thig_ims_enc.c File Reference

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Detailed Description

I-CSCF Module - THIG Operations.

Author:

Florin Dinu fdi -at- fokus dot fraunhofer dot de

Definition in file thig_ims_enc.c.

#include "thig_ims_enc.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "../../mem/mem.h"
#include "base64.h"

Go to the source code of this file.

Defines
#define	USE_BASE64   1
	Using base64 encoding reduces the length of the encrypted strings.
Functions
DWORD	Here (DWORD x)
void	printstr (char *text, str x)
	prints a message and the contents of the str structure
int	thig_key_and_cipher_init (keyInstance *ki, cipherInstance *ci)
	Initializes the structures that hold the keys and the cipher.
str	thig_encrypt (str src)
	Encrypts a string (str struct).
str	thig_decrypt (str encoded)
	Decrypts a string(str struct).
Variables
keyInstance	ki
cipherInstance	ci
int	keySize = 256
	key size
int	mode = MODE_CFB1
	Twofish mode.
int	byteCnt = BLOCK_SIZE/8

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Define Documentation

#define USE_BASE64   1

Using base64 encoding reduces the length of the encrypted strings.

Definition at line 63 of file thig_ims_enc.c.

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Function Documentation

DWORD Here

(

DWORD

x

)

Definition at line 69 of file thig_ims_enc.c.

                   {
    unsigned int mask=~0U;

    return (* (((DWORD *)&x)-1)) & mask;
}

void printstr	(	char *	text,
		str	x
	)

prints a message and the contents of the str structure

Parameters:

	text	- some text
	x	- some string

Definition at line 86 of file thig_ims_enc.c.

References NULL.

Referenced by thig_decrypt(), and thig_encrypt().

{
    int i;
    if(text!=NULL)
        printf("%s 0x",text);
    for(i=0;i<x.len;i++)
        printf("%.02x", (unsigned char)x.s[i]);
    printf("\n");
}

int thig_key_and_cipher_init	(	keyInstance *	ki,
		cipherInstance *	ci
	)

Initializes the structures that hold the keys and the cipher.

Parameters:

	ki	- the structure where the key information is to be stored
	ci	- the structure where the cipher information is to be stored

Returns:

1

Definition at line 103 of file thig_ims_enc.c.

References BLOCK_SIZE, ci, cipherInit(), DIR_ENCRYPT, keySize, ki, makeKey(), mode, NULL, reKey(), and TRUE.

Referenced by icscf_mod_init().

                                                                  {
    int i;
    BYTE iv[BLOCK_SIZE/8];
    if (makeKey(ki,DIR_ENCRYPT,keySize,NULL) != TRUE)
        return 1;               /* 'dummy' setup for a 128-bit key */
    if (cipherInit(ci,mode,NULL) != TRUE)
        return 1;               /* 'dummy' setup for cipher */
    
    /* choose a key */
    for (i=0;i<keySize/32;i++)  
        (*ki).key32[i]=0x10003 * rand();
    reKey(ki);                  /* run the key schedule */
    
    /* set the initialization vector */
    for (i=0;i<sizeof(iv);i++)
            iv[i]=(BYTE) rand();
    memcpy((*ci).iv32,iv,sizeof((*ci).iv32));   /* copy the IV to ci */
    return 1;
}

str thig_encrypt

(

str

src

)

Encrypts a string (str struct).

Parameters:

src

- the string that needs to be encrypted.Must NOT contain

Returns:

- the encrypted string, allocated in this function.

Definition at line 133 of file thig_ims_enc.c.

References base16_encode(), base64_encode(), blockEncrypt(), byteCnt, ci, ki, M_NAME, and printstr().

Referenced by I_THIG_encrypt_header().

{
    int padding;
    str my_text={0,0},enc_text={0,0};
    cipherInstance ci2 = ci;
    str encoded={0,0};
    
    padding = (src.len%byteCnt)==0?0:byteCnt-(src.len%byteCnt);
    LOG(L_ERR,"DBG:"M_NAME":encrypt:String has length %d so needs padding %d\n",src.len,padding);

    my_text.len = src.len+padding;
    my_text.s = pkg_malloc(my_text.len);
    if (!my_text.s){
        LOG(L_ERR,"ERR:"M_NAME":encrypt: error allocating %d bytes\n",my_text.len);
        goto error;
    }   
    memcpy(my_text.s,src.s,src.len);
    memset(my_text.s+src.len,0,my_text.len-src.len);
    
    enc_text.s = pkg_malloc(my_text.len);
    if (!enc_text.s){
        LOG(L_ERR,"ERR:"M_NAME":encrypt: error allocating %d bytes\n",my_text.len);
        goto error;     
    }
    enc_text.len = my_text.len;

    printstr("String bef :",my_text);
    if (blockEncrypt(&ci2,&ki,(unsigned char*)my_text.s,my_text.len*8,(unsigned char*)enc_text.s) != my_text.len*8){
        LOG(L_ERR,"DBG:"M_NAME":encrypt: Error in encryption phase\n");
        goto error;
    }
    printstr("String aft :",enc_text);

#ifdef USE_BASE64
    encoded = base64_encode(enc_text);
#else
    encoded = base16_encode(enc_text);
#endif
    
    if (my_text.s) pkg_free(my_text.s);
    if (enc_text.s) pkg_free(enc_text.s);
    return encoded; 
error:
    if (my_text.s) pkg_free(my_text.s);
    if (enc_text.s) pkg_free(enc_text.s);
    enc_text.s = 0;enc_text.len=0;
    return enc_text;        
}

str thig_decrypt

(

str

encoded

)

Decrypts a string(str struct).

Parameters:

encoded

- the string that needs to be decrypted

Returns:

- the decoded string.Memory allocation takes place in this function.

Definition at line 189 of file thig_ims_enc.c.

References base16_decode(), base64_decode(), blockDecrypt(), ci, ki, M_NAME, and printstr().

Referenced by I_THIG_decrypt_header().

{
    str src;
    str my_text={0,0},dec_text={0,0};
    cipherInstance ci2 = ci;

#ifdef USE_BASE64
    src = base64_decode(encoded);
#else
    src = base16_decode(encoded);
#endif
    if (!src.len) return dec_text;

    my_text = src;
    dec_text.s = pkg_malloc(my_text.len);
    if (!dec_text.s){
        LOG(L_ERR,"ERR:"M_NAME":decrypt: error allocating %d bytes\n",my_text.len);
        goto error;     
    }
    dec_text.len = my_text.len;
    
    printstr("String bef :",my_text);

    if (blockDecrypt(&ci2,&ki,(unsigned char*)my_text.s,my_text.len*8,(unsigned char*)dec_text.s) != my_text.len*8){
        LOG(L_ERR,"DBG:"M_NAME":decrypt: Error in encryption phase\n");
        goto error;
    }
    while(dec_text.s[dec_text.len-1]==0 && dec_text.len>0)
        dec_text.len--;
    printstr("String aft :",dec_text);
    if (src.s) pkg_free(src.s);
    return dec_text;
error:
    if (src.s) pkg_free(src.s);
    if (dec_text.s) pkg_free(dec_text.s);
    dec_text.s = 0;dec_text.len=0;
    return dec_text;    
}

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Variable Documentation

keyInstance ki

Definition at line 65 of file thig_ims_enc.c.

cipherInstance ci

Definition at line 66 of file thig_ims_enc.c.

int keySize = 256

key size

Definition at line 75 of file thig_ims_enc.c.

Referenced by thig_key_and_cipher_init().

int mode = MODE_CFB1

Twofish mode.

Definition at line 76 of file thig_ims_enc.c.

Referenced by thig_key_and_cipher_init().

int byteCnt = BLOCK_SIZE/8

Definition at line 77 of file thig_ims_enc.c.

Referenced by thig_encrypt().

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