/* 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_grpc/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. // // Note: AES-GCM should only be used with 12-byte (96-bit) nonces. Although it // is specified to take a variable-length nonce, nonces with other lengths are // effectively randomized, which means one must consider collisions. Unless // implementing an existing protocol which has already specified incorrect // parameters, only use 12-byte nonces. OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_gcm(void); // EVP_aead_aes_192_gcm is AES-192 in Galois Counter Mode. // // WARNING: AES-192 is superfluous and shouldn't exist. NIST should never have // defined it. Use only when interop with another system requires it, never // de novo. // // Note: AES-GCM should only be used with 12-byte (96-bit) nonces. Although it // is specified to take a variable-length nonce, nonces with other lengths are // effectively randomized, which means one must consider collisions. Unless // implementing an existing protocol which has already specified incorrect // parameters, only use 12-byte nonces. OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_192_gcm(void); // EVP_aead_aes_256_gcm is AES-256 in Galois Counter Mode. // // Note: AES-GCM should only be used with 12-byte (96-bit) nonces. Although it // is specified to take a variable-length nonce, nonces with other lengths are // effectively randomized, which means one must consider collisions. Unless // implementing an existing protocol which has already specified incorrect // parameters, only use 12-byte nonces. 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 8439. OPENSSL_EXPORT const EVP_AEAD *EVP_aead_chacha20_poly1305(void); // EVP_aead_xchacha20_poly1305 is ChaCha20-Poly1305 with an extended nonce that // makes random generation of nonces safe. OPENSSL_EXPORT const EVP_AEAD *EVP_aead_xchacha20_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_aead_aes_128_gcm_randnonce is AES-128 in Galois Counter Mode with // internal nonce generation. The 12-byte nonce is appended to the tag // and is generated internally. The "tag", for the purpurses of the API, is thus // 12 bytes larger. The nonce parameter when using this AEAD must be // zero-length. Since the nonce is random, a single key should not be used for // more than 2^32 seal operations. // // Warning: this is for use for FIPS compliance only. It is probably not // suitable for other uses. Using standard AES-GCM AEADs allows one to achieve // the same effect, but gives more control over nonce storage. OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_gcm_randnonce(void); // EVP_aead_aes_256_gcm_randnonce is AES-256 in Galois Counter Mode with // internal nonce generation. The 12-byte nonce is appended to the tag // and is generated internally. The "tag", for the purpurses of the API, is thus // 12 bytes larger. The nonce parameter when using this AEAD must be // zero-length. Since the nonce is random, a single key should not be used for // more than 2^32 seal operations. // // Warning: this is for use for FIPS compliance only. It is probably not // suitable for other uses. Using standard AES-GCM AEADs allows one to achieve // the same effect, but gives more control over nonce storage. OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_gcm_randnonce(void); // EVP_aead_aes_128_ccm_bluetooth is AES-128-CCM with M=4 and L=2 (4-byte tags // and 13-byte nonces), as decribed in the Bluetooth Core Specification v5.0, // Volume 6, Part E, Section 1. OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_ccm_bluetooth(void); // EVP_aead_aes_128_ccm_bluetooth_8 is AES-128-CCM with M=8 and L=2 (8-byte tags // and 13-byte nonces), as used in the Bluetooth Mesh Networking Specification // v1.0. OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_ccm_bluetooth_8(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. union evp_aead_ctx_st_state { uint8_t opaque[580]; uint64_t alignment; }; // 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; union evp_aead_ctx_st_state 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 24 // 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_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_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); // EVP_aead_aes_128_gcm_tls13 is AES-128 in Galois Counter Mode using the TLS // 1.3 nonce construction. OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_128_gcm_tls13(void); // EVP_aead_aes_256_gcm_tls13 is AES-256 in Galois Counter Mode using the TLS // 1.3 nonce construction. OPENSSL_EXPORT const EVP_AEAD *EVP_aead_aes_256_gcm_tls13(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 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++" { BSSL_NAMESPACE_BEGIN 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) BSSL_NAMESPACE_END } // extern C++ #endif #endif #endif // OPENSSL_HEADER_AEAD_H