cipher.h (7186B)
1/* 2 * QEMU Crypto cipher algorithms 3 * 4 * Copyright (c) 2015 Red Hat, Inc. 5 * 6 * This library is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU Lesser General Public 8 * License as published by the Free Software Foundation; either 9 * version 2.1 of the License, or (at your option) any later version. 10 * 11 * This library is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 * Lesser General Public License for more details. 15 * 16 * You should have received a copy of the GNU Lesser General Public 17 * License along with this library; if not, see <http://www.gnu.org/licenses/>. 18 * 19 */ 20 21#ifndef QCRYPTO_CIPHER_H 22#define QCRYPTO_CIPHER_H 23 24#include "qapi/qapi-types-crypto.h" 25 26typedef struct QCryptoCipher QCryptoCipher; 27typedef struct QCryptoCipherDriver QCryptoCipherDriver; 28 29/* See also "QCryptoCipherAlgorithm" and "QCryptoCipherMode" 30 * enums defined in qapi/crypto.json */ 31 32/** 33 * QCryptoCipher: 34 * 35 * The QCryptoCipher object provides a way to perform encryption 36 * and decryption of data, with a standard API, regardless of the 37 * algorithm used. It further isolates the calling code from the 38 * details of the specific underlying implementation, whether 39 * built-in, libgcrypt or nettle. 40 * 41 * Each QCryptoCipher object is capable of performing both 42 * encryption and decryption, and can operate in a number 43 * or modes including ECB, CBC. 44 * 45 * <example> 46 * <title>Encrypting data with AES-128 in CBC mode</title> 47 * <programlisting> 48 * QCryptoCipher *cipher; 49 * uint8_t key = ....; 50 * size_t keylen = 16; 51 * uint8_t iv = ....; 52 * 53 * if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { 54 * error_report(errp, "Feature <blah> requires AES cipher support"); 55 * return -1; 56 * } 57 * 58 * cipher = qcrypto_cipher_new(QCRYPTO_CIPHER_ALG_AES_128, 59 * QCRYPTO_CIPHER_MODE_CBC, 60 * key, keylen, 61 * errp); 62 * if (!cipher) { 63 * return -1; 64 * } 65 * 66 * if (qcrypto_cipher_set_iv(cipher, iv, keylen, errp) < 0) { 67 * return -1; 68 * } 69 * 70 * if (qcrypto_cipher_encrypt(cipher, rawdata, encdata, datalen, errp) < 0) { 71 * return -1; 72 * } 73 * 74 * qcrypto_cipher_free(cipher); 75 * </programlisting> 76 * </example> 77 * 78 */ 79 80struct QCryptoCipher { 81 QCryptoCipherAlgorithm alg; 82 QCryptoCipherMode mode; 83 const QCryptoCipherDriver *driver; 84}; 85 86/** 87 * qcrypto_cipher_supports: 88 * @alg: the cipher algorithm 89 * @mode: the cipher mode 90 * 91 * Determine if @alg cipher algorithm in @mode is supported by the 92 * current configured build 93 * 94 * Returns: true if the algorithm is supported, false otherwise 95 */ 96bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg, 97 QCryptoCipherMode mode); 98 99/** 100 * qcrypto_cipher_get_block_len: 101 * @alg: the cipher algorithm 102 * 103 * Get the required data block size in bytes. When 104 * encrypting data, it must be a multiple of the 105 * block size. 106 * 107 * Returns: the block size in bytes 108 */ 109size_t qcrypto_cipher_get_block_len(QCryptoCipherAlgorithm alg); 110 111 112/** 113 * qcrypto_cipher_get_key_len: 114 * @alg: the cipher algorithm 115 * 116 * Get the required key size in bytes. 117 * 118 * Returns: the key size in bytes 119 */ 120size_t qcrypto_cipher_get_key_len(QCryptoCipherAlgorithm alg); 121 122 123/** 124 * qcrypto_cipher_get_iv_len: 125 * @alg: the cipher algorithm 126 * @mode: the cipher mode 127 * 128 * Get the required initialization vector size 129 * in bytes, if one is required. 130 * 131 * Returns: the IV size in bytes, or 0 if no IV is permitted 132 */ 133size_t qcrypto_cipher_get_iv_len(QCryptoCipherAlgorithm alg, 134 QCryptoCipherMode mode); 135 136 137/** 138 * qcrypto_cipher_new: 139 * @alg: the cipher algorithm 140 * @mode: the cipher usage mode 141 * @key: the private key bytes 142 * @nkey: the length of @key 143 * @errp: pointer to a NULL-initialized error object 144 * 145 * Creates a new cipher object for encrypting/decrypting 146 * data with the algorithm @alg in the usage mode @mode. 147 * 148 * The @key parameter provides the bytes representing 149 * the encryption/decryption key to use. The @nkey parameter 150 * specifies the length of @key in bytes. Each algorithm has 151 * one or more valid key lengths, and it is an error to provide 152 * a key of the incorrect length. 153 * 154 * The returned cipher object must be released with 155 * qcrypto_cipher_free() when no longer required 156 * 157 * Returns: a new cipher object, or NULL on error 158 */ 159QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg, 160 QCryptoCipherMode mode, 161 const uint8_t *key, size_t nkey, 162 Error **errp); 163 164/** 165 * qcrypto_cipher_free: 166 * @cipher: the cipher object 167 * 168 * Release the memory associated with @cipher that 169 * was previously allocated by qcrypto_cipher_new() 170 */ 171void qcrypto_cipher_free(QCryptoCipher *cipher); 172 173G_DEFINE_AUTOPTR_CLEANUP_FUNC(QCryptoCipher, qcrypto_cipher_free) 174 175/** 176 * qcrypto_cipher_encrypt: 177 * @cipher: the cipher object 178 * @in: buffer holding the plain text input data 179 * @out: buffer to fill with the cipher text output data 180 * @len: the length of @in and @out buffers 181 * @errp: pointer to a NULL-initialized error object 182 * 183 * Encrypts the plain text stored in @in, filling 184 * @out with the resulting ciphered text. Both the 185 * @in and @out buffers must have the same size, 186 * given by @len. 187 * 188 * Returns: 0 on success, or -1 on error 189 */ 190int qcrypto_cipher_encrypt(QCryptoCipher *cipher, 191 const void *in, 192 void *out, 193 size_t len, 194 Error **errp); 195 196 197/** 198 * qcrypto_cipher_decrypt: 199 * @cipher: the cipher object 200 * @in: buffer holding the cipher text input data 201 * @out: buffer to fill with the plain text output data 202 * @len: the length of @in and @out buffers 203 * @errp: pointer to a NULL-initialized error object 204 * 205 * Decrypts the cipher text stored in @in, filling 206 * @out with the resulting plain text. Both the 207 * @in and @out buffers must have the same size, 208 * given by @len. 209 * 210 * Returns: 0 on success, or -1 on error 211 */ 212int qcrypto_cipher_decrypt(QCryptoCipher *cipher, 213 const void *in, 214 void *out, 215 size_t len, 216 Error **errp); 217 218/** 219 * qcrypto_cipher_setiv: 220 * @cipher: the cipher object 221 * @iv: the initialization vector or counter (CTR mode) bytes 222 * @niv: the length of @iv 223 * @errpr: pointer to a NULL-initialized error object 224 * 225 * If the @cipher object is setup to use a mode that requires 226 * initialization vectors or counter, this sets the @niv 227 * bytes. The @iv data should have the same length as the 228 * cipher key used when originally constructing the cipher 229 * object. It is an error to set an initialization vector 230 * or counter if the cipher mode does not require one. 231 * 232 * Returns: 0 on success, -1 on error 233 */ 234int qcrypto_cipher_setiv(QCryptoCipher *cipher, 235 const uint8_t *iv, size_t niv, 236 Error **errp); 237 238#endif /* QCRYPTO_CIPHER_H */