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