github.com/zntrio/harp/v2@v2.0.9/pkg/sdk/value/encryption/branca/transformer.go (about)

     1  // Licensed to Elasticsearch B.V. under one or more contributor
     2  // license agreements. See the NOTICE file distributed with
     3  // this work for additional information regarding copyright
     4  // ownership. Elasticsearch B.V. licenses this file to you under
     5  // the Apache License, Version 2.0 (the "License"); you may
     6  // not use this file except in compliance with the License.
     7  // You may obtain a copy of the License at
     8  //
     9  //     http://www.apache.org/licenses/LICENSE-2.0
    10  //
    11  // Unless required by applicable law or agreed to in writing,
    12  // software distributed under the License is distributed on an
    13  // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    14  // KIND, either express or implied.  See the License for the
    15  // specific language governing permissions and limitations
    16  // under the License.
    17  
    18  package branca
    19  
    20  import (
    21  	"context"
    22  	"encoding/base64"
    23  	"fmt"
    24  	"strings"
    25  
    26  	"github.com/essentialkaos/branca"
    27  
    28  	"github.com/zntrio/harp/v2/pkg/sdk/value"
    29  	"github.com/zntrio/harp/v2/pkg/sdk/value/encryption"
    30  )
    31  
    32  func init() {
    33  	encryption.Register("branca", Transformer)
    34  }
    35  
    36  // Transformer returns a branca encryption transformer.
    37  func Transformer(key string) (value.Transformer, error) {
    38  	// Remove the prefix
    39  	key = strings.TrimPrefix(key, "branca:")
    40  
    41  	// Decode key
    42  	k, err := base64.URLEncoding.DecodeString(key)
    43  	if err != nil {
    44  		return nil, fmt.Errorf("branca: unable to decode key: %w", err)
    45  	}
    46  
    47  	// Check given keys
    48  	codec, err := branca.NewBranca(k)
    49  	if err != nil {
    50  		return nil, fmt.Errorf("branca: unable to initialize the key: %w", err)
    51  	}
    52  
    53  	// Return decorator constructor
    54  	return &brancaTransformer{
    55  		codec: codec,
    56  	}, nil
    57  }
    58  
    59  // -----------------------------------------------------------------------------
    60  
    61  type brancaTransformer struct {
    62  	codec *branca.Branca
    63  }
    64  
    65  func (d *brancaTransformer) To(_ context.Context, input []byte) ([]byte, error) {
    66  	// Encrypt value
    67  	out, err := d.codec.Encode(input)
    68  	if err != nil {
    69  		return nil, fmt.Errorf("branca: unable to transform input value: %w", err)
    70  	}
    71  
    72  	// No error
    73  	return out, nil
    74  }
    75  
    76  func (d *brancaTransformer) From(_ context.Context, input []byte) ([]byte, error) {
    77  	// Decrypt value without checking expiration
    78  	out, err := d.codec.Decode(input)
    79  	if err != nil {
    80  		return nil, fmt.Errorf("branca: unable to decrypt branca token: %w", err)
    81  	}
    82  
    83  	// No error
    84  	return out.Payload(), nil
    85  }