kcapi_cipher_decrypt - Man Page

decrypt data (synchronous one shot)

Synopsis

ssize_t kcapi_cipher_decrypt(struct kcapi_handle * handle, const uint8_t * in, size_t inlen, const uint8_t * iv, uint8_t * out, size_t outlen, int access);

Arguments

handle

[in] cipher handle

in

[in] ciphertext data buffer

inlen

[in] length of in buffer

iv

[in] IV to be used for cipher operation

out

[out] plaintext data buffer

outlen

[in] length of out bufferS

access

[in] kernel access type (KCAPI_ACCESS_HEURISTIC - use internal heuristic for fastest kernel access; KCAPI_ACCESS_VMSPLICE - use vmsplice access; KCAPI_ACCESS_SENDMSG - sendmsg access)

Description

It is perfectly legal to use the same buffer as the plaintext and ciphertext pointers. That would mean that after the encryption operation, the ciphertext is overwritten with the plaintext.

The memory should be aligned at the page boundary using posix_memalign(sysconf(_SC_PAGESIZE)), If it is not aligned at the page boundary, the vmsplice call may not send all data to the kernel.

The IV buffer must be exactly kcapi_cipher_ivsize bytes in size.

return number of bytes decrypted upon success; a negative errno-style error code if an error occurred

Author

Stephan Mueller <smueller@chronox.de>

Author.

Info

July 2021 libkcapi Manual 1.3.1 Programming Interface