| /* Copyright (c) 2014, Google Inc. |
| * |
| * Permission to use, copy, modify, and/or distribute this software for any |
| * purpose with or without fee is hereby granted, provided that the above |
| * copyright notice and this permission notice appear in all copies. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
| * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
| * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY |
| * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
| * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION |
| * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN |
| * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ |
| |
| #ifndef OPENSSL_HEADER_AEAD_H |
| #define OPENSSL_HEADER_AEAD_H |
| |
| #include <openssl/base.h> |
| |
| #if defined(__cplusplus) |
| extern "C" { |
| #endif |
| |
| |
| // Authenticated Encryption with Additional Data. |
| // |
| // AEAD couples confidentiality and integrity in a single primitive. AEAD |
| // algorithms take a key and then can seal and open individual messages. Each |
| // message has a unique, per-message nonce and, optionally, additional data |
| // which is authenticated but not included in the ciphertext. |
| // |
| // The |EVP_AEAD_CTX_init| function initialises an |EVP_AEAD_CTX| structure and |
| // performs any precomputation needed to use |aead| with |key|. The length of |
| // the key, |key_len|, is given in bytes. |
| // |
| // The |tag_len| argument contains the length of the tags, in bytes, and allows |
| // for the processing of truncated authenticators. A zero value indicates that |
| // the default tag length should be used and this is defined as |
| // |EVP_AEAD_DEFAULT_TAG_LENGTH| in order to make the code clear. Using |
| // truncated tags increases an attacker's chance of creating a valid forgery. |
| // Be aware that the attacker's chance may increase more than exponentially as |
| // would naively be expected. |
| // |
| // When no longer needed, the initialised |EVP_AEAD_CTX| structure must be |
| // passed to |EVP_AEAD_CTX_cleanup|, which will deallocate any memory used. |
| // |
| // With an |EVP_AEAD_CTX| in hand, one can seal and open messages. These |
| // operations are intended to meet the standard notions of privacy and |
| // authenticity for authenticated encryption. For formal definitions see |
| // Bellare and Namprempre, "Authenticated encryption: relations among notions |
| // and analysis of the generic composition paradigm," Lecture Notes in Computer |
| // Science B<1976> (2000), 531–545, |
| // http://www-cse.ucsd.edu/~mihir/papers/oem.html. |
| // |
| // When sealing messages, a nonce must be given. The length of the nonce is |
| // fixed by the AEAD in use and is returned by |EVP_AEAD_nonce_length|. *The |
| // nonce must be unique for all messages with the same key*. This is critically |
| // important - nonce reuse may completely undermine the security of the AEAD. |
| // Nonces may be predictable and public, so long as they are unique. Uniqueness |
| // may be achieved with a simple counter or, if large enough, may be generated |
| // randomly. The nonce must be passed into the "open" operation by the receiver |
| // so must either be implicit (e.g. a counter), or must be transmitted along |
| // with the sealed message. |
| // |
| // The "seal" and "open" operations are atomic - an entire message must be |
| // encrypted or decrypted in a single call. Large messages may have to be split |
| // up in order to accommodate this. When doing so, be mindful of the need not to |
| // repeat nonces and the possibility that an attacker could duplicate, reorder |
| // or drop message chunks. For example, using a single key for a given (large) |
| // message and sealing chunks with nonces counting from zero would be secure as |
| // long as the number of chunks was securely transmitted. (Otherwise an |
| // attacker could truncate the message by dropping chunks from the end.) |
| // |
| // The number of chunks could be transmitted by prefixing it to the plaintext, |
| // for example. This also assumes that no other message would ever use the same |
| // key otherwise the rule that nonces must be unique for a given key would be |
| // violated. |
| // |
| // The "seal" and "open" operations also permit additional data to be |
| // authenticated via the |ad| parameter. This data is not included in the |
| // ciphertext and must be identical for both the "seal" and "open" call. This |
| // permits implicit context to be authenticated but may be empty if not needed. |
| // |
| // The "seal" and "open" operations may work in-place if the |out| and |in| |
| // arguments are equal. Otherwise, if |out| and |in| alias, input data may be |
| // overwritten before it is read. This situation will cause an error. |
| // |
| // The "seal" and "open" operations return one on success and zero on error. |
| |
| |
| // AEAD algorithms. |
| |
| // EVP_aead_aes_128_gcm is AES-128 in Galois Counter Mode. |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_gcm(void); |
| |
| // EVP_aead_aes_256_gcm is AES-256 in Galois Counter Mode. |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_gcm(void); |
| |
| // EVP_aead_chacha20_poly1305 is the AEAD built from ChaCha20 and |
| // Poly1305 as described in RFC 7539. |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_chacha20_poly1305(void); |
| |
| // EVP_aead_aes_128_ctr_hmac_sha256 is AES-128 in CTR mode with HMAC-SHA256 for |
| // authentication. The nonce is 12 bytes; the bottom 32-bits are used as the |
| // block counter, thus the maximum plaintext size is 64GB. |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_ctr_hmac_sha256(void); |
| |
| // EVP_aead_aes_256_ctr_hmac_sha256 is AES-256 in CTR mode with HMAC-SHA256 for |
| // authentication. See |EVP_aead_aes_128_ctr_hmac_sha256| for details. |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_ctr_hmac_sha256(void); |
| |
| // EVP_aead_aes_128_gcm_siv is AES-128 in GCM-SIV mode. See |
| // https://tools.ietf.org/html/draft-irtf-cfrg-gcmsiv-02 |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_gcm_siv(void); |
| |
| // EVP_aead_aes_256_gcm_siv is AES-256 in GCM-SIV mode. See |
| // https://tools.ietf.org/html/draft-irtf-cfrg-gcmsiv-02 |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_gcm_siv(void); |
| |
| // EVP_has_aes_hardware returns one if we enable hardware support for fast and |
| // constant-time AES-GCM. |
| OPENSSL_EXPORT int EVP_has_aes_hardware(void); |
| |
| |
| // Utility functions. |
| |
| // EVP_AEAD_key_length returns the length, in bytes, of the keys used by |
| // |aead|. |
| OPENSSL_EXPORT size_t EVP_AEAD_key_length(const EVP_AEAD *aead); |
| |
| // EVP_AEAD_nonce_length returns the length, in bytes, of the per-message nonce |
| // for |aead|. |
| OPENSSL_EXPORT size_t EVP_AEAD_nonce_length(const EVP_AEAD *aead); |
| |
| // EVP_AEAD_max_overhead returns the maximum number of additional bytes added |
| // by the act of sealing data with |aead|. |
| OPENSSL_EXPORT size_t EVP_AEAD_max_overhead(const EVP_AEAD *aead); |
| |
| // EVP_AEAD_max_tag_len returns the maximum tag length when using |aead|. This |
| // is the largest value that can be passed as |tag_len| to |
| // |EVP_AEAD_CTX_init|. |
| OPENSSL_EXPORT size_t EVP_AEAD_max_tag_len(const EVP_AEAD *aead); |
| |
| |
| // AEAD operations. |
| |
| // An EVP_AEAD_CTX represents an AEAD algorithm configured with a specific key |
| // and message-independent IV. |
| typedef struct evp_aead_ctx_st { |
| const EVP_AEAD *aead; |
| // aead_state is an opaque pointer to whatever state the AEAD needs to |
| // maintain. |
| void *aead_state; |
| // tag_len may contain the actual length of the authentication tag if it is |
| // known at initialization time. |
| uint8_t tag_len; |
| } EVP_AEAD_CTX; |
| |
| // EVP_AEAD_MAX_KEY_LENGTH contains the maximum key length used by |
| // any AEAD defined in this header. |
| #define EVP_AEAD_MAX_KEY_LENGTH 80 |
| |
| // EVP_AEAD_MAX_NONCE_LENGTH contains the maximum nonce length used by |
| // any AEAD defined in this header. |
| #define EVP_AEAD_MAX_NONCE_LENGTH 16 |
| |
| // EVP_AEAD_MAX_OVERHEAD contains the maximum overhead used by any AEAD |
| // defined in this header. |
| #define EVP_AEAD_MAX_OVERHEAD 64 |
| |
| // EVP_AEAD_DEFAULT_TAG_LENGTH is a magic value that can be passed to |
| // EVP_AEAD_CTX_init to indicate that the default tag length for an AEAD should |
| // be used. |
| #define EVP_AEAD_DEFAULT_TAG_LENGTH 0 |
| |
| // EVP_AEAD_CTX_zero sets an uninitialized |ctx| to the zero state. It must be |
| // initialized with |EVP_AEAD_CTX_init| before use. It is safe, but not |
| // necessary, to call |EVP_AEAD_CTX_cleanup| in this state. This may be used for |
| // more uniform cleanup of |EVP_AEAD_CTX|. |
| OPENSSL_EXPORT void EVP_AEAD_CTX_zero(EVP_AEAD_CTX *ctx); |
| |
| // EVP_AEAD_CTX_new allocates an |EVP_AEAD_CTX|, calls |EVP_AEAD_CTX_init| and |
| // returns the |EVP_AEAD_CTX|, or NULL on error. |
| OPENSSL_EXPORT EVP_AEAD_CTX *EVP_AEAD_CTX_new(const EVP_AEAD *aead, |
| const uint8_t *key, |
| size_t key_len, size_t tag_len); |
| |
| // EVP_AEAD_CTX_free calls |EVP_AEAD_CTX_cleanup| and |OPENSSL_free| on |
| // |ctx|. |
| OPENSSL_EXPORT void EVP_AEAD_CTX_free(EVP_AEAD_CTX *ctx); |
| |
| // EVP_AEAD_CTX_init initializes |ctx| for the given AEAD algorithm. The |impl| |
| // argument is ignored and should be NULL. Authentication tags may be truncated |
| // by passing a size as |tag_len|. A |tag_len| of zero indicates the default |
| // tag length and this is defined as EVP_AEAD_DEFAULT_TAG_LENGTH for |
| // readability. |
| // |
| // Returns 1 on success. Otherwise returns 0 and pushes to the error stack. In |
| // the error case, you do not need to call |EVP_AEAD_CTX_cleanup|, but it's |
| // harmless to do so. |
| OPENSSL_EXPORT int EVP_AEAD_CTX_init(EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, |
| const uint8_t *key, size_t key_len, |
| size_t tag_len, ENGINE *impl); |
| |
| // EVP_AEAD_CTX_cleanup frees any data allocated by |ctx|. It is a no-op to |
| // call |EVP_AEAD_CTX_cleanup| on a |EVP_AEAD_CTX| that has been |memset| to |
| // all zeros. |
| OPENSSL_EXPORT void EVP_AEAD_CTX_cleanup(EVP_AEAD_CTX *ctx); |
| |
| // EVP_AEAD_CTX_seal encrypts and authenticates |in_len| bytes from |in| and |
| // authenticates |ad_len| bytes from |ad| and writes the result to |out|. It |
| // returns one on success and zero otherwise. |
| // |
| // This function may be called concurrently with itself or any other seal/open |
| // function on the same |EVP_AEAD_CTX|. |
| // |
| // At most |max_out_len| bytes are written to |out| and, in order to ensure |
| // success, |max_out_len| should be |in_len| plus the result of |
| // |EVP_AEAD_max_overhead|. On successful return, |*out_len| is set to the |
| // actual number of bytes written. |
| // |
| // The length of |nonce|, |nonce_len|, must be equal to the result of |
| // |EVP_AEAD_nonce_length| for this AEAD. |
| // |
| // |EVP_AEAD_CTX_seal| never results in a partial output. If |max_out_len| is |
| // insufficient, zero will be returned. If any error occurs, |out| will be |
| // filled with zero bytes and |*out_len| set to zero. |
| // |
| // If |in| and |out| alias then |out| must be == |in|. |
| OPENSSL_EXPORT int EVP_AEAD_CTX_seal(const EVP_AEAD_CTX *ctx, uint8_t *out, |
| size_t *out_len, size_t max_out_len, |
| const uint8_t *nonce, size_t nonce_len, |
| const uint8_t *in, size_t in_len, |
| const uint8_t *ad, size_t ad_len); |
| |
| // EVP_AEAD_CTX_open authenticates |in_len| bytes from |in| and |ad_len| bytes |
| // from |ad| and decrypts at most |in_len| bytes into |out|. It returns one on |
| // success and zero otherwise. |
| // |
| // This function may be called concurrently with itself or any other seal/open |
| // function on the same |EVP_AEAD_CTX|. |
| // |
| // At most |in_len| bytes are written to |out|. In order to ensure success, |
| // |max_out_len| should be at least |in_len|. On successful return, |*out_len| |
| // is set to the the actual number of bytes written. |
| // |
| // The length of |nonce|, |nonce_len|, must be equal to the result of |
| // |EVP_AEAD_nonce_length| for this AEAD. |
| // |
| // |EVP_AEAD_CTX_open| never results in a partial output. If |max_out_len| is |
| // insufficient, zero will be returned. If any error occurs, |out| will be |
| // filled with zero bytes and |*out_len| set to zero. |
| // |
| // If |in| and |out| alias then |out| must be == |in|. |
| OPENSSL_EXPORT int EVP_AEAD_CTX_open(const EVP_AEAD_CTX *ctx, uint8_t *out, |
| size_t *out_len, size_t max_out_len, |
| const uint8_t *nonce, size_t nonce_len, |
| const uint8_t *in, size_t in_len, |
| const uint8_t *ad, size_t ad_len); |
| |
| // EVP_AEAD_CTX_seal_scatter encrypts and authenticates |in_len| bytes from |in| |
| // and authenticates |ad_len| bytes from |ad|. It writes |in_len| bytes of |
| // ciphertext to |out| and the authentication tag to |out_tag|. It returns one |
| // on success and zero otherwise. |
| // |
| // This function may be called concurrently with itself or any other seal/open |
| // function on the same |EVP_AEAD_CTX|. |
| // |
| // Exactly |in_len| bytes are written to |out|, and up to |
| // |EVP_AEAD_max_overhead+extra_in_len| bytes to |out_tag|. On successful |
| // return, |*out_tag_len| is set to the actual number of bytes written to |
| // |out_tag|. |
| // |
| // |extra_in| may point to an additional plaintext input buffer if the cipher |
| // supports it. If present, |extra_in_len| additional bytes of plaintext are |
| // encrypted and authenticated, and the ciphertext is written (before the tag) |
| // to |out_tag|. |max_out_tag_len| must be sized to allow for the additional |
| // |extra_in_len| bytes. |
| // |
| // The length of |nonce|, |nonce_len|, must be equal to the result of |
| // |EVP_AEAD_nonce_length| for this AEAD. |
| // |
| // |EVP_AEAD_CTX_seal_scatter| never results in a partial output. If |
| // |max_out_tag_len| is insufficient, zero will be returned. If any error |
| // occurs, |out| and |out_tag| will be filled with zero bytes and |*out_tag_len| |
| // set to zero. |
| // |
| // If |in| and |out| alias then |out| must be == |in|. |out_tag| may not alias |
| // any other argument. |
| OPENSSL_EXPORT int EVP_AEAD_CTX_seal_scatter( |
| const EVP_AEAD_CTX *ctx, uint8_t *out, |
| uint8_t *out_tag, size_t *out_tag_len, size_t max_out_tag_len, |
| const uint8_t *nonce, size_t nonce_len, |
| const uint8_t *in, size_t in_len, |
| const uint8_t *extra_in, size_t extra_in_len, |
| const uint8_t *ad, size_t ad_len); |
| |
| // EVP_AEAD_CTX_open_gather decrypts and authenticates |in_len| bytes from |in| |
| // and authenticates |ad_len| bytes from |ad| using |in_tag_len| bytes of |
| // authentication tag from |in_tag|. If successful, it writes |in_len| bytes of |
| // plaintext to |out|. It returns one on success and zero otherwise. |
| // |
| // This function may be called concurrently with itself or any other seal/open |
| // function on the same |EVP_AEAD_CTX|. |
| // |
| // The length of |nonce|, |nonce_len|, must be equal to the result of |
| // |EVP_AEAD_nonce_length| for this AEAD. |
| // |
| // |EVP_AEAD_CTX_open_gather| never results in a partial output. If any error |
| // occurs, |out| will be filled with zero bytes. |
| // |
| // If |in| and |out| alias then |out| must be == |in|. |
| OPENSSL_EXPORT int EVP_AEAD_CTX_open_gather( |
| const EVP_AEAD_CTX *ctx, uint8_t *out, const uint8_t *nonce, |
| size_t nonce_len, const uint8_t *in, size_t in_len, const uint8_t *in_tag, |
| size_t in_tag_len, const uint8_t *ad, size_t ad_len); |
| |
| // EVP_AEAD_CTX_aead returns the underlying AEAD for |ctx|, or NULL if one has |
| // not been set. |
| OPENSSL_EXPORT const EVP_AEAD *EVP_AEAD_CTX_aead(const EVP_AEAD_CTX *ctx); |
| |
| |
| // TLS-specific AEAD algorithms. |
| // |
| // These AEAD primitives do not meet the definition of generic AEADs. They are |
| // all specific to TLS and should not be used outside of that context. They must |
| // be initialized with |EVP_AEAD_CTX_init_with_direction|, are stateful, and may |
| // not be used concurrently. Any nonces are used as IVs, so they must be |
| // unpredictable. They only accept an |ad| parameter of length 11 (the standard |
| // TLS one with length omitted). |
| |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_cbc_sha1_tls(void); |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_cbc_sha1_tls_implicit_iv(void); |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_cbc_sha256_tls(void); |
| |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_cbc_sha1_tls(void); |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_cbc_sha1_tls_implicit_iv(void); |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_cbc_sha256_tls(void); |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_cbc_sha384_tls(void); |
| |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_des_ede3_cbc_sha1_tls(void); |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_des_ede3_cbc_sha1_tls_implicit_iv(void); |
| |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_null_sha1_tls(void); |
| |
| // EVP_aead_aes_128_gcm_tls12 is AES-128 in Galois Counter Mode using the TLS |
| // 1.2 nonce construction. |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_gcm_tls12(void); |
| |
| // EVP_aead_aes_256_gcm_tls12 is AES-256 in Galois Counter Mode using the TLS |
| // 1.2 nonce construction. |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_gcm_tls12(void); |
| |
| |
| // SSLv3-specific AEAD algorithms. |
| // |
| // These AEAD primitives do not meet the definition of generic AEADs. They are |
| // all specific to SSLv3 and should not be used outside of that context. They |
| // must be initialized with |EVP_AEAD_CTX_init_with_direction|, are stateful, |
| // and may not be used concurrently. They only accept an |ad| parameter of |
| // length 9 (the standard TLS one with length and version omitted). |
| |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_cbc_sha1_ssl3(void); |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_cbc_sha1_ssl3(void); |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_des_ede3_cbc_sha1_ssl3(void); |
| OPENSSL_EXPORT const EVP_AEAD *EVP_aead_null_sha1_ssl3(void); |
| |
| |
| // Obscure functions. |
| |
| // evp_aead_direction_t denotes the direction of an AEAD operation. |
| enum evp_aead_direction_t { |
| evp_aead_open, |
| evp_aead_seal, |
| }; |
| |
| // EVP_AEAD_CTX_init_with_direction calls |EVP_AEAD_CTX_init| for normal |
| // AEADs. For TLS-specific and SSL3-specific AEADs, it initializes |ctx| for a |
| // given direction. |
| OPENSSL_EXPORT int EVP_AEAD_CTX_init_with_direction( |
| EVP_AEAD_CTX *ctx, const EVP_AEAD *aead, const uint8_t *key, size_t key_len, |
| size_t tag_len, enum evp_aead_direction_t dir); |
| |
| // EVP_AEAD_CTX_get_iv sets |*out_len| to the length of the IV for |ctx| and |
| // sets |*out_iv| to point to that many bytes of the current IV. This is only |
| // meaningful for AEADs with implicit IVs (i.e. CBC mode in SSLv3 and TLS 1.0). |
| // |
| // It returns one on success or zero on error. |
| OPENSSL_EXPORT int EVP_AEAD_CTX_get_iv(const EVP_AEAD_CTX *ctx, |
| const uint8_t **out_iv, size_t *out_len); |
| |
| // EVP_AEAD_CTX_tag_len computes the exact byte length of the tag written by |
| // |EVP_AEAD_CTX_seal_scatter| and writes it to |*out_tag_len|. It returns one |
| // on success or zero on error. |in_len| and |extra_in_len| must equal the |
| // arguments of the same names passed to |EVP_AEAD_CTX_seal_scatter|. |
| OPENSSL_EXPORT int EVP_AEAD_CTX_tag_len(const EVP_AEAD_CTX *ctx, |
| size_t *out_tag_len, |
| const size_t in_len, |
| const size_t extra_in_len); |
| |
| |
| #if defined(__cplusplus) |
| } // extern C |
| |
| #if !defined(BORINGSSL_NO_CXX) |
| extern "C++" { |
| |
| namespace bssl { |
| |
| using ScopedEVP_AEAD_CTX = |
| internal::StackAllocated<EVP_AEAD_CTX, void, EVP_AEAD_CTX_zero, |
| EVP_AEAD_CTX_cleanup>; |
| |
| BORINGSSL_MAKE_DELETER(EVP_AEAD_CTX, EVP_AEAD_CTX_free) |
| |
| } // namespace bssl |
| |
| } // extern C++ |
| #endif |
| |
| #endif |
| |
| #endif // OPENSSL_HEADER_AEAD_H |