Generate SSH key pair in Go

main.go

// Note: There were a couple blogposts I used to write this but for the life of me can't seem to find them. Will update with references if I do. 

// generateSSHKeyPair creates a private & public key pair
func generateSSHKeyPair(bitSize int) (privateKey []byte, publicKey []byte, err error) {
	// generate private key
	pKey, err := generatePrivateKey(keySize)
	if err != nil {
		return nil, nil, errors.Wrap(err, "failed to create private key")
	}

	// generate public key
	pubKey, err := generatePublicKey(&pKey.PublicKey)
	if err != nil {
		return nil, nil, errors.Wrap(err, "failed to create public key")
	}

	return convertToPem(pKey), pubKey, nil
}

// generatePrivateKey generates and returns a rsa private key
func generatePrivateKey(keySize int) (*rsa.PrivateKey, error) {
	pKey, err := rsa.GenerateKey(rand.Reader, keySize)
	if err != nil {
		return nil, err
	}

	if err := pKey.Validate(); err != nil {
		return nil, err
	}

	return pKey, nil
}

// generatePublicKey generates and returns a public ssh key (from private key) as []byte
func generatePublicKey(pKey *rsa.PublicKey) ([]byte, error) {
	pubKey, err := ssh.NewPublicKey(pKey)
	if err != nil {
		return nil, err
	}

	return ssh.MarshalAuthorizedKey(pubKey), nil
}

// convertToPem converts an rsa.PrivateKey to a []byte pem format key
func convertToPem(pKey *rsa.PrivateKey) []byte {
	pDer := x509.MarshalPKCS1PrivateKey(pKey)

	return pem.EncodeToMemory(&pem.Block{
		Headers: nil,
		Type:    "RSA PRIVATE KEY",
		Bytes:   pDer,
	})
}