*Decrypt a cipher*

## Synopsis:

#include <qcrypto/qcrypto.h>

int qcrypto_cipher_decrypt(qcrypto_ctx_t *ctx,
const uint8_t *in,
size_t insize,
uint8_t *out,
size_t *outsize)

## Arguments:

`ctx`
- The algorithm context object.
`in`
- The input data.
`insize`
- The input data size.
`out`
- The output data.
`outsize`
- The combined size of the output data and the decrypted data.

## Library:

libqcrypto
## Description:

This function decrypts ciphertext data using the specified symmetric key. For stream ciphers (block size == 1), the *out* buffer should be at least as large as the *in* buffer. If the input is a multiple of the block size (block size > 1), the *out* buffer should be at least as large as the *in* buffer; otherwise, the *out* buffer needs to be at least one block larger.

## Returns:

QCRYPTO_R_EOK if successful or `qcrypto_errno` if an error occurred.