Manual Pages  — CRYPTO

• SYNOPSIS
• DESCRIPTION
• THEORY OF OPERATION
• SYMMETRIC-KEY OPERATION
• Algorithms
• IOCTL Request Descriptions
• SEE ALSO
• HISTORY
• BUGS

struct crypt_find_op {
    int     crid;       /* driver id + flags */
    char    name[32];   /* device/driver name */
};

struct session_op {
    uint32_t cipher;    /* e.g. CRYPTO_AES_CBC */
    uint32_t mac;       /* e.g. CRYPTO_SHA2_256_HMAC */

    uint32_t keylen;    /* cipher key */
    const void *key;
    int mackeylen;      /* mac key */
    const void *mackey;

    uint32_t ses;       /* returns: ses # */
};

Multiple sessions may be bound to a single file descriptor. The session ID returned in sessp->ses is supplied as a required field in the operation structure crypt_op for future encryption or hashing requests.

For non-zero privacy algorithms, the privacy algorithm must be specified in sessp->cipher, the key length in sessp->keylen, and the key value in the octets addressed by sessp->key.

For keyed one-way hash algorithms, the one-way hash must be specified in sessp->mac, the key length in sessp->mackey, and the key value in the octets addressed by sessp->mackeylen.

Support for a specific combination of fused privacy and integrity-check algorithms depends on whether the underlying hardware supports that combination. Not all combinations are supported by all hardware, even if the hardware supports each operation as a stand-alone non-fused operation.

struct session2_op {
    uint32_t cipher;    /* e.g. CRYPTO_AES_CBC */
    uint32_t mac;       /* e.g. CRYPTO_SHA2_256_HMAC */

    uint32_t keylen;    /* cipher key */
    const void *key;
    int mackeylen;      /* mac key */
    const void *mackey;

    uint32_t ses;       /* returns: ses # */
    int crid;           /* driver id + flags (rw) */
    int ivlen;          /* length of nonce/IV */
    int maclen;         /* length of MAC/tag */
    int pad[2];         /* for future expansion */
};

sessp->crid requests either a specific crypto device or a class of devices (software vs hardware).

sessp->ivlen specifies the length of the IV or nonce supplied with each request. If this field is set to zero, the default IV or nonce length is used.

sessp->maclen specifies the length of the MAC or authentication tag supplied or computed by each request. If this field is set to zero, the full MAC is used.

The sessp->pad field must be initialized to zero.

struct crypt_op {
    uint32_t ses;
    uint16_t op;        /* e.g. COP_ENCRYPT */
    uint16_t flags;
    u_int len;
    const void *src;
    void *dst;
    void *mac;          /* must be large enough for result */
    const void *iv;
};

If a session is using either fused encrypt-then-authenticate or an AEAD algorithm, decryption operations require the associated hash as an input. If the hash is incorrect, the operation will fail with EBADMSG and the output buffer will remain unchanged.

struct crypt_aead {
    uint32_t ses;
    uint16_t op;        /* e.g. COP_ENCRYPT */
    uint16_t flags;
    u_int len;
    u_int aadlen;
    u_int ivlen;
    const void *src;
    void *dst;
    const void *aad;    /* additional authenticated data */
    void *tag;          /* must fit for chosen TAG length */
    const void *iv;
};