105 lines
2.7 KiB
Go
105 lines
2.7 KiB
Go
package crypto
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import (
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"errors"
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"runtime"
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"apigo.cc/go/safe"
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)
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// Symmetric 封装对称加密的生命周期与安全存储
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type Symmetric struct {
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cipher SymmetricCipher
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key *safe.SafeBuf
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iv *safe.SafeBuf
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}
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// NewSymmetric 基于已有的 SafeBuf 创建 Symmetric
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func NewSymmetric(cipher SymmetricCipher, safeKeyBuf, safeIvBuf *safe.SafeBuf) (*Symmetric, error) {
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s := &Symmetric{cipher: cipher, key: safeKeyBuf, iv: safeIvBuf}
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runtime.SetFinalizer(s, func(obj *Symmetric) { obj.Close() })
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return s, nil
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}
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// NewSymmetricAndEraseKey 创建并自动擦除传入的密钥与 IV
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func NewSymmetricAndEraseKey(cipher SymmetricCipher, key, iv []byte) (*Symmetric, error) {
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defer safe.ZeroMemory(key)
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defer safe.ZeroMemory(iv)
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return NewSymmetricWithOutEraseKey(cipher, key, iv)
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}
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// NewSymmetricWithOutEraseKey 创建但不擦除传入的密钥与 IV，支持密钥长度自动适配（混淆防御）
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func NewSymmetricWithOutEraseKey(cipher SymmetricCipher, key, iv []byte) (*Symmetric, error) {
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keySize := 16
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if len(key) >= 32 {
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keySize = 32
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} else if len(key) >= 24 {
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keySize = 24
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} else if len(key) < 16 {
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return nil, errors.New("key size is too short, at least 16 bytes required")
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}
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// 自动适配长度，允许传入超长 buffer 以混淆特征
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s := &Symmetric{
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cipher: cipher,
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key: safe.NewSafeBuf(key[:keySize]),
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iv: safe.NewSafeBuf(iv),
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}
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runtime.SetFinalizer(s, func(obj *Symmetric) { obj.Close() })
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return s, nil
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}
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// Close 销毁加密实例并擦除密钥
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func (s *Symmetric) Close() {
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if s.key != nil {
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s.key.Close()
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}
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if s.iv != nil {
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s.iv.Close()
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}
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}
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// Encrypt 使用 SafeBuf 传入明文进行加密
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func (s *Symmetric) Encrypt(safeBuf *safe.SafeBuf) ([]byte, error) {
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buf := safeBuf.Open()
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defer buf.Close()
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return s.EncryptBytes(buf.Data)
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}
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// EncryptBytes 使用字节切片传入明文进行加密
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func (s *Symmetric) EncryptBytes(data []byte) ([]byte, error) {
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key := s.key.Open()
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defer key.Close()
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iv := s.iv.Open()
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defer iv.Close()
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return s.cipher.Encrypt(data, key.Data, iv.Data)
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}
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// Decrypt 进行解密并返回一个受保护的 SafeBuf
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func (s *Symmetric) Decrypt(data []byte) (*safe.SafeBuf, error) {
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buf, err := s.DecryptBytes(data)
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if err != nil {
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return nil, err
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}
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defer safe.ZeroMemory(buf)
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return safe.NewSafeBuf(buf), nil
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}
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// DecryptBytes 进行解密并返回原始明文字节
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func (s *Symmetric) DecryptBytes(data []byte) ([]byte, error) {
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key := s.key.Open()
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defer key.Close()
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iv := s.iv.Open()
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defer iv.Close()
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return s.cipher.Decrypt(data, key.Data, iv.Data)
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}
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// DecryptBytesN 解密失败时返回原始数据 (静默解密)
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func (s *Symmetric) DecryptBytesN(data []byte) []byte {
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r, err := s.DecryptBytes(data)
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if err != nil {
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return data
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}
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return r
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}
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