*
 *-------------------------------------------------------------------
 */
int DigestInitialize(Tcl_Interp *interp, DigestState *statePtr, const EVP_MD *md,
	const EVP_CIPHER *cipher, Tcl_Obj *keyObj, EVP_MAC *mac) {
    int key_len = 0, res = 0;
    const unsigned char *key = NULL;

    dprintf("Called");

    /* Create contexts */
    switch(statePtr->format & 0xFF0) {
    case TYPE_MD:
	statePtr->ctx = EVP_MD_CTX_new();
	res = (statePtr->ctx != NULL);
	break;

 *-------------------------------------------------------------------
 *
 * DigestUpdate --
 *
 *	Update a hash function with data
 *
 * Returns:
 *	TCL_OK if successful or TCL_ERROR for failure with result set
 *	to error message if do_result is true.
 *
 * Side effects:
 *	Adds buf data to hash function or sets result to error message
 *
 *-------------------------------------------------------------------
 */
int DigestUpdate(DigestState *statePtr, char *buf, size_t read, int do_result) {
    int res = 0;

    dprintf("Called");

    switch(statePtr->format & 0xFF0) {
    case TYPE_MD:
        res = EVP_DigestUpdate(statePtr->ctx, buf, read);
	break;
    case TYPE_HMAC:
        res = HMAC_Update(statePtr->hctx, buf, read);
	break;
    case TYPE_CMAC:
        res = CMAC_Update(statePtr->cctx, buf, read);
	break;
    }

    if (!res && do_result) {
	Tcl_AppendResult(statePtr->interp, "Update failed: ", REASON(), NULL);
	return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *-------------------------------------------------------------------
 *
 * DigestFinalize --
 *

 *
 *-------------------------------------------------------------------
 */
int DigestFinalize(Tcl_Interp *interp, DigestState *statePtr, Tcl_Obj **resultObj) {
    unsigned char md_buf[EVP_MAX_MD_SIZE];
    unsigned int ulen;
    int res = 0, md_len = 0;

    dprintf("Called");

    /* Finalize cryptography function and get result */
    switch(statePtr->format & 0xFF0) {
    case TYPE_MD:
	if (!(statePtr->format & IS_XOF)) {
	    res = EVP_DigestFinal_ex(statePtr->ctx, md_buf, &ulen);
	    md_len = (int) ulen;

    /* Get bytes from underlying channel */
    parent = Tcl_GetStackedChannel(statePtr->self);
    read = Tcl_ReadRaw(parent, buf, toRead);

    /* Update hash function */
    if (read > 0) {
	/* Have data */
	if (DigestUpdate(statePtr, buf, (size_t) read, 0) != TCL_OK) {
	    Tcl_SetChannelError(statePtr->self, Tcl_ObjPrintf("Update failed: %s", REASON()));
	    *errorCodePtr = EINVAL;
	    return 0;
	}
	/* This is correct */
	read = -1;
	*errorCodePtr = EAGAIN;

    /* Abort if nothing to process */
    if (toWrite <= 0 || statePtr->self == (Tcl_Channel) NULL) {
	return 0;
    }

    /* Update hash function */
    if (toWrite > 0 && DigestUpdate(statePtr, buf, (size_t) toWrite, 0) != TCL_OK) {
	Tcl_SetChannelError(statePtr->self, Tcl_ObjPrintf("Update failed: %s", REASON()));
	*errorCodePtr = EINVAL;
	return 0;
    }
    return toWrite;
}

 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Adds transform to channel and sets result to channel id or error message.
 *
 *----------------------------------------------------------------------
 */

static int DigestChannelHandler(Tcl_Interp *interp, const char *channel, const EVP_MD *md,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj, EVP_MAC *mac) {
    int mode; /* OR-ed combination of TCL_READABLE and TCL_WRITABLE */
    Tcl_Channel chan;
    DigestState *statePtr;

    dprintf("Called");

    /* Validate args */
    if (channel == (const char *) NULL) {
	return TCL_ERROR;
    }

    /* Get channel Id */

 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Removes transform from channel or sets result to error message.
 *
 *----------------------------------------------------------------------
 */

static int DigestUnstackObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    Tcl_Channel chan;
    int mode; /* OR-ed combination of TCL_READABLE and TCL_WRITABLE  */

    dprintf("Called");

    /* Validate arg count */
    if (objc != 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "channelId");
	return TCL_ERROR;
    }

 *-------------------------------------------------------------------
 */
int DigestInstanceObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
    DigestState *statePtr = (DigestState *) clientData;
    int fn, len = 0;
    char *buf = NULL;
    static const char *instance_fns [] = { "finalize", "update", NULL };

    dprintf("Called");

    /* Validate arg count */
    if (objc < 2 || objc > 3) {
	Tcl_WrongNumArgs(interp, 1, objv, "function ?data?");
	return TCL_ERROR;
    }

	    buf = Tcl_GetByteArrayFromObj(objv[2], &len);
	} else {
	    Tcl_WrongNumArgs(interp, 1, objv, "update data");
	    return TCL_ERROR;
	}

	/* Update hash function */
	if (DigestUpdate(statePtr, buf, (size_t) len, 1) != TCL_OK) {
	    return TCL_ERROR;
	}

    } else {
	/* Finalize hash function and calculate message digest */
	if (DigestFinalize(interp, statePtr, NULL) != TCL_OK) {
	    return TCL_ERROR;

 *
 *-------------------------------------------------------------------
 */
int DigestCommandHandler(Tcl_Interp *interp, Tcl_Obj *cmdObj, const EVP_MD *md,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj, EVP_MAC *mac) {
    DigestState *statePtr;
    char *cmdName = Tcl_GetStringFromObj(cmdObj, NULL);

    dprintf("Called");

    /* Create state data structure */
    if ((statePtr = DigestStateNew(interp, format)) == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Sets result to message digest or error message
 *
 *-------------------------------------------------------------------
 */

int DigestDataHandler(Tcl_Interp *interp, Tcl_Obj *dataObj, const EVP_MD *md,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj, EVP_MAC *mac) {
    char *data;
    int data_len;
    DigestState *statePtr;

    dprintf("Called");

    /* Get data */
    data = Tcl_GetByteArrayFromObj(dataObj, &data_len);
    if (data == NULL) {
	Tcl_SetResult(interp, "No data", NULL);
	return TCL_ERROR;
    }

    /* Create state data structure */
    if ((statePtr = DigestStateNew(interp, format)) == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

    /* Calc Digest, abort for error */
    if (DigestInitialize(interp, statePtr, md, cipher, keyObj, mac) != TCL_OK ||
	DigestUpdate(statePtr, data, (size_t) data_len, 1) != TCL_OK ||
	DigestFinalize(interp, statePtr, NULL) != TCL_OK) {
	DigestStateFree(statePtr);
	return TCL_ERROR;
    }

    /* Clean-up */
    DigestStateFree(statePtr);

 *	TCL_OK or TCL_ERROR
 *
 * Side effects:
 *	Result is message digest or error message
 *
 *-------------------------------------------------------------------
 */
int DigestFileHandler(Tcl_Interp *interp, Tcl_Obj *inFileObj, const EVP_MD *md,
	const EVP_CIPHER *cipher, int format, Tcl_Obj *keyObj, EVP_MAC *mac) {
    DigestState *statePtr;
    Tcl_Channel chan = NULL;
    unsigned char buf[BUFFER_SIZE];
    int res = TCL_OK, len;

    dprintf("Called");

    /* Create state data structure */
    if ((statePtr = DigestStateNew(interp, format)) == NULL) {
	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

    /* Open file channel, abort for error */
    chan = Tcl_FSOpenFileChannel(interp, inFileObj, "rb", 0444);
    if (chan == (Tcl_Channel) NULL) {
	DigestStateFree(statePtr);
	return TCL_ERROR;
    }

    /* Configure channel */
    if ((res = Tcl_SetChannelOption(interp, chan, "-translation", "binary")) != TCL_OK) {
	goto done;
    }
    Tcl_SetChannelBufferSize(chan, BUFFER_SIZE);

    /* Initialize hash function */
    if ((res = DigestInitialize(interp, statePtr, md, cipher, keyObj, mac)) != TCL_OK) {
	goto done;
    }

    /* Read file data and update hash function */
    while (!Tcl_Eof(chan)) {
	len = Tcl_ReadRaw(chan, (char *) buf, BUFFER_SIZE);
	if (len > 0) {
	    if (DigestUpdate(statePtr, &buf[0], (size_t) len, 1) != TCL_OK) {
		res = TCL_ERROR;
		goto done;
	    }
	}
    }

    /* Finalize hash function and calculate message digest */

    int idx, start = 1, format = HEX_FORMAT, res = TCL_OK;
    Tcl_Obj *cipherObj = NULL, *cmdObj = NULL, *dataObj = NULL, *digestObj = NULL;
    Tcl_Obj *fileObj = NULL, *keyObj = NULL, *macObj = NULL;
    const char *channel = NULL, *opt;
    const EVP_MD *md = NULL;
    const EVP_CIPHER *cipher = NULL;
    EVP_MAC *mac = NULL;

    dprintf("Called");

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

    /* Validate arg count */
    if (objc < 3 || objc > 12) {
	Tcl_WrongNumArgs(interp, 1, objv, "?-bin|-hex? ?-cipher name? ?-digest name? ?-key key? ?-mac name? [-channel chan | -command cmdName | -file filename | ?-data? data]");

#include <stdio.h>
#include <string.h>
#include <openssl/evp.h>
#if OPENSSL_VERSION_NUMBER >= 0x30000000L
#include <openssl/params.h>
#endif

/* Macros */
#define BUFFER_SIZE	32768

/* Encryption functions */
#define TYPE_MD		0x010
#define TYPE_HMAC	0x020
#define TYPE_CMAC	0x040
#define TYPE_MAC	0x080
#define TYPE_ENCRYPT	0x100
#define TYPE_DECRYPT	0x200

    if (type == TYPE_ENCRYPT) {
	res = EVP_EncryptUpdate(ctx, outbuf, out_len, data, data_len);
    } else {
	res = EVP_DecryptUpdate(ctx, outbuf, out_len, data, data_len);
    }

    if (res) {

	return TCL_OK;
    } else {
	Tcl_AppendResult(interp, "Update failed: ", REASON(), NULL);
	return TCL_ERROR;
    }
}

    if (type == TYPE_ENCRYPT) {
	res = EVP_EncryptFinal_ex(ctx, outbuf, out_len);
    } else {
	res = EVP_DecryptFinal_ex(ctx, outbuf, out_len);
    }

    if (res) {

	return TCL_OK;
    } else {
	Tcl_AppendResult(interp, "Finalize failed: ", REASON(), NULL);
	return TCL_ERROR;
    }
}

 *	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) {
    EVP_CIPHER_CTX *ctx = NULL;
    int data_len = 0, out_len = 0, len = 0, res = TCL_OK;
    unsigned char *data, *outbuf;
    Tcl_Obj *resultObj;

    dprintf("Called");

    /* Get data */
    if (dataObj != NULL) {

	Tcl_AppendResult(interp, "Memory allocation error", (char *) NULL);
	return TCL_ERROR;
    }

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

done:
    /* Set output result */
    if (res == TCL_OK) {
	outbuf = Tcl_SetByteArrayLength(resultObj, out_len);
	Tcl_SetObjResult(interp, resultObj);
    } else {
	Tcl_DecrRefCount(resultObj);
	/* Result is error message */
    }

    /* Clean up */
    if (ctx != NULL) {
	EVP_CIPHER_CTX_free(ctx);
    }
    return res;
}

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

/*
 *-------------------------------------------------------------------
 *
 * EncryptFileHandler --
 *
 *	Perform encryption function on a block of data and return result.
 *
 * Returns:
 *	TCL_OK or TCL_ERROR
 *
 * 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) {
    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+1024];

    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)) != TCL_OK) {
	goto done;
    }

    /* Read file data from inFile, encrypt/decrypt it, then output to outFile */
    while (!Tcl_Eof(in)) {
	int read = Tcl_ReadRaw(in, (char *) in_buf, BUFFER_SIZE);
	if (read > 0) {
	    if ((res = EncryptUpdate(interp, type, ctx, out_buf, &out_len, in_buf, read)) == TCL_OK) {
		if (out_len > 0) {
		    len = Tcl_WriteRaw(out, (const char *) out_buf, out_len);
		    if (len >= 0) {
			total += len;
		    } else {
			Tcl_AppendResult(interp, "Write error: ", Tcl_ErrnoMsg(Tcl_GetErrno()), (char *) NULL);
			res = TCL_ERROR;
			goto done;
		    }
		}
	    } else {
		goto done;
	    }
	} else if (read < 0) {
	    Tcl_AppendResult(interp, "Read error: ", Tcl_ErrnoMsg(Tcl_GetErrno()), (char *) NULL);
	    res = TCL_ERROR;
	    goto done;
	}
    }

    /* Finalize data and write any remaining data in block */
    if ((res = EncryptFinalize(interp, type, ctx, out_buf, &out_len)) == TCL_OK) {
	if (out_len > 0) {
	    len = Tcl_WriteRaw(out, (const char *) out_buf, out_len);
	    if (len >= 0) {
		total += len;
	    } else {
		Tcl_AppendResult(interp, "Write error: ", Tcl_ErrnoMsg(Tcl_GetErrno()), (char *) NULL);
		res = TCL_ERROR;
		goto done;
	    }
	}
	Tcl_SetObjResult(interp, Tcl_NewIntObj(total));
    } else {
	goto done;
    }

done:
    /* Clean up */
    if (in != NULL) {
	Tcl_Close(interp, in);
    }
    if (out != NULL) {
	Tcl_Close(interp, out);
    }
    if (ctx != NULL) {
	EVP_CIPHER_CTX_free(ctx);
    }
    return res;
}

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

    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? [-infile filename -outfile filename | -data data]");
	return TCL_ERROR;
    }

    /* Get options */
    for (int idx = 1; idx < objc; idx++) {
	opt = Tcl_GetStringFromObj(objv[idx], NULL);

	if (opt[0] != '-') {
	    break;
	}

	OPTOBJ("-cipher", cipherObj);
	OPTOBJ("-data", dataObj);
	OPTOBJ("-digest", digestObj);
	OPTOBJ("-infile", inFileObj);
	OPTOBJ("-outfile", outFileObj);
	OPTOBJ("-key", keyObj);
	OPTOBJ("-iv", ivObj);

	OPTBAD("option", "-cipher, -data, -digest, -infile, -key, -iv, -outfile");
	return TCL_ERROR;
    }

    /* Check for required options */
    if (cipherObj == NULL) {
	Tcl_AppendResult(interp, "No cipher", NULL);
    } else if (keyObj == NULL) {
	Tcl_AppendResult(interp, "No key", 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);
    } else if (dataObj != NULL) {
	res = EncryptDataHandler(interp, type, dataObj, cipherObj, digestObj, keyObj, ivObj);
    } else {
	Tcl_AppendResult(interp, "No operation specified: Use -data, -infile, or -outfile option", NULL);
	res = TCL_ERROR;
    }
    return res;
}

/*
 *-------------------------------------------------------------------