Section outline

  • A cyclic redundancy check (CRC) is a code used to detect errors to raw data as it travels through a network or a digital storage device, like your computer or cell phone. The data is checked by looking at the check value, which is the remainder of a polynomial division. If the check values do not match, then the data is corrupted 1 .
    ::循环冗余检查( CRC) 是用于检测原始数据在通过网络或数字存储设备( 如您的计算机或手机) 运行时的错误的代码。 数据通过检查值来检查, 即多式分区的剩余值。 如果检查值不匹配, 那么数据将被损坏 1 。

    The number of terms in the remainder or the number of bits in the check value is indicated in the name. CRC-8, CRC-16, CRC-32, and CRC-64 are commonly used.
    ::以余值表示的术语数或检查值中的位数。 通常使用CRC-8、CRC-16、CRC-32和CRC-64。

    The divisor is called the generator polynomial. In our example, we will use x + 1 . The message or data to be checked is the dividend.
    ::divisor 被称为生成器多元数。 在我们的例子中, 我们将使用 x+1 。 要检查的信息或数据是红利 。

    lesson content

    Suppose our data is x 3 + x 2 + x . We want to find the check value, so we will divide x 3 + x 2 + x  by x + 1 .
    ::假设我们的数据是 x3+x2+x。 我们想要找到检查值, 所以我们会将 x3+x2+xx除以 x+1 。

    1. Perform the division.
      ::执行分队。

    Data is transferred in binary as 0’s and 1’s. 0’s represent even terms and 1’s represent odd terms. Since the remainder -1 is odd, the check value is 1.
    ::数据以二进制以 0 和 1 的 方式传输。 0 表示偶数, 1 表示奇数。 由于剩下的 - 1 是奇数, 检查值为 1 。

    1. Using x + 1  as the generator polynomial, determine if messages represented by x 5 + x 3 + x 2 + 1  and x 4 + x 2  are corrupted, that is, do the check values agree?
      ::使用 x+1 作为生成器的多位数, 确定 x5+x3+x2+1 和 x4+x2 所代表的信件是否损坏, 即检查值是否一致 ?
    1. What if the generator polynomial is x 2 + 1 ? Does it show what you found in 2?
      ::如果生成器的多数值为 x2+1 呢? 它是否显示您在 2 中找到的东西 ?
    1. Create an example with a generator of x + 1  that shows corrupted data. (The coefficients in your message polynomial should be either 0 or 1).
      ::以 x+1 生成器创建示例, 该生成器显示已损坏的数据 。 (您信件中多位数的系数应该是 0 或 1 ) 。

    by Somanshu Choudhary connects code words to polynomials.
    ::由Somanshu Choudhary将代码词与多义词连接起来。

    References
    ::参考参考资料

    1. "Cyclic Redundancy Check," last edited May 17, 2017, https://en.wikipedia.org/wiki/Cyclic_redundancy_check.
    ::1. 2017年5月17日编辑的上一期《网络冗余检查》,https://en.wikipedia.org/wiki/Cyclic_redundancy_check