private static byte[] computeIV(iOS_Sha1Crypto sha1, int block) throws CryptoException {
		sha1.update(CryptoUtil.htonl(block));
		byte[] bytes = sha1.decrypt();
		byte[] iv = Arrays.copyOfRange(bytes, 0, 16);
		return iv;
	}
Creates a DMG decrypting {@link InputStream}, reading from the provided
{@link ByteProvider}.
<p>
The crypto keys for the DMG file are found by using the name of the container file
this DMG is embedded in (ie. the name of the .ipsw) and the name of this dmg file to
query the {@link CryptoKeyFactory}.

@param containerName Name of the containing .ipsw file
@param dmgName Name of this DMG file
@param provider stream to be wrapped.  Will be closed when this stream is closed.
@throws IOException if io error or crypto problem.
Ghidra/Features/FileFormats/src/main/java/ghidra/file/formats/ios/dmg/DmgDecryptorStream.java