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ql-owo-lp/Crypto-lab5-cracker.c

Last active December 15, 2015 10:19
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for CIS 644 Lab 5
Raw
ciphertext.html
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<META NAME="hexdata" CONTENT="GHex export to HTML">
</HEAD>
<BODY>
<TABLE BORDER="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="33%">
&nbsp;
</TD>
<TD WIDTH="33%" ALIGN="CENTER">
ciphertext:
</TD>
<TD WIDTH="33%" ALIGN="RIGHT">
&nbsp;
</TD>
</TR>
</TABLE>
<CENTER>
<TABLE BORDER="1" CELLSPACING="2" CELLPADDING="2">
<TR>
<TD>
<TABLE BORDER="0" CELLSPACING="0" CELLPADDING="0">
<TR>
<TD>
<PRE>00000000</PRE>
</TD>
</TR>
<TR>
<TD>
<PRE>00000011</PRE>
</TD>
</TR>
</TABLE>
</TD>
<TD>
<TABLE BORDER="0" CELLSPACING="0" CELLPADDING="0">
<TR>
<TD>
<PRE>8d 20 e5 05 6a 8d 24 d0 46 2c e7 4e 49 04 c1 b5 13</PRE>
</TD>
</TR>
<TR>
<TD>
<PRE>e1 0d 1d f4 a2 ef 2a d4 54 0f ae 1c a0 aa f9 </PRE>
</TD>
</TR>
<TR>
<TD>
<PRE></PRE>
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<TABLE BORDER="0" CELLSPACING="0" CELLPADDING="0">
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<PRE>. ..j.$.F,.NI....</PRE></TD>
</TR>
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<PRE>......*.T......</PRE></TD>
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</TABLE>
</CENTER>
<HR WIDTH="100%">Hex dump generated by <B>gtkhex-1.0</B>
</BODY>
</HTML>
Raw
Crypto-lab5-cracker.c
/*
For AES encryption/decryption lab. -> CIS 644 / Sp13 -> Kevin Wang
*/
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <openssl/evp.h>
int main () {
read_words("words.txt");
return 0;
}
int do_crypt1(char *_key)
{
unsigned char outbuf[1024];
int outlen, tmplen, i;
// init key and iv
unsigned char key[16];
unsigned char iv[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
char intext[] = "This is a top secret.";
strncpy((char *)key, _key, 16);
// append space
for (i=15;i>0;i--) {
if (key[i]==0)
key[i]=' ';
}
EVP_CIPHER_CTX ctx;
FILE *out;
EVP_CIPHER_CTX_init(&ctx);
EVP_EncryptInit_ex(&ctx, EVP_aes_128_cbc(), NULL, key, iv);
if(!EVP_EncryptUpdate(&ctx, outbuf, &outlen, intext, strlen(intext)))
{
/* Error */
return 0;
}
if(!EVP_EncryptFinal_ex(&ctx, outbuf + outlen, &tmplen))
{
/* Error */
return 0;
}
outlen += tmplen;
EVP_CIPHER_CTX_cleanup(&ctx);
out = fopen("test", "wb");
fwrite(outbuf, 1, outlen, out);
fclose(out);
return 1;
}
int do_crypt(char *_key)
{
unsigned char inbuf[1024], outbuf[1024 + EVP_MAX_BLOCK_LENGTH];
int inlen, outlen, tmplen, do_encrypt=0, i;
FILE *in, *out;
unsigned char key[16];
unsigned char iv[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
unsigned char intext[] = "This is a top secret.";
EVP_CIPHER_CTX ctx;
in = fopen ("ciphertext", "rb");
strncpy((char *)key, _key, 16);
// append space
for (i=15;i>0;i--) {
if (key[i]==0 || key[i]==13 || key[i]==10 || key[i]=='\0')
key[i]=' ';
}
/* Don't set key or IV because we will modify the parameters */
EVP_CIPHER_CTX_init(&ctx);
EVP_CipherInit_ex(&ctx, EVP_aes_128_cbc(), NULL, key, iv, do_encrypt);
for(;;)
{
inlen = fread(inbuf, 1, 1024, in);
if(inlen <= 0) break;
if(!EVP_CipherUpdate(&ctx, outbuf, &outlen, inbuf, inlen))
{
/* Error */
EVP_CIPHER_CTX_cleanup(&ctx);
fclose(in);
return 0;
}
}
fclose(in);
if(!EVP_CipherFinal_ex(&ctx, outbuf + outlen, &tmplen))
{
/* Error */
EVP_CIPHER_CTX_cleanup(&ctx);
return 0;
}
outlen += tmplen;
EVP_CIPHER_CTX_cleanup(&ctx);
out = fopen("test1", "wt");
fwrite(outbuf, 1, outlen, out);
fclose(out);
// strcmp(outbuf, intext) doesn't work
for (i=0;i<21;i++) {
if (*(outbuf+i) != intext[i]) return 0;
}
return 1;
}
// read key (words) from specific file
int read_words (char * file) {
FILE *fr;
fr = fopen (file, "rt");
char word[16]; // at most 16 characters
while(fgets(word, 16, fr) != NULL)
{
if (do_crypt(word))
printf("Found! key is %s", word);
}
fclose(fr); /* close the file prior to exiting the routine */
return 0;
}
Raw
Makefile
INC=/usr/local/ssl/include/
LIB=/usr/local/ssl/lib/
all:
gcc -I$(INC) -L$(LIB) -o enc Crypto-lab5-cracker.c -lcrypto
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