func Transformer()

in pkg/sdk/value/encryption/jwe/builders.go [79:122]
39 lines of code
13 McCabe index (conditional complexity)

func Transformer(algorithm KeyAlgorithm, key string) (value.Transformer, error) {
	switch algorithm {
	case AES128_KW:
		// Try to decode the key
		k, err := base64.URLEncoding.DecodeString(key)
		if err != nil {
			return nil, fmt.Errorf("jwe: unable to decode key: %w", err)
		}
		if len(k) < 16 {
			return nil, errors.New("jwe: key too short")
		}
		return transformer(k, jose.A128KW, jose.A128GCM)
	case AES192_KW:
		// Try to decode the key
		k, err := base64.URLEncoding.DecodeString(key)
		if err != nil {
			return nil, fmt.Errorf("jwe: unable to decode key: %w", err)
		}
		if len(k) < 24 {
			return nil, errors.New("jwe: key too short")
		}
		return transformer(k, jose.A192KW, jose.A192GCM)
	case AES256_KW:
		// Try to decode the key
		k, err := base64.URLEncoding.DecodeString(key)
		if err != nil {
			return nil, fmt.Errorf("jwe: unable to decode key: %w", err)
		}
		if len(k) < 32 {
			return nil, errors.New("jwe: key too short")
		}
		return transformer(k, jose.A256KW, jose.A256GCM)
	case PBES2_HS256_A128KW:
		return transformer(key, jose.PBES2_HS256_A128KW, jose.A128GCM)
	case PBES2_HS384_A192KW:
		return transformer(key, jose.PBES2_HS384_A192KW, jose.A192GCM)
	case PBES2_HS512_A256KW:
		return transformer(key, jose.PBES2_HS512_A256KW, jose.A256GCM)
	default:
	}

	// Unsupported encryption scheme.
	return nil, fmt.Errorf("unsupported jwe algorithm '%s'", algorithm)
}