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Moved Bytes to the main package. Added a SharedSecret class to parse

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encrypted secrets retrieved from the database.
This commit is contained in:
akwizgran
2011-08-11 19:14:20 +01:00
parent df972e294d
commit 7545a1cc8f
8 changed files with 68 additions and 26 deletions
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36
components/net/sf/briar/crypto/CryptoComponentImpl.java
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@@ -68,33 +68,31 @@ class CryptoComponentImpl implements CryptoComponent {
}
}
public SecretKey deriveMacKey(byte[] secret, boolean alice) {
if(alice) return deriveKey("MACA", secret);
else return deriveKey("MACB", secret);
public SecretKey deriveMacKey(byte[] secret) {
SharedSecret s = new SharedSecret(secret);
if(s.getAlice()) return deriveKey("MACA", s.getIv(), s.getCiphertext());
else return deriveKey("MACB", s.getIv(), s.getCiphertext());
}
private SecretKey deriveKey(String name, byte[] secret) {
private SecretKey deriveKey(String name, IvParameterSpec iv,
byte[] ciphertext) {
MessageDigest digest = getMessageDigest();
try {
digest.update(name.getBytes("UTF-8"));
} catch(UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
byte[] decrypted = decryptSharedSecret(secret);
byte[] decrypted = decryptSharedSecret(iv, ciphertext);
digest.update(decrypted);
Arrays.fill(decrypted, (byte) 0);
Arrays.fill(decrypted, (byte) 0); // Destroy the plaintext secret
return new SecretKeySpec(digest.digest(), SECRET_KEY_ALGO);
}
private byte[] decryptSharedSecret(byte[] secret) {
// The first 16 bytes of the stored secret are the IV
if(secret.length <= 16) throw new IllegalArgumentException();
IvParameterSpec iv = new IvParameterSpec(secret, 0, 16);
private byte[] decryptSharedSecret(IvParameterSpec iv, byte[] ciphertext) {
try {
// Decrypt and return the remainder of the stored secret
Cipher c = Cipher.getInstance(SECRET_STORAGE_ALGO, PROVIDER);
c.init(Cipher.DECRYPT_MODE, secretStorageKey, iv);
return c.doFinal(secret, 16, secret.length - 16);
return c.doFinal(ciphertext);
} catch(BadPaddingException e) {
throw new RuntimeException(e);
} catch(IllegalBlockSizeException e) {
@@ -112,14 +110,16 @@ class CryptoComponentImpl implements CryptoComponent {
}
}
public SecretKey derivePacketKey(byte[] secret, boolean alice) {
if(alice) return deriveKey("PKTA", secret);
else return deriveKey("PKTB", secret);
public SecretKey derivePacketKey(byte[] secret) {
SharedSecret s = new SharedSecret(secret);
if(s.getAlice()) return deriveKey("PKTA", s.getIv(), s.getCiphertext());
else return deriveKey("PKTB", s.getIv(), s.getCiphertext());
}
public SecretKey deriveTagKey(byte[] secret, boolean alice) {
if(alice) return deriveKey("TAGA", secret);
else return deriveKey("TAGB", secret);
public SecretKey deriveTagKey(byte[] secret) {
SharedSecret s = new SharedSecret(secret);
if(s.getAlice()) return deriveKey("TAGA", s.getIv(), s.getCiphertext());
else return deriveKey("TAGB", s.getIv(), s.getCiphertext());
}
public KeyPair generateKeyPair() {