// Create the original client.
u, _ := url.Parse("https://examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com")
b := &cos.BaseURL{BucketURL: u}
c := cos.NewClient(b, &http.Client{
    Transport: &cos.AuthorizationTransport{
        SecretID: os.Getenv("SECRETID"),  // User `SecretId`. We recommend that you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/37140?from_cn_redirect=1.
        SecretKey: os.Getenv("SECRETKEY"),  // User `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit  https://www.tencentcloud.com/document/product/598/37140?from_cn_redirect=1.
    },
})

// Sample 1. Upload an object.
name := "test/example"

// An identifier that determines a unique master encryption key, which also needs to be passed in during decryption.
// During KMS encryption, set it to EncryptionContext. Up to 1,024 characters are supported. If a value is specified in Encrypt, the same value should be passed to Decrypt.
materialDesc := make(map[string]string)
//materialDesc["desc"] = "material information of your master encrypt key"

// Create a KMS client.
kmsclient, _ := coscrypto.NewKMSClient(c.GetCredential(), "ap-guangzhou")
// Create the KMS master encryption key, whose identifier, materialDesc, should correspond to the master encryption key one to one.
kmsID := os.Getenv("KMSID")
masterCipher, _ := coscrypto.CreateMasterKMS(kmsclient, kmsID, materialDesc)
// Create an encryption client.
client := coscrypto.NewCryptoClient(c, masterCipher)

contentLength := 1024*1024*10 + 1
originData := make([]byte, contentLength)
_, err := rand.Read(originData)
f := bytes.NewReader(originData)
// Encrypt data upon upload.
_, err = client.Object.Put(context.Background(), name, f, nil)
log_status(err)

// Decrypt data upon download.
resp, err := client.Object.Get(context.Background(), name, nil)
log_status(err)
defer resp.Body.Close()
decryptedData, _ := ioutil.ReadAll(resp.Body)
if bytes.Compare(decryptedData, originData[rangeStart:rangeEnd+1]) != 0 {
    fmt.Println("Error: encryptedData != originData")
}

// Create the original client.
u, _ := url.Parse("https://examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com")
b := &cos.BaseURL{BucketURL: u}
c := cos.NewClient(b, &http.Client{
    Transport: &cos.AuthorizationTransport{
        SecretID: os.Getenv("SECRETID"),  // User `SecretId`. We recommend that you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/37140?from_cn_redirect=1.
        SecretKey: os.Getenv("SECRETKEY"),  // User `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit  https://www.tencentcloud.com/document/product/598/37140?from_cn_redirect=1.
    },
})

// Sample 1. Upload an object.
name := "test/example"

// An identifier that determines a unique master encryption key, which also needs to be passed in during decryption.
// During KMS encryption, set it to EncryptionContext. Up to 1,024 characters are supported. If a value is specified in Encrypt, the same value should be passed to Decrypt.
materialDesc := make(map[string]string)
//materialDesc["desc"] = "material information of your master encrypt key"

// Create a KMS client.
kmsclient, _ := coscrypto.NewKMSClient(c.GetCredential(), "ap-guangzhou")
// Create the KMS master encryption key, whose identifier, materialDesc, should correspond to the master encryption key one to one.
kmsID := os.Getenv("KMSID")
masterCipher, _ := coscrypto.CreateMasterKMS(kmsclient, kmsID, materialDesc)
// Create an encryption client.
client := coscrypto.NewCryptoClient(c, masterCipher)

// Encrypt data upon upload.
_, err = client.Object.PutFromFile(context.Background(), name, filepath, nil)
if err != nil{
    //ERROR
}

// Decrypt data upon download.
_, err = client.Object.GetToFile(context.Background(), name, "./test.download", nil)
if err != nil{
    //ERROR
}

// Create the original client.
u, _ := url.Parse("https://examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com")
b := &cos.BaseURL{BucketURL: u}
c := cos.NewClient(b, &http.Client{
    Transport: &cos.AuthorizationTransport{
        SecretID: os.Getenv("SECRETID"),  // User `SecretId`. We recommend that you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit https://www.tencentcloud.com/document/product/598/37140?from_cn_redirect=1.
        SecretKey: os.Getenv("SECRETKEY"),  // User `SecretKey`. We recommend you use a sub-account key and follow the principle of least privilege to reduce risks. For information about how to obtain a sub-account key, visit  https://www.tencentcloud.com/document/product/598/37140?from_cn_redirect=1.
    },
})

// Sample 1. Upload an object.
name := "test/example"

// An identifier that determines a unique master encryption key, which also needs to be passed in during decryption.
// During KMS encryption, set it to EncryptionContext. Up to 1,024 characters are supported. If a value is specified in Encrypt, the same value should be passed to Decrypt.
materialDesc := make(map[string]string)
//materialDesc["desc"] = "material information of your master encrypt key"

// Create a KMS client.
kmsclient, _ := coscrypto.NewKMSClient(c.GetCredential(), "ap-guangzhou")
// Create the KMS master encryption key, whose identifier, materialDesc, should correspond to the master encryption key one to one.
kmsID := os.Getenv("KMSID")
masterCipher, _ := coscrypto.CreateMasterKMS(kmsclient, kmsID, materialDesc)
// Create an encryption client.
client := coscrypto.NewCryptoClient(c, masterCipher)

filepath := "test"
stat, err := os.Stat(filepath)
if err !- nil {
    // ERROR
}
contentLength := stat.Size()

// Multipart upload
// Each part should be aligned to 16 bytes and not smaller than 1 MB.
partSize := (contentLength / 16 / 3) * 16
if partSize < int64(1024*1024) {
    partSize = int64(1024*1024)
}
cryptoCtx := coscrypto.CryptoContext{
    DataSize: contentLength,
    // Each part should be aligned to 16 bytes.
    PartSize: partSize,
}
// Split the data.
_, chunks, _, err := cos.SplitFileIntoChunks(filepath, cryptoCtx.PartSize)
if err !- nil {
    // ERROR
}

// init mulitupload
v, _, err := client.Object.InitiateMultipartUpload(context.Background(), name, nil, &cryptoCtx)
if err !- nil {
    // ERROR
}

// part upload
optcom := &cos.CompleteMultipartUploadOptions{}
for _, chunk := range chunks {
    fd, err := os.Open(filepath)
    if err !- nil {
        // ERROR
    }        
    opt := &cos.ObjectUploadPartOptions{
        ContentLength: chunk.Size,
    }
    fd.Seek(chunk.OffSet, os.SEEK_SET)
    resp, err := client.Object.UploadPart(context.Background(), name, v.UploadID, chunk.Number, cos.LimitReadCloser(fd, chunk.Size), opt, &cryptoCtx)
    if err !- nil {
        // ERROR
    }
    optcom.Parts = append(optcom.Parts, cos.Object{
        PartNumber: chunk.Number, ETag: resp.Header.Get("ETag"),
    })
}
// complete upload
_, _, err = client.Object.CompleteMultipartUpload(context.Background(), name, v.UploadID, optcom)
if err !- nil {
    // ERROR
}

_, err = client.Object.GetToFile(context.Background(), name, "test.download", nil)
if err !- nil {
    // ERROR
}