92 lines
1.8 KiB
Go
92 lines
1.8 KiB
Go
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package fernet
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import (
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"crypto/rand"
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"encoding/base64"
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"encoding/hex"
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"errors"
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"io"
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)
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var (
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errKeyLen = errors.New("fernet: key decodes to wrong size")
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errNoKeys = errors.New("fernet: no keys provided")
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)
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// Key represents a key.
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type Key [32]byte
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func (k *Key) cryptBytes() []byte {
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return k[len(k)/2:]
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}
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func (k *Key) signBytes() []byte {
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return k[:len(k)/2]
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}
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// Generate initializes k with pseudorandom data from package crypto/rand.
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func (k *Key) Generate() error {
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_, err := io.ReadFull(rand.Reader, k[:])
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return err
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}
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// Encode returns the URL-safe base64 encoding of k.
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func (k *Key) Encode() string {
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return encoding.EncodeToString(k[:])
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}
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// DecodeKey decodes a key from s and returns it. The key can be in
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// hexadecimal, standard base64, or URL-safe base64.
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func DecodeKey(s string) (*Key, error) {
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var b []byte
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var err error
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if s == "" {
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return nil, errors.New("empty key")
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}
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if len(s) == hex.EncodedLen(len(Key{})) {
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b, err = hex.DecodeString(s)
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} else {
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b, err = base64.StdEncoding.DecodeString(s)
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if err != nil {
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b, err = base64.URLEncoding.DecodeString(s)
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}
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}
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if err != nil {
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return nil, err
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}
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if len(b) != len(Key{}) {
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return nil, errKeyLen
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}
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k := new(Key)
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copy(k[:], b)
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return k, nil
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}
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// DecodeKeys decodes each element of a using DecodeKey and returns the
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// resulting keys. Requires at least one key.
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func DecodeKeys(a ...string) ([]*Key, error) {
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if len(a) == 0 {
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return nil, errNoKeys
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}
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var err error
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ks := make([]*Key, len(a))
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for i, s := range a {
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ks[i], err = DecodeKey(s)
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if err != nil {
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return nil, err
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}
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}
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return ks, nil
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}
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// MustDecodeKeys is like DecodeKeys, but panics if an error occurs.
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// It simplifies safe initialization of global variables holding
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// keys.
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func MustDecodeKeys(a ...string) []*Key {
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k, err := DecodeKeys(a...)
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if err != nil {
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panic(err)
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}
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return k
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}
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