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  (   ˆÐÏÎÍÌl–Ðz¾”ªC]Šq@¹pM\êbÑ¿Ëƒ}æÛÊÉÈ &    -- Copyright (C) by Yichun Zhang (agentzh)


--local asn1 = require "resty.asn1"
local ffi = require "ffi"
local ffi_new = ffi.new
local ffi_gc = ffi.gc
local ffi_str = ffi.string
local ffi_copy = ffi.copy
local C = ffi.C
local setmetatable = setmetatable
--local error = error
local type = type


local _M = { _VERSION = '0.16' }

local mt = { __index = _M }

local EVP_CTRL_AEAD_SET_IVLEN = 0x09
local EVP_CTRL_AEAD_GET_TAG = 0x10
local EVP_CTRL_AEAD_SET_TAG = 0x11

ffi.cdef[[
typedef struct engine_st ENGINE;

typedef struct evp_cipher_st EVP_CIPHER;
typedef struct evp_cipher_ctx_st EVP_CIPHER_CTX;

typedef struct env_md_ctx_st EVP_MD_CTX;
typedef struct env_md_st EVP_MD;

const EVP_MD *EVP_md5(void);
const EVP_MD *EVP_sha(void);
const EVP_MD *EVP_sha1(void);
const EVP_MD *EVP_sha224(void);
const EVP_MD *EVP_sha256(void);
const EVP_MD *EVP_sha384(void);
const EVP_MD *EVP_sha512(void);

const EVP_CIPHER *EVP_aes_128_ecb(void);
const EVP_CIPHER *EVP_aes_128_cbc(void);
const EVP_CIPHER *EVP_aes_128_cfb1(void);
const EVP_CIPHER *EVP_aes_128_cfb8(void);
const EVP_CIPHER *EVP_aes_128_cfb128(void);
const EVP_CIPHER *EVP_aes_128_ofb(void);
const EVP_CIPHER *EVP_aes_128_ctr(void);
const EVP_CIPHER *EVP_aes_192_ecb(void);
const EVP_CIPHER *EVP_aes_192_cbc(void);
const EVP_CIPHER *EVP_aes_192_cfb1(void);
const EVP_CIPHER *EVP_aes_192_cfb8(void);
const EVP_CIPHER *EVP_aes_192_cfb128(void);
const EVP_CIPHER *EVP_aes_192_ofb(void);
const EVP_CIPHER *EVP_aes_192_ctr(void);
const EVP_CIPHER *EVP_aes_256_ecb(void);
const EVP_CIPHER *EVP_aes_256_cbc(void);
const EVP_CIPHER *EVP_aes_256_cfb1(void);
const EVP_CIPHER *EVP_aes_256_cfb8(void);
const EVP_CIPHER *EVP_aes_256_cfb128(void);
const EVP_CIPHER *EVP_aes_256_ofb(void);
const EVP_CIPHER *EVP_aes_128_gcm(void);
const EVP_CIPHER *EVP_aes_192_gcm(void);
const EVP_CIPHER *EVP_aes_256_gcm(void);

EVP_CIPHER_CTX *EVP_CIPHER_CTX_new();
void EVP_CIPHER_CTX_free(EVP_CIPHER_CTX *a);
int EVP_CIPHER_CTX_block_size(const EVP_CIPHER_CTX *ctx);

int EVP_CIPHER_CTX_set_padding(EVP_CIPHER_CTX *ctx, int padding);

int EVP_EncryptInit_ex(EVP_CIPHER_CTX *ctx,const EVP_CIPHER *cipher,
        ENGINE *impl, unsigned char *key, const unsigned char *iv);

int EVP_EncryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
        const unsigned char *in, int inl);

int EVP_EncryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl);

int EVP_DecryptInit_ex(EVP_CIPHER_CTX *ctx,const EVP_CIPHER *cipher,
        ENGINE *impl, unsigned char *key, const unsigned char *iv);

int EVP_DecryptUpdate(EVP_CIPHER_CTX *ctx, unsigned char *out, int *outl,
        const unsigned char *in, int inl);

int EVP_DecryptFinal_ex(EVP_CIPHER_CTX *ctx, unsigned char *outm, int *outl);

int EVP_BytesToKey(const EVP_CIPHER *type,const EVP_MD *md,
        const unsigned char *salt, const unsigned char *data, int datal,
        int count, unsigned char *key,unsigned char *iv);

int EVP_CIPHER_CTX_ctrl(EVP_CIPHER_CTX *ctx, int type, int arg, void *ptr);
]]

local hash
hash = {
    md5 = C.EVP_md5(),
    sha1 = C.EVP_sha1(),
    sha224 = C.EVP_sha224(),
    sha256 = C.EVP_sha256(),
    sha384 = C.EVP_sha384(),
    sha512 = C.EVP_sha512()
}
_M.hash = hash

local EVP_MAX_BLOCK_LENGTH = 32

local cipher
cipher = function (size, _cipher)
    local _size = size or 128
    local _cipher = _cipher or "cbc"
    local func = "EVP_aes_" .. _size .. "_" .. _cipher
    if C[func] then
        return { size=_size, cipher=_cipher, method=C[func]()}
    else
        return nil
    end
end
_M.cipher = cipher

function _M.new(self, key, salt, _cipher, _hash, hash_rounds, iv_len, enable_padding)
    local encrypt_ctx = C.EVP_CIPHER_CTX_new()
    if encrypt_ctx == nil then
        return nil, "no memory"
    end

    ffi_gc(encrypt_ctx, C.EVP_CIPHER_CTX_free)

    local decrypt_ctx = C.EVP_CIPHER_CTX_new()
    if decrypt_ctx == nil then
        return nil, "no memory"
    end

    ffi_gc(decrypt_ctx, C.EVP_CIPHER_CTX_free)

    local _cipher = _cipher or cipher()
    local _hash = _hash