HashHelper

com.ajaxjs.util.HashHelper computes digests and HMACs. Hashing is not reversible encryption; MD5 and SHA-1 are legacy digests, unsuitable for collision-resistant security decisions. Plain hashes are not password-storage schemes.

Construct with an algorithm name and String (UTF-8) or byte[]. hash() dispatches names beginning exactly with Hmac to getMac(), otherwise to getMessageDigest(). hashAsStr() returns lowercase hex; hashAsBase64() returns padded Base64, and hashAsBase64(true) omits padding.

HMAC keys

setKey(String) uses UTF-8 key bytes; setKeyBase64(String) decodes key material. They return the instance. A missing key throws IllegalStateException; no random key is generated. Unsupported algorithms fail rather than returning null.

import com.ajaxjs.util.HashHelper;

String digest = HashHelper.sha256("hello");
String mac = new HashHelper(HashHelper.HMAC_SHA256, "hello")
        .setKey("example-only-key").hashAsBase64();
String sameMac = HashHelper.hmacSHA256("hello", "example-only-key", false);

Convenience methods

md5(String), md5(byte[]), md5(InputStream), sha1(String) and sha256(String) return lowercase hex. hmacMD5, hmacSHA1 and hmacSHA256 take (String data, String key, boolean isWithoutPadding) and return Base64.

Stream ownership: current md5(InputStream) uses DataReader and closes the input stream, despite its Javadoc saying otherwise. Do not reuse it afterward. It processes chunks instead of loading the entire file. Protect real HMAC keys; the example key is not a production secret.