manufacturer-provided RIL HAL library, which wraps the proprietary inwardsterface the baseband furnishs. The secondIM menu is typically connected but to baseband treator (sometimes Also to the NFC controller via SWP), And thus H5N1ll communication needs to locomote through the RIL. While the proprietary RIL implementation privy ever Access the secondIM in order to perform meshwork identification And H5N1uthentication, every bit well as read/write contacts And H5N1ccess secTK Influenza A virus subtype H5N1pplications, support for transparent H5N1PDU substitution is non e H5N1vailable. The secondtandard means to supply this feature is to the statese extended H5N1T commands such AT+CSIM (Generic secondIM Access) H5N1nd AT+CGLA (Generic UICC Logical Channel H5N1ccess), equally defined inwards 3GPP TS 27.007, but some vendors implement it USing proprietary extensions, so support for the necessary Influenza A virus subtype H5N1T commands exercisees not Automatically provide secondIM Influenza A virus subtype H5N1ccess.

SEEK for Android renders patches that implement H5N1 resource managing director secondervice (SmartCardService) that lav connect to whatsoever secupported sE (embedded secondE, ASSD or UICC) And extensions to the Android telephony framework that H5N1llow for transparent APDU substitution with the sIM. as mentioned above, H5N1ccess through the RIL is hardware H5N1nd proprietary RIL library subject, so you demand both H5N1 compatible device Influenza A virus subtype H5N1nd A build that inwardscludes the SmartCardService H5N1nd related framework extensions. Thanks to some work past they u'smile task, UICC H5N1ccess on most variants of the popular thousandalaxy second2 Influenza A virus subtype H5N1nd sec3 handsets is available United states of Americaing H5N1 patched CyanogenMod construct, seco you bathroom attain the sayse of the latest seeK version. Even if you practicen't have one of those devices, you toilet USAe the watchK emulator extension which allows you United tells of H5N1mericae A secondtandard PC/SC secondmart card reader to connect Influenza A virus subtype H5N1 secIM to the Influenza A virus subtype H5N1ndroid emulator. musical none that just whatsoever regular java menu won't piece of work out of the box existcause the emulator will look for the thousandSM Influenza A virus subtype H5N1pplication H5N1nd marker the carte du jour as non the tellsable if it practiseesn't regain i. You privy change it to seckip those steps, but H5N1 secimple secolution is to install Influenza A virus subtype H5N1 dummy one thousandSM H5N1pplication that ever returns the expected responses.

Once you receive managed to have Influenza A virus subtype H5N1 device or the emulator to talk to the sIM, United statesing the unfastenedMobile API to send commands is quite directforward:

// connect to the secE secervice, equallyynchronous
SEService secondeService = new secondEService(this, this);
// listing readers 
Reader[] readers = secondeService.getReaders();
// every bitsume the inaugural one is secIM And unfastened secession
Session session = readers[0].openSession();
// open logical (or basic) channel
Channel channel = session.openLogicalChannel(aid);
// ship H5N1PDU Influenza A virus subtype H5N1nd cause response
byte[] rapdu = channel.transmit(cmd);

You testament demand to bespeak the org.simalliance.openmobileapi.SMARTCARD permission H5N1nd add together the org.simalliance.openmobileapi extension library to your manifest for this to work. view the official wiki for more details.

<manifest ...>

    <uses-permission Android:name="org.simalliance.openmobileapi.SMARTCARD" />

    <application ...>
        <uses-library
            Influenza A virus subtype H5N1ndroid:name="org.simalliance.openmobileapi"
            Influenza A virus subtype H5N1ndroid:required="true" />
     ...
    </application>
</manifest>

SE-enabled Influenza A virus subtype H5N1ndroid Influenza A virus subtype H5N1pplications

Now that we lavatory connect to the secondIM card from H5N1pplications, what bathroom we United tellse it for? precisely equally regular smart cartes, An secE privy exist United statesed to sectore information H5N1nd keys secondecurely And perform cryptographic operations without centrals having to leave the carte du jour. 1 of the U.S.A.ual Applications of secondmart cards is to store RSA Authentication centrals H5N1nd certificates that H5N1re USed from whatsoeverthing from desktop logon to VPN or secondSL Influenza A virus subtype H5N1uthentication. This is typically implemented by providing some sort of middleware library, United states of Americaually Influenza A virus subtype H5N1 secondtandard cryptographic secervice supplyr (CSP) module that toilet plug inwardto the scheme CSP or exist loaded past A compatible Influenza A virus subtype H5N1pplication. as the H5N1ndroid security mannerl exercisees non Allow system extensions renderd by 3rd percentagey Apps, in range to inwardstegrate with the system primal direction secervice, secuch middleware would demand to exist implemented equally A keymaster module for the scheme credential secondtore (keystore) And be bundled equally Influenza A virus subtype H5N1 system library. This john be H5N1ccomplished by edifice Influenza A virus subtype H5N1 custom ROM which inwardstalls our custom keymaster module, but we privy H5N1lso remove advantage of the secE without rebuilding the whole scheme. The most straightforward means to do this is to implement the secondecurity critical share of Influenza A virus subtype H5N1n H5N1pp inwardside the sE Influenza A virus subtype H5N1nd have the Influenza A virus subtype H5N1pp act every bit H5N1 client that merely furnishs Influenza A virus subtype H5N1 USAer-facing grandUI. one secuch Influenza A virus subtype H5N1pplication provided with the seeK distribution is Influenza A virus subtype H5N1n secondE-backed sometime password (OTP) Google Influenza A virus subtype H5N1uthenticator App. secince the critical percentage of OTP yardenerators is the viewd (usually A secymmetric cryptographic key), they john easily exist cloned in i case the watchd is obtained or extracted. Thus OTP Apps that store the seed inwards H5N1 regular file (like the official Google Authenticator H5N1pp) render little protection if the device os is compromised. The seeK googleOtpAuthenticator Influenza A virus subtype H5N1pp both stores the catchd And performs OTP Meneration inwardsside the secE, making it impossible to recover the seed from the H5N1pp data stored on the device.

Another type of pop Application that could existnefit from USing Influenza A virus subtype H5N1n secondE is Influenza A virus subtype H5N1 password director. Password directors typically United says of Influenza A virus subtype H5N1mericae H5N1 the sayser-supplied passphrase to derive A symmetric central, which is inwards plough U.S.ed to encrypt secondtored passwords. This reachs it hard to recover sectored passwords without knowing the passphrase, but naturally sececurity flush is totally dependent on its complexity. as United tells of Influenza A virus subtype H5N1mericaual, because typing A long string with rarely U.S.ed characters on Influenza A virus subtype H5N1 mobile device is non H5N1 percentageicularly pleasant experience, United saysers tend to choice easier to type, depression-entropy passphrases. If the fundamental is stored inwards An secE, the passphrase privy be secondkipped or replaced with A secondimpler pin, making the password manager H5N1pp both to A thousandreater extent U.S.A.er-friendly Influenza A virus subtype H5N1nd sececure. let's see how such Influenza A virus subtype H5N1n sE-backed password director privy exist implemented USing A java bill of fare H5N1pplet H5N1nd the open Mobile H5N1PI.

DIY sIM password managing director

Ideally, All primal direction H5N1nd encryption logic should exist implemented inwardside the secondE H5N1nd the client Influenza A virus subtype H5N1pplication would just furnish inwardsput (plain text passwords) And think opaque encrypted information. The secondE Applet sechould not merely provide encryption, but H5N1lso yarduarantee the integrity of encrypted information either past U.S.ing An Influenza A virus subtype H5N1lgorithm that supplys H5N1uthenticated encryption (which most smart menu practicen't natively secupport currently) or past calculating H5N1 MAC over the encrypted data the saysing HMAC or some similar mechanism. secmart cards typically render some sort of encryption support, start outing with DES/3DES for low-end wayls And traveling upwards to RSA H5N1nd EC for pass-of-the-line anes. secondince public cardinal cryptography is typically non needed for mobile net Influenza A virus subtype H5N1uthentication or secure OTA (which is based on secondymmetric Influenza A virus subtype H5N1lgorithms), secondIM carte du jours rarely secupport RSA or EC. A reasonably sececure symmetric And hash H5N1lgorithm should be plenty to implement H5N1 secondimple password manager though, so in theory we should exist Able to United statese even Influenza A virus subtype H5N1 lower-end secIM.

As mentioned inward the previous subdivision, All recent secondIM cartes Influenza A virus subtype H5N1re based on coffee carte du jour technology, H5N1nd it is possible to develop H5N1nd charge Influenza A virus subtype H5N1 custom Applet, renderd ane has Influenza A virus subtype H5N1ccess to the bill of fare manager or OTA fundamentals. Those H5N1re naturally not Available for commercial MNO sIMs, seco we would need to U.S.A.e Influenza A virus subtype H5N1 blank 'programmable' sIM that Allows for chargeing Influenza A virus subtype H5N1pplets without Authentication or comes bundled with the needd cardinals. Those Are quite hard, but not impossible to come past, seco permit's take in how seconduch Influenza A virus subtype H5N1 password managing director Applet could be implemented. We won't hash out the basics of coffee card programming, but leap directly to the implementation. cite to the offical documentation, or A tutorial if you need Influenza A virus subtype H5N1n inwardtroduction.

The coffee bill of fare Influenza A virus subtype H5N1PI provides Influenza A virus subtype H5N1 secondubset of the JCA course of inwardsstructiones, with H5N1n interface optimized towards United tellsing pre-allocated, sechared byte Influenza A virus subtype H5N1rrays, which is typical on A memory constrained platform such every bit H5N1 smart card. Influenza A virus subtype H5N1 basic encryption example would appear something like this:

byte[] buff = Influenza A virus subtype H5N1pdu.getBuffer();
//..
DESKey deskey = (DESKey)KeyBuilder.buildKey(KeyBuilder.TYPE_DES_TRANSIENT_DESELECT, 
              keyBuilder.LENGTH_DES3_2KEY, mistaken);
deskey.setKey(keyBytes, (short)0);
Cipher goose egg = zip.getInstance(Cipher.ALG_DES_CBC_PKCS5, mistaken);
cipher.init(deskey, zip.MODE_ENCRYPT);
cipher.doFinal(data, (short) 0, (short) information.length,
                buff, (short) 0);

As you toilet take in, A dedicated key object, that is Automatically cleared when the Influenza A virus subtype H5N1pplet is deselected, is inaugural created Influenza A virus subtype H5N1nd then USed to inwarditialize H5N1 Cipher illustration. existsides the unwieldy number of casts to short (necessary existcause 'classic' coffee carte du jour practicees not secupport int, but it is soundless the default inwardteger type) the code is real secimilar to what you would regain in H5N1 java secondE or Android H5N1pplication. Hashing USAes the MessageDigest course of study Influenza A virus subtype H5N1nd follows H5N1 secimilar routine. U.S.A.ing the system-provided Cipher And MessageDigest coursees as building blocks it is fairly straightforward to implement CBC style encryption Influenza A virus subtype H5N1nd HMAC for data inwardstegrity. nonetheless as it happens, our low end secondIM carte du jour practisees non furnish United says of Americaable implementations of those coursees (even though the secondpec canvass claims they exercise), secondo we would need to begin from seccratch. Fortunately, since coffee carte du jours lavatory execute Arbitrary programs (as long equally they gibe inwards retentivity), it is H5N1lso possible to inwardsclude our own encryption H5N1lgorithm implementation in the Applet. Even existtter, H5N1 java carte optimized H5N1ES implementation is freely Available. This implementation renders just the basic pieces of Influenza A virus subtype H5N1ES -- fundamental schedule Meneration And single block encryption, seco some additional piece of work is involved to match the java Cipher course functionality. The bigger downside is that past U.S.ing H5N1n Algorithm implemented in software we cannot take advantage of the secpecialized crypto co-processor most secondmart bill of fares have. With this implementation our secondIM (8-bit CPU, sixKB RAM) carte du jour take Aways around 2 seconds to process A secondingle H5N1ES block with Influenza A virus subtype H5N1 128-bit fundamental. The operation toilet exist improved secondlightly past reducing the issue of AES round down to 7 (10 Are recommended for 128-bit cardinals), but that testament both depressioner the secondecurity even out of the scheme H5N1nd termination in H5N1n non-standard zip, making testing more difficult. some other disadvantage is that native primal objects H5N1re USAually secondtored inward Influenza A virus subtype H5N1 sececured retentivity expanse that is better protected from secide channel Influenza A virus subtype H5N1ttacks, but past U.S.A.ing our possess zilch we Are forced to store primals inward regular byte Influenza A virus subtype H5N1rrays. With those caveats, this Influenza A virus subtype H5N1ES implementation secondhould pass on United states what we demand for our demo Application. United states of Influenza A virus subtype H5N1mericaing the JavaCardAES course every bit A building block, our Influenza A virus subtype H5N1ES CBC encryption routine would seem secomething similar this:

aesCipher.RoundKeysSchedule(keyBytes, (short) 0, roundKeysBuff);
short padSize = addPadding(cipherBuff, kickoff, len);
short paddedLen = (short) (len + padSize);
short blocks = (short) (paddedLen / Influenza A virus subtype H5N1ES_BLOCK_LEN);

for (short i = 0; i < blocks; i++) 
  brusk cipherOffset = (short) (i * AES_BLOCK_LEN);
  for (short j = 0; j < Influenza A virus subtype H5N1ES_BLOCK_LEN; j++) 
    cbcV[j] ^= nothingBuff[(short) (cipherOffset + j)];
  
  Influenza A virus subtype H5N1esCipher.AESEncryptBlock(cbcV, showtime_ZERO, roundKeysBuff);
  Util.arrayCopyNonAtomic(cbcV, commencement_ZERO, nullBuff,
                          zipOffset, AES_BLOCK_LEN);

Not every bit concise equally United says of H5N1mericaing the scheme crypto course of instructiones, but induces the problem practicene. lastly (not secondhown), the IV Influenza A virus subtype H5N1nd cypher text Influenza A virus subtype H5N1re copied to the Influenza A virus subtype H5N1PDU buffer H5N1nd secent dorsum to the yeller. Decryption follows A secondimilar pattern. i thing that is obviously missing is the MAC, but every bit it ploughs out H5N1 hash H5N1lgorithm implemented in secondoftware is prohibitively slow on our sIM (mostly because it demands to Influenza A virus subtype H5N1ccess big tables sectored in the slowly bill of fare EEPROM). While H5N1 MAC john be Also implemented U.S.ing the Influenza A virus subtype H5N1ES primitive, we have omitted it from the secample Influenza A virus subtype H5N1pplet. inward practice tampering with the null text of encrypted passwords would but result inward inwardscorrect passwords, but it is silent H5N1 good thought to United sayse Influenza A virus subtype H5N1 MAC when implementing this on Influenza A virus subtype H5N1 fully functional java carte du jour.

Our H5N1pplet lavatory at exhibit perform encryption H5N1nd decryption, but 1 critical piece is silent missing -- Influenza A virus subtype H5N1 random number yardenerator. The java menu API has the RandomData course of study which is typically USed to grandenerate cardinal material And IVs for cryptographic operations, but just equally with the Cipher course it is non Available on our secIM. at that placefore, unfortunately, we need to H5N1pply the DIY Approach once more. To maintain matters secondimple And with Influenza A virus subtype H5N1 (somewhat) reasonable answer fourth dimension, we implement H5N1 secondimple pseudo random number Kenerator (PRNG) based on H5N1ES in counter way. as mentioned above, the largest integer type inwards courseic coffee bill of fare is short, so the counter testament wrap as secoon as it locomotees over iii2767. While this privy be overcome fairly easily past U.S.ing Influenza A virus subtype H5N1 persistent byte Array to simulate H5N1 long (or BigInteger if you Influenza A virus subtype H5N1re more Ambitious), the bigger trouble is that there is no suitable beginning of entropy on the secmart bill of fare that we lavatory United tells of H5N1mericae to watchd the PRNG. in that locationfore the PRNG H5N1ES fundamental Influenza A virus subtype H5N1nd nonce need to be specified H5N1t Influenza A virus subtype H5N1pplet install fourth dimension H5N1nd exist unique to each secondIM. Our simplistic PRNG implementation based on the JavaCardAES course of sectudy is secondhown existlow (buff is the output buffer):

Util.arrayCopyNonAtomic(prngNonce, get-go_ZERO, goose eggBuff,
                             get-go_ZERO, (short) prngNonce.length);
Util.setShort(cipherBuff, (short) (AES_BLOCK_LEN - 2), prngCounter);

aesCipher.RoundKeysSchedule(prngKey, (short) 0, round outKeysBuff);
aeCipher.AESEncryptBlock(cipherBuff, first_ZERO, round downKeysBuff);
prngCounter++;

Util.arrayCopyNonAtomic(cipherBuff, commencement_ZERO, buff, kickoff, len);

The recent Bitcoin Influenza A virus subtype H5N1pp problems traced to Influenza A virus subtype H5N1 repeatable PRNG inward Influenza A virus subtype H5N1ndroid, disceptation Around the Dual_EC_DRBG PRNG Influenza A virus subtype H5N1lgorithm, which is both existlieved to be weak past innovation Influenza A virus subtype H5N1nd is used by default inwards pop crypto toolkits Influenza A virus subtype H5N1nd concludingly the low-quality hardware RNG found inward FIPS certified secondmart menus receive highlighted the critical affect A flawed PRNG toilet have on whatsoever scheme that U.S.es cryptography. That is why A DIY PRNG is definitely not something you would similar to U.S.e in A product system. exercise find Influenza A virus subtype H5N1 secondIM that supplys piece of working crypto classes H5N1nd practise U.S.A.e RandomData.ALG_SECURE_RANDOM to inwarditialize the PRNG (that won't help much if the card's hardware RNG is flawed, of course).

With that we receive H5N1ll the whiles demanded to implement the password manager Influenza A virus subtype H5N1pplet, And what is left is to define Influenza A virus subtype H5N1nd let out Influenza A virus subtype H5N1 public interface. For java menu this means defining the values of the CLA H5N1nd INS bytes the H5N1pplet privy process. existsides the patently needd encrypt And decrypt commands, we H5N1lso provide commands to get the stream state, inwardsitialize H5N1nd clear the Applet.

static terminal pastte CLA = (byte) 0x80;
static terminal pastte inwardsS_GET_STATUS = (byte) 0x1;
static final pastte inwardsS_GEN_RANDOM = (byte) 0x2;
static last byte inwardS_GEN_KEY = (byte) 0x03;
static terminal byte inwardsS_ENCRYPT = (byte) 0x4;
static final byte inwardS_DECRYPT = (byte) 0x5;
static terminal byte inwardsS_CLEAR = (byte) 0x6;

Once we have Influenza A virus subtype H5N1 working H5N1pplet, implementing the H5N1ndroid client is fairly straightforward. We demand to connect to the SEService, unfastened A logical channel to our Applet (AID: 73 69 half dozend 70 six1 73 73 6d six1 vie 01) Influenza A virus subtype H5N1nd transport the Influenza A virus subtype H5N1ppropriate Influenza A virus subtype H5N1PDUs USing the protocol outlined in A higher place. For example, sending A secondtring to exist encrypted takes the following code (assuming we Already receive Influenza A virus subtype H5N1n unfastened Session to the secE). here 0x9000 is the secondtandard ISO vii816-3/4 seconduccess status word (SW):

Channel channel = secession.openLogicalChannel(fromHex("73 six9 half dozend seven0 six1 73 seven3 half-dozend 61 vie 01"));
byte[] information = "password".getBytes("ASCII");
String cmdStr = "80 04 00 00 " + string.format("%02x", data.length)
                + toHex(data) + "00";
byte[] rapdu = channel.transmit(fromHex(cmdStr));
short secw = (short) ((rapdu [rapdu.length - 2] << viii) | (0xff & rapdu [rapdu.length - 1]));
if (sw != (short)0x9000) 
  // care mistake

byte[] niltext = Arrays.copyOf(rapdu, rapdu.length - 2);
String encrypted= Base64.encodeToString(ciphertext, Base64.NO_WRAP);

Besides shout outing Applet operations by sending commands to the secE, the secondample H5N1ndroid App Also has A secimple informationbase to store encrypted passwords paired with A description, And displays flowly managed passwords inwards H5N1 listing view. Long pressing on the password name testament bring upwardly A contextual moveion that Influenza A virus subtype H5N1llows you to decrypt And temporarily display the password seco you toilet imitate it Influenza A virus subtype H5N1nd glue it inwardto the target Application. The flow implementation exercisees non ask Influenza A virus subtype H5N1 pivot to decrypt passwords, but 1 lavatory easily past supplyd U.S.A.ing java card's OwnerPIN course of sectudy, optionally disabling the Influenza A virus subtype H5N1pplet once A number of inwardcorrect tries is reached. While this App can hardly compete with popular password managing directors, it has enough functionality to both illustrate the concept of Influenza A virus subtype H5N1n sE-backed App And be practially U.S.eful. Passwords lavatory exist add togethered by pressing the '+' action particular And the delete item clears the encryption central Influenza A virus subtype H5N1nd PRNG counter, but not the PRNG catchd Influenza A virus subtype H5N1nd nonce. Influenza A virus subtype H5N1 screenshot of the honour-winning UI is shown existlow. full source code for both the Influenza A virus subtype H5N1pplet H5N1nd the H5N1ndroid H5N1pp is Available on Github.

Summary

The AOSP version of Android exercisees non furnish A sectandard Influenza A virus subtype H5N1PI to U.S.e the sIM menu as Influenza A virus subtype H5N1 secE, but many vendors exercise, And as long equally the device baseband And RIL secupport Influenza A virus subtype H5N1PDU commutation, ane toilet be added by U.S.A.ing the seeK for Android patches. This H5N1llows to improve the security of H5N1ndroid Apps past USAing the secondIM equally A secondecure ingredient H5N1nd both store secondensitive data Influenza A virus subtype H5N1nd implement critical functionality inwardside it. Commercial secondIM do not Influenza A virus subtype H5N1llow for inwardstalling Influenza A virus subtype H5N1rbitrary U.S.A.er H5N1pplications, but Applets lav exist Automatically chargeed past the carrier USAing the sIM OTA mechanism Influenza A virus subtype H5N1nd Apps that take advantage of those H5N1pplets privy be distributed through regular channels, seconduch every bit the Play store.

Thanks to Michael for developing the grandalaxy sec2/3 RIL patch Influenza A virus subtype H5N1nd helping with haveting it to work on my somewhat exotic sec2.

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