This is because RFB depends on Data Encryption Standard DES encoding, and us export restrictions effectively prevent Tcl from bundling DES.

这是因为RF B依赖于数据加密标准(Data Encryption Standard, DES)编码，并且美国的出口限制有效地阻止了Tcl捆绑DES。

youdao

Represents the base class for the Data Encryption Standard (DES) algorithm from which all DES implementations must derive.

表示所有DES实现都必须从中派生的数据加密标准（DES）算法的基类。

youdao

To encrypt its data, the pen uses an algorithm called Rijndael, which the National Institute for Standards and Technology is planning to use as the Advanced Encryption Standard, which will replace the existing Data Encryption Standard (DES), which is currently being phased out of use.

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