Consulthink at GDG Dev Fest Rome 2013 Android Key Management
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Consulthink at GDG Dev Fest Rome 2013 Android Key Management
![Android Security
Key Management
RSA Digital Signature
Digital Signature
Authentication, Non-Repudiation and Integrity
RSA Private key to Sign
RSA Public Key to Verify
KeyStore.Entry entry = ks.getEntry(DEVKEY1, null);
byte[] data = DevFest Rome 2013!.getBytes();
Signature s = Signature.getInstance(SHA256withRSA);
s.initSign(((KeyStore.PrivateKeyEntry) entry).getPrivateKey());
s.update(data);
byte[] signature = s.sign();
String result = null;
result = Base64.encodeToString(signature, Base64.DEFAULT);
Accesso chiave Pubblica e Privata
identificata dallALIAS==DEVKEY1
Scelta dellalgoritmo
Chiave Privata per firmare
Firma e codifica in
Base64](https://image.slidesharecdn.com/gdg-devfest-rome-2013androidkeymanagement-140115060032-phpapp02/85/Consulthink-at-GDG-Dev-Fest-Rome-2013-Android-Key-Management-19-320.jpg)
![Android Security
Key Management
Verify RSA Digital Signature
byte[] data = input.getBytes();
byte[] signature;
signature = Base64.decode(signatureStr, Base64.DEFAULT);
KeyStore.Entry entry = ks.getEntry(DEVKEY1, null);
Signature s = Signature.getInstance("SHA256withRSA");
s.initVerify(((KeyStore.PrivateKeyEntry) entry).getCertificate());
s.update(data);
boolean valid = s.verify(signature);
Decodifica Base64
Accesso chiave Pubblica e Privata
identificata dallALIAS==DEVKEY1
Scelta dellalgoritmo
Chiave Pubblica nel
certificato utilizzata per
verificare
TRUE == Verified
FALSE== Not Verified](https://image.slidesharecdn.com/gdg-devfest-rome-2013androidkeymanagement-140115060032-phpapp02/85/Consulthink-at-GDG-Dev-Fest-Rome-2013-Android-Key-Management-20-320.jpg)
![Android Security
Key Management
RSA Encryption
Encryption
Confidentiality
RSA Public key to Encrypt
RSA Private key to Decrypt
PublicKey publicKeyEnc = ((KeyStore.PrivateKeyEntry) entry)
.getCertificate().getPublicKey();
String textToEncrypt = new String("DevFest Rome 2013");
byte[] textToEncryptToByte = textToEncrypt.getBytes();
Cipher encCipher = null;
byte[] encryptedText = null;
encCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
encCipher.init(Cipher.ENCRYPT_MODE, publicKeyEnc);
encryptedText = encCipher.doFinal(textToEncryptToByte);
Accesso alla chiave
pubblica per cifrare
Scelta algoritmo
Encryption con chiave
pubblica
Testo Cifrato](https://image.slidesharecdn.com/gdg-devfest-rome-2013androidkeymanagement-140115060032-phpapp02/85/Consulthink-at-GDG-Dev-Fest-Rome-2013-Android-Key-Management-21-320.jpg)
![Android Security
Key Management
RSA Decryption
Cipher decCipher = null;
byte[] plainTextByte = null;
decCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
decCipher.init(Cipher.DECRYPT_MODE,
((KeyStore.PrivateKeyEntry) entry).getPrivateKey());
plainTextByte = decCipher.doFinal(ecryptedText);
String plainText = new String(plainTextByte);
Scelta algoritmo
Decryption con la
chiave privata
Decryption con chiave privata
Testo decifrato](https://image.slidesharecdn.com/gdg-devfest-rome-2013androidkeymanagement-140115060032-phpapp02/85/Consulthink-at-GDG-Dev-Fest-Rome-2013-Android-Key-Management-22-320.jpg)
Consulthink at GDG Dev Fest Rome 2013 Android Key Management
- 1. Android Security Key Management Roberto Gassir (r.gassira@mseclab.com) Roberto Piccirillo (r.piccirillo@mseclab.com)
- 2. Android Security Key Management Roberto Piccirillo Senior Security Analyst - Mobile Security Lab Vulnerability Assessment (IT, Mobile Application) Hijacking Mobile Data Connection BlackHat Europe 2009 DeepSec Vienna 2009 HITB Amsterdam 2010 Android Secure Development @robpicone
- 3. Android Security Key Management Roberto Gassir Senior Security Analyst - Mobile Security Lab Vulnerability Assessment (IT, Mobile Application) Hijacking Mobile Data Connection BlackHat Europe 2009 DeepSec Vienna 2009 HITB Amsterdam 2010 Android Secure Development IpTrack Developer @robgas
- 4. Android Security Key Management Agenda Key Management e CryptoSystem Mobile Application: protezione dei dati Key Management in Android e sue evoluzioni Keychain e AndroidKeyStore Tipologie di AndroidKeyStore Codelab Generazione chiave pubblica/privata Accesso AndroidKeyStore Digital signature e Encryption
- 5. Android Security Key Management Key Management "Key management is the management of cryptographic keys in a cryptosystem."
- 6. Android Security Key Management CryptoSystem "refers to a suite of algorithms needed to implement a particular form of encryption and decryption" Tipologie di encryption: Symmetric Key Algorithms Identical encryption key for encryption/decryption Asymmetric Key Algorithms Different key for encryption/decryption
- 7. Android Security Key Management In app? Protezione dati riservati Dati dell'applicazione Dati su /sdcard Chiavi di cifratura Scambio sicuro di dati Documento Mail SMS Chiave di sessione Firma digitale Documento Mail
- 8. Android Security Key Management Key Management in Android Application Level File nell'applicazione ( Shared Prefs, File, ... ) Code Obfuscation Generazione a run-time
- 9. Android Security Key Management Key Management in Android "User" level PBKDF2 (Password Based Key Derivation Function) Algoritmo di generazione ( PBEWithSHA256And256BitAES-CBC-BC ) Salt Numero di Iterazioni System Level KeyChain (da >= 4.0 ) AndroidKeyStore (ufficiale da >= 4.3)
- 10. Android Security Key Management KeyChain e AndroidKeyStore KeyChain Accessibile da qualunque applicazione AndroidKeyStore Accessibile alla singola applicazione ed al singolo utente Memorizza solo coppia chiave pubblica/privata RSA 2048
- 11. Android Security Key Management Key Management Evolution API LEVEL 14 API LEVEL 18 Global Level: KeyChain ( Public API ) App Level: KeyStore ( Closed API ) Global Level Only: Default TrustStore cacerts.bks (ROOTED device) Global Level: KeyChain ( Public API ) App Level and per User Level: AndroidKeyStore ( Public API )
- 12. Android Security Key Management AndroidKeyStore Storage Due tipologie di Storage Hardware-backed (Nexus 7, Nexus 4, Nexus 5 :-) con OS >= 4.3) Secure Element TPM TrustZone Software only (Rimanenti dispositivi con OS >= 4.3)
- 13. Android Security Key Management Storage? import android.security.KeyChain; if (KeyChain.isBoundKeyAlgorithm("RSA")) // Hardware-Backed else // Software Only
- 15. Android Security Key Management Cosa faremo CodeLab diviso in 4 step: 1.Generazioni Chiavi 2.Accesso AndroidKeyStore 3.Firma e Verifica 4.Cifratura/Decifratura
- 16. Android Security Key Management Definizione Specifiche Certificato Context cx = getActivity(); String pkg = cx.getPackageName(); Calendar notBefore = Calendar.getInstance(); Calendar notAfter = Calendar.getInstance(); notAfter.add(1, Calendar.YEAR); import android.security.KeyPairGeneratorSpec.Builder; Builder builder = new KeyPairGeneratorSpec.Builder(cx); builder.setAlias(DEVKEY1); String infocert = String.format("CN=%s, OU=%s", DEVKEY1, pkg); builder.setSubject(new X500Principal(infocert)); builder.setSerialNumber(BigInteger.ONE); builder.setStartDate(notBefore.getTime()); builder.setEndDate(notAfter.getTime()); KeyPairGeneratorSpec spec = builder.build(); Definizione Paramentri Temporali Self-Signed X.509 Common Name (CN) Subject (OU) Serial Number Generazione delle specifiche del Certificato ALIAS per indicizzare il certificato
- 17. Android Security Key Management Generazione chiave pubblica/privata KeyPairGenerator kpGenerator; kpGenerator = KeyPairGenerator .getInstance("RSA", "AndroidKeyStore"); kpGenerator.initialize(spec); KeyPair kp; kp = kpGenerator.generateKeyPair(); Engine per generazione chiave Privata/Pubblica Istanza Engine con: Algoritmo RSA Provider: AndroidKeyStore Init Engine con le specifiche del certificato Dopo la generazione, le chiavi saranno memorizzate in Android Key Store e potranno essere recuperate mediante lALIAS Generazione chiave Privata/Pubblica
- 18. Android Security Key Management Abbiamo il riferimento keyStore che utilizzeremo per accedere alla coppia chiave Pubblica/Privata mediante lidentificativo ALIAS Dovrebbe essere utilizzato nel caso si ha un InputStream da caricare (per esempio il nome di un KeyStore importato). Se non invocato lapplicazione andr in CRASH Inizializzazione Android Key Store keyStore = KeyStore.getInstance("AndroidKeyStore"); keyStore.load(null); Richiesta di Android Key Store
- 19. Android Security Key Management RSA Digital Signature Digital Signature Authentication, Non-Repudiation and Integrity RSA Private key to Sign RSA Public Key to Verify KeyStore.Entry entry = ks.getEntry(DEVKEY1, null); byte[] data = DevFest Rome 2013!.getBytes(); Signature s = Signature.getInstance(SHA256withRSA); s.initSign(((KeyStore.PrivateKeyEntry) entry).getPrivateKey()); s.update(data); byte[] signature = s.sign(); String result = null; result = Base64.encodeToString(signature, Base64.DEFAULT); Accesso chiave Pubblica e Privata identificata dallALIAS==DEVKEY1 Scelta dellalgoritmo Chiave Privata per firmare Firma e codifica in Base64
- 20. Android Security Key Management Verify RSA Digital Signature byte[] data = input.getBytes(); byte[] signature; signature = Base64.decode(signatureStr, Base64.DEFAULT); KeyStore.Entry entry = ks.getEntry(DEVKEY1, null); Signature s = Signature.getInstance("SHA256withRSA"); s.initVerify(((KeyStore.PrivateKeyEntry) entry).getCertificate()); s.update(data); boolean valid = s.verify(signature); Decodifica Base64 Accesso chiave Pubblica e Privata identificata dallALIAS==DEVKEY1 Scelta dellalgoritmo Chiave Pubblica nel certificato utilizzata per verificare TRUE == Verified FALSE== Not Verified
- 21. Android Security Key Management RSA Encryption Encryption Confidentiality RSA Public key to Encrypt RSA Private key to Decrypt PublicKey publicKeyEnc = ((KeyStore.PrivateKeyEntry) entry) .getCertificate().getPublicKey(); String textToEncrypt = new String("DevFest Rome 2013"); byte[] textToEncryptToByte = textToEncrypt.getBytes(); Cipher encCipher = null; byte[] encryptedText = null; encCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); encCipher.init(Cipher.ENCRYPT_MODE, publicKeyEnc); encryptedText = encCipher.doFinal(textToEncryptToByte); Accesso alla chiave pubblica per cifrare Scelta algoritmo Encryption con chiave pubblica Testo Cifrato
- 22. Android Security Key Management RSA Decryption Cipher decCipher = null; byte[] plainTextByte = null; decCipher = Cipher.getInstance("RSA/ECB/PKCS1Padding"); decCipher.init(Cipher.DECRYPT_MODE, ((KeyStore.PrivateKeyEntry) entry).getPrivateKey()); plainTextByte = decCipher.doFinal(ecryptedText); String plainText = new String(plainTextByte); Scelta algoritmo Decryption con la chiave privata Decryption con chiave privata Testo decifrato
- 23. Android Security Key Management Si osserva che... Vari tipi di screen lock La scelta di screen lock impatta sulla persistenza delle chiavi generate Cambiando il tipo di screen lock le chiavi vengono cancellate
- 24. Android Security Key Management Comportamento atteso? La documentazione riporta Le chiavi non dovrebbero essere cancellate quando il tipo di screen lock viene cambiato dallutente
- 25. Android Security Key Management Cryptographic stuff on devices Device con Storage Hardware-backed Device con Storage Software-only
- 26. Android Security Key Management References http://developer.android.com/about/versions/android-4.3.html#Security http://developer.android.com/reference/java/security/KeyStore.html http://en.wikipedia.org/wiki/Encryption http://en.wikipedia.org/wiki/Digital_signature http://nelenkov.blogspot.it/2013/08/credential-storage-enhancements- android-43.html http://nelenkov.blogspot.it/2012/05/storing-application-secrets-in-androids.html http://nelenkov.blogspot.it/2012/04/using-password-based-encryption-on.html http://nelenkov.blogspot.it/2011/11/ics-credential-storage-implementation.html http://developer.android.com/reference/android/security/ KeyPairGeneratorSpec.html
- 27. Android Security Key Management Grazie Q&A www.mseclab.com www.consulthink.it research@mseclab.com
- 28. Android Security Key Management Requisiti Portatile Eclipse con ADT Plugin 22.3.0 SDK Android 4.4 ( API 19 ) Android SDK Build-tools 19