crypto/src/main/java/org/springframework/security/crypto/util/EncodingUtils.java
public static byte[] concatenate(byte[]... arrays) {
		int length = 0;
		for (byte[] array : arrays) {
			length += array.length;
		}
		byte[] newArray = new byte[length];
		int destPos = 0;
		for (byte[] array : arrays) {
			System.arraycopy(array, 0, newArray, destPos, array.length);
			destPos += array.length;
		}
		return newArray;
	}
public static byte[] concatenate(byte[]... arrays) {
		int length = 0;
		for (byte[] array : arrays) {
			length += array.length;
		}
		byte[] newArray = new byte[length];
		int destPos = 0;
		for (byte[] array : arrays) {
			System.arraycopy(array, 0, newArray, destPos, array.length);
			destPos += array.length;
		}
		return newArray;
	}
Combine the individual byte arrays into one array.