Java Code Examples for com.amazonaws.encryptionsdk.CryptoAlgorithm#deserialize()

/**
 * Parse the algorithm identifier in the provided bytes. It looks for 2
 * bytes representing a short primitive type in the provided bytes starting
 * at the specified off.
 * 
 * <p>
 * If successful, it returns the number of parsed bytes which is the size of
 * the short primitive type. On failure, it throws a parse exception.
 * 
 * @param b
 *            the byte array to parse.
 * @param off
 *            the offset in the byte array to use when parsing.
 * @return
 *         the number of parsed bytes which is the size of the short
 *         primitive type.
 * @throws ParseException
 *             if there are not sufficient bytes to parse the algorithm
 *             identifier.
 */
private int parseAlgoId(final byte[] b, final int off) throws ParseException {
    cryptoAlgoVal_ = PrimitivesParser.parseShort(b, off);
    if (CryptoAlgorithm.deserialize(cryptoAlgoVal_) == null) {
        throw new BadCiphertextException("Invalid algorithm identifier in ciphertext");
    }
    return Short.SIZE / Byte.SIZE;
}
 

/**
 * Parse the header tag in the provided bytes. It uses the crypto algorithm
 * identifier to determine the length of the tag to parse. It looks for
 * bytes of size defined by the tag length in the provided bytes starting at
 * the specified off.
 * 
 * <p>
 * If successful, it returns the size of the parsed bytes which is the tag
 * length determined from the crypto algorithm identifier. On failure, it
 * throws a parse exception.
 * 
 * @param b
 *            the byte array to parse.
 * @param off
 *            the offset in the byte array to use when parsing.
 * @return
 *         the size of the parsed bytes which is the tag length determined
 *         from the crypto algorithm identifier.
 * @throws ParseException
 *             if there are not sufficient bytes to parse the header tag.
 */
private int parseHeaderTag(final byte[] b, final int off) throws ParseException {
    final int len = b.length - off;
    final CryptoAlgorithm cryptoAlgo = CryptoAlgorithm.deserialize(cryptoAlgoVal_);
    final int tagLen = cryptoAlgo.getTagLen();
    if (len >= tagLen) {
        headerTag_ = Arrays.copyOfRange(b, off, off + tagLen);
        return tagLen;
    } else {
        throw new ParseException("Not enough bytes to parse header tag");
    }
}
 

/**
 * Return the crypto algorithm identifier set in the header.
 * 
 * @return
 *         the CryptoAlgorithm enum value representing the identifier set in
 *         the header.
 */
public CryptoAlgorithm getCryptoAlgoId() {
    return CryptoAlgorithm.deserialize(cryptoAlgoVal_);
}