| Platform SDK: Cryptography |
Key BLOBs are structures that store keys outside a CSP key container. Every key BLOB consists of one or more fixed-length header structures followed by the key data itself. The key data is variable in length and is often encrypted.
Key BLOBs consist of binary data. The size of a key BLOB varies depending on the BLOB type and the key size.
Unless stated otherwise, all multibyte numbers are stored in little-endian format; that is, the first byte of a number is the least significant and the last byte is the most significant. For example, the four byte hexadecimal number 0x12345678 will be stored as:
78 56 34 12
This is the most common format for computers running versions of Microsoft® Windows®.
Standard structure formats include the following.
| Structure format | Description |
|---|---|
| BLOBHEADER | Structure used at the beginning of all key BLOB structures. |
| Simple Key BLOBs | BLOB format for an encrypted session key. |
| Public Key BLOBs | BLOB format for a public key. |
| Private Key BLOBs | BLOB format for a private key in encrypted form. |
| Symmetric Wrapped Key Blobs | BLOB format for exporting a symmetric key wrapped with another symmetric key. |