mirror of
https://github.com/dnote/dnote
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73526a943c* Implement login and logout * Add encrypt util * Use v2 * Abstract common interface between db and tx * Fix test * Check login * Fix test * Fix login * Fix path * Improve test * Fix output
107 lines
2.8 KiB
Go
107 lines
2.8 KiB
Go
// Package crypt provides cryptographic funcitonalities
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package crypt
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"crypto/sha256"
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"encoding/base64"
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"io"
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"github.com/dnote/cli/log"
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"github.com/pkg/errors"
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"golang.org/x/crypto/hkdf"
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"golang.org/x/crypto/pbkdf2"
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)
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var aesGcmNonceSize = 12
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func runHkdf(secret, salt, info []byte) ([]byte, error) {
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r := hkdf.New(sha256.New, secret, salt, info)
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ret := make([]byte, 32)
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_, err := io.ReadFull(r, ret)
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if err != nil {
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return []byte{}, errors.Wrap(err, "reading key bytes")
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}
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return ret, nil
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}
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// MakeKeys derives, from the given credential, a key set comprising of an encryption key
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// and an authentication key
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func MakeKeys(password, email []byte, iteration int) ([]byte, []byte, error) {
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masterKey := pbkdf2.Key([]byte(password), []byte(email), iteration, 32, sha256.New)
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log.Debug("email: %s, password: %s", email, password)
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authKey, err := runHkdf(masterKey, email, []byte("auth"))
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if err != nil {
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return nil, nil, errors.Wrap(err, "deriving auth key")
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}
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return masterKey, authKey, nil
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}
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// AesGcmEncrypt encrypts the plaintext using AES in a GCM mode. It returns
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// a ciphertext prepended by a 12 byte pseudo-random nonce, encoded in base64.
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func AesGcmEncrypt(key, plaintext []byte) (string, error) {
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if key == nil {
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return "", errors.New("no key provided")
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}
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block, err := aes.NewCipher(key)
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if err != nil {
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return "", errors.Wrap(err, "initializing aes")
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}
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aesgcm, err := cipher.NewGCM(block)
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if err != nil {
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return "", errors.Wrap(err, "initializing gcm")
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}
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nonce := make([]byte, aesGcmNonceSize)
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if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
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return "", errors.Wrap(err, "generating nonce")
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}
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ciphertext := aesgcm.Seal(nonce, nonce, []byte(plaintext), nil)
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cipherKeyB64 := base64.StdEncoding.EncodeToString(ciphertext)
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return cipherKeyB64, nil
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}
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// AesGcmDecrypt decrypts the encrypted data using AES in a GCM mode. The data should be
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// a base64 encoded string in the format of 12 byte nonce followed by a ciphertext.
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func AesGcmDecrypt(key []byte, dataB64 string) ([]byte, error) {
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if key == nil {
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return nil, errors.New("no key provided")
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}
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data, err := base64.StdEncoding.DecodeString(dataB64)
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if err != nil {
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return nil, errors.Wrap(err, "decoding base64 data")
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}
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block, err := aes.NewCipher(key)
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if err != nil {
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return nil, errors.Wrap(err, "initializing aes")
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}
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aesgcm, err := cipher.NewGCM(block)
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if err != nil {
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return nil, errors.Wrap(err, "initializing gcm")
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}
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if len(data) < aesGcmNonceSize {
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return nil, errors.Wrap(err, "malformed data")
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}
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nonce, ciphertext := data[:aesGcmNonceSize], data[aesGcmNonceSize:]
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plaintext, err := aesgcm.Open(nil, nonce, ciphertext, nil)
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if err != nil {
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return nil, errors.Wrap(err, "decrypting")
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}
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return plaintext, nil
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}
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