How to properly use Cryptohash lib

[RETN]

Hi masters,

I am new here on tuts4you.

I need help of you guys.

I am coding an personal hasher tool in ASM with the help of cryptohash lib.

I am having problem with EnCrypters like MARS

It's not giving me proper hash and not decryting it too.

Here is a piece of code, I have coded.

                        invoke GetDlgItemText,hWin,EDIT_KEY,addr key,sizeof key
			mov keysize,eax
			invoke GetDlgItemText,hWin,EDIT_INPUT,addr inbuff,sizeof inbuff
			invoke MARSSetKey,addr key,keysize
			invoke MARSEncrypt,addr inbuff,addr hash
			invoke HexEncode,addr hash,16,addr outbuff
			invoke SetDlgItemText,hWin,EDIT_HASH,addr outbuff
			invoke RtlZeroMemory,addr inbuff,sizeof inbuff
			invoke MARSDecrypt,addr outbuff,addr inbuff
			invoke SetDlgItemText,hWin,EDIT_DECRYPTEDHASH,addr inbuff

For more, I have attached my project of winASM, kindly solve the issue.

If possible please tell me how to use all Encrypters of cryptohash.

Thanking you

RETN

New Folder.zip

[kao]

1) MARS is a block cipher, and MARSEncrypt encrypts one block (128bits = 16bytes) at a time

2) If input was less than 16 bytes, your code will encrypt some garbage too.

3) Before decrypting *perhaps* you should set the decryption key again.

4) But the biggest problem is here:

invoke GetDlgItemText,hWin,EDIT_KEY,addr key,sizeof key
mov keysize,eax
invoke GetDlgItemText,hWin,EDIT_INPUT,addr inbuff,sizeof inbuffinvoke MARSSetKey,addr key,keysize
invoke MARSEncrypt,addr inbuff,addr hash   ----> encrypted output goes to "hash". 
invoke HexEncode,addr hash,16,addr outbuff  ----> "outbuff" now contains string representation of encrypted data
invoke SetDlgItemText,hWin,EDIT_HASH,addr outbuffinvoke RtlZeroMemory,addr inbuff,sizeof inbuff
invoke MARSDecrypt,addr outbuff,addr inbuff ----> you should decrypt "hash", not outbuff. 
invoke SetDlgItemText,hWin,EDIT_DECRYPTEDHASH,addr inbuff

[Blue]

Nice question and Nice answer Kao, it will be useful.

Thanks

[RETN]

Thanks Kao,

But help me on this.

I am using Rijandael and XTEA from cryptolib and having two different problems.

When Using Rijandael the program crashes when I click on Calculate and when

I am using XTEA the program hangs.

Here are codes :

XTEA :

invoke XTEAInit,addr key,addr keysize
		invoke XTEAEncrypt,addr instring,addr tempbuff
		invoke HexEncode,addr tempbuff,bvalue,addr outstring
		invoke SetDlgItemInt,hWin,1038,bvalue,0
		invoke SetDlgItemText,hWin,1024,addr outstring

[RETN]

Thanks Kao,

But help me on this.

I am using Rijandael and XTEA from cryptolib and having two different problems.

When Using Rijandael the program crashes when I click on Calculate and when

I am using XTEA the program hangs.

Here are codes :

XTEA :

                invoke XTEAInit,addr key,addr keysize  ; keysize is length of key
		invoke XTEAEncrypt,addr instring,addr tempbuff
		invoke HexEncode,addr tempbuff,16,addr outstring
		invoke SetDlgItemText,hWin,1024,addr outstring

Rijandael :

invoke RijndaelInit,addr key,keysize
		invoke RijndaelEncrypt,addr instring,addr tempbuff
		invoke HexEncode,addr tempbuff,bvalue,addr outstring
		invoke SetDlgItemInt,hWin,1038,bvalue,0
		invoke SetDlgItemText,hWin,1024,addr outstring