53 lines
1.5 KiB
Go
53 lines
1.5 KiB
Go
package transferv3
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import (
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"crypto/aes"
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"crypto/cipher"
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"encoding/base64"
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"encoding/json"
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"fmt"
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)
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// DecryptResource 解密回调 resource（文档：AEAD_AES_256_GCM，密钥 APIv3 32 字节，密文=实际密文+16 字节 tag）
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func DecryptResource(ciphertextBase64, nonce, associatedData string, apiV3Key []byte) ([]byte, error) {
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if len(apiV3Key) != 32 {
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return nil, fmt.Errorf("apiV3 key must be 32 bytes, got %d", len(apiV3Key))
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}
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raw, err := base64.StdEncoding.DecodeString(ciphertextBase64)
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if err != nil {
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return nil, fmt.Errorf("base64 decode: %w", err)
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}
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if len(raw) < 16 {
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return nil, fmt.Errorf("ciphertext too short")
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}
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tag := raw[len(raw)-16:]
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ctext := raw[:len(raw)-16]
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block, err := aes.NewCipher(apiV3Key)
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if err != nil {
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return nil, err
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}
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aead, err := cipher.NewGCM(block)
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if err != nil {
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return nil, err
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}
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plain, err := aead.Open(nil, []byte(nonce), append(ctext, tag...), []byte(associatedData))
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if err != nil {
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return nil, fmt.Errorf("aes-gcm decrypt: %w", err)
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}
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return plain, nil
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}
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// DecryptResourceJSON 解密并解析为 JSON 对象（回调解密后的 resource）
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func DecryptResourceJSON(ciphertextBase64, nonce, associatedData string, apiV3Key []byte) (map[string]interface{}, error) {
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plain, err := DecryptResource(ciphertextBase64, nonce, associatedData, apiV3Key)
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if err != nil {
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return nil, err
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}
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var out map[string]interface{}
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if err := json.Unmarshal(plain, &out); err != nil {
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return nil, err
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}
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return out, nil
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}
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