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STRUCT CIPHER_ALG(9) Programming Interface STRUCT CIPHER_ALG(9)

NAME

struct_cipher_alg - single-block symmetric ciphers definition

SYNOPSIS

struct cipher_alg {
  unsigned int cia_min_keysize;
  unsigned int cia_max_keysize;
  int (* cia_setkey) (struct crypto_tfm *tfm, const u8 *key,unsigned int keylen);
  void (* cia_encrypt) (struct crypto_tfm *tfm, u8 *dst, const u8 *src);
  void (* cia_decrypt) (struct crypto_tfm *tfm, u8 *dst, const u8 *src);
};

MEMBERS

cia_min_keysize
Minimum key size supported by the transformation. This is the smallest key length supported by this transformation algorithm. This must be set to one of the pre-defined values as this is not hardware specific. Possible values for this field can be found via git grep “_MIN_KEY_SIZE” include/crypto/

cia_max_keysize

Maximum key size supported by the transformation. This is the largest key length supported by this transformation algorithm. This must be set to one of the pre-defined values as this is not hardware specific. Possible values for this field can be found via git grep “_MAX_KEY_SIZE” include/crypto/

cia_setkey

Set key for the transformation. This function is used to either program a supplied key into the hardware or store the key in the transformation context for programming it later. Note that this function does modify the transformation context. This function can be called multiple times during the existence of the transformation object, so one must make sure the key is properly reprogrammed into the hardware. This function is also responsible for checking the key length for validity.

cia_encrypt

Encrypt a single block. This function is used to encrypt a single block of data, which must be cra_blocksize big. This always operates on a full cra_blocksize and it is not possible to encrypt a block of smaller size. The supplied buffers must therefore also be at least of cra_blocksize size. Both the input and output buffers are always aligned to cra_alignmask. In case either of the input or output buffer supplied by user of the crypto API is not aligned to cra_alignmask, the crypto API will re-align the buffers. The re-alignment means that a new buffer will be allocated, the data will be copied into the new buffer, then the processing will happen on the new buffer, then the data will be copied back into the original buffer and finally the new buffer will be freed. In case a software fallback was put in place in the cra_init call, this function might need to use the fallback if the algorithm doesn't support all of the key sizes. In case the key was stored in transformation context, the key might need to be re-programmed into the hardware in this function. This function shall not modify the transformation context, as this function may be called in parallel with the same transformation object.

cia_decrypt

Decrypt a single block. This is a reverse counterpart to cia_encrypt, and the conditions are exactly the same.

DESCRIPTION

All fields are mandatory and must be filled.

AUTHORS

Stephan Mueller <smueller@chronox.de>
Author.

Marek Vasut <marek@denx.de>

Author.

COPYRIGHT

April 2019 Kernel Hackers Manual 4.9.