<?php

namespace TablePress\PhpOffice\PhpSpreadsheet\Shared\Xlsx;

use TablePress\PhpOffice\PhpSpreadsheet\Reader\Exception;
use TablePress\PhpOffice\PhpSpreadsheet\Shared\File as SharedFile;
use TablePress\PhpOffice\PhpSpreadsheet\Shared\OLE;
use SimpleXMLElement;
use Stringable;
use Throwable;

/** ECMA-376 Agile Encryption (AES-256/SHA-512 profile). */
final class AgileEncryption
{
	public const MAX_SPIN_COUNT = 10000000;

	private const BLOCK_KEY_VERIFIER = "\xFE\xA7\xD2\x76\x3B\x4B\x9E\x79";

	private const BLOCK_KEY_VERIFIER_HASH = "\xD7\xAA\x0F\x6D\x30\x61\x34\x4E";

	private const BLOCK_KEY_ENCRYPTED_KEY = "\x14\x6E\x0B\xE7\xAB\xAC\xD0\xD6";

	private const BLOCK_KEY_HMAC_KEY = "\x5F\xB2\xAD\x01\x0C\xB9\xE1\xF6";

	private const BLOCK_KEY_HMAC_VALUE = "\xA0\x67\x7F\x02\xB2\x2C\x84\x33";

	private const BLOCK_SIZE = 16;

	private const SEGMENT_SIZE = 4096;

	private const ENCRYPTION_NAMESPACE = 'http://schemas.microsoft.com/office/2006/encryption';

	private const PASSWORD_NAMESPACE = 'http://schemas.microsoft.com/office/2006/keyEncryptor/password';

	private const PASSWORD_KEY_ENCRYPTOR_URI = 'http://schemas.microsoft.com/office/2006/keyEncryptor/password';

	private const CFB_SECTOR_SIZE = 512;

	private const CFB_MINI_SECTOR_SIZE = 64;

	private const CFB_MINI_STREAM_CUTOFF = 4096;

	private const CFB_FAT_ENTRIES_PER_SECTOR = self::CFB_SECTOR_SIZE >> 2;

	private const CFB_DIFAT_ENTRIES_IN_HEADER = 109;

	private const CFB_DIFAT_ENTRIES_PER_SECTOR = self::CFB_FAT_ENTRIES_PER_SECTOR - 1;

	private const CFB_DIRECTORY_ENTRIES_PER_SECTOR = self::CFB_SECTOR_SIZE >> 7;

	private const CFB_MINI_SECTORS_PER_SECTOR = self::CFB_SECTOR_SIZE >> 6;

	private const DIRECTORY_ENCRYPTED_PACKAGE = 1;

	private const DIRECTORY_DATA_SPACES = 2;

	private const DIRECTORY_VERSION = 3;

	private const DIRECTORY_DATA_SPACE_MAP = 4;

	private const DIRECTORY_DATA_SPACE_INFO = 5;

	private const DIRECTORY_STRONG_ENCRYPTION_DATA_SPACE = 6;

	private const DIRECTORY_TRANSFORM_INFO = 7;

	private const DIRECTORY_STRONG_ENCRYPTION_TRANSFORM = 8;

	private const DIRECTORY_PRIMARY = 9;

	private const DIRECTORY_ENCRYPTION_INFO = 10;

	private const CFB_DIRECTORY_ENTRY_COUNT = self::DIRECTORY_ENCRYPTION_INFO + 1;

	private const STREAM_ENCRYPTED_PACKAGE = 'EncryptedPackage';

	private const STORAGE_DATA_SPACES = "\x06DataSpaces";

	private const STREAM_VERSION = 'Version';

	private const STREAM_DATA_SPACE_MAP = 'DataSpaceMap';

	private const STORAGE_DATA_SPACE_INFO = 'DataSpaceInfo';

	private const STREAM_STRONG_ENCRYPTION_DATA_SPACE = 'StrongEncryptionDataSpace';

	private const STORAGE_TRANSFORM_INFO = 'TransformInfo';

	private const STORAGE_STRONG_ENCRYPTION_TRANSFORM = 'StrongEncryptionTransform';

	private const STREAM_PRIMARY = "\x06Primary";

	private const STREAM_ENCRYPTION_INFO = 'EncryptionInfo';

	/** @var array<string, array{string, int}> */
	private const HASH_ALGORITHMS = [
		'SHA1' => ['sha1', 20],
		'SHA256' => ['sha256', 32],
		'SHA384' => ['sha384', 48],
		'SHA512' => ['sha512', 64],
	];

	/**
	 * @return array{keyDataSalt: string, passwordSalt: string, encryptedVerifier: string, encryptedVerifierHash: string, encryptedKey: string, encryptedHmacKey: string, encryptedHmacValue: string, spinCount: int, keyBits: int, hashAlgorithm: string, hashSize: int}
	 */
	public static function parse(string $encryptionInfo, int $maxSpinCount = self::MAX_SPIN_COUNT): array
	{
		if (substr($encryptionInfo, 0, 8) !== "\x04\x00\x04\x00\x40\x00\x00\x00") {
			throw new Exception('Unsupported XLSX encryption profile.');
		}

		$xml = @simplexml_load_string((string) substr($encryptionInfo, 8));
		if (!$xml instanceof SimpleXMLElement) {
			throw new Exception('Malformed XLSX encryption information.');
		}
		$namespaces = $xml->getDocNamespaces(true) ?: [];
		if ($xml->getName() !== 'encryption' || !in_array(self::ENCRYPTION_NAMESPACE, $namespaces, true) || !in_array(self::PASSWORD_NAMESPACE, $namespaces, true)) {
			throw new Exception('Unsupported XLSX encryption profile.');
		}
		$xml->registerXPathNamespace('e', self::ENCRYPTION_NAMESPACE);
		$xml->registerXPathNamespace('p', self::PASSWORD_NAMESPACE);
		$keyDataNodes = $xml->xpath('/e:encryption/e:keyData') ?: [];
		$integrityNodes = $xml->xpath('/e:encryption/e:dataIntegrity') ?: [];
		$keyEncryptorNodes = $xml->xpath('/e:encryption/e:keyEncryptors/e:keyEncryptor') ?: [];
		$encryptedKeyNodes = $xml->xpath('/e:encryption/e:keyEncryptors/e:keyEncryptor/p:encryptedKey') ?: [];
		$keyData = $keyDataNodes[0] ?? null;
		$integrity = $integrityNodes[0] ?? null;
		$keyEncryptor = $keyEncryptorNodes[0] ?? null;
		$encryptedKey = $encryptedKeyNodes[0] ?? null;
		if (!$keyData instanceof SimpleXMLElement || !$integrity instanceof SimpleXMLElement || !$keyEncryptor instanceof SimpleXMLElement || !$encryptedKey instanceof SimpleXMLElement || count($keyDataNodes) !== 1 || count($integrityNodes) !== 1 || count($keyEncryptorNodes) !== 1 || count($encryptedKeyNodes) !== 1) {
			throw new Exception('Unsupported XLSX encryption profile.');
		}
		$keyBits = self::decimalAttribute($keyData, 'keyBits');
		$hashAlgorithm = (string) $keyData['hashAlgorithm'];
		$hashSize = self::decimalAttribute($keyData, 'hashSize');
		$spinCount = self::decimalAttribute($encryptedKey, 'spinCount');
		$keyDataSaltSize = self::decimalAttribute($keyData, 'saltSize');
		$keyDataBlockSize = self::decimalAttribute($keyData, 'blockSize');
		$encryptedKeySaltSize = self::decimalAttribute($encryptedKey, 'saltSize');
		$encryptedKeyBlockSize = self::decimalAttribute($encryptedKey, 'blockSize');
		$encryptedKeyBits = self::decimalAttribute($encryptedKey, 'keyBits');
		$encryptedKeyHashSize = self::decimalAttribute($encryptedKey, 'hashSize');
		if (
			(string) $keyData['cipherAlgorithm'] !== 'AES' || (string) $keyData['cipherChaining'] !== 'ChainingModeCBC'
			|| !self::isSupportedProfile($keyBits, $hashAlgorithm, $hashSize) || $keyDataSaltSize !== 16 || $keyDataBlockSize !== 16
			|| (string) $encryptedKey['cipherAlgorithm'] !== 'AES'
			|| (string) $encryptedKey['cipherChaining'] !== 'ChainingModeCBC'
			|| (string) $encryptedKey['hashAlgorithm'] !== $hashAlgorithm || $encryptedKeySaltSize !== 16 || $encryptedKeyBlockSize !== 16 || $encryptedKeyBits !== $keyBits
			|| $encryptedKeyHashSize !== $hashSize || $spinCount > min($maxSpinCount, self::MAX_SPIN_COUNT)
			|| (string) $keyEncryptor['uri'] !== self::PASSWORD_KEY_ENCRYPTOR_URI
		) {
			throw new Exception('Unsupported XLSX encryption profile.');
		}

		$result = [
			'keyDataSalt' => self::decode($keyData['saltValue']),
			'passwordSalt' => self::decode($encryptedKey['saltValue']),
			'encryptedVerifier' => self::decode($encryptedKey['encryptedVerifierHashInput']),
			'encryptedVerifierHash' => self::decode($encryptedKey['encryptedVerifierHashValue']),
			'encryptedKey' => self::decode($encryptedKey['encryptedKeyValue']),
			'encryptedHmacKey' => self::decode($integrity['encryptedHmacKey']),
			'encryptedHmacValue' => self::decode($integrity['encryptedHmacValue']),
			'spinCount' => $spinCount,
			'keyBits' => $keyBits,
			'hashAlgorithm' => $hashAlgorithm,
			'hashSize' => $hashSize,
		];
		if (
			strlen($result['keyDataSalt']) !== 16 || strlen($result['passwordSalt']) !== 16
			|| strlen($result['encryptedVerifier']) !== 16 || strlen($result['encryptedVerifierHash']) !== self::paddedLength($hashSize)
			|| strlen($result['encryptedKey']) !== self::paddedLength(intdiv($keyBits, 8)) || strlen($result['encryptedHmacKey']) !== self::paddedLength($hashSize)
			|| strlen($result['encryptedHmacValue']) !== self::paddedLength($hashSize)
		) {
			throw new Exception('Malformed XLSX encryption information.');
		}

		return $result;
	}

	/** @param array{keyDataSalt: string, passwordSalt: string, encryptedVerifier: string, encryptedVerifierHash: string, encryptedKey: string, encryptedHmacKey: string, encryptedHmacValue: string, spinCount: int, keyBits: int, hashAlgorithm: string, hashSize: int} $info */
	public static function decrypt(array $info, string $encryptedPackage, string $password): string
	{
		if ($password === '') {
			throw new Exception('XLSX encryption password required.');
		}
		if (strlen($encryptedPackage) < 8) {
			throw new Exception('Malformed encrypted XLSX package.');
		}
		$hash = self::passwordHash($password, $info['passwordSalt'], $info['spinCount'], $info['hashAlgorithm']);
		$verifierKey = self::deriveKey($hash, self::BLOCK_KEY_VERIFIER, $info['hashAlgorithm'], $info['keyBits']);
		$verifierHashKey = self::deriveKey($hash, self::BLOCK_KEY_VERIFIER_HASH, $info['hashAlgorithm'], $info['keyBits']);
		$verifier = self::aesDecrypt($info['encryptedVerifier'], $verifierKey, $info['passwordSalt'], $info['keyBits']);
		$expectedHash = self::aesDecrypt($info['encryptedVerifierHash'], $verifierHashKey, $info['passwordSalt'], $info['keyBits']);
		if (!hash_equals(self::hash($info['hashAlgorithm'], $verifier), (string) substr($expectedHash, 0, $info['hashSize']))) {
			throw new Exception('XLSX encryption password is incorrect.');
		}
		$secretKey = self::aesDecrypt($info['encryptedKey'], self::deriveKey($hash, self::BLOCK_KEY_ENCRYPTED_KEY, $info['hashAlgorithm'], $info['keyBits']), $info['passwordSalt'], $info['keyBits']);
		$secretKey = (string) substr($secretKey, 0, intdiv($info['keyBits'], 8));
		if (strlen($secretKey) !== intdiv($info['keyBits'], 8)) {
			throw new Exception('Malformed XLSX encryption information.');
		}
		self::verifyIntegrity($info, $secretKey, $encryptedPackage);
		$size = self::unpackSize(substr($encryptedPackage, 0, 8));
		$offset = 8;
		$plain = '';
		for ($block = 0; $size > 0; ++$block) {
			$length = min(self::SEGMENT_SIZE, $size);
			$cipherLength = (int) (ceil($length / self::BLOCK_SIZE) * self::BLOCK_SIZE);
			$cipher = (string) substr($encryptedPackage, $offset, $cipherLength);
			if (strlen($cipher) !== $cipherLength) {
				throw new Exception('Malformed encrypted XLSX package.');
			}
			$iv = self::iv($info['keyDataSalt'], pack('V', $block), $info['hashAlgorithm']);
			$plain .= substr(self::aesDecrypt($cipher, $secretKey, $iv, $info['keyBits']), 0, $length);
			$offset += $cipherLength;
			$size -= $length;
		}
		if ($offset !== strlen($encryptedPackage)) {
			throw new Exception('Malformed encrypted XLSX package.');
		}

		return $plain;
	}

	/** @param array{keyDataSalt: string, passwordSalt: string, encryptedVerifier: string, encryptedVerifierHash: string, encryptedKey: string, encryptedHmacKey: string, encryptedHmacValue: string, spinCount: int, keyBits: int, hashAlgorithm: string, hashSize: int} $info */
	public static function decryptFile(array $info, string $inputFilename, string $outputFilename, string $password): void
	{
		if ($password === '') {
			throw new Exception('XLSX encryption password required.');
		}
		$input = @fopen($inputFilename, 'rb');
		if ($input === false) {
			throw new Exception('Could not open XLSX package for decryption.');
		}

		try {
			$hash = self::passwordHash($password, $info['passwordSalt'], $info['spinCount'], $info['hashAlgorithm']);
			$verifier = self::aesDecrypt($info['encryptedVerifier'], self::deriveKey($hash, self::BLOCK_KEY_VERIFIER, $info['hashAlgorithm'], $info['keyBits']), $info['passwordSalt'], $info['keyBits']);
			$expected = self::aesDecrypt($info['encryptedVerifierHash'], self::deriveKey($hash, self::BLOCK_KEY_VERIFIER_HASH, $info['hashAlgorithm'], $info['keyBits']), $info['passwordSalt'], $info['keyBits']);
			if (!hash_equals(self::hash($info['hashAlgorithm'], $verifier), (string) substr($expected, 0, $info['hashSize']))) {
				throw new Exception('XLSX encryption password is incorrect.');
			}
			$secretKey = (string) substr(self::aesDecrypt($info['encryptedKey'], self::deriveKey($hash, self::BLOCK_KEY_ENCRYPTED_KEY, $info['hashAlgorithm'], $info['keyBits']), $info['passwordSalt'], $info['keyBits']), 0, intdiv($info['keyBits'], 8));
			if (strlen($secretKey) !== intdiv($info['keyBits'], 8)) {
				throw new Exception('Malformed XLSX encryption information.');
			}
			self::verifyIntegrityFile($info, $secretKey, $input);
			$output = @fopen($outputFilename, 'wb');
			if ($output === false) {
				throw new Exception('Could not open XLSX package for decryption.');
			}
			rewind($input);

			try {
				$size = self::unpackSize(self::read($input, 8));
				for ($block = 0; $size > 0; ++$block) {
					$length = min(self::SEGMENT_SIZE, $size);
					$cipher = self::read($input, self::paddedLength($length));
					$iv = self::iv($info['keyDataSalt'], pack('V', $block), $info['hashAlgorithm']);
					self::write($output, (string) substr(self::aesDecrypt($cipher, $secretKey, $iv, $info['keyBits']), 0, $length));
					$size -= $length;
				}
				if (fread($input, 1) !== '') {
					throw new Exception('Malformed encrypted XLSX package.');
				}
			} finally {
				fclose($output);
			}
		} finally {
			fclose($input);
		}
	}

	/**
	 * Create the EncryptionInfo and EncryptedPackage streams for an Agile-encrypted XLSX.
	 *
	 * @return array{encryptionInfo: string, encryptedPackage: string}
	 */
	public static function encrypt(string $plainPackage, string $password, int $keyBits = 256, string $hashAlgorithm = 'SHA512', int $spinCount = 100000): array
	{
		if ($password === '') {
			throw new Exception('XLSX encryption password required.');
		}
		if (!self::isSupportedProfile($keyBits, $hashAlgorithm, self::HASH_ALGORITHMS[$hashAlgorithm][1] ?? 0) || $spinCount < 0 || $spinCount > self::MAX_SPIN_COUNT) {
			throw new Exception('Unsupported XLSX encryption profile.');
		}

		$passwordSalt = random_bytes(self::BLOCK_SIZE);
		$keyDataSalt = random_bytes(self::BLOCK_SIZE);
		$hashSize = self::hashSize($hashAlgorithm);
		$passwordHash = self::passwordHash($password, $passwordSalt, $spinCount, $hashAlgorithm);
		$verifier = random_bytes(self::BLOCK_SIZE);
		$secretKey = random_bytes(self::keyLength($keyBits));
		$encryptedVerifier = self::aesEncrypt($verifier, self::deriveKey($passwordHash, self::BLOCK_KEY_VERIFIER, $hashAlgorithm, $keyBits), $passwordSalt, $keyBits);
		$encryptedVerifierHash = self::aesEncrypt(str_pad(self::hash($hashAlgorithm, $verifier), self::paddedLength($hashSize), "\x00"), self::deriveKey($passwordHash, self::BLOCK_KEY_VERIFIER_HASH, $hashAlgorithm, $keyBits), $passwordSalt, $keyBits);
		$encryptedKey = self::aesEncrypt(str_pad($secretKey, self::paddedLength(strlen($secretKey)), "\x00"), self::deriveKey($passwordHash, self::BLOCK_KEY_ENCRYPTED_KEY, $hashAlgorithm, $keyBits), $passwordSalt, $keyBits);

		$encryptedPackage = self::packSize(strlen($plainPackage));
		for ($block = 0, $offset = 0; $offset < strlen($plainPackage); ++$block, $offset += self::SEGMENT_SIZE) {
			$segment = (string) substr($plainPackage, $offset, self::SEGMENT_SIZE);
			$iv = self::iv($keyDataSalt, pack('V', $block), $hashAlgorithm);
			$encryptedPackage .= self::aesEncrypt(str_pad($segment, self::paddedLength(strlen($segment)), "\x00"), $secretKey, $iv, $keyBits);
		}

		$hmacKey = random_bytes(self::hashSize($hashAlgorithm));
		$hmacKeyIv = self::iv($keyDataSalt, self::BLOCK_KEY_HMAC_KEY, $hashAlgorithm);
		$hmacValueIv = self::iv($keyDataSalt, self::BLOCK_KEY_HMAC_VALUE, $hashAlgorithm);
		$encryptedHmacKey = self::aesEncrypt(str_pad($hmacKey, self::paddedLength($hashSize), "\x00"), $secretKey, $hmacKeyIv, $keyBits);
		$encryptedHmacValue = self::aesEncrypt(str_pad(hash_hmac(self::HASH_ALGORITHMS[$hashAlgorithm][0], $encryptedPackage, $hmacKey, true), self::paddedLength($hashSize), "\x00"), $secretKey, $hmacValueIv, $keyBits);

		$encryptionInfo = "\x04\x00\x04\x00\x40\x00\x00\x00" . self::encryptionInfoXml(
			$keyDataSalt,
			$passwordSalt,
			$encryptedVerifier,
			$encryptedVerifierHash,
			$encryptedKey,
			$encryptedHmacKey,
			$encryptedHmacValue,
			$keyBits,
			$hashAlgorithm,
			$hashSize,
			$spinCount
		);

		return ['encryptionInfo' => $encryptionInfo, 'encryptedPackage' => $encryptedPackage];
	}

	/**
	 * Encrypt a ZIP package without loading either package into memory.
	 *
	 * @return array{encryptionInfo: string, encryptedPackageFilename: string}
	 */
	public static function encryptFile(string $plainPackageFilename, string $password, int $keyBits = 256, string $hashAlgorithm = 'SHA512', int $spinCount = 100000): array
	{
		if ($password === '') {
			throw new Exception('XLSX encryption password required.');
		}
		if (!self::isSupportedProfile($keyBits, $hashAlgorithm, self::HASH_ALGORITHMS[$hashAlgorithm][1] ?? 0) || $spinCount < 0 || $spinCount > self::MAX_SPIN_COUNT) {
			throw new Exception('Unsupported XLSX encryption profile.');
		}
		$size = @filesize($plainPackageFilename);
		if ($size === false) {
			throw new Exception('Could not determine XLSX package size.');
		}
		$input = fopen($plainPackageFilename, 'rb');
		if ($input === false) {
			throw new Exception('Could not open XLSX package for encryption.');
		}
		$encryptedPackageFilename = SharedFile::temporaryFilename();
		$output = fopen($encryptedPackageFilename, 'wb');
		if ($output === false) {
			fclose($input);
			@unlink($encryptedPackageFilename);

			throw new Exception('Could not create encrypted XLSX package.');
		}

		try {
			$passwordSalt = random_bytes(self::BLOCK_SIZE);
			$keyDataSalt = random_bytes(self::BLOCK_SIZE);
			$hashSize = self::hashSize($hashAlgorithm);
			$passwordHash = self::passwordHash($password, $passwordSalt, $spinCount, $hashAlgorithm);
			$verifier = random_bytes(self::BLOCK_SIZE);
			$secretKey = random_bytes(self::keyLength($keyBits));
			$encryptedVerifier = self::aesEncrypt($verifier, self::deriveKey($passwordHash, self::BLOCK_KEY_VERIFIER, $hashAlgorithm, $keyBits), $passwordSalt, $keyBits);
			$encryptedVerifierHash = self::aesEncrypt(str_pad(self::hash($hashAlgorithm, $verifier), self::paddedLength($hashSize), "\x00"), self::deriveKey($passwordHash, self::BLOCK_KEY_VERIFIER_HASH, $hashAlgorithm, $keyBits), $passwordSalt, $keyBits);
			$encryptedKey = self::aesEncrypt(str_pad($secretKey, self::paddedLength(strlen($secretKey)), "\x00"), self::deriveKey($passwordHash, self::BLOCK_KEY_ENCRYPTED_KEY, $hashAlgorithm, $keyBits), $passwordSalt, $keyBits);
			$hmacKey = random_bytes(self::hashSize($hashAlgorithm));
			$hmac = hash_init(self::HASH_ALGORITHMS[$hashAlgorithm][0], HASH_HMAC, $hmacKey);
			$header = self::packSize($size);
			self::write($output, $header);
			hash_update($hmac, $header);
			$remaining = $size;
			for ($block = 0; $remaining > 0; ++$block) {
				$length = min(self::SEGMENT_SIZE, $remaining);
				$segment = fread($input, $length);
				if ($segment === false || strlen($segment) !== $length) {
					throw new Exception('Could not read XLSX package for encryption.');
				}
				$iv = self::iv($keyDataSalt, pack('V', $block), $hashAlgorithm);
				$cipher = self::aesEncrypt(str_pad($segment, self::paddedLength(strlen($segment)), "\x00"), $secretKey, $iv, $keyBits);
				self::write($output, $cipher);
				hash_update($hmac, $cipher);
				$remaining -= $length;
			}
			$extra = fread($input, 1);
			if ($extra === false || $extra !== '') {
				throw new Exception('XLSX package changed while being encrypted.');
			}
			$hmacKeyIv = self::iv($keyDataSalt, self::BLOCK_KEY_HMAC_KEY, $hashAlgorithm);
			$hmacValueIv = self::iv($keyDataSalt, self::BLOCK_KEY_HMAC_VALUE, $hashAlgorithm);
			$encryptedHmacKey = self::aesEncrypt(str_pad($hmacKey, self::paddedLength($hashSize), "\x00"), $secretKey, $hmacKeyIv, $keyBits);
			$encryptedHmacValue = self::aesEncrypt(str_pad(hash_final($hmac, true), self::paddedLength($hashSize), "\x00"), $secretKey, $hmacValueIv, $keyBits);
			$encryptionInfo = "\x04\x00\x04\x00\x40\x00\x00\x00" . self::encryptionInfoXml($keyDataSalt, $passwordSalt, $encryptedVerifier, $encryptedVerifierHash, $encryptedKey, $encryptedHmacKey, $encryptedHmacValue, $keyBits, $hashAlgorithm, $hashSize, $spinCount);
		} catch (Throwable $e) {
			@unlink($encryptedPackageFilename);

			throw $e;
		} finally {
			fclose($input);
			fclose($output);
		}

		return ['encryptionInfo' => $encryptionInfo, 'encryptedPackageFilename' => $encryptedPackageFilename];
	}

	/**
	 * Write an Office encrypted package CFB container using a file-backed EncryptedPackage stream.
	 *
	 * @param resource $fileHandle
	 */
	public static function writeContainerFromFile($fileHandle, string $encryptionInfo, string $encryptedPackageFilename): void
	{
		$containerFilename = SharedFile::temporaryFilename();
		$container = fopen($containerFilename, 'w+b');
		if ($container === false) {
			@unlink($containerFilename);

			throw new Exception('Could not create encrypted XLSX container.');
		}

		try {
			self::writeEcma376Container($container, $encryptionInfo, $encryptedPackageFilename);
			rewind($container);
			while (!feof($container)) {
				$data = fread($container, 8192);
				if ($data === false) {
					throw new Exception('Could not read encrypted XLSX container.');
				}
				if ($data !== '' && fwrite($fileHandle, $data) !== strlen($data)) {
					throw new Exception('Could not write encrypted XLSX container.');
				}
			}
		} finally {
			fclose($container);
			@unlink($containerFilename);
		}
	}

	/**
	 * Serialize the ECMA-376 encrypted-package CFB layout. The directory tree
	 * is prescribed by the Data Spaces structure; sector allocation is dynamic
	 * so normal workbook size is not artificially constrained.
	 *
	 * @param resource $fileHandle
	 */
	private static function writeEcma376Container($fileHandle, string $encryptionInfo, string $encryptedPackageFilename): void
	{
		$packageSize = filesize($encryptedPackageFilename);
		if ($packageSize === false || $packageSize < self::CFB_MINI_STREAM_CUTOFF || $packageSize > 0xFFFFFFFF) {
			throw new Exception('Malformed encrypted XLSX package.');
		}
		$smallStreams = [
			self::DIRECTORY_VERSION => [self::STREAM_VERSION, self::dataSpacesVersion()],
			self::DIRECTORY_DATA_SPACE_MAP => [self::STREAM_DATA_SPACE_MAP, self::dataSpaceMap()],
			self::DIRECTORY_STRONG_ENCRYPTION_DATA_SPACE => [self::STREAM_STRONG_ENCRYPTION_DATA_SPACE, self::strongEncryptionDataSpace()],
			self::DIRECTORY_PRIMARY => [self::STREAM_PRIMARY, self::primaryTransform()],
			self::DIRECTORY_ENCRYPTION_INFO => [self::STREAM_ENCRYPTION_INFO, $encryptionInfo],
		];
		$miniStarts = array_fill_keys(array_keys($smallStreams), 0);
		$miniFat = [];
		$miniCount = 0;
		foreach ($smallStreams as $id => [, $content]) {
			if (strlen($content) >= self::CFB_MINI_STREAM_CUTOFF) {
				throw new Exception('Malformed XLSX encryption information.');
			}
			$count = (int) ceil(strlen($content) / self::CFB_MINI_SECTOR_SIZE);
			$miniStarts[$id] = $miniCount;
			for ($i = 0; $i < $count - 1; ++$i) {
				$miniFat[$miniCount + $i] = $miniCount + $i + 1;
			}
			$miniFat[$miniCount + $count - 1] = 0xFFFFFFFE;
			$miniCount += $count;
		}
		$miniFatSectors = (int) ceil($miniCount / self::CFB_FAT_ENTRIES_PER_SECTOR);
		$miniFat = array_pad($miniFat, $miniFatSectors * self::CFB_FAT_ENTRIES_PER_SECTOR, 0xFFFFFFFF);
		$miniDataSectors = (int) ceil($miniCount / self::CFB_MINI_SECTORS_PER_SECTOR);
		$directorySectors = (int) ceil(self::CFB_DIRECTORY_ENTRY_COUNT / self::CFB_DIRECTORY_ENTRIES_PER_SECTOR);
		$packageSectors = (int) ceil($packageSize / self::CFB_SECTOR_SIZE);
		$contentSectors = $miniFatSectors + $directorySectors + $miniDataSectors + $packageSectors;
		$fatSectors = 1;
		$difatSectors = 0;
		do {
			$requiredFatSectors = (int) ceil(($contentSectors + $fatSectors + $difatSectors) / self::CFB_FAT_ENTRIES_PER_SECTOR);
			$requiredDifatSectors = $requiredFatSectors <= self::CFB_DIFAT_ENTRIES_IN_HEADER ? 0 : (int) ceil(($requiredFatSectors - self::CFB_DIFAT_ENTRIES_IN_HEADER) / self::CFB_DIFAT_ENTRIES_PER_SECTOR);
			$changed = $requiredFatSectors !== $fatSectors || $requiredDifatSectors !== $difatSectors;
			$fatSectors = $requiredFatSectors;
			$difatSectors = $requiredDifatSectors;
		} while ($changed);
		$miniFatSector = $fatSectors;
		$directorySector = $miniFatSector + $miniFatSectors;
		$miniDataSector = $directorySector + $directorySectors;
		$packageSector = $miniDataSector + $miniDataSectors;
		$difatSector = $packageSector + $packageSectors;

		self::write($fileHandle, self::cfbHeader($fatSectors, $directorySector, $miniFatSector, $miniFatSectors, $difatSector, $difatSectors));
		$fat = array_fill(0, $fatSectors * self::CFB_FAT_ENTRIES_PER_SECTOR, 0xFFFFFFFF);
		for ($sector = 0; $sector < $fatSectors; ++$sector) {
			$fat[$sector] = 0xFFFFFFFD;
		}
		self::chainFat($fat, $miniFatSector, $miniFatSectors);
		self::chainFat($fat, $directorySector, $directorySectors);
		self::chainFat($fat, $miniDataSector, $miniDataSectors);
		self::chainFat($fat, $packageSector, $packageSectors);
		for ($sector = 0; $sector < $difatSectors; ++$sector) {
			$fat[$difatSector + $sector] = 0xFFFFFFFC;
		}
		self::write($fileHandle, self::packSectors($fat));
		self::write($fileHandle, self::packSectors($miniFat));

		$entries = [
			// CFB sibling trees sort by name length, then case-folded UTF-16 code points.
			self::directoryEntry('Root Entry', 5, 1, 0xFFFFFFFF, 0xFFFFFFFF, self::DIRECTORY_ENCRYPTION_INFO, $miniDataSector, $miniCount * self::CFB_MINI_SECTOR_SIZE),
			self::directoryEntry(self::STREAM_ENCRYPTED_PACKAGE, 2, 0, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, $packageSector, $packageSize),
			self::directoryEntry(self::STORAGE_DATA_SPACES, 1, 0, 0xFFFFFFFF, 0xFFFFFFFF, self::DIRECTORY_DATA_SPACE_MAP, 0, 0),
			self::directoryEntry(self::STREAM_VERSION, 2, 0, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, $miniStarts[self::DIRECTORY_VERSION], strlen($smallStreams[self::DIRECTORY_VERSION][1])),
			self::directoryEntry(self::STREAM_DATA_SPACE_MAP, 2, 1, self::DIRECTORY_VERSION, self::DIRECTORY_DATA_SPACE_INFO, 0xFFFFFFFF, $miniStarts[self::DIRECTORY_DATA_SPACE_MAP], strlen($smallStreams[self::DIRECTORY_DATA_SPACE_MAP][1])),
			self::directoryEntry(self::STORAGE_DATA_SPACE_INFO, 1, 0, 0xFFFFFFFF, 0xFFFFFFFF, self::DIRECTORY_TRANSFORM_INFO, 0, 0),
			self::directoryEntry(self::STREAM_STRONG_ENCRYPTION_DATA_SPACE, 2, 0, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, $miniStarts[self::DIRECTORY_STRONG_ENCRYPTION_DATA_SPACE], strlen($smallStreams[self::DIRECTORY_STRONG_ENCRYPTION_DATA_SPACE][1])),
			self::directoryEntry(self::STORAGE_TRANSFORM_INFO, 1, 1, self::DIRECTORY_STRONG_ENCRYPTION_DATA_SPACE, 0xFFFFFFFF, self::DIRECTORY_STRONG_ENCRYPTION_TRANSFORM, 0, 0),
			self::directoryEntry(self::STORAGE_STRONG_ENCRYPTION_TRANSFORM, 1, 1, 0xFFFFFFFF, 0xFFFFFFFF, self::DIRECTORY_PRIMARY, 0, 0),
			self::directoryEntry(self::STREAM_PRIMARY, 2, 1, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, $miniStarts[self::DIRECTORY_PRIMARY], strlen($smallStreams[self::DIRECTORY_PRIMARY][1])),
			self::directoryEntry(self::STREAM_ENCRYPTION_INFO, 2, 1, self::DIRECTORY_DATA_SPACES, self::DIRECTORY_ENCRYPTED_PACKAGE, 0xFFFFFFFF, $miniStarts[self::DIRECTORY_ENCRYPTION_INFO], strlen($smallStreams[self::DIRECTORY_ENCRYPTION_INFO][1])),
		];
		self::write($fileHandle, str_pad(implode('', $entries), $directorySectors * self::CFB_SECTOR_SIZE, "\x00"));
		$miniData = str_repeat("\x00", $miniDataSectors * self::CFB_SECTOR_SIZE);
		foreach ($smallStreams as $id => [, $content]) {
			$miniData = substr_replace($miniData, $content, $miniStarts[$id] * self::CFB_MINI_SECTOR_SIZE, strlen($content));
		}
		self::write($fileHandle, $miniData);
		$package = fopen($encryptedPackageFilename, 'rb');
		if ($package === false) {
			throw new Exception('Could not open encrypted XLSX package.');
		}

		try {
			while (!feof($package)) {
				$data = fread($package, 8192);
				if ($data === false) {
					throw new Exception('Could not read encrypted XLSX package.');
				}
				if ($data !== '') {
					self::write($fileHandle, $data);
				}
			}
		} finally {
			fclose($package);
		}
		$padding = $packageSectors * self::CFB_SECTOR_SIZE - $packageSize;
		if ($padding > 0) {
			self::write($fileHandle, str_repeat("\x00", $padding));
		}
		for ($sector = 0; $sector < $difatSectors; ++$sector) {
			$firstFatSector = self::CFB_DIFAT_ENTRIES_IN_HEADER + $sector * self::CFB_DIFAT_ENTRIES_PER_SECTOR;
			$fatReferences = [];
			for ($i = 0; $i < self::CFB_DIFAT_ENTRIES_PER_SECTOR; ++$i) {
				$fatReferences[] = $firstFatSector + $i < $fatSectors ? $firstFatSector + $i : 0xFFFFFFFF;
			}
			$fatReferences[] = $sector + 1 < $difatSectors ? $difatSector + $sector + 1 : 0xFFFFFFFE;
			self::write($fileHandle, self::packSectors($fatReferences));
		}
	}

	/** @param int[] $fat */
	private static function chainFat(array &$fat, int $start, int $count): void
	{
		for ($i = 0; $i < $count - 1; ++$i) {
			$fat[$start + $i] = $start + $i + 1;
		}
		$fat[$start + $count - 1] = 0xFFFFFFFE;
	}

	/** @param int[] $sectors */
	private static function packSectors(array $sectors): string
	{
		return pack('V*', ...$sectors);
	}

	private static function cfbHeader(int $fatSectors, int $directorySector, int $miniFatSector, int $miniFatSectors, int $difatSector, int $difatSectors): string
	{
		$headerDifat = [];
		for ($sector = 0; $sector < self::CFB_DIFAT_ENTRIES_IN_HEADER; ++$sector) {
			$headerDifat[] = $sector < $fatSectors ? $sector : 0xFFFFFFFF;
		}

		return "\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1" . str_repeat("\x00", 16)
			. pack('v8', 0x3E, 3, 0xFFFE, 9, 6, 0, 0, 0)
			. pack('V8', 0, $fatSectors, $directorySector, 0, self::CFB_MINI_STREAM_CUTOFF, $miniFatSector, $miniFatSectors, $difatSectors === 0 ? 0xFFFFFFFE : $difatSector)
			. pack('V', $difatSectors) . self::packSectors($headerDifat);
	}

	private static function directoryEntry(string $name, int $type, int $color, int $left, int $right, int $child, int $start, int $size): string
	{
		$name = OLE::ascToUcs($name);

		return str_pad($name, 64, "\x00") . pack('vCCVVV', strlen($name) + 2, $type, $color, $left, $right, $child)
			. str_repeat("\x00", 16) . pack('V', 0) . str_repeat("\x00", 16)
			. pack('V2', $start, $size % 4294967296) . pack('V', intdiv($size, 4294967296));
	}

	/**
				 * @param mixed $value
				 */
				private static function decode($value): string
	{
		if (!is_string($value) && !(is_object($value) && method_exists($value, '__toString'))) {
			throw new Exception('Malformed XLSX encryption information.');
		}
		$result = base64_decode((string) $value, true);
		if ($result === false) {
			throw new Exception('Malformed XLSX encryption information.');
		}

		return $result;
	}

	private static function decimalAttribute(SimpleXMLElement $element, string $name): int
	{
		$value = (string) $element[$name];
		$maximum = (string) PHP_INT_MAX;
		if ($value === '' || !ctype_digit($value) || strlen($value) > strlen($maximum) || (strlen($value) === strlen($maximum) && $value > $maximum)) {
			throw new Exception('Malformed XLSX encryption information.');
		}

		return (int) $value;
	}

	private static function passwordHash(string $password, string $salt, int $spinCount, string $algorithm = 'SHA512'): string
	{
		$hash = self::hash($algorithm, $salt . mb_convert_encoding($password, 'UTF-16LE', 'UTF-8'));
		for ($i = 0; $i < $spinCount; ++$i) {
			$hash = self::hash($algorithm, pack('V', $i) . $hash);
		}

		return $hash;
	}

	private static function deriveKey(string $hash, string $blockKey, string $algorithm = 'SHA512', int $keyBits = 256): string
	{
		return (string) substr(str_pad(self::hash($algorithm, $hash . $blockKey), intdiv($keyBits, 8), "\x36"), 0, intdiv($keyBits, 8));
	}

	private static function aesDecrypt(string $data, string $key, string $iv, int $keyBits = 256): string
	{
		self::assertOpenSslAvailable();
		$result = openssl_decrypt($data, 'aes-' . $keyBits . '-cbc', $key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv);
		if ($result === false) {
			throw new Exception('Malformed XLSX encrypted data.');
		}

		return $result;
	}

	private static function aesEncrypt(string $data, string $key, string $iv, int $keyBits = 256): string
	{
		self::assertOpenSslAvailable();
		$result = openssl_encrypt($data, 'aes-' . $keyBits . '-cbc', $key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING, $iv);
		if ($result === false) {
			throw new Exception('Could not encrypt XLSX data.');
		}

		return $result;
	}

	private static function isSupportedProfile(int $keyBits, string $hashAlgorithm, int $hashSize): bool
	{
		return in_array($keyBits, [128, 192, 256], true)
			&& isset(self::HASH_ALGORITHMS[$hashAlgorithm])
			&& self::HASH_ALGORITHMS[$hashAlgorithm][1] === $hashSize;
	}

	private static function hash(string $algorithm, string $data): string
	{
		return hash(self::HASH_ALGORITHMS[$algorithm][0], $data, true);
	}

	/** @return positive-int */
	private static function hashSize(string $algorithm): int
	{
		switch ($algorithm) {
									case 'SHA1':
										return 20;
									case 'SHA256':
										return 32;
									case 'SHA384':
										return 48;
									case 'SHA512':
										return 64;
									default:
										throw new Exception('Unsupported XLSX encryption profile.');
								}
	}

	/** @return positive-int */
	private static function keyLength(int $keyBits): int
	{
		switch ($keyBits) {
									case 128:
										return 16;
									case 192:
										return 24;
									case 256:
										return 32;
									default:
										throw new Exception('Unsupported XLSX encryption profile.');
								}
	}

	private static function iv(string $salt, string $blockKey, string $algorithm): string
	{
		return substr(str_pad(self::hash($algorithm, $salt . $blockKey), self::BLOCK_SIZE, "\x36"), 0, self::BLOCK_SIZE);
	}

	private static function paddedLength(int $length): int
	{
		return (int) (ceil($length / self::BLOCK_SIZE) * self::BLOCK_SIZE);
	}

	private static function assertOpenSslAvailable(): void
	{
		if (!function_exists('openssl_encrypt') || !function_exists('openssl_decrypt')) {
			throw new Exception('XLSX encryption requires the OpenSSL extension.');
		}
	}

	private static function packSize(int $size): string
	{
		if ($size < 0) {
			throw new Exception('XLSX package is too large to encrypt.');
		}

		return pack('V2', $size % 4294967296, intdiv($size, 4294967296));
	}

	private static function unpackSize(string $data): int
	{
		$unpackedSize = unpack('Vlow/Vhigh', $data);
		if ($unpackedSize === false || !isset($unpackedSize['low'], $unpackedSize['high']) || !is_int($unpackedSize['low']) || !is_int($unpackedSize['high'])) {
			throw new Exception('Malformed encrypted XLSX package.');
		}

		return self::sizeFromWords($unpackedSize['low'], $unpackedSize['high'], PHP_INT_SIZE, PHP_INT_MAX);
	}

	private static function sizeFromWords(int $low, int $high, int $integerSize, int $integerMax): int
	{
		if ($integerSize < 8) {
			if ($high !== 0 || $low > $integerMax) {
				throw new Exception('Encrypted XLSX package is too large for this platform.');
			}

			return $low;
		}
		if ($high > 0x7FFFFFFF) {
			throw new Exception('Encrypted XLSX package is too large for this platform.');
		}

		return $low + $high * 4294967296;
	}

	/** @param resource $fileHandle */
	private static function write($fileHandle, string $data): void
	{
		if (fwrite($fileHandle, $data) !== strlen($data)) {
			throw new Exception('Could not write encrypted XLSX package.');
		}
	}

	/** @param resource $fileHandle */
	private static function read($fileHandle, int $length): string
	{
		if ($length < 1) {
			throw new Exception('Malformed encrypted XLSX package.');
		}
		$data = fread($fileHandle, $length);
		if ($data === false || strlen($data) !== $length) {
			throw new Exception('Malformed encrypted XLSX package.');
		}

		return $data;
	}

	private static function encryptionInfoXml(string $keyDataSalt, string $passwordSalt, string $encryptedVerifier, string $encryptedVerifierHash, string $encryptedKey, string $encryptedHmacKey, string $encryptedHmacValue, int $keyBits = 256, string $hashAlgorithm = 'SHA512', int $hashSize = 64, int $spinCount = 100000): string
	{
		$base64 = static fn (string $value): string => base64_encode($value);

		return '<?xml version="1.0" encoding="UTF-8" standalone="yes"?>'
			. '<encryption xmlns="http://schemas.microsoft.com/office/2006/encryption" xmlns:p="http://schemas.microsoft.com/office/2006/keyEncryptor/password">'
			. '<keyData saltSize="16" blockSize="16" keyBits="' . $keyBits . '" hashSize="' . $hashSize . '" cipherAlgorithm="AES" cipherChaining="ChainingModeCBC" hashAlgorithm="' . $hashAlgorithm . '" saltValue="' . $base64($keyDataSalt) . '"/>'
			. '<dataIntegrity encryptedHmacKey="' . $base64($encryptedHmacKey) . '" encryptedHmacValue="' . $base64($encryptedHmacValue) . '"/>'
			. '<keyEncryptors><keyEncryptor uri="http://schemas.microsoft.com/office/2006/keyEncryptor/password"><p:encryptedKey spinCount="' . $spinCount . '" saltSize="16" blockSize="16" keyBits="' . $keyBits . '" hashSize="' . $hashSize . '" cipherAlgorithm="AES" cipherChaining="ChainingModeCBC" hashAlgorithm="' . $hashAlgorithm . '" saltValue="' . $base64($passwordSalt) . '" encryptedVerifierHashInput="' . $base64($encryptedVerifier) . '" encryptedVerifierHashValue="' . $base64($encryptedVerifierHash) . '" encryptedKeyValue="' . $base64($encryptedKey) . '"/></keyEncryptor></keyEncryptors></encryption>';
	}

	private static function dataSpacesVersion(): string
				{
					if (!hex2bin('3c0000004d006900630072006f0073006f00660074002e0043006f006e007400610069006e00650072002e004400610074006100530070006100630065007300010000000100000001000000')) {
						throw new Exception('Could not generate XLSX encryption DataSpaces stream.');
					}
					return hex2bin('3c0000004d006900630072006f0073006f00660074002e0043006f006e007400610069006e00650072002e004400610074006100530070006100630065007300010000000100000001000000');
				}

	private static function primaryTransform(): string
				{
					if (!hex2bin('58000000010000004c0000007b00460046003900410033004600300033002d0035003600450046002d0034003600310033002d0042004400440035002d003500410034003100430031004400300037003200340036007d004e0000004d006900630072006f0073006f00660074002e0043006f006e007400610069006e00650072002e0045006e006300720079007000740069006f006e005400720061006e00730066006f0072006d00000001000000010000000100000000000000000000000000000004000000')) {
						throw new Exception('Could not generate XLSX encryption DataSpaces stream.');
					}
					return hex2bin('58000000010000004c0000007b00460046003900410033004600300033002d0035003600450046002d0034003600310033002d0042004400440035002d003500410034003100430031004400300037003200340036007d004e0000004d006900630072006f0073006f00660074002e0043006f006e007400610069006e00650072002e0045006e006300720079007000740069006f006e005400720061006e00730066006f0072006d00000001000000010000000100000000000000000000000000000004000000');
				}

	private static function dataSpaceMap(): string
				{
					if (!hex2bin('08000000010000006800000001000000000000002000000045006e0063007200790070007400650064005000610063006b00610067006500320000005300740072006f006e00670045006e006300720079007000740069006f006e004400610074006100530070006100630065000000')) {
						throw new Exception('Could not generate XLSX encryption DataSpaces stream.');
					}
					return hex2bin('08000000010000006800000001000000000000002000000045006e0063007200790070007400650064005000610063006b00610067006500320000005300740072006f006e00670045006e006300720079007000740069006f006e004400610074006100530070006100630065000000');
				}

	private static function strongEncryptionDataSpace(): string
				{
					if (!hex2bin('0800000001000000320000005300740072006f006e00670045006e006300720079007000740069006f006e005400720061006e00730066006f0072006d000000')) {
						throw new Exception('Could not generate XLSX encryption DataSpaces stream.');
					}
					return hex2bin('0800000001000000320000005300740072006f006e00670045006e006300720079007000740069006f006e005400720061006e00730066006f0072006d000000');
				}

	/** @param array{keyDataSalt: string, passwordSalt: string, encryptedVerifier: string, encryptedVerifierHash: string, encryptedKey: string, encryptedHmacKey: string, encryptedHmacValue: string, spinCount: int, keyBits: int, hashAlgorithm: string, hashSize: int} $info */
	private static function verifyIntegrity(array $info, string $secretKey, string $encryptedPackage): void
	{
		$hmacKeyIv = self::iv($info['keyDataSalt'], self::BLOCK_KEY_HMAC_KEY, $info['hashAlgorithm']);
		$hmacValueIv = self::iv($info['keyDataSalt'], self::BLOCK_KEY_HMAC_VALUE, $info['hashAlgorithm']);
		$hmacKey = (string) substr(self::aesDecrypt($info['encryptedHmacKey'], $secretKey, $hmacKeyIv, $info['keyBits']), 0, $info['hashSize']);
		$expected = self::aesDecrypt($info['encryptedHmacValue'], $secretKey, $hmacValueIv, $info['keyBits']);
		if (!hash_equals(hash_hmac(self::HASH_ALGORITHMS[$info['hashAlgorithm']][0], $encryptedPackage, $hmacKey, true), (string) substr($expected, 0, $info['hashSize']))) {
			throw new Exception('Encrypted XLSX package integrity check failed.');
		}
	}

	/**
	 * @param array{keyDataSalt: string, passwordSalt: string, encryptedVerifier: string, encryptedVerifierHash: string, encryptedKey: string, encryptedHmacKey: string, encryptedHmacValue: string, spinCount: int, keyBits: int, hashAlgorithm: string, hashSize: int} $info
	 * @param resource $input
	 */
	private static function verifyIntegrityFile(array $info, string $secretKey, $input): void
	{
		$hmacKeyIv = self::iv($info['keyDataSalt'], self::BLOCK_KEY_HMAC_KEY, $info['hashAlgorithm']);
		$hmacValueIv = self::iv($info['keyDataSalt'], self::BLOCK_KEY_HMAC_VALUE, $info['hashAlgorithm']);
		$hmacKey = (string) substr(self::aesDecrypt($info['encryptedHmacKey'], $secretKey, $hmacKeyIv, $info['keyBits']), 0, $info['hashSize']);
		$expected = self::aesDecrypt($info['encryptedHmacValue'], $secretKey, $hmacValueIv, $info['keyBits']);
		$hmac = hash_init(self::HASH_ALGORITHMS[$info['hashAlgorithm']][0], HASH_HMAC, $hmacKey);
		while (!feof($input)) {
			$data = fread($input, 8192);
			if ($data === false) {
				throw new Exception('Could not read encrypted XLSX package.');
			}
			if ($data !== '') {
				hash_update($hmac, $data);
			}
		}
		if (!hash_equals(hash_final($hmac, true), (string) substr($expected, 0, $info['hashSize']))) {
			throw new Exception('Encrypted XLSX package integrity check failed.');
		}
	}
}