我想使用NfcA在MIFARE Ultralight EV1(MFOUL21)标签上设置和取消设置密码保护吗？ Android上的标签技术.

我知道我会为此使用nfcA.transceive()方法,但是我不确定该方法的参数是什么,所以有人可以提供代码段来设置和取消设置密码吗？

更新：

关于TapLinx库,我基本上希望使用nfcA.transceive(…)代码段,其等效于：

> ultralightEV1.programPwd(passwordBytes);
> ultralightEV1.programPack(packBytes);
> ultralightEV1.enablePasswordProtection(enabled,fromPageNum);
> ultralightEV1.authenticatePwd(passwordBytes);

解决方法:

认证

ultralightEV1.authenticatePwd(passwordBytes);

为了使用MIFARE Ultralight EV1标签(或NTAG21x)的密码进行身份验证,您需要发送PWD_AUTH(0x1B)命令(并可能验证PACK响应是否符合您的期望)：

byte[] pass = { (byte)0x12, (byte)0x34, (byte)0x56, (byte)0x78 };
byte[] pack = { (byte)0x9A, (byte)0xBC };

byte[] response = nfc.transceive(new byte[] {
    (byte) 0x1B, // PWD_AUTH
    pass[0], pass[1], pass[2], pass[3]
});
if ((response != null) && (response.length >= 2)) {
    // success
    byte[] packReceived = Arrays.copyOf(response, 2);
    if (Arrays.equal(packReceived, pack)) {
        // PACK verified, so tag is authentic (not really, but that whole
        // PWD_AUTH/PACK authentication mechanism was not really meant to
        // bring much security, I hope; same with the NTAG signature btw.)
    }
}

设置密码和密码确认

ultralightEV1.programPwd(passwordBytes);
ultralightEV1.programPack(packBytes);

对于MF0UL11,密码位于第0x12页,密码确认(PACK)位于第0x13页(配置页从0x10开始).对于MF0UL21,密码位于第0x27页,密码确认(PACK)位于第0x28页(配置页从0x25开始).

为了动态地发现您的标签是MF0UL11还是MF0UL21,您可以发送GET_VERSION(0x60)命令：

int cfgOffset = -1;

byte[] response = nfc.transceive(new byte[] {
    (byte) 0x60 // GET_VERSION
});
if ((response != null) && (response.length >= 8)) {
    // success
    if ((response[0] == (byte)0x00) && (response[1] == (byte)0x04)) {
        // tag is from NXP
        if (response[2] == (byte)0x03) {
            // MIFARE Ultralight
            if ((response[4] == (byte)0x01) && (response[5] == (byte)0x00) {
                // MIFARE Ultralight EV1 (V0)
                switch (response[6]) {
                    case (byte)0x0B:
                        // MF0UL11
                        cfgOffset = 0x010;
                        break;
                    case (byte)0x0E:
                        // MF0UL11
                        cfgOffset = 0x025;
                        break;

                    default:
                        // unknown
                        break;
                }
            }
        }
    }
}

找到配置页面的开始后,可以使用WRITE(0xA2)命令更新这些页面的值(假设您已使用当前密码进行了身份验证,或者配置页面未受保护)：

byte[] response = nfc.transceive(new byte[] {
    (byte) 0xA2, // WRITE
    (byte)((cfgOffset + 2) & 0x0FF),    // page address
    pass[0], pass[1], pass[2], pass[3]  // new page data
});
response = nfc.transceive(new byte[] {
    (byte) 0xA2, // WRITE
    (byte)((cfgOffset + 3) & 0x0FF),          // page address
    pack[0], pack[1], (byte)0x00, (byte)0x00  // new page data (always need to write full page)
});

启用密码保护

ultralightEV1.enablePasswordProtection(enabled, fromPageNum);

为了启用密码保护,您需要配置需要密码的第一页(AUTH0,MF0UL11 /页0x25 MF0UL21在页0x10上的字节3),并且需要配置保护模式(PROT,on字节0的位7). MF0UL11的第0x11页/ MF0UL21的第0x26页).

通常,您通常会先读取(READ(0x30)命令)这些页面的旧值,更新受影响的位和字节,然后将新值写入标记：

int fromPageNum = 4;
boolean enableProtection = true;
boolean enableReadProtection = true;
byte[] response = nfc.transceive(new byte[] {
    (byte) 0x30, // READ
    (byte)(cfgOffset & 0x0FF)  // page address
});
if ((response != null) && (response.length >= 16)) {
    // success
    // NOTE that READ will return *4 pages* starting at page address
    byte auth0 = (byte)0xFF;
    if (enableProtection || enableReadProtection) {
        auth0 = (byte)(fromPageNum & 0x0FF);
    }
    byte[] writeResponse = nfc.transceive(new byte[] {
        (byte) 0xA2, // WRITE
        (byte)((cfgOffset + 0) & 0x0FF),              // page address
        response[0], response[1], response[2], auth0  // new page data
    });
    byte access = (byte)(response[4] & 0x07F);
    if (enableProtection && enableReadProtection) {
        access |= (byte)0x80;
    }
    byte[] writeResponse = nfc.transceive(new byte[] {
        (byte) 0xA2, // WRITE
        (byte)((cfgOffset + 1) & 0x0FF),                // page address
        access, response[5], response[6], response[7],  // new page data
    });
}