package tokbox.com.opentok.util;
import java.security.SignatureException;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
public class GenerateMac {
private static final String HMAC_SHA1_ALGORITHM = "HmacSHA1";
private static String hexmap[];
static {
//No good way to convert to hex, built a map table
hexmap = new String[256];
hexmap[0] = "00";
hexmap[1] = "01";
hexmap[2] = "02";
hexmap[3] = "03";
hexmap[4] = "04";
hexmap[5] = "05";
hexmap[6] = "06";
hexmap[7] = "07";
hexmap[8] = "08";
hexmap[9] = "09";
hexmap[10] = "0a";
hexmap[11] = "0b";
hexmap[12] = "0c";
hexmap[13] = "0d";
hexmap[14] = "0e";
hexmap[15] = "0f";
for (int i = 16; i < 256; i++) {
hexmap[i] = Integer.toHexString(i);
}
}
public static String get_hex(final byte byt) {
return hexmap[((short)(byt & 0xff))];
}
public static String calculateRFC2104HMAC(final String data, final String key) throws java.security.SignatureException {
/**
*@param data
* The data to be signed. (The wbxml as a string of Hex digits.)
*@param key
* The signing key. (E.g. USERPIN of '1234')
*/
final StringBuilder hexMAC = new StringBuilder();
try {
// Get an hmac_sha1 key from the raw key bytes
final byte[] keyBytes = key.getBytes();
final SecretKeySpec signingKey = new SecretKeySpec(keyBytes, HMAC_SHA1_ALGORITHM);
// Get an hmac_sha1 Mac instance and initialize with the signing key
final Mac mac = Mac.getInstance(HMAC_SHA1_ALGORITHM);
mac.init(signingKey);
// Compute the hmac on input data bytes
final byte[] rawHmac = mac.doFinal(data.getBytes());
for(int i=0;i<rawHmac.length;i++) {
hexMAC.append(get_hex(rawHmac[i]));
}
// Convert raw bytes to Hex
//byte[] hexBytes = new Hex().encode(rawHmac);
// Covert array of Hex bytes to a String
//result = new String(hexBytes, "ISO-8859-1");
}
catch (Exception e) {
throw new SignatureException("Failed to generate HMAC : " + e.getMessage());
}
return hexMAC.toString();
}
}