Android Hash

public class Hash {

    /**
     * 16진수를 문자열로 변환
     * @param data 변환할 16진수
     * @return 변환된 16진수 문자열
     */
    private static String convertToHex(byte[] data) {
        StringBuilder buf = new StringBuilder();
        for (byte b : data) {
            int halfbyte = (b >>> 4) & 0x0F;
            int two_halfs = 0;
            do {
                buf.append((0 <= halfbyte) && (halfbyte <= 9) ? (char) ('0' + halfbyte) : (char) ('a' + (halfbyte - 10)));
                halfbyte = b & 0x0F;
            } while (two_halfs++ < 1);
        }
        return buf.toString();
    }

    /**
     * 문자열의 SHA-1 해쉬값 얻기
     * @param text SHA-1 해쉬값을 얻어올 문자열
     * @return text 의 SHA-1 해쉬 String
     */
    public static String SHA1(String text) throws NoSuchAlgorithmException, UnsupportedEncodingException {
        MessageDigest md = MessageDigest.getInstance("SHA-1");
        md.update(text.getBytes("iso-8859-1"), 0, text.length());
        byte[] sha1hash = md.digest();
        return convertToHex(sha1hash);
    }

    /**
     * 문자열의 HMAC 해쉬값 얻기
     * @param type 사용할 HMAC 알고리즘 ("HmacSHA1")
     * @param value HMAC 해쉬값을 얻어올 문자열
     * @param key HMAC 해쉬값 생성에 필요한 key
     * @return value 의 HMAC 해쉬 String
     */
    public static String HMAC(String type, String value, String key) throws NoSuchAlgorithmException, InvalidKeyException{
        javax.crypto.Mac mac = javax.crypto.Mac.getInstance(type);
        javax.crypto.spec.SecretKeySpec secret = new javax.crypto.spec.SecretKeySpec(key.getBytes(), type);
        mac.init(secret);
        byte[] digest = mac.doFinal(value.getBytes());
        StringBuilder sb = new StringBuilder(digest.length*2);
        String s;
        for (byte b : digest){
            s = Integer.toHexString(b&0xFF);
            if(s.length() == 1) sb.append('0');
            sb.append(s);
        }
        return sb.toString();
    }

}