grafana/k6 · error

invalid algorithm: %s

Error message

invalid algorithm: %s

What it means

Returned by createHMAC when parseHashFunc returns nil for the requested algorithm — a sentinel-style guard where '%s' names the unsupported algorithm string. It fires before any HMAC work begins, when the algorithm passed to crypto.hmac() is not one of the supported digest names (e.g. a typo like 'sha-256' instead of 'sha256', or an unsupported algorithm like 'ripemd160' which is digest-only).

Source

Thrown at internal/js/modules/k6/crypto/crypto.go:169

	return hasher.Digest(outputEncoding)
}

// hexEncode returns a string with the hex representation of the provided byte
// array or ArrayBuffer.
func (c *Crypto) hexEncode(data any) (string, error) {
	d, err := common.ToBytes(data)
	if err != nil {
		return "", err
	}
	return hex.EncodeToString(d), nil
}

// createHMAC returns a new HMAC hash using the given algorithm and key.
func (c *Crypto) createHMAC(algorithm string, key any) (*Hasher, error) {
	h := c.parseHashFunc(algorithm)
	if h == nil {
		return nil, fmt.Errorf("invalid algorithm: %s", algorithm)
	}

	kb, err := common.ToBytes(key)
	if err != nil {
		return nil, err
	}
	return &Hasher{runtime: c.vu.Runtime(), hash: hmac.New(h, kb)}, nil
}

// HMAC returns a new HMAC hash of input using the given algorithm and key
// in the given encoding.
func (c *Crypto) hmac(algorithm string, key, input any, outputEncoding string) (any, error) {
	hasher, err := c.createHMAC(algorithm, key)
	if err != nil {
		return nil, err
	}
	err = hasher.Update(input)
	if err != nil {

View on GitHub (pinned to 01ffac6f24)

Solutions

1. Use a supported algorithm: md4, md5, sha1, sha256, sha384, or sha512
2. Check for typos and hyphenated names (sha-256 is invalid; use sha256)
3. Note ripemd160 is available for digests but not for HMAC in this module

When it happens

Trigger: Thrown at internal/js/modules/k6/crypto/crypto.go:169 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of grafana/k6@01ffac6f24 (2026-08-18). Data as JSON: /api/errors/8816b9868b4e16fd. Report an issue: GitHub.