package com.winsun.smsUtils;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

public class HMACSHA1 {

	private static final String HMAC_SHA1 = "HmacSHA1";

	/**
	 * 生成签名数据
	 * 
	 * @param data 待加密的数据
	 * @param key 加密使用的key
	 * @throws InvalidKeyException
	 * @throws NoSuchAlgorithmException
	 */
	public static String getSignature( String data, String key ) throws Exception {
		byte[] keyBytes = key.getBytes();
		SecretKeySpec signingKey = new SecretKeySpec( keyBytes, HMAC_SHA1 );
		Mac mac = Mac.getInstance( HMAC_SHA1 );
		mac.init( signingKey );
		byte[] rawHmac = mac.doFinal( data.getBytes() );
		StringBuilder sb = new StringBuilder();
		for( byte b : rawHmac ) {
			sb.append( byteToHexString( b ) );
		}
		return sb.toString();
	}

	private static String byteToHexString( byte ib ) {
		char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
		char[] ob = new char[2];
		ob[0] = Digit[(ib >>> 4) & 0X0f];
		ob[1] = Digit[ib & 0X0F];
		String s = new String( ob );
		return s;
	}
}
