1. An apparatus comprising: an encryption circuit for encrypting a plurality of data blocks of a data segment, the encryption circuit configured to selectively switch between a blockwise independent randomized (BIR) encryption mode and a cipher block chaining (CBC) encryption mode based on a configurable feedback stride; wherein the encryption circuit comprises a combiner circuit, a block cipher circuit, and a sequence generator circuit; the block cipher circuit comprising a plurality m of pipelined stages for simultaneously processing, in a pipelined fashion, a plurality m of different bit vector-data block combinations corresponding to m data blocks of the data segment that are generated by the combiner circuit to thereby generate a plurality of encrypted data blocks, the value for m being configurable to define the feedback stride; and the sequence generator configured to selectively switch between the BIR encryption mode and the CBC encryption mode, wherein the sequence generator is further configured to (1) generate and output a plurality of randomized blockwise independent bit vectors while in the BIR encryption mode, and (2) generate and output a plurality of blockwise dependent bit vectors while in the CBC encryption mode, the blockwise dependent bit vectors being based on a previously encrypted bit vector-data block combination fed back from the block cipher circuit; the combiner circuit being configured to (1) receive a streaming input of the data blocks, (2) receive an input of the bit vectors output by the sequence generator circuit, and (3) reversibly combine the received bit vectors with the received streaming data blocks to generate a plurality of bit vector-data block combinations for delivery to the block cipher circuit; and wherein the sequence generator is further configured to (1) operate in the BIR encryption mode while the block cipher circuit is processing the bit vector-data block combinations corresponding to the first m data blocks of the same data segment, and (2) switch to the CBC encryption mode in response to the block cipher circuit completing encryption of at least the bit vector-data block combination corresponding to the first of the m data blocks, the block cipher circuit thereby being configured to generate the plurality of encrypted data blocks wherein at least the first m encrypted data blocks of the same data segment are encrypted in combination with blockwise independent bit vectors and wherein a plurality of the other encrypted data blocks of the same data segment are encrypted in combination with blockwise dependent bit vectors.