ellite/Wallos · error · InvalidArgumentException

Invalid "algorithm" parameter.

Error message

Invalid "algorithm" parameter.

What it means

OTP classes store the HMAC hash algorithm as a URI parameter. getDigest() reads the 'algorithm' parameter and throws this InvalidArgumentException when the stored value is missing, not a string, or an empty string, because a digest cannot be computed otherwise.

Solutions

1. Call setParameter('algorithm', 'sha1') (or sha256/sha512) on the OTP object before using it
2. If parsing a provisioning URI, ensure the otpauth:// URI contains a non-empty algorithm query parameter
3. Check the object's getParameters() output to confirm what 'algorithm' currently holds

Example fix

// before
$totp->setParameter('algorithm', null);
echo $totp->getDigest();
// after
$totp->setParameter('algorithm', 'sha256');
echo $totp->getDigest();

$params = $otp->getParameters();
if (!isset($params['algorithm']) || !is_string($params['algorithm']) || $params['algorithm'] === '') {
    $otp->setParameter('algorithm', 'sha1');
}

function hasAlgorithm($otp): bool {
    $v = $otp->getParameters()['algorithm'] ?? null;
    return is_string($v) && $v !== '';
}

try {
    $digest = $otp->getDigest();
} catch (\InvalidArgumentException $e) {
    $otp->setParameter('algorithm', 'sha1');
    $digest = $otp->getDigest();
}

When it happens

Trigger: Calling getDigest() (directly or indirectly via at()/verify()) on an OTP object whose 'algorithm' parameter was never set, was set to null, or was set to a non-string/empty value bypassing the parameter map validation.

Common situations: Constructing a TOTP/HOTP programmatically with setParameter('algorithm', null), loading a provisioning URI whose query string has an empty algorithm= value, or upgrading library versions where the algorithm was previously defaulted silently.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Counter must be at least 0.
• Unsupported " " OTP type
• Invalid "counter" parameter.
• The counter must be at least 0.
• Invalid data.

AI-assisted analysis of ellite/Wallos@52820e87ca (2026-09-13). Data as JSON: /api/errors/107f249700b3ba15. Report an issue: GitHub.

Appendix: source

Thrown at libs/OTPHP/ParameterTrait.php:96

    }

    public function setIssuerIncludedAsParameter(bool $issuer_included_as_parameter): void
    {
        $this->issuer_included_as_parameter = $issuer_included_as_parameter;
    }

    public function getDigits(): int
    {
        $value = $this->getParameter('digits');
        (is_int($value) && $value > 0) || throw new InvalidArgumentException('Invalid "digits" parameter.');

        return $value;
    }

    public function getDigest(): string
    {
        $value = $this->getParameter('algorithm');
        (is_string($value) && $value !== '') || throw new InvalidArgumentException('Invalid "algorithm" parameter.');

        return $value;
    }

    public function hasParameter(string $parameter): bool
    {
        return array_key_exists($parameter, $this->parameters);
    }

    public function getParameter(string $parameter): mixed
    {
        if ($this->hasParameter($parameter)) {
            return $this->getParameters()[$parameter];
        }

        throw new InvalidArgumentException(sprintf('Parameter "%s" does not exist', $parameter));
    }

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