Blizzard
66 lines
1.5 KiB
Go
66 lines
1.5 KiB
Go
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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"crypto/sha256"
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"encoding/base64"
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"fmt"
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"io"
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)
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const appSecret = "ai-expert-sidebar-v1-local-©2026"
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// deriveKey produces a 32-byte AES key from the application secret.
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func deriveKey() []byte {
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sum := sha256.Sum256([]byte(appSecret))
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return sum[:]
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}
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// EncryptAPIKey encrypts a plaintext API key. Returns "" for empty input.
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func EncryptAPIKey(plaintext string) (string, error) {
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if plaintext == "" {
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return "", nil
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}
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block, err := aes.NewCipher(deriveKey())
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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 = io.ReadFull(rand.Reader, 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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// DecryptAPIKey decrypts a base64-encoded AES-256-GCM ciphertext. Returns "" for empty input.
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func DecryptAPIKey(ciphertext64 string) (string, error) {
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if ciphertext64 == "" {
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return "", nil
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}
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data, err := base64.StdEncoding.DecodeString(ciphertext64)
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if err != nil {
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return "", fmt.Errorf("base64 decode: %w", err)
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}
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block, err := aes.NewCipher(deriveKey())
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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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ns := gcm.NonceSize()
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if len(data) < ns {
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return "", fmt.Errorf("ciphertext too short")
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}
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plain, err := gcm.Open(nil, data[:ns], data[ns:], nil)
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return string(plain), err
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}
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