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Changed the message format to store the author and group inline - this

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doesn't take a huge amount of space and allows every message to be
self-certifying.
This commit is contained in:
akwizgran
2011-07-25 21:14:16 +01:00
parent 586d1739ae
commit 3f61d0c3df
18 changed files with 317 additions and 127 deletions
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77
components/net/sf/briar/protocol/MessageReader.java
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@@ -6,11 +6,12 @@ import java.security.MessageDigest;
import java.security.PublicKey;
import java.security.Signature;
import java.security.SignatureException;
import java.security.spec.InvalidKeySpecException;
import net.sf.briar.api.crypto.CryptoComponent;
import net.sf.briar.api.crypto.KeyParser;
import net.sf.briar.api.protocol.Author;
import net.sf.briar.api.protocol.AuthorId;
import net.sf.briar.api.protocol.GroupId;
import net.sf.briar.api.protocol.Group;
import net.sf.briar.api.protocol.Message;
import net.sf.briar.api.protocol.MessageId;
import net.sf.briar.api.protocol.Tags;
@@ -21,15 +22,19 @@ import net.sf.briar.api.serial.Reader;
class MessageReader implements ObjectReader<Message> {
private final ObjectReader<Group> groupReader;
private final ObjectReader<Author> authorReader;
private final KeyParser keyParser;
private final Signature signature;
private final MessageDigest messageDigest;
MessageReader(KeyParser keyParser, Signature signature,
MessageDigest messageDigest) {
this.keyParser = keyParser;
this.signature = signature;
this.messageDigest = messageDigest;
MessageReader(CryptoComponent crypto, ObjectReader<Group> groupReader,
ObjectReader<Author> authorReader) {
this.groupReader = groupReader;
this.authorReader = authorReader;
keyParser = crypto.getKeyParser();
signature = crypto.getSignature();
messageDigest = crypto.getMessageDigest();
}
public Message readObject(Reader r) throws IOException {
@@ -44,49 +49,49 @@ class MessageReader implements ObjectReader<Message> {
byte[] b = r.readBytes();
if(b.length != UniqueId.LENGTH) throw new FormatException();
MessageId parent = new MessageId(b);
// Read the group ID
r.readUserDefinedTag(Tags.GROUP_ID);
b = r.readBytes();
if(b.length != UniqueId.LENGTH) throw new FormatException();
GroupId group = new GroupId(b);
// Read the group
r.addObjectReader(Tags.GROUP, groupReader);
Group group = r.readUserDefined(Tags.GROUP, Group.class);
r.removeObjectReader(Tags.GROUP);
// Read the author, if there is one
r.addObjectReader(Tags.AUTHOR, authorReader);
Author author = null;
if(r.hasNull()) r.readNull();
else author = r.readUserDefined(Tags.AUTHOR, Author.class);
r.removeObjectReader(Tags.AUTHOR);
// Read the timestamp
long timestamp = r.readInt64();
if(timestamp < 0L) throw new FormatException();
// Hash the author's nick and public key to get the author ID
DigestingConsumer digesting = new DigestingConsumer(messageDigest);
messageDigest.reset();
r.addConsumer(digesting);
r.readString();
byte[] encodedKey = r.readBytes();
r.removeConsumer(digesting);
AuthorId author = new AuthorId(messageDigest.digest());
// Skip the message body
r.readBytes();
// Record the length of the signed data
int messageLength = (int) counting.getCount();
// Read the signature
byte[] sig = r.readBytes();
// Read the author's signature, if there is one
byte[] authorSig = null;
if(author == null) r.readNull();
else authorSig = r.readBytes();
// That's all, folks
r.removeConsumer(counting);
r.removeConsumer(copying);
// Verify the signature
PublicKey publicKey;
try {
publicKey = keyParser.parsePublicKey(encodedKey);
} catch(InvalidKeySpecException e) {
throw new FormatException();
}
byte[] raw = copying.getCopy();
try {
signature.initVerify(publicKey);
signature.update(raw, 0, messageLength);
if(!signature.verify(sig)) throw new SignatureException();
} catch(GeneralSecurityException e) {
throw new FormatException();
// Verify the author's signature, if there is one
if(author != null) {
try {
PublicKey publicKey =
keyParser.parsePublicKey(author.getPublicKey());
signature.initVerify(publicKey);
signature.update(raw, 0, messageLength);
if(!signature.verify(authorSig)) throw new SignatureException();
} catch(GeneralSecurityException e) {
throw new FormatException();
}
}
// Hash the message, including the signature, to get the message ID
messageDigest.reset();
messageDigest.update(raw);
MessageId id = new MessageId(messageDigest.digest());
return new MessageImpl(id, parent, group, author, timestamp, raw);
AuthorId authorId = author == null ? AuthorId.NONE : author.getId();
return new MessageImpl(id, parent, group.getId(), authorId, timestamp,
raw);
}
}