> it was the only way they could think of to allow an arbitrary block of ciphertext to be decrypted without decrypting the prior blocks (i.e. they needed random

> it was the only way they could think of to allow an arbitrary block of ciphertext to be decrypted without decrypting the prior blocks (i.e. they needed random access as opposed to decrypting the entire ciphertext every time). CBC mode does support that, though (decryption is parallelizable, but not encryption).