| /* --------------------------------------------------------------------------- |
| * |
| * AEAD API 0.12 - 23-MAY-2012 |
| * |
| * This file gives an interface appropriate for many authenticated |
| * encryption with associated data (AEAD) implementations. It does not try |
| * to accommodate all possible options or limitations that an implementation |
| * might have -- you should consult the documentation of your chosen |
| * implementation to find things like RFC 5116 constants, alignment |
| * requirements, whether the incremental interface is supported, etc. |
| * |
| * This file is in the public domain. It is provided "as is", without |
| * warranty of any kind. Use at your own risk. |
| * |
| * Comments are welcome: Ted Krovetz <ted@krovetz>. |
| * |
| * ------------------------------------------------------------------------ */ |
| |
| #ifndef _AE_H_ |
| #define _AE_H_ |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /* -------------------------------------------------------------------------- |
| * |
| * Constants |
| * |
| * ----------------------------------------------------------------------- */ |
| |
| /* Return status codes: Negative return values indicate an error occurred. |
| * For full explanations of error values, consult the implementation's |
| * documentation. */ |
| #define AE_SUCCESS (0) /* Indicates successful completion of call */ |
| #define AE_INVALID (-1) /* Indicates bad tag during decryption */ |
| #define AE_NOT_SUPPORTED (-2) /* Indicates unsupported option requested */ |
| |
| /* Flags: When data can be processed "incrementally", these flags are used |
| * to indicate whether the submitted data is the last or not. */ |
| #define AE_FINALIZE (1) /* This is the last of data */ |
| #define AE_PENDING (0) /* More data of is coming */ |
| |
| /* -------------------------------------------------------------------------- |
| * |
| * AEAD opaque structure definition |
| * |
| * ----------------------------------------------------------------------- */ |
| |
| typedef struct _ae_ctx ae_ctx; |
| |
| /* -------------------------------------------------------------------------- |
| * |
| * Data Structure Routines |
| * |
| * ----------------------------------------------------------------------- */ |
| |
| ae_ctx* ae_allocate(void* misc); /* Allocate ae_ctx, set optional ptr */ |
| void ae_free(ae_ctx* ctx); /* Deallocate ae_ctx struct */ |
| int ae_clear(ae_ctx* ctx); /* Undo initialization */ |
| int ae_ctx_sizeof(void); /* Return sizeof(ae_ctx) */ |
| /* ae_allocate() allocates an ae_ctx structure, but does not initialize it. |
| * ae_free() deallocates an ae_ctx structure, but does not zero it. |
| * ae_clear() zeroes sensitive values associated with an ae_ctx structure |
| * and deallocates any auxiliary structures allocated during ae_init(). |
| * ae_ctx_sizeof() returns sizeof(ae_ctx), to aid in any static allocations. |
| */ |
| |
| /* -------------------------------------------------------------------------- |
| * |
| * AEAD Routines |
| * |
| * ----------------------------------------------------------------------- */ |
| |
| int ae_init(ae_ctx* ctx, const void* key, int key_len, int nonce_len, int tag_len); |
| /* -------------------------------------------------------------------------- |
| * |
| * Initialize an ae_ctx context structure. |
| * |
| * Parameters: |
| * ctx - Pointer to an ae_ctx structure to be initialized |
| * key - Pointer to user-supplied key |
| * key_len - Length of key supplied, in bytes |
| * nonce_len - Length of nonces to be used for this key, in bytes |
| * tag_len - Length of tags to be produced for this key, in bytes |
| * |
| * Returns: |
| * AE_SUCCESS - Success. Ctx ready for use. |
| * AE_NOT_SUPPORTED - An unsupported length was supplied. Ctx is untouched. |
| * Otherwise - Error. Check implementation documentation for codes. |
| * |
| * ----------------------------------------------------------------------- */ |
| |
| int ae_encrypt(ae_ctx* ctx, const void* nonce, const void* pt, int pt_len, const void* ad, |
| int ad_len, void* ct, void* tag, int final); |
| /* -------------------------------------------------------------------------- |
| * |
| * Encrypt plaintext; provide for authentication of ciphertext/associated data. |
| * |
| * Parameters: |
| * ctx - Pointer to an ae_ctx structure initialized by ae_init. |
| * nonce - Pointer to a nonce_len (defined in ae_init) byte nonce. |
| * pt - Pointer to plaintext bytes to be encrypted. |
| * pt_len - number of bytes pointed to by pt. |
| * ad - Pointer to associated data. |
| * ad_len - number of bytes pointed to by ad. |
| * ct - Pointer to buffer to receive ciphertext encryption. |
| * tag - Pointer to receive authentication tag; or NULL |
| * if tag is to be bundled into the ciphertext. |
| * final - Non-zero if this call completes the plaintext being encrypted. |
| * |
| * If nonce!=NULL then a message is being initiated. If final!=0 |
| * then a message is being finalized. If final==0 or nonce==NULL |
| * then the incremental interface is being used. If nonce!=NULL and |
| * ad_len<0, then use same ad as last message. |
| * |
| * Returns: |
| * non-negative - Number of bytes written to ct. |
| * AE_NOT_SUPPORTED - Usage mode unsupported (eg, incremental and/or sticky). |
| * Otherwise - Error. Check implementation documentation for codes. |
| * |
| * ----------------------------------------------------------------------- */ |
| |
| int ae_decrypt(ae_ctx* ctx, const void* nonce, const void* ct, int ct_len, const void* ad, |
| int ad_len, void* pt, const void* tag, int final); |
| /* -------------------------------------------------------------------------- |
| * |
| * Decrypt ciphertext; provide authenticity of plaintext and associated data. |
| * |
| * Parameters: |
| * ctx - Pointer to an ae_ctx structure initialized by ae_init. |
| * nonce - Pointer to a nonce_len (defined in ae_init) byte nonce. |
| * ct - Pointer to ciphertext bytes to be decrypted. |
| * ct_len - number of bytes pointed to by ct. |
| * ad - Pointer to associated data. |
| * ad_len - number of bytes pointed to by ad. |
| * pt - Pointer to buffer to receive plaintext decryption. |
| * tag - Pointer to tag_len (defined in ae_init) bytes; or NULL |
| * if tag is bundled into the ciphertext. Non-NULL tag is only |
| * read when final is non-zero. |
| * final - Non-zero if this call completes the ciphertext being decrypted. |
| * |
| * If nonce!=NULL then "ct" points to the start of a ciphertext. If final!=0 |
| * then "in" points to the final piece of ciphertext. If final==0 or nonce== |
| * NULL then the incremental interface is being used. If nonce!=NULL and |
| * ad_len<0, then use same ad as last message. |
| * |
| * Returns: |
| * non-negative - Number of bytes written to pt. |
| * AE_INVALID - Authentication failure. |
| * AE_NOT_SUPPORTED - Usage mode unsupported (eg, incremental and/or sticky). |
| * Otherwise - Error. Check implementation documentation for codes. |
| * |
| * NOTE !!! NOTE !!! -- The ciphertext should be assumed possibly inauthentic |
| * until it has been completely written and it is |
| * verified that this routine did not return AE_INVALID. |
| * |
| * ----------------------------------------------------------------------- */ |
| |
| #ifdef __cplusplus |
| } /* closing brace for extern "C" */ |
| #endif |
| |
| #endif /* _AE_H_ */ |
