grafana/k6 · error

key's handle isn't an RSA public/private key, got: %T

Error message

key's handle isn't an RSA public/private key, got: %T

What it means

Raised by exportRSAJWK when the CryptoKey being exported does not hold an *rsa.PrivateKey or *rsa.PublicKey in its internal handle — the type switch on key.handle fell through to the default branch, reporting the actual Go type. Means exportKey('jwk') was called on a key that is not RSA (e.g. an EC or HMAC key paired with an RSA export call path), or the key object was constructed inconsistently.

Source

Thrown at internal/js/modules/k6/webcrypto/jwk.go:424

	switch rsaKey := key.handle.(type) {
	case *rsa.PrivateKey:
		exported.Set("n", base64URLEncode(rsaKey.N.Bytes()))
		exported.Set("e", base64URLEncode(big.NewInt(int64(rsaKey.E)).Bytes()))
		exported.Set("d", base64URLEncode(rsaKey.D.Bytes()))
		exported.Set("p", base64URLEncode(rsaKey.Primes[0].Bytes()))
		exported.Set("q", base64URLEncode(rsaKey.Primes[1].Bytes()))
		exported.Set("dp", base64URLEncode(rsaKey.Precomputed.Dp.Bytes()))
		exported.Set("dq", base64URLEncode(rsaKey.Precomputed.Dq.Bytes()))
		exported.Set("qi", base64URLEncode(rsaKey.Precomputed.Qinv.Bytes()))
	case *rsa.PublicKey:
		exported.Set("n", base64URLEncode(rsaKey.N.Bytes()))
		exported.Set("e", base64URLEncode(big.NewInt(int64(rsaKey.E)).Bytes()))
	case rsa.PublicKey:
		exported.Set("n", base64URLEncode(rsaKey.N.Bytes()))
		exported.Set("e", base64URLEncode(big.NewInt(int64(rsaKey.E)).Bytes()))
	default:
		return nil, fmt.Errorf("key's handle isn't an RSA public/private key, got: %T", key.handle)
	}

	return exported, nil
}

View on GitHub (pinned to 01ffac6f24)

Solutions

1. Only export keys as RSA JWK when they were generated/imported with an RSA algorithm (RSASSA-PKCS1-v1_5, RSA-PSS, RSA-OAEP)
2. Check the %T value in the message to see what key type you actually hold, and export with the matching format/algorithm

When it happens

Trigger: Thrown at internal/js/modules/k6/webcrypto/jwk.go:424 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/d717d27355560219. Report an issue: GitHub.