//     Input: ClientKey, bucket, object, metadata, object_data
//     -              IV := Random({0,1}²⁵⁶)
//     -       ObjectKey := SHA256(ClientKey || Random({0,1}²⁵⁶))
//     -       KeyEncKey := HMAC-SHA256(ClientKey, IV || 'SSE-C' || 'DAREv2-HMAC-SHA256' || bucket || '/' || object)
//     -       SealedKey := DAREv2_Enc(KeyEncKey, ObjectKey)
//     - enc_object_data := DAREv2_Enc(ObjectKey, object_data)
//     -        metadata <- IV

	streamingContentSHA256        = "STREAMING-AWS4-HMAC-SHA256-PAYLOAD"
	streamingContentSHA256Trailer = "STREAMING-AWS4-HMAC-SHA256-PAYLOAD-TRAILER"
	signV4ChunkedAlgorithm        = "AWS4-HMAC-SHA256-PAYLOAD"
	signV4ChunkedAlgorithmTrailer = "AWS4-HMAC-SHA256-TRAILER"
	streamingContentEncoding      = "aws-chunked"
	awsTrailerHeader              = "X-Amz-Trailer"

	}
	var (
		sealingKey   [32]byte
		encryptedKey bytes.Buffer
	)
	mac := hmac.New(sha256.New, extKey)
	mac.Write(iv[:])
	mac.Write([]byte(domain))
	mac.Write([]byte(SealAlgorithm))
	mac.Write([]byte(path.Join(bucket, object))) // use path.Join for canonical 'bucket/object'
	mac.Sum(sealingKey[:0])

aes128-cbc
3des-cbc
```

`--sftp=mac-algos=...` specifies a default set of MAC algorithms in preference order.
This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed because they have 
reached the end of their useful life.

Valid values: 

```
hmac******@****.***
hmac******@****.***
hmac-sha2-256
hmac-sha2-512
hmac-sha1
hmac-sha1-96
```

	"github.com/minio/minio/internal/auth"
	"github.com/minio/minio/internal/hash/sha256"
	xhttp "github.com/minio/minio/internal/http"
)

// AWS Signature Version '4' constants.
const (
	signV4Algorithm = "AWS4-HMAC-SHA256"
	iso8601Format   = "20060102T150405Z"
	yyyymmdd        = "20060102"
)

type serviceType string

const (
	serviceS3  serviceType = "s3"
	serviceSTS serviceType = "sts"
)

	iv, nonce := random[:16], random[16:]

	var aead cipher.AEAD
	switch keyType {
	case kms.AES256:
		mac := hmac.New(sha256.New, s.key)
		mac.Write(iv)
		sealingKey := mac.Sum(nil)

		block, err := aes.NewCipher(sealingKey)
		if err != nil {
			return nil, err
		}
		aead, err = cipher.NewGCM(block)
		if err != nil {
			return nil, err

// supportedMACs specifies a default set of MAC algorithms in preference order.
// This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed
// because they have reached the end of their useful life.
// https://cs.opensource.google/go/x/crypto/+/refs/tags/v0.22.0:ssh/common.go;l=85
var supportedMACs = []string{
	"hmac******@****.***", "hmac******@****.***", "hmac-sha2-256", "hmac-sha2-512", "hmac-sha1", "hmac-sha1-96",
}

	if err != nil {
		t.Fatal(err)
	}

import (
	"bytes"
	"crypto"
	"crypto/hmac"
	"encoding/base64"
	"errors"
	"fmt"
	"hash"
	"sync"
	"time"

	"github.com/buger/jsonparser"
	"github.com/dustin/go-humanize"
	jwtgo "github.com/golang-jwt/jwt/v4"
	jsoniter "github.com/json-iterator/go"
)

// SigningMethodHMAC - Implements the HMAC-SHA family of signing methods signing methods

	contentLengthCondStr := `["content-length-range", 1024, 1048576]`
	// Add the algorithm condition, only accept AWS SignV4 Sha256.
	algorithmConditionStr := `["eq", "$x-amz-algorithm", "AWS4-HMAC-SHA256"]`
	// Add the date condition, only accept the current date.
	dateConditionStr := fmt.Sprintf(`["eq", "$x-amz-date", "%s"]`, t.Format(iso8601DateFormat))
	// Add the credential string, only accept the credential passed.