OpenNHP/opennhp · error

failed to create ChaCha20-Poly1305

Error message

failed to create ChaCha20-Poly1305: %w

What it means

AeadFromKey(GCM_CHACHA20POLY1305, key) wraps chacha20poly1305.New(key[:]) errors with this message. golang.org/x/crypto/chacha20poly1305.New fails only when the key is not exactly 32 bytes (chacha20poly1305.KeySize); OpenNHP passes the full 32-byte SymmetricKeySize array, so failure implies nil/mis-sized key material or dependency issues. The ChaCha20-Poly1305 suite is an alternative AEAD available in the GcmTypeEnum.

Solutions

1. Ensure the 32-byte key array is fully derived (ECDH shared secret + KDF) before calling AeadFromKey
2. Log the wrapped error — it will state the expected 32-byte key size
3. Verify SymmetricKeySize equals 32 and chacha20poly1305.KeySize matches in your build
4. Run go mod verify to ensure unmodified golang.org/x/crypto
5. Test with go test ./nhp/core/... to reproduce against known-good keys

Example fix

// before
key := make([]byte, 16) // wrong length, cast into fixed array
aead, _ := core.AeadFromKey(core.GCM_CHACHA20POLY1305, (*[core.SymmetricKeySize]byte)(unsafe.Pointer(&key[0])))
// after
shared := ecdh.SharedSecret(peerPub)
if len(shared) != core.SymmetricKeySize {
    return fmt.Errorf("derived key length %d, want %d", len(shared), core.SymmetricKeySize)
}
var key [core.SymmetricKeySize]byte
copy(key[:], shared)
aead, err := core.AeadFromKey(core.GCM_CHACHA20POLY1305, &key)
if err != nil {
    return err
}

if key == nil {
    return errors.New("ChaCha20-Poly1305 key not initialized")
}
if core.SymmetricKeySize != chacha20poly1305.KeySize {
    return fmt.Errorf("SymmetricKeySize %d != required %d", core.SymmetricKeySize, chacha20poly1305.KeySize)
}

aead, err := core.AeadFromKey(core.GCM_CHACHA20POLY1305, &key)
if err != nil {
    return fmt.Errorf("ChaCha20-Poly1305 setup failed: %w", err)
}

When it happens

Trigger: Calling AeadFromKey with GCM_CHACHA20POLY1305 and a nil *[SymmetricKeySize]byte, an array not fully populated by the KDF, or a x/crypto build where chacha20poly1305 constants differ.

Common situations: Custom code selecting the ChaCha20-Poly1305 GCM type before the ECDH key derivation completes; unsafe casting of shorter slices into the fixed-size array; dependency pinning problems.

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

• Failed to decrypt ztdo file
• failed to create AES cipher
• unsupported GCM type
• failed to create AES cipher for CBC
• failed to create AES cipher for CBC decryption

AI-assisted analysis of OpenNHP/opennhp@6e04ca5ff0 (2026-09-07). Data as JSON: /api/errors/dbf9f461d84d96ef. Report an issue: GitHub.

Appendix: source

Thrown at nhp/core/crypto.go:178

			return nil, fmt.Errorf("failed to create AES-GCM: %w", err)
		}
		return aead, nil

	case GCM_SM4:
		sm4Block, err := sm4.NewCipher(key[:16])
		if err != nil {
			return nil, fmt.Errorf("failed to create SM4 cipher: %w", err)
		}
		aead, err := cipher.NewGCM(sm4Block)
		if err != nil {
			return nil, fmt.Errorf("failed to create SM4-GCM: %w", err)
		}
		return aead, nil

	case GCM_CHACHA20POLY1305:
		aead, err := chacha20poly1305.New(key[:])
		if err != nil {
			return nil, fmt.Errorf("failed to create ChaCha20-Poly1305: %w", err)
		}
		return aead, nil

	default:
		return nil, fmt.Errorf("unsupported GCM type: %d", t)
	}
}

func CBCEncryption(t GcmTypeEnum, key *[SymmetricKeySize]byte, plaintext []byte, inPlace bool) ([]byte, error) {
	var block cipher.Block
	var iv []byte
	var err error
	switch t {
	case GCM_AES256:
		block, err = aes.NewCipher(key[:])
		if err != nil {
			return nil, fmt.Errorf("failed to create AES cipher for CBC: %w", err)
		}

View on GitHub (pinned to 6e04ca5ff0)