void des_ecb_encrypt(des_cblock *input, des_cblock *output,
des_key_schedule ks, int enc)
{
register DES_LONG l;
DES_LONG ll[2];
const unsigned char *in=&(*input)[0];
unsigned char *out = &(*output)[0];
c2l(in,l); ll[0]=l;
c2l(in,l); ll[1]=l;
des_encrypt1(ll,ks,enc);
l=ll[0]; l2c(l,out);
l=ll[1]; l2c(l,out);
l=ll[0]=ll[1]=0;
}
DES_LONG des_cbc_cksum(const unsigned char *in, des_cblock *output,
long length,
des_key_schedule schedule, const_des_cblock *ivec)
{
register DES_LONG tout0,tout1,tin0,tin1;
register long l=length;
DES_LONG tin[2];
unsigned char *out = &(*output)[0];
const unsigned char *iv = &(*ivec)[0];
c2l(iv,tout0);
c2l(iv,tout1);
for (; l>0; l-=8)
{
if (l >= 8)
{
c2l(in,tin0);
c2l(in,tin1);
}
else
c2ln(in,tin0,tin1,l);
tin0^=tout0; tin[0]=tin0;
tin1^=tout1; tin[1]=tin1;
des_encrypt1((DES_LONG *)tin,schedule,DES_ENCRYPT);
/* fix 15/10/91 eay - thanks to [email protected] */
tout0=tin[0];
tout1=tin[1];
}
if (out != NULL)
{
l2c(tout0,out);
l2c(tout1,out);
}
tout0=tin0=tin1=tin[0]=tin[1]=0;
return(tout1);
}
void des_ede3_cbcm_encrypt(const unsigned char *in, unsigned char *out,
long length, des_key_schedule ks1, des_key_schedule ks2,
des_key_schedule ks3, des_cblock *ivec1, des_cblock *ivec2,
int enc)
{
register DES_LONG tin0,tin1;
register DES_LONG tout0,tout1,xor0,xor1,m0,m1;
register long l=length;
DES_LONG tin[2];
unsigned char *iv1,*iv2;
iv1 = &(*ivec1)[0];
iv2 = &(*ivec2)[0];
if (enc)
{
c2l(iv1,m0);
c2l(iv1,m1);
c2l(iv2,tout0);
c2l(iv2,tout1);
for (l-=8; l>=-7; l-=8)
{
tin[0]=m0;
tin[1]=m1;
des_encrypt1(tin,ks3,1);
m0=tin[0];
m1=tin[1];
if(l < 0)
{
c2ln(in,tin0,tin1,l+8);
}
else
{
c2l(in,tin0);
c2l(in,tin1);
}
tin0^=tout0;
tin1^=tout1;
tin[0]=tin0;
tin[1]=tin1;
des_encrypt1(tin,ks1,1);
tin[0]^=m0;
tin[1]^=m1;
des_encrypt1(tin,ks2,0);
tin[0]^=m0;
tin[1]^=m1;
des_encrypt1(tin,ks1,1);
tout0=tin[0];
tout1=tin[1];
l2c(tout0,out);
l2c(tout1,out);
}
iv1=&(*ivec1)[0];
l2c(m0,iv1);
l2c(m1,iv1);
iv2=&(*ivec2)[0];
l2c(tout0,iv2);
l2c(tout1,iv2);
}
else
{
register DES_LONG t0,t1;
c2l(iv1,m0);
c2l(iv1,m1);
c2l(iv2,xor0);
c2l(iv2,xor1);
for (l-=8; l>=-7; l-=8)
{
tin[0]=m0;
tin[1]=m1;
des_encrypt1(tin,ks3,1);
m0=tin[0];
m1=tin[1];
c2l(in,tin0);
c2l(in,tin1);
t0=tin0;
t1=tin1;
tin[0]=tin0;
tin[1]=tin1;
des_encrypt1(tin,ks1,0);
tin[0]^=m0;
tin[1]^=m1;
des_encrypt1(tin,ks2,1);
tin[0]^=m0;
tin[1]^=m1;
des_encrypt1(tin,ks1,0);
tout0=tin[0];
tout1=tin[1];
tout0^=xor0;
tout1^=xor1;
if(l < 0)
{
l2cn(tout0,tout1,out,l+8);
}
else
{
l2c(tout0,out);
l2c(tout1,out);
}
xor0=t0;
xor1=t1;
}
iv1=&(*ivec1)[0];
l2c(m0,iv1);
l2c(m1,iv1);
iv2=&(*ivec2)[0];
l2c(xor0,iv2);
l2c(xor1,iv2);
}
tin0=tin1=tout0=tout1=xor0=xor1=0;
tin[0]=tin[1]=0;
}
void des_ncbc_encrypt(const unsigned char *in, unsigned char *out, long length,
des_key_schedule schedule, des_cblock *ivec, int enc)
{
register DES_LONG tin0,tin1;
register DES_LONG tout0,tout1,xor0,xor1;
register long l=length;
DES_LONG tin[2];
unsigned char *iv;
iv = &(*ivec)[0];
if (enc)
{
c2l(iv,tout0);
c2l(iv,tout1);
for (l-=8; l>=0; l-=8)
{
c2l(in,tin0);
c2l(in,tin1);
tin0^=tout0;
tin[0]=tin0;
tin1^=tout1;
tin[1]=tin1;
des_encrypt1((DES_LONG *)tin,schedule,DES_ENCRYPT);
tout0=tin[0];
l2c(tout0,out);
tout1=tin[1];
l2c(tout1,out);
}
if (l != -8)
{
c2ln(in,tin0,tin1,l+8);
tin0^=tout0;
tin[0]=tin0;
tin1^=tout1;
tin[1]=tin1;
des_encrypt1((DES_LONG *)tin,schedule,DES_ENCRYPT);
tout0=tin[0];
l2c(tout0,out);
tout1=tin[1];
l2c(tout1,out);
}
iv = &(*ivec)[0];
l2c(tout0,iv);
l2c(tout1,iv);
}
else
{
c2l(iv,xor0);
c2l(iv,xor1);
for (l-=8; l>=0; l-=8)
{
c2l(in,tin0);
tin[0]=tin0;
c2l(in,tin1);
tin[1]=tin1;
des_encrypt1((DES_LONG *)tin,schedule,DES_DECRYPT);
tout0=tin[0]^xor0;
tout1=tin[1]^xor1;
l2c(tout0,out);
l2c(tout1,out);
xor0=tin0;
xor1=tin1;
}
if (l != -8)
{
c2l(in,tin0);
tin[0]=tin0;
c2l(in,tin1);
tin[1]=tin1;
des_encrypt1((DES_LONG *)tin,schedule,DES_DECRYPT);
tout0=tin[0]^xor0;
tout1=tin[1]^xor1;
l2cn(tout0,tout1,out,l+8);
xor0=tin0;
xor1=tin1;
}
iv = &(*ivec)[0];
l2c(xor0,iv);
l2c(xor1,iv);
}
tin0=tin1=tout0=tout1=xor0=xor1=0;
tin[0]=tin[1]=0;
}
/**
* Encrypts a plaintext string
* @param plaintext - the plaintext string
* @return - the encrypted ciphertext string
*/
string DES::encrypt(const string& plaintext)
{
//LOGIC:
//1. Check to make sure that the block is exactly 8 characters (i.e. 64 bits)
//2. Declare an array DES_LONG block[2];
//3. Use ctol() to convert the first 4 chars into long; store the result in block[0]
//4. Use ctol() to convert the second 4 chars into long; store the resul in block[1]
//5. Perform des_encrypt1 in order to encrypt the block using this->key (see sample codes for details)
//6. Convert the first ciphertext long to 4 characters using ltoc()
//7. Convert the second ciphertext long to 4 characters using ltoc()
//8. Save the results in the resulting 8-byte string (e.g. bytes[8])
//9. Convert the string (e.g. bytes[8]) to a C++ string.
//10.Return the C++ string
string ptext = plaintext;
size_t number_of_padding = 0;
while (ptext.size() < 8)
{
ptext.append("0");
number_of_padding++;
}
// convert int to a character in ASCII
char number_of_padding_char = '0' + number_of_padding;
/**
* put the number of padding at the end of padded plaintext block
* pad only one zero may be a special case?
* std::string.back() should not be used on the empty string
* it's important to do the bound checking when dealing with end of string
* we will remove the padding in the cipher.cpp
*/
if (number_of_padding > 0 && number_of_padding < 8) {
size_t last_index = ptext.length() - 1;
ptext.at(last_index) = number_of_padding_char;
}
DES_LONG block[2];
//Convert C++ string to c-string
char cstr1[4];
char cstr2[4];
ptext.copy(cstr1, 4, 0);
cstr1[4] = '\0';
ptext.copy(cstr2, 4, 4);
cstr2[4] = '\0';
unsigned char ucstr1[4];
memset(ucstr1, 0, sizeof(ucstr1));
for (int i = 0; i < sizeof(cstr1); i++) {
ucstr1[i] = cstr1[i];
}
ucstr1[sizeof(cstr1)] = '\0';
unsigned char ucstr2[4];
memset(ucstr2, 0, sizeof(ucstr2));
for (int i = 0; i < sizeof(cstr2); i++) {
ucstr2[i] = cstr2[i];
}
ucstr2[sizeof(cstr2)] = '\0';
//Convert first 4 chars into Long Int
block[0] = ctol(ucstr1);
block[1] = ctol(ucstr2);
//Encrypt
des_encrypt1(block,key,ENC);
//Convert long to c string
unsigned char txtText1[4];
unsigned char txtText2[4];
ltoc(block[0], txtText1);
ltoc(block[1], txtText2);
//Convert c string to C++ string
string convertcstr1 = "";
for (int i = 0; i < sizeof(txtText1); i++) {
convertcstr1.push_back(txtText1[i]);
}
string convertcstr2 = "";
for (int i = 0; i < sizeof(txtText2); i++) {
convertcstr2.push_back(txtText2[i]);
}
//cout << "ciphertext: " << convertcstr1 + convertcstr2 << endl;
//cout << "decrypt test: " << decrypt(convertcstr1 + convertcstr2) << "|" << endl;
return convertcstr1 + convertcstr2;
}
/**
* Decrypts a string of ciphertext
* @param ciphertext - the ciphertext
* @return - the plaintext
*/
string DES::decrypt(const string& ciphertext)
{
//LOGIC:
// Same logic as encrypt(), except in step 5. decrypt instead of encrypting
DES_LONG block[2];
//Convert C++ string to c-string
/*const char* cstrText1 = ciphertext.substr(0,4).c_str();
const char* cstrText2 = ciphertext.substr(4,4).c_str();
char cstr1[4], cstr2[4];
strncpy (cstr1, cstrText1, sizeof(cstrText1));
strncpy (cstr2, cstrText2, sizeof(cstrText2));
*/
char cstr1[4];
char cstr2[4];
ciphertext.copy(cstr1, 4, 0);
cstr1[4] = '\0';
ciphertext.copy(cstr2, 4, 4);
cstr2[4] = '\0';
unsigned char ucstr1[4];
memset(ucstr1, 0, sizeof(ucstr1));
for (int i = 0; i < sizeof(cstr1); i++) {
ucstr1[i] = cstr1[i];
}
ucstr1[sizeof(cstr1)] = '\0';
unsigned char ucstr2[4];
memset(ucstr2, 0, sizeof(ucstr2));
for (int i = 0; i < sizeof(cstr2); i++) {
ucstr2[i] = cstr2[i];
}
ucstr2[sizeof(cstr2)] = '\0';
//Convert first 4 chars into Long Int
block[0] = ctol(ucstr1);
block[1] = ctol(ucstr2);
//Decrypt
des_encrypt1(block,key,DEC);
//Convert Long back to c string
unsigned char txtText1[4];
unsigned char txtText2[4];
ltoc(block[0], txtText1);
ltoc(block[1], txtText2);
//Convert c string to C++ string
string convertcstr1 = "";
for (int i = 0; i < sizeof(txtText1); i++) {
convertcstr1.push_back(txtText1[i]);
}
string convertcstr2 = "";
for (int i = 0; i < sizeof(txtText2); i++) {
convertcstr2.push_back(txtText2[i]);
}
//cout << "length of plaintext: " << test.length() << endl;
return convertcstr1 + convertcstr2;
}
