Main Page | See live article | Alphabetical index An initialization vector in a block cipher is a block of bits that is combined with the first block of data in any of several feedback modes. In some cryptosystems it is random and is sent with the ciphertext; in others, such as a disk encryption subsystem, it is based on some info, such as the file's inode, that does not have to be put in the ciphertext. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.