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Key derivation fixes, renamed a key derivation method.

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This commit is contained in:
akwizgran
2016-03-30 12:02:49 +01:00
parent a8fa6339fb
commit e78ba2e806
5 changed files with 35 additions and 52 deletions
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51
briar-core/src/org/briarproject/crypto/CryptoComponentImpl.java
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@@ -63,24 +63,22 @@ class CryptoComponentImpl implements CryptoComponent {
return s.getBytes(Charset.forName("US-ASCII"));
}
// KDF label for bluetooth master key derivation
private static final byte[] BT_MASTER = ascii("MASTER");
// KDF labels for bluetooth confirmation code derivation
private static final byte[] BT_A_CONFIRM = ascii("ALICE_CONFIRMATION_CODE");
private static final byte[] BT_B_CONFIRM = ascii("BOB_CONFIRMATION_CODE");
// KDF labels for bluetooth invitation stream header key derivation
private static final byte[] BT_A_INVITE = ascii("ALICE_INVITATION_KEY");
private static final byte[] BT_B_INVITE = ascii("BOB_INVITATION_KEY");
// KDF labels for bluetooth signature nonce derivation
private static final byte[] BT_A_NONCE = ascii("ALICE_SIGNATURE_NONCE");
private static final byte[] BT_B_NONCE = ascii("BOB_SIGNATURE_NONCE");
// KDF labels for contact exchange stream header key derivation
private static final byte[] A_INVITE = ascii("ALICE_INVITATION_KEY");
private static final byte[] B_INVITE = ascii("BOB_INVITATION_KEY");
// KDF labels for contact exchange signature nonce derivation
private static final byte[] A_SIG_NONCE = ascii("ALICE_SIGNATURE_NONCE");
private static final byte[] B_SIG_NONCE = ascii("BOB_SIGNATURE_NONCE");
// Hash label for BQP public key commitment derivation
private static final byte[] COMMIT = ascii("COMMIT");
// Hash label for BQP shared secret derivation
// Hash label for shared secret derivation
private static final byte[] SHARED_SECRET = ascii("SHARED_SECRET");
// KDF label for BQP confirmation key derivation
private static final byte[] CONFIRMATION_KEY = ascii("CONFIRMATION_KEY");
// KDF label for BQP master key derivation
// KDF label for master key derivation
private static final byte[] MASTER_KEY = ascii("MASTER_KEY");
// KDF labels for tag key derivation
private static final byte[] A_TAG = ascii("ALICE_TAG_KEY");
@@ -210,12 +208,14 @@ class CryptoComponentImpl implements CryptoComponent {
return ByteUtils.readUint(b, CODE_BITS);
}
public SecretKey deriveBTInvitationKey(SecretKey master, boolean alice) {
return new SecretKey(macKdf(master, alice ? BT_A_INVITE : BT_B_INVITE));
public SecretKey deriveHeaderKey(SecretKey master,
boolean alice) {
return new SecretKey(macKdf(master, alice ? A_INVITE : B_INVITE));
}
public byte[] deriveSignatureNonce(SecretKey master, boolean alice) {
return macKdf(master, alice ? BT_A_NONCE : BT_B_NONCE);
public byte[] deriveSignatureNonce(SecretKey master,
boolean alice) {
return macKdf(master, alice ? A_SIG_NONCE : B_SIG_NONCE);
}
public byte[] deriveKeyCommitment(byte[] publicKey) {
@@ -438,29 +438,6 @@ class CryptoComponentImpl implements CryptoComponent {
}
}
// Key derivation function based on a hash function - see NIST SP 800-56A,
// section 5.8
private byte[] hashKdf(byte[]... inputs) {
Digest digest = new Blake2sDigest();
// The output of the hash function must be long enough to use as a key
int hashLength = digest.getDigestSize();
if (hashLength < SecretKey.LENGTH) throw new IllegalStateException();
// Calculate the hash over the concatenated length-prefixed inputs
byte[] length = new byte[INT_32_BYTES];
for (byte[] input : inputs) {
ByteUtils.writeUint32(input.length, length, 0);
digest.update(length, 0, length.length);
digest.update(input, 0, input.length);
}
byte[] hash = new byte[hashLength];
digest.doFinal(hash, 0);
// The output is the first SecretKey.LENGTH bytes of the hash
if (hash.length == SecretKey.LENGTH) return hash;
byte[] truncated = new byte[SecretKey.LENGTH];
System.arraycopy(hash, 0, truncated, 0, truncated.length);
return truncated;
}
// Key derivation function based on a pseudo-random function - see
// NIST SP 800-108, section 5.1
private byte[] macKdf(SecretKey key, byte[]... inputs) {