53 lines
1.6 KiB
PHP
53 lines
1.6 KiB
PHP
<?php
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namespace Misuzu;
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use InvalidArgumentException;
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use Index\Serialisation\Base32;
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class TOTPGenerator {
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public const DIGITS = 6;
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public const INTERVAL = 30000;
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public function __construct(private string $secretKey) {}
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public static function generateKey(): string {
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return Base32::encode(random_bytes(16));
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}
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public static function timecode(?int $timestamp = null): int {
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$timestamp ??= time();
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return (int)(($timestamp * 1000) / self::INTERVAL);
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}
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public function generate(?int $timecode = null): string {
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$timecode ??= self::timecode();
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$hash = hash_hmac('sha1', pack('J', $timecode), Base32::decode($this->secretKey), true);
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$offset = ord($hash[strlen($hash) - 1]) & 0x0F;
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$bin = 0;
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$bin |= (ord($hash[$offset]) & 0x7F) << 24;
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$bin |= (ord($hash[$offset + 1]) & 0xFF) << 16;
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$bin |= (ord($hash[$offset + 2]) & 0xFF) << 8;
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$bin |= (ord($hash[$offset + 3]) & 0xFF);
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$otp = $bin % pow(10, self::DIGITS);
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return str_pad((string)$otp, self::DIGITS, '0', STR_PAD_LEFT);
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}
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public function generateRange(int $range = 1, ?int $timecode = null): array {
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if($range < 1)
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throw new InvalidArgumentException('$range must be greater than 0.');
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$timecode ??= self::timecode();
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$tokens = [$this->generate($timecode)];
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for($i = 1; $i <= $range; ++$i)
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$tokens[] = $this->generate($timecode - $i);
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for($i = 1; $i <= $range; ++$i)
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$tokens[] = $this->generate($timecode + $i);
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return $tokens;
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}
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}
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