【单选题】
DES，即（）。
A、船上交货
B、船边交货
C、边境交货
D、码头交货
查看正确答案
A、A. 3DES is muchmore secure than DES. B、B. Both DES and 3DES are stream ciphers. C、C. DES uses 64 bitkeys， although the effective key lengthis only 56bits. D、D. The decryption operation for both DES and 3DES is the same as the encryption operation. E、E. DES can only be used for encryption， whereas 3DES can also be used for authentication.
