Java重复hmacSHA1哈希如何转换为PHP？

Question

如何将以下Java转换为PHP

byte[] byteArray1 = key1.getBytes("UTF8");
byte[] byteArray2 = key2.getBytes("UTF8");
byte[] byteArray3 = key3.getBytes("UTF8");
byte[] byteArray4 = key4.getBytes("UTF8");

Mac mac = Mac.getInstance("HmacSHA1");
SecretKeySpec derivedKey = new SecretKeySpec(byteArray1, "HmacSha1");
mac.init(derivedKey); derivedKey = new SecretKeySpec(mac.doFinal(byteArray2), "HmacSha1"); }
mac.init(derivedKey); derivedKey = new SecretKeySpec(mac.doFinal(byteArray3), "HmacSha1");
mac.init(derivedKey); derivedKey = new SecretKeySpec(mac.doFinal(byteArray4), "HmacSha1");

从我所做的所有研究来看，如果去掉最后两行，我们可以将其巧妙地转换为PHP，如下所示：

hash_hmac("sha1", $key2, $key1, true);

但是，如何将这种类型的重复哈希转换为PHP

注意：我尝试了以下方法，但没有成功：

$derivedKey = hash_hmac("sha1", $key2, $key1, true);
$derivedKey = hash_hmac("sha1", $key3, $derivedKey, true);
$derivedKey = hash_hmac("sha1", $key4, $derivedKey, true);