package net.oauth.signature;
import java.io.UnsupportedEncodingException;
import java.security.GeneralSecurityException;
import java.util.Arrays;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import net.oauth.OAuth;
import net.oauth.OAuthException;
/**
* @author John Kristian
* @hide
*/
class HMAC_SHA1 extends OAuthSignatureMethod {
@Override
protected String getSignature(String baseString) throws OAuthException {
try {
String signature = base64Encode(computeSignature(baseString));
return signature;
} catch (GeneralSecurityException e) {
throw new OAuthException(e);
} catch (UnsupportedEncodingException e) {
throw new OAuthException(e);
}
}
@Override
protected boolean isValid(String signature, String baseString)
throws OAuthException {
try {
byte[] expected = computeSignature(baseString);
byte[] actual = decodeBase64(signature);
return Arrays.equals(expected, actual);
} catch (GeneralSecurityException e) {
throw new OAuthException(e);
} catch (UnsupportedEncodingException e) {
throw new OAuthException(e);
}
}
private byte[] computeSignature(String baseString)
throws GeneralSecurityException, UnsupportedEncodingException {
SecretKey key = null;
synchronized (this) {
if (this.key == null) {
String keyString = OAuth.percentEncode(getConsumerSecret())
+ '&' + OAuth.percentEncode(getTokenSecret());
byte[] keyBytes = keyString.getBytes(ENCODING);
this.key = new SecretKeySpec(keyBytes, MAC_NAME);
}
key = this.key;
}
Mac mac = Mac.getInstance(MAC_NAME);
mac.init(key);
byte[] text = baseString.getBytes(ENCODING);
return mac.doFinal(text);
}
/** ISO-8859-1 or US-ASCII would work, too. */
private static final String ENCODING = OAuth.ENCODING;
private static final String MAC_NAME = "HmacSHA1";
private SecretKey key = null;
@Override
public void setConsumerSecret(String consumerSecret) {
synchronized (this) {
key = null;
}
super.setConsumerSecret(consumerSecret);
}
@Override
public void setTokenSecret(String tokenSecret) {
synchronized (this) {
key = null;
}
super.setTokenSecret(tokenSecret);
}
}
