Key blobs are the data structures that store keys when they are not inside of a CSP. Every key blob consists of one or more fixed-length header structures, followed by the key data itself. This key data is variable in length, and often encrypted.
Each key blob consists of binary data. The size of a key blob will vary depending on the blob type and the key size.
Unless stated otherwise, all multibyte numbers are stored in little-endian format, meaning that the first byte of a number is the least significant and the last byte is the most significant. This is the most common format for computers running Windows.