接口加密

internal/xkapi/client.go

@@ -104,9 +104,10 @@ func (c *Client) doJSON(req *http.Request, out any) error {
 		return fmt.Errorf("http %d: %s", resp.StatusCode, string(body))
 	}
 	var envelope struct {
-		Code    int             `json:"code"`
-		Result  json.RawMessage `json:"result"`
-		Message string          `json:"message"`
+		Code            int             `json:"code"`
+		Result          json.RawMessage `json:"result"`
+		ResultEncrypted bool            `json:"result_encrypted"`
+		Message         string          `json:"message"`
 	}
 	if err := json.Unmarshal(body, &envelope); err != nil {
 		return err
@@ -114,10 +115,22 @@ func (c *Client) doJSON(req *http.Request, out any) error {
 	if envelope.Code != 0 {
 		return fmt.Errorf("api code %d: %s", envelope.Code, envelope.Message)
 	}
-	if out != nil && len(envelope.Result) > 0 {
-		return json.Unmarshal(envelope.Result, out)
+	if out == nil || len(envelope.Result) == 0 {
+		return nil
 	}
-	return nil
+	resultJSON := envelope.Result
+	if envelope.ResultEncrypted {
+		var cipherStr string
+		if err := json.Unmarshal(envelope.Result, &cipherStr); err != nil {
+			return fmt.Errorf("parse encrypted result: %w", err)
+		}
+		plain, err := DecryptBody(cipherStr, c.token)
+		if err != nil {
+			return fmt.Errorf("decrypt result: %w", err)
+		}
+		resultJSON = []byte(plain)
+	}
+	return json.Unmarshal(resultJSON, out)
 }
 
 // BatchCreate 创建同步批次，返回 batch_id。

internal/xkapi/crypto.go

@@ -0,0 +1,122 @@
+package xkapi
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+)
+
+// DeriveTransitAESKey 从 HY_TRANSIT_API_TOKEN 派生 AES-128 密钥（与 PHP HyTransitCryptoService 一致）。
+func DeriveTransitAESKey(token string) []byte {
+	sum := sha256.Sum256([]byte(token))
+	return sum[:16]
+}
+
+// EncryptBody AES-128-ECB + PKCS7 加密为 Base64（与 PHP HyTransitCryptoService 一致）。
+func EncryptBody(plain, token string) (string, error) {
+	return encryptTransitBody(plain, token)
+}
+
+func encryptTransitBody(plain, token string) (string, error) {
+	key := DeriveTransitAESKey(token)
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return "", err
+	}
+	data := pkcs7Pad([]byte(plain), block.BlockSize())
+	out := make([]byte, len(data))
+	ecb := newECBEncrypter(block)
+	ecb.CryptBlocks(out, data)
+	return base64.StdEncoding.EncodeToString(out), nil
+}
+
+func pkcs7Pad(data []byte, blockSize int) []byte {
+	pad := blockSize - (len(data) % blockSize)
+	padding := make([]byte, pad)
+	for i := range padding {
+		padding[i] = byte(pad)
+	}
+	return append(data, padding...)
+}
+
+type ecbEncrypter struct {
+	b         cipher.Block
+	blockSize int
+}
+
+func newECBEncrypter(b cipher.Block) *ecbEncrypter {
+	return &ecbEncrypter{b: b, blockSize: b.BlockSize()}
+}
+
+func (x *ecbEncrypter) CryptBlocks(dst, src []byte) {
+	if len(src)%x.blockSize != 0 {
+		panic("invalid padding")
+	}
+	for len(src) > 0 {
+		x.b.Encrypt(dst, src[:x.blockSize])
+		src = src[x.blockSize:]
+		dst = dst[x.blockSize:]
+	}
+}
+
+// DecryptBody AES-128-ECB + PKCS7 解密 Base64 密文（与 PHP AesUtilService / hy.EncryptBody 对称）。
+func DecryptBody(ciphertext, token string) (string, error) {
+	raw, err := base64.StdEncoding.DecodeString(ciphertext)
+	if err != nil {
+		return "", fmt.Errorf("base64 decode: %w", err)
+	}
+	key := DeriveTransitAESKey(token)
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return "", err
+	}
+	if len(raw)%block.BlockSize() != 0 {
+		return "", fmt.Errorf("ciphertext length not multiple of block size")
+	}
+	out := make([]byte, len(raw))
+	ecb := newECBDecrypter(block)
+	ecb.CryptBlocks(out, raw)
+	plain, err := pkcs7Unpad(out, block.BlockSize())
+	if err != nil {
+		return "", err
+	}
+	return string(plain), nil
+}
+
+func pkcs7Unpad(data []byte, blockSize int) ([]byte, error) {
+	if len(data) == 0 || len(data)%blockSize != 0 {
+		return nil, fmt.Errorf("invalid padding size")
+	}
+	pad := int(data[len(data)-1])
+	if pad == 0 || pad > blockSize || pad > len(data) {
+		return nil, fmt.Errorf("invalid padding")
+	}
+	for i := 0; i < pad; i++ {
+		if data[len(data)-1-i] != byte(pad) {
+			return nil, fmt.Errorf("invalid padding bytes")
+		}
+	}
+	return data[:len(data)-pad], nil
+}
+
+type ecbDecrypter struct {
+	b         cipher.Block
+	blockSize int
+}
+
+func newECBDecrypter(b cipher.Block) *ecbDecrypter {
+	return &ecbDecrypter{b: b, blockSize: b.BlockSize()}
+}
+
+func (x *ecbDecrypter) CryptBlocks(dst, src []byte) {
+	if len(src)%x.blockSize != 0 {
+		panic("invalid padding")
+	}
+	for len(src) > 0 {
+		x.b.Decrypt(dst, src[:x.blockSize])
+		src = src[x.blockSize:]
+		dst = dst[x.blockSize:]
+	}
+}

internal/xkapi/crypto_test.go

@@ -0,0 +1,49 @@
+package xkapi
+
+import (
+	"encoding/hex"
+	"encoding/json"
+	"testing"
+)
+
+// 固定向量须与 xk-api scripts/hy_transit_crypto_vector.php 输出一致。
+const (
+	vectorTransitToken  = "test-transit-api-token-for-golden-vector"
+	vectorPlainJSON     = `{"batch_id":12,"organID":"o1","organName":"测试机构"}`
+	vectorDerivedKeyHex = "0887a3ab67abbbeda0901b562799c248"
+	vectorEncrypted     = "V5D6xp9Txjj6lUB42NMgySnLw2ZC+nEVdYkbiufEtKEyYbMpNhuxeiAhnpg0xmw+ktGYuwnf9oeS8HbwBjJBBw=="
+)
+
+func TestDeriveTransitAESKeyGolden(t *testing.T) {
+	got := hex.EncodeToString(DeriveTransitAESKey(vectorTransitToken))
+	if got != vectorDerivedKeyHex {
+		t.Fatalf("derived key %s != %s", got, vectorDerivedKeyHex)
+	}
+}
+
+func TestEncryptGoldenMatchesVector(t *testing.T) {
+	enc, err := EncryptBody(vectorPlainJSON, vectorTransitToken)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if enc != vectorEncrypted {
+		t.Fatalf("encrypted %s != %s", enc, vectorEncrypted)
+	}
+}
+
+func TestDecryptGoldenVector(t *testing.T) {
+	plain, err := DecryptBody(vectorEncrypted, vectorTransitToken)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if plain != vectorPlainJSON {
+		t.Fatalf("plain %q != %q", plain, vectorPlainJSON)
+	}
+	var decoded map[string]any
+	if err := json.Unmarshal([]byte(plain), &decoded); err != nil {
+		t.Fatal(err)
+	}
+	if decoded["batch_id"] != float64(12) {
+		t.Fatalf("batch_id %v", decoded["batch_id"])
+	}
+}