d2b5af56cf
This reverts commits:8d79ed674019fdcb52348d79ed6740Because WebRTC (at least) includes our headers in an extern "C" block, which precludes having any C++ in them. Change-Id: Ia849f43795a40034cbd45b22ea680b51aab28b2d
339 lines
16 KiB
C
339 lines
16 KiB
C
/* Copyright (c) 2014, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#ifndef OPENSSL_HEADER_AEAD_H
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#define OPENSSL_HEADER_AEAD_H
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#include <openssl/base.h>
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#if defined(__cplusplus)
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extern "C" {
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#endif
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/* Authenticated Encryption with Additional Data.
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*
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* AEAD couples confidentiality and integrity in a single primitive. AEAD
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* algorithms take a key and then can seal and open individual messages. Each
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* message has a unique, per-message nonce and, optionally, additional data
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* which is authenticated but not included in the ciphertext.
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*
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* The |EVP_AEAD_CTX_init| function initialises an |EVP_AEAD_CTX| structure and
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* performs any precomputation needed to use |aead| with |key|. The length of
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* the key, |key_len|, is given in bytes.
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*
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* The |tag_len| argument contains the length of the tags, in bytes, and allows
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* for the processing of truncated authenticators. A zero value indicates that
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* the default tag length should be used and this is defined as
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* |EVP_AEAD_DEFAULT_TAG_LENGTH| in order to make the code clear. Using
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* truncated tags increases an attacker's chance of creating a valid forgery.
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* Be aware that the attacker's chance may increase more than exponentially as
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* would naively be expected.
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*
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* When no longer needed, the initialised |EVP_AEAD_CTX| structure must be
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* passed to |EVP_AEAD_CTX_cleanup|, which will deallocate any memory used.
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*
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* With an |EVP_AEAD_CTX| in hand, one can seal and open messages. These
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* operations are intended to meet the standard notions of privacy and
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* authenticity for authenticated encryption. For formal definitions see
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* Bellare and Namprempre, "Authenticated encryption: relations among notions
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* and analysis of the generic composition paradigm," Lecture Notes in Computer
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* Science B<1976> (2000), 531–545,
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* http://www-cse.ucsd.edu/~mihir/papers/oem.html.
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*
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* When sealing messages, a nonce must be given. The length of the nonce is
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* fixed by the AEAD in use and is returned by |EVP_AEAD_nonce_length|. *The
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* nonce must be unique for all messages with the same key*. This is critically
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* important - nonce reuse may completely undermine the security of the AEAD.
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* Nonces may be predictable and public, so long as they are unique. Uniqueness
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* may be achieved with a simple counter or, if large enough, may be generated
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* randomly. The nonce must be passed into the "open" operation by the receiver
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* so must either be implicit (e.g. a counter), or must be transmitted along
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* with the sealed message.
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*
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* The "seal" and "open" operations are atomic - an entire message must be
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* encrypted or decrypted in a single call. Large messages may have to be split
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* up in order to accomodate this. When doing so, be mindful of the need not to
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* repeat nonces and the possibility that an attacker could duplicate, reorder
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* or drop message chunks. For example, using a single key for a given (large)
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* message and sealing chunks with nonces counting from zero would be secure as
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* long as the number of chunks was securely transmitted. (Otherwise an
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* attacker could truncate the message by dropping chunks from the end.)
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*
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* The number of chunks could be transmitted by prefixing it to the plaintext,
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* for example. This also assumes that no other message would ever use the same
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* key otherwise the rule that nonces must be unique for a given key would be
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* violated.
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*
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* The "seal" and "open" operations also permit additional data to be
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* authenticated via the |ad| parameter. This data is not included in the
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* ciphertext and must be identical for both the "seal" and "open" call. This
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* permits implicit context to be authenticated but may be empty if not needed.
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*
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* The "seal" and "open" operations may work in-place if the |out| and |in|
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* arguments are equal. They may also be used to shift the data left inside the
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* same buffer if |out| is less than |in|. However, |out| may not point inside
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* the input data otherwise the input may be overwritten before it has been
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* read. This situation will cause an error.
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*
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* The "seal" and "open" operations return one on success and zero on error. */
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/* AEAD algorithms. */
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/* EVP_aead_aes_128_gcm is AES-128 in Galois Counter Mode. */
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_gcm(void);
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/* EVP_aead_aes_256_gcm is AES-256 in Galois Counter Mode. */
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_gcm(void);
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/* EVP_aead_chacha20_poly1305 is the AEAD built from ChaCha20 and
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* Poly1305 as described in RFC 7539. */
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_chacha20_poly1305(void);
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/* EVP_aead_chacha20_poly1305_old is an AEAD built from ChaCha20 and
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* Poly1305 that is used in the experimental ChaCha20-Poly1305 TLS cipher
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* suites. */
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_chacha20_poly1305_old(void);
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/* EVP_aead_aes_128_key_wrap is AES-128 Key Wrap mode. This should never be
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* used except to interoperate with existing systems that use this mode.
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*
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* If the nonce is empty then the default nonce will be used, otherwise it must
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* be eight bytes long. The input must be a multiple of eight bytes long. No
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* additional data can be given to this mode. */
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_key_wrap(void);
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/* EVP_aead_aes_256_key_wrap is AES-256 in Key Wrap mode. This should never be
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* used except to interoperate with existing systems that use this mode.
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*
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* See |EVP_aead_aes_128_key_wrap| for details. */
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_key_wrap(void);
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/* EVP_aead_aes_128_ctr_hmac_sha256 is AES-128 in CTR mode with HMAC-SHA256 for
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* authentication. The nonce is 12 bytes; the bottom 32-bits are used as the
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* block counter, thus the maximum plaintext size is 64GB. */
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_ctr_hmac_sha256(void);
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/* EVP_aead_aes_256_ctr_hmac_sha256 is AES-256 in CTR mode with HMAC-SHA256 for
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* authentication. See |EVP_aead_aes_128_ctr_hmac_sha256| for details. */
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_ctr_hmac_sha256(void);
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/* EVP_has_aes_hardware returns one if we enable hardware support for fast and
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* constant-time AES-GCM. */
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OPENSSL_EXPORT int EVP_has_aes_hardware(void);
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/* Utility functions. */
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/* EVP_AEAD_key_length returns the length, in bytes, of the keys used by
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* |aead|. */
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OPENSSL_EXPORT size_t EVP_AEAD_key_length(const EVP_AEAD *aead);
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/* EVP_AEAD_nonce_length returns the length, in bytes, of the per-message nonce
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* for |aead|. */
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OPENSSL_EXPORT size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead);
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/* EVP_AEAD_max_overhead returns the maximum number of additional bytes added
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* by the act of sealing data with |aead|. */
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OPENSSL_EXPORT size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead);
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/* EVP_AEAD_max_tag_len returns the maximum tag length when using |aead|. This
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* is the largest value that can be passed as |tag_len| to
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* |EVP_AEAD_CTX_init|. */
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OPENSSL_EXPORT size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead);
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/* AEAD operations. */
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/* An EVP_AEAD_CTX represents an AEAD algorithm configured with a specific key
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* and message-independent IV. */
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typedef struct evp_aead_ctx_st {
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const EVP_AEAD *aead;
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/* aead_state is an opaque pointer to whatever state the AEAD needs to
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* maintain. */
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void *aead_state;
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} EVP_AEAD_CTX;
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/* EVP_AEAD_MAX_KEY_LENGTH contains the maximum key length used by
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* any AEAD defined in this header. */
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#define EVP_AEAD_MAX_KEY_LENGTH 80
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/* EVP_AEAD_MAX_NONCE_LENGTH contains the maximum nonce length used by
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* any AEAD defined in this header. */
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#define EVP_AEAD_MAX_NONCE_LENGTH 16
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/* EVP_AEAD_MAX_OVERHEAD contains the maximum overhead used by any AEAD
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* defined in this header. */
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#define EVP_AEAD_MAX_OVERHEAD 64
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/* EVP_AEAD_DEFAULT_TAG_LENGTH is a magic value that can be passed to
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* EVP_AEAD_CTX_init to indicate that the default tag length for an AEAD should
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* be used. */
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#define EVP_AEAD_DEFAULT_TAG_LENGTH 0
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/* EVP_AEAD_CTX_zero sets an uninitialized |ctx| to the zero state. It must be
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* initialized with |EVP_AEAD_CTX_init| before use. It is safe, but not
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* necessary, to call |EVP_AEAD_CTX_cleanup| in this state. This may be used for
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* more uniform cleanup of |EVP_AEAD_CTX|. */
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OPENSSL_EXPORT void EVP_AEAD_CTX_zero(EVP_AEAD_CTX *ctx);
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/* EVP_AEAD_CTX_init initializes |ctx| for the given AEAD algorithm. The |impl|
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* argument is ignored and should be NULL. Authentication tags may be truncated
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* by passing a size as |tag_len|. A |tag_len| of zero indicates the default
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* tag length and this is defined as EVP_AEAD_DEFAULT_TAG_LENGTH for
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* readability.
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*
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* Returns 1 on success. Otherwise returns 0 and pushes to the error stack. In
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* the error case, you do not need to call |EVP_AEAD_CTX_cleanup|, but it's
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* harmless to do so. */
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OPENSSL_EXPORT int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead,
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const uint8_t *key, size_t key_len,
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size_t tag_len, ENGINE *impl);
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/* EVP_AEAD_CTX_cleanup frees any data allocated by |ctx|. It is a no-op to
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* call |EVP_AEAD_CTX_cleanup| on a |EVP_AEAD_CTX| that has been |memset| to
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* all zeros. */
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OPENSSL_EXPORT void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx);
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/* EVP_AEAD_CTX_seal encrypts and authenticates |in_len| bytes from |in| and
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* authenticates |ad_len| bytes from |ad| and writes the result to |out|. It
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* returns one on success and zero otherwise.
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*
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* This function may be called (with the same |EVP_AEAD_CTX|) concurrently with
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* itself or |EVP_AEAD_CTX_open|.
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*
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* At most |max_out_len| bytes are written to |out| and, in order to ensure
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* success, |max_out_len| should be |in_len| plus the result of
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* |EVP_AEAD_max_overhead|. On successful return, |*out_len| is set to the
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* actual number of bytes written.
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*
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* The length of |nonce|, |nonce_len|, must be equal to the result of
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* |EVP_AEAD_nonce_length| for this AEAD.
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*
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* |EVP_AEAD_CTX_seal| never results in a partial output. If |max_out_len| is
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* insufficient, zero will be returned. (In this case, |*out_len| is set to
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* zero.)
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*
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* If |in| and |out| alias then |out| must be == |in|. */
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OPENSSL_EXPORT int EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, uint8_t *out,
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size_t *out_len, size_t max_out_len,
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const uint8_t *nonce, size_t nonce_len,
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const uint8_t *in, size_t in_len,
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const uint8_t *ad, size_t ad_len);
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/* EVP_AEAD_CTX_open authenticates |in_len| bytes from |in| and |ad_len| bytes
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* from |ad| and decrypts at most |in_len| bytes into |out|. It returns one on
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* success and zero otherwise.
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*
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* This function may be called (with the same |EVP_AEAD_CTX|) concurrently with
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* itself or |EVP_AEAD_CTX_seal|.
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*
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* At most |in_len| bytes are written to |out|. In order to ensure success,
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* |max_out_len| should be at least |in_len|. On successful return, |*out_len|
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* is set to the the actual number of bytes written.
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*
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* The length of |nonce|, |nonce_len|, must be equal to the result of
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* |EVP_AEAD_nonce_length| for this AEAD.
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*
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* |EVP_AEAD_CTX_open| never results in a partial output. If |max_out_len| is
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* insufficient, zero will be returned. (In this case, |*out_len| is set to
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* zero.)
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*
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* If |in| and |out| alias then |out| must be == |in|. */
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OPENSSL_EXPORT int EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, uint8_t *out,
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size_t *out_len, size_t max_out_len,
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const uint8_t *nonce, size_t nonce_len,
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const uint8_t *in, size_t in_len,
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const uint8_t *ad, size_t ad_len);
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/* TLS-specific AEAD algorithms.
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*
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* These AEAD primitives do not meet the definition of generic AEADs. They are
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* all specific to TLS and should not be used outside of that context. They must
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* be initialized with |EVP_AEAD_CTX_init_with_direction|, are stateful, and may
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* not be used concurrently. Any nonces are used as IVs, so they must be
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* unpredictable. They only accept an |ad| parameter of length 11 (the standard
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* TLS one with length omitted). */
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_rc4_md5_tls(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_rc4_sha1_tls(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_cbc_sha1_tls(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_cbc_sha1_tls_implicit_iv(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_cbc_sha256_tls(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_cbc_sha1_tls(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_cbc_sha1_tls_implicit_iv(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_cbc_sha256_tls(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_cbc_sha384_tls(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_des_ede3_cbc_sha1_tls(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_des_ede3_cbc_sha1_tls_implicit_iv(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_null_sha1_tls(void);
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/* SSLv3-specific AEAD algorithms.
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*
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* These AEAD primitives do not meet the definition of generic AEADs. They are
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* all specific to SSLv3 and should not be used outside of that context. They
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* must be initialized with |EVP_AEAD_CTX_init_with_direction|, are stateful,
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* and may not be used concurrently. They only accept an |ad| parameter of
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* length 9 (the standard TLS one with length and version omitted). */
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_rc4_md5_ssl3(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_rc4_sha1_ssl3(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_cbc_sha1_ssl3(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_cbc_sha1_ssl3(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_des_ede3_cbc_sha1_ssl3(void);
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OPENSSL_EXPORT const EVP_AEAD *EVP_aead_null_sha1_ssl3(void);
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/* Obscure functions. */
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/* evp_aead_direction_t denotes the direction of an AEAD operation. */
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enum evp_aead_direction_t {
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evp_aead_open,
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evp_aead_seal,
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};
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/* EVP_AEAD_CTX_init_with_direction calls |EVP_AEAD_CTX_init| for normal
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* AEADs. For TLS-specific and SSL3-specific AEADs, it initializes |ctx| for a
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* given direction. */
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OPENSSL_EXPORT int EVP_AEAD_CTX_init_with_direction(
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EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, const uint8_t *key, size_t key_len,
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size_t tag_len, enum evp_aead_direction_t dir);
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/* EVP_AEAD_CTX_get_rc4_state sets |*out_key| to point to an RC4 key structure.
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* It returns one on success or zero if |ctx| doesn't have an RC4 key. */
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OPENSSL_EXPORT int EVP_AEAD_CTX_get_rc4_state(const EVP_AEAD_CTX *ctx,
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const RC4_KEY **out_key);
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/* EVP_AEAD_CTX_get_iv sets |*out_len| to the length of the IV for |ctx| and
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* sets |*out_iv| to point to that many bytes of the current IV. This is only
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* meaningful for AEADs with implicit IVs (i.e. CBC mode in SSLv3 and TLS 1.0).
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*
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* It returns one on success or zero on error. */
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OPENSSL_EXPORT int EVP_AEAD_CTX_get_iv(const EVP_AEAD_CTX *ctx,
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const uint8_t **out_iv, size_t *out_len);
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#if defined(__cplusplus)
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} /* extern C */
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#endif
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#endif /* OPENSSL_HEADER_AEAD_H */
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