Libgcrypt makes it possible to load additional `cipher modules'; these ciphers can be used just like the cipher algorithms that are built into the library directly. For an introduction into extension modules, see See Modules.
This is the `module specification structure' needed for registering cipher modules, which has to be filled in by the user before it can be used to register a module. It contains the following members:
const char *name
- The primary name of the algorithm.
const char **aliases
- A list of strings that are `aliases' for the algorithm. The list must be terminated with a NULL element.
gcry_cipher_oid_spec_t *oids
- A list of OIDs that are to be associated with the algorithm. The list's last element must have it's `oid' member set to NULL. See below for an explanation of this type.
size_t blocksize
- The block size of the algorithm, in bytes.
size_t keylen
- The length of the key, in bits.
size_t contextsize
- The size of the algorithm-specific `context', that should be allocated for each handle.
gcry_cipher_setkey_t setkey
- The function responsible for initializing a handle with a provided key. See below for a description of this type.
gcry_cipher_encrypt_t encrypt
- The function responsible for encrypting a single block. See below for a description of this type.
gcry_cipher_decrypt_t decrypt
- The function responsible for decrypting a single block. See below for a description of this type.
gcry_cipher_stencrypt_t stencrypt
- Like `encrypt', for stream ciphers. See below for a description of this type.
gcry_cipher_stdecrypt_t stdecrypt
- Like `decrypt', for stream ciphers. See below for a description of this type.
This type is used for associating a user-provided algorithm implementation with certain OIDs. It contains the following members:
const char *oid
- Textual representation of the OID.
int mode
- Cipher mode for which this OID is valid.
Type for the `setkey' function, defined as: gcry_err_code_t (*gcry_cipher_setkey_t) (void *c, const unsigned char *key, unsigned keylen)
Type for the `encrypt' function, defined as: gcry_err_code_t (*gcry_cipher_encrypt_t) (void *c, const unsigned char *outbuf, const unsigned char *inbuf)
Type for the `decrypt' function, defined as: gcry_err_code_t (*gcry_cipher_decrypt_t) (void *c, const unsigned char *outbuf, const unsigned char *inbuf)
Type for the `stencrypt' function, defined as: gcry_err_code_t (*gcry_cipher_stencrypt_t) (void *c, const unsigned char *outbuf, const unsigned char *, unsigned int n)
Type for the `stdecrypt' function, defined as: gcry_err_code_t (*gcry_cipher_stdecrypt_t) (void *c, const unsigned char *outbuf, const unsigned char *, unsigned int n)
Register a new cipher module whose specification can be found in cipher. On success, a new algorithm ID is stored in algorithm_id and a pointer representing this module is stored in module. Deprecated; the module register interface will be removed in a future version.
Unregister the cipher identified by module, which must have been registered with gcry_cipher_register.
Get a list consisting of the IDs of the loaded cipher modules. If list is zero, write the number of loaded cipher modules to list_length and return. If list is non-zero, the first *list_length algorithm IDs are stored in list, which must be of according size. In case there are less cipher modules than *list_length, *list_length is updated to the correct number.