*
 * Side effects:
 *	No result or error message
 *
 *-------------------------------------------------------------------
 */
int EncryptInitialize(Tcl_Interp *interp, int type, EVP_CIPHER_CTX **ctx,
	Tcl_Obj *cipherObj, Tcl_Obj *keyObj, Tcl_Obj *ivObj, int padding) {
    const EVP_CIPHER *cipher;
    void *keyString = NULL, *ivString = NULL;
    Tcl_Size key_len = 0, iv_len = 0;
    int res, max;
    unsigned char key[EVP_MAX_KEY_LENGTH], iv[EVP_MAX_IV_LENGTH];

    dprintf("Called");

    /* Create context */
    if((*ctx = EVP_CIPHER_CTX_new()) == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

    /* Initialize the operation */
    if (type == TYPE_ENCRYPT) {
	res = EVP_EncryptInit_ex(*ctx, cipher, NULL, NULL, NULL);
    } else {
	res = EVP_DecryptInit_ex(*ctx, cipher, NULL, NULL, NULL);
    }

    if(!res) {
	Tcl_AppendResult(interp, "Initialize failed: ", GET_ERR_REASON(), (char *) NULL);
	return TCL_ERROR;
    }

    /* Turn off PKCS#7 padding */
    if (!padding) {
	EVP_CIPHER_CTX_set_padding(*ctx, padding);
    }

    /* Set key and IV */
    if (type == TYPE_ENCRYPT) {
	res = EVP_EncryptInit_ex(*ctx, NULL, NULL, key, iv);
    } else {
	res = EVP_DecryptInit_ex(*ctx, NULL, NULL, key, iv);
    }

    if(!res) {
	Tcl_AppendResult(interp, "Set key and IV failed: ", GET_ERR_REASON(), (char *) NULL);
	return TCL_ERROR;
    }

    /* Erase buffers */
    memset(key, 0, EVP_MAX_KEY_LENGTH);
    memset(iv, 0, EVP_MAX_IV_LENGTH);
    return TCL_OK;
}

 *
 * Side effects:
 *	Adds transform to channel and sets result to channel id or error message.
 *
 *----------------------------------------------------------------------
 */
static int EncryptChannelHandler(Tcl_Interp *interp, int type, const char *channel,
	Tcl_Obj *cipherObj, Tcl_Obj *digestObj, Tcl_Obj *keyObj, Tcl_Obj *ivObj, int padding) {
    int mode; /* OR-ed combination of TCL_READABLE and TCL_WRITABLE */
    Tcl_Channel chan;
    EncryptState *statePtr;

    dprintf("Called");

    /* Validate args */

	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }
    statePtr->self = chan;
    statePtr->mode = mode;

    /* Initialize function */
    if (EncryptInitialize(interp, type, &statePtr->ctx, cipherObj, keyObj, ivObj, padding) != TCL_OK) {
	EncryptStateFree(statePtr);
	return TCL_ERROR;
    }

    /* Stack channel */
    statePtr->self = Tcl_StackChannel(interp, &encryptChannelType, (ClientData) statePtr, mode, chan);
    if (statePtr->self == (Tcl_Channel) NULL) {

 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Creates command or error message
 *
 *-------------------------------------------------------------------
 */
int EncryptCommandHandler(Tcl_Interp *interp, int type, Tcl_Obj *cmdObj, Tcl_Obj *cipherObj,
	Tcl_Obj *digestObj, Tcl_Obj *keyObj, Tcl_Obj *ivObj, int padding) {
    EncryptState *statePtr;
    char *cmdName = Tcl_GetString(cmdObj);

    dprintf("Called");

    if ((statePtr = EncryptStateNew(interp, type)) == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

    /* Initialize function */
    if (EncryptInitialize(interp, type, &statePtr->ctx, cipherObj, keyObj, ivObj, padding) != TCL_OK) {
	EncryptStateFree(statePtr);
	return TCL_ERROR;
    }

    /* Create instance command */
    statePtr->token = Tcl_CreateObjCommand(interp, cmdName, EncryptInstanceObjCmd,
	(ClientData) statePtr, EncryptCommandDeleteHandler);

 *
 * Side effects:
 *	Sets result or error message
 *
 *-------------------------------------------------------------------
 */
int EncryptDataHandler(Tcl_Interp *interp, int type, Tcl_Obj *dataObj, Tcl_Obj *cipherObj,
	Tcl_Obj *digestObj, Tcl_Obj *keyObj, Tcl_Obj *ivObj, int padding) {
    EVP_CIPHER_CTX *ctx = NULL;
    int out_len = 0, len = 0, res = TCL_OK;
    Tcl_Size data_len = 0;
    unsigned char *data, *out_buf;
    Tcl_Obj *resultObj;

    dprintf("Called");

    out_buf = Tcl_SetByteArrayLength(resultObj, data_len+EVP_MAX_BLOCK_LENGTH);
    if (resultObj == NULL || out_buf == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

    /* Perform operation */
    if (EncryptInitialize(interp, type, &ctx, cipherObj, keyObj, ivObj, padding) != TCL_OK ||
	EncryptUpdate(interp, type, ctx, out_buf, &out_len, data, data_len) != TCL_OK ||
	EncryptFinalize(interp, type, ctx, out_buf+out_len, &len) != TCL_OK) {
	res = TCL_ERROR;
	goto done;
    }
    out_len += len;

 * Side effects:
 *	Encrypts or decrypts inFile data to outFile and sets result to
 *	size of outFile, or an error message.
 *
 *-------------------------------------------------------------------
 */
int EncryptFileHandler(Tcl_Interp *interp, int type, Tcl_Obj *inFileObj, Tcl_Obj *outFileObj,
	Tcl_Obj *cipherObj, Tcl_Obj *digestObj, Tcl_Obj *keyObj, Tcl_Obj *ivObj, int padding) {
    EVP_CIPHER_CTX *ctx = NULL;
    int total = 0, res, out_len = 0, len;
    Tcl_Channel in = NULL, out = NULL;
    unsigned char in_buf[BUFFER_SIZE];
    unsigned char out_buf[BUFFER_SIZE+EVP_MAX_BLOCK_LENGTH];

    dprintf("Called");

    /* Open input file */
    if ((in = Tcl_FSOpenFileChannel(interp, inFileObj, "rb", 0444)) == (Tcl_Channel) NULL) {
	return TCL_ERROR;
    }

    /* Open output file */
    if ((out = Tcl_FSOpenFileChannel(interp, outFileObj, "wb", 0644)) == (Tcl_Channel) NULL) {
	Tcl_Close(interp, in);
	return TCL_ERROR;
    }

    /* Initialize operation */
    if ((res = EncryptInitialize(interp, type, &ctx, cipherObj, keyObj, ivObj, padding)) != TCL_OK) {
	goto done;
    }

    /* Read file data from inFile, encrypt/decrypt it, then output to outFile */
    while (!Tcl_Eof(in)) {
	Tcl_Size read = Tcl_ReadRaw(in, (char *) in_buf, BUFFER_SIZE);
	if (read > 0) {

    return res;
}

/*******************************************************************/

static const char *command_opts [] = {
    "-chan", "-channel", "-cipher", "-command", "-data", "-digest", "-infile", "-filename",
    "-outfile", "-hash", "-iv", "-key", "-mac", "-padding", NULL};

enum _command_opts {
    _opt_chan, _opt_channel, _opt_cipher, _opt_command, _opt_data, _opt_digest, _opt_infile,
    _opt_filename, _opt_outfile, _opt_hash, _opt_iv, _opt_key, _opt_mac, _opt_padding
};

/*
 *-------------------------------------------------------------------
 *
 * EncryptMain --
 *

 *
 *-------------------------------------------------------------------
 */
static int EncryptMain(int type, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    Tcl_Obj *cipherObj = NULL, *cmdObj = NULL, *dataObj = NULL, *digestObj = NULL;
    Tcl_Obj *inFileObj = NULL, *outFileObj = NULL, *keyObj = NULL, *ivObj = NULL, *macObj = NULL;
    const char *channel = NULL, *opt;
    int res, start = 1, padding = 1;
    Tcl_Size fn;

    dprintf("Called");

    /* Clear interp result */
    Tcl_ResetResult(interp);

    /* Validate arg count */
    if (objc < 3 || objc > 12) {
	Tcl_WrongNumArgs(interp, 1, objv, "?-cipher? name ?-digest name? -key key ?-iv string? ?-mac name? ?-padding boolean? [-channel chan | -command cmdName | -infile filename -outfile filename | ?-data? data]");
	return TCL_ERROR;
    }

    /* Special case of first arg is cipher */
    opt = Tcl_GetString(objv[start]);
    if (opt[0] != '-') {
	switch(type) {

	    break;
	case _opt_key:
	    keyObj = objv[idx];
	    break;
	case _opt_mac:
	    macObj = objv[idx];
	    break;
	case _opt_padding:
    	    GET_OPT_BOOL(objv[idx], &padding);
	    break;
	}
    }

    /* Check for required options */
    if (cipherObj == NULL) {
	Tcl_AppendResult(interp, "No cipher", (char *) NULL);
    } else if (keyObj == NULL) {
	Tcl_AppendResult(interp, "No key", (char *) NULL);
	return TCL_ERROR;
    }

    /* Perform encryption function on file, stacked channel, using instance command, or data blob */
    if (inFileObj != NULL && outFileObj != NULL) {
	res = EncryptFileHandler(interp, type, inFileObj, outFileObj, cipherObj, digestObj, keyObj, ivObj, padding);
    } else if (channel != NULL) {
	res = EncryptChannelHandler(interp, type, channel, cipherObj, digestObj, keyObj, ivObj, padding);
    } else if (cmdObj != NULL) {
	res = EncryptCommandHandler(interp, type, cmdObj, cipherObj, digestObj, keyObj, ivObj, padding);
    } else if (dataObj != NULL) {
	res = EncryptDataHandler(interp, type, dataObj, cipherObj, digestObj, keyObj, ivObj, padding);
    } else {
	Tcl_AppendResult(interp, "No operation specified: Use -channel, -command, -data, or -infile option", (char *) NULL);
	res = TCL_ERROR;
    }
    return res;
}