236 lines
6.9 KiB
C
236 lines
6.9 KiB
C
/*
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* QEMU Crypto cipher algorithms
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*
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* Copyright (c) 2015 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef QCRYPTO_CIPHER_H
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#define QCRYPTO_CIPHER_H
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#include "qapi-types.h"
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typedef struct QCryptoCipher QCryptoCipher;
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/* See also "QCryptoCipherAlgorithm" and "QCryptoCipherMode"
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* enums defined in qapi/crypto.json */
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/**
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* QCryptoCipher:
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*
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* The QCryptoCipher object provides a way to perform encryption
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* and decryption of data, with a standard API, regardless of the
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* algorithm used. It further isolates the calling code from the
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* details of the specific underlying implementation, whether
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* built-in, libgcrypt or nettle.
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*
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* Each QCryptoCipher object is capable of performing both
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* encryption and decryption, and can operate in a number
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* or modes including ECB, CBC.
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*
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* <example>
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* <title>Encrypting data with AES-128 in CBC mode</title>
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* <programlisting>
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* QCryptoCipher *cipher;
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* uint8_t key = ....;
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* size_t keylen = 16;
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* uint8_t iv = ....;
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*
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* if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) {
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* error_report(errp, "Feature <blah> requires AES cipher support");
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* return -1;
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* }
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*
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* cipher = qcrypto_cipher_new(QCRYPTO_CIPHER_ALG_AES_128,
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* QCRYPTO_CIPHER_MODE_CBC,
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* key, keylen,
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* errp);
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* if (!cipher) {
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* return -1;
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* }
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*
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* if (qcrypto_cipher_set_iv(cipher, iv, keylen, errp) < 0) {
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* return -1;
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* }
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*
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* if (qcrypto_cipher_encrypt(cipher, rawdata, encdata, datalen, errp) < 0) {
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* return -1;
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* }
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*
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* qcrypto_cipher_free(cipher);
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* </programlisting>
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* </example>
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*
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*/
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struct QCryptoCipher {
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QCryptoCipherAlgorithm alg;
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QCryptoCipherMode mode;
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void *opaque;
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};
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/**
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* qcrypto_cipher_supports:
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* @alg: the cipher algorithm
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* @mode: the cipher mode
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*
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* Determine if @alg cipher algorithm in @mode is supported by the
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* current configured build
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*
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* Returns: true if the algorithm is supported, false otherwise
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*/
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bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg,
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QCryptoCipherMode mode);
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/**
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* qcrypto_cipher_get_block_len:
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* @alg: the cipher algorithm
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*
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* Get the required data block size in bytes. When
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* encrypting data, it must be a multiple of the
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* block size.
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*
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* Returns: the block size in bytes
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*/
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size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg);
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/**
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* qcrypto_cipher_get_key_len:
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* @alg: the cipher algorithm
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*
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* Get the required key size in bytes.
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*
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* Returns: the key size in bytes
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*/
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size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg);
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/**
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* qcrypto_cipher_get_iv_len:
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* @alg: the cipher algorithm
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* @mode: the cipher mode
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*
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* Get the required initialization vector size
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* in bytes, if one is required.
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*
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* Returns: the IV size in bytes, or 0 if no IV is permitted
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*/
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size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg,
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QCryptoCipherMode mode);
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/**
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* qcrypto_cipher_new:
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* @alg: the cipher algorithm
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* @mode: the cipher usage mode
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* @key: the private key bytes
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* @nkey: the length of @key
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* @errp: pointer to a NULL-initialized error object
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*
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* Creates a new cipher object for encrypting/decrypting
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* data with the algorithm @alg in the usage mode @mode.
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*
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* The @key parameter provides the bytes representing
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* the encryption/decryption key to use. The @nkey parameter
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* specifies the length of @key in bytes. Each algorithm has
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* one or more valid key lengths, and it is an error to provide
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* a key of the incorrect length.
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*
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* The returned cipher object must be released with
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* qcrypto_cipher_free() when no longer required
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*
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* Returns: a new cipher object, or NULL on error
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*/
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QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
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QCryptoCipherMode mode,
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const uint8_t *key, size_t nkey,
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Error **errp);
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/**
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* qcrypto_cipher_free:
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* @cipher: the cipher object
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*
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* Release the memory associated with @cipher that
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* was previously allocated by qcrypto_cipher_new()
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*/
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void qcrypto_cipher_free(QCryptoCipher *cipher);
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/**
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* qcrypto_cipher_encrypt:
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* @cipher: the cipher object
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* @in: buffer holding the plain text input data
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* @out: buffer to fill with the cipher text output data
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* @len: the length of @in and @out buffers
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* @errp: pointer to a NULL-initialized error object
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*
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* Encrypts the plain text stored in @in, filling
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* @out with the resulting ciphered text. Both the
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* @in and @out buffers must have the same size,
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* given by @len.
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*
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* Returns: 0 on success, or -1 on error
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*/
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int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
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const void *in,
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void *out,
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size_t len,
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Error **errp);
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/**
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* qcrypto_cipher_decrypt:
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* @cipher: the cipher object
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* @in: buffer holding the cipher text input data
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* @out: buffer to fill with the plain text output data
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* @len: the length of @in and @out buffers
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* @errp: pointer to a NULL-initialized error object
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*
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* Decrypts the cipher text stored in @in, filling
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* @out with the resulting plain text. Both the
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* @in and @out buffers must have the same size,
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* given by @len.
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*
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* Returns: 0 on success, or -1 on error
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*/
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int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
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const void *in,
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void *out,
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size_t len,
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Error **errp);
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/**
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* qcrypto_cipher_setiv:
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* @cipher: the cipher object
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* @iv: the initialization vector or counter (CTR mode) bytes
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* @niv: the length of @iv
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* @errpr: pointer to a NULL-initialized error object
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*
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* If the @cipher object is setup to use a mode that requires
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* initialization vectors or counter, this sets the @niv
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* bytes. The @iv data should have the same length as the
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* cipher key used when originally constructing the cipher
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* object. It is an error to set an initialization vector
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* or counter if the cipher mode does not require one.
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*
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* Returns: 0 on success, -1 on error
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*/
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int qcrypto_cipher_setiv(QCryptoCipher *cipher,
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const uint8_t *iv, size_t niv,
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Error **errp);
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#endif /* QCRYPTO_CIPHER_H */
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