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/*
 * Ellitpic Curve Integrated Encryption Scheme (ECIES)
 * see http://www.secg.org/sec1-v2.pdf (section 5)
 * SEC1: Elliptic Curve Cryptography version 2.0
 */

#ifndef HEADER_ECIES_H
#define HEADER_ECIES_H

#include <openssl/ec.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
#include <openssl/asn1.h>
#include <openssl/kdf2.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
ECIESAlgorithmSet ALGORITHM ::= {
	{OID ecies-recommendedParameters} |
	{OID ecies-specifiedParameters PARMS ECIESParameters},
	... -- Future combinations may be added
}
*/

typedef struct ecies_params_st {
	/*
	KDFSet ALGORITHM ::= {
		{ OID x9-63-kdf PARMS HashAlgorithm } |
		{ OID nist-concatenation-kdf PARMS HashAlgorithm } |
		{ OID tls-kdf PARMS HashAlgorithm } |
		{ OID ikev2-kdf PARMS HashAlgorithm }
		... -- Future combinations may be added
	}
	*/
	int kdf_nid;
	const EVP_MD *kdf_md;

	/*
	SYMENCSet ALGORITHM ::= {
		{ OID xor-in-ecies } |
		{ OID tdes-cbc-in-ecies } |
		{ OID aes128-cbc-in-ecies } |
		{ OID aes192-cbc-in-ecies } |
		{ OID aes256-cbc-in-ecies } |
		{ OID aes128-ctr-in-ecies } |
		{ OID aes192-ctr-in-ecies } |
		{ OID aes256-ctr-in-ecies } ,
		... -- Future combinations may be added
	}
	*/
	int enc_nid;

	/*
	MACSet ALGORITHM ::= {
		{ OID hmac-full-ecies PARMS HashAlgorithm} |
		{ OID hmac-half-ecies PARMS HashAlgorithm} |
		{ OID cmac-aes128-ecies } |
		{ OID cmac-aes192-ecies } |
		{ OID cmac-aes256-ecies } ,
		... -- Future combinations may be added
	}
	*/
	int mac_nid;
	const EVP_MD *hmac_md;

} ECIES_PARAMS;

ECIES_PARAMS *ECIES_PARAMS_new(void);
int ECIES_PARAMS_init_with_recommended(ECIES_PARAMS *param);
ECIES_PARAMS *ECIES_PARAMS_dup(const ECIES_PARAMS *param);
KDF_FUNC ECIES_PARAMS_get_kdf(const ECIES_PARAMS *param);
int ECIES_PARAMS_get_enc(const ECIES_PARAMS *param, size_t inlen,
	const EVP_CIPHER **enc_cipher, size_t *enckeylen, size_t *ciphertextlen);
int ECIES_PARAMS_get_mac(const ECIES_PARAMS *param,
	const EVP_MD **hmac_md, const EVP_CIPHER **cmac_cipher,
	unsigned int *mackeylen, unsigned int *maclen);
void ECIES_PARAMS_free(ECIES_PARAMS *param);

int i2d_ECIESParameters(const ECIES_PARAMS *param, unsigned char **out);
ECIES_PARAMS *d2i_ECIESParameters(ECIES_PARAMS **param,
	const unsigned char **in, long len);


typedef struct ecies_ciphertext_value_st {
	ASN1_OCTET_STRING *ephem_point;
	ASN1_OCTET_STRING *ciphertext;
	ASN1_OCTET_STRING *mactag;
} ECIES_CIPHERTEXT_VALUE;

DECLARE_ASN1_FUNCTIONS(ECIES_CIPHERTEXT_VALUE)


ECIES_CIPHERTEXT_VALUE *ECIES_do_encrypt(const ECIES_PARAMS *param,
	const unsigned char *in, size_t inlen, EC_KEY *ec_key);
int ECIES_do_decrypt(const ECIES_PARAMS *param, const ECIES_CIPHERTEXT_VALUE *in,
	unsigned char *out, size_t *outlen, EC_KEY *ec_key);
int ECIES_encrypt(const ECIES_PARAMS *param,
	const unsigned char *in, size_t inlen,
	unsigned char *out, size_t *outlen, EC_KEY *ec_key);
int ECIES_decrypt(const ECIES_PARAMS *param,
	const unsigned char *in, size_t inlen,
	unsigned char *out, size_t *outlen, EC_KEY *ec_key);

int ECIES_encrypt_with_recommended(const unsigned char *in, size_t inlen,
	unsigned char *out, size_t *outlen, EC_KEY *ec_key);
int ECIES_decrypt_with_recommended(const unsigned char *in, size_t inlen,
	unsigned char *out, size_t *outlen, EC_KEY *ec_key);


#ifdef __cplusplus
}
#endif
#endif