kcapi_cipher_stream_update_last - Man Page

ssize_t kcapi_cipher_stream_update_last(struct kcapi_handle * handle, struct iovec * iov, size_t iovlen);

handle

iov

iovlen

Using this function call, more plaintext for encryption or ciphertext for decryption can be submitted to the kernel​.

This call is identical to the kcapi_cipher_stream_update call with the exception that it marks the last data buffer before the cipher operation is triggered​. This is call is important for stream ciphers like CTR or CTS mode when providing the last block​. It is permissible to provide a zero buffer if all data including the last block is already provided by kcapi_cipher_stream_update​.

If this call is not made for stream ciphers with input data that is not a multiple of the block size of the block cipher, the kernel will not return the last block that contains less data than the block size of the block cipher​. For example, sending 257 bytes of data to be encrypted with ctr(aes), the kernel will return only 256 bytes without this call​.

return number of bytes sent to the kernel upon success; a negative errno-style error code if an error occurred

Stephan Mueller <​smueller@chronox.de​>