56 lines
1.4 KiB
Go
56 lines
1.4 KiB
Go
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// Package crypto provides AES-256-GCM encrypt/decrypt for exchange
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// credentials stored in the database, keyed by the app_secret from
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// data/settings.conf (see internal/config).
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package crypto
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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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"encoding/base64"
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"fmt"
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)
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// Encrypt returns nonce||ciphertext, base64-encoded, for storage in a DB column.
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func Encrypt(key []byte, plaintext string) (string, error) {
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block, err := aes.NewCipher(key)
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if err != nil {
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return "", err
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}
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gcm, err := cipher.NewGCM(block)
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if err != nil {
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return "", err
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}
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nonce := make([]byte, gcm.NonceSize())
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if _, err := rand.Read(nonce); err != nil {
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return "", err
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}
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sealed := gcm.Seal(nonce, nonce, []byte(plaintext), nil)
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return base64.StdEncoding.EncodeToString(sealed), nil
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}
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// Decrypt reverses Encrypt.
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func Decrypt(key []byte, encoded string) (string, error) {
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raw, err := base64.StdEncoding.DecodeString(encoded)
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if err != nil {
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return "", err
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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 "", err
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}
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gcm, err := cipher.NewGCM(block)
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if err != nil {
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return "", err
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}
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if len(raw) < gcm.NonceSize() {
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return "", fmt.Errorf("ciphertext too short")
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}
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nonce, ciphertext := raw[:gcm.NonceSize()], raw[gcm.NonceSize():]
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plaintext, err := gcm.Open(nil, nonce, ciphertext, nil)
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if err != nil {
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return "", err
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}
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return string(plaintext), nil
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}
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