gpmp::RC4 Class Reference

#include <rc4.hpp>

Public Member Functions
void	byte_swap (uint8_t *a, uint8_t *b)
void	trad_swap (unsigned char *a, unsigned char *b)
void	XOR_swap (unsigned char *a, unsigned char *b)
void	KSA (char *key, unsigned char *S, int swap_type)
void	PRGA (unsigned char *S, char *plaintext, unsigned char *ciphertext, int swap_type)
std::string	store_hash (char *plaintext, unsigned char *hashtext, int swap_type)
unsigned char *	compute (char *key, char *plaintext, unsigned char *hashtext, int swap_type)

Detailed Description

Examples

rc4.cpp.

Definition at line 71 of file rc4.hpp.

Member Function Documentation

byte_swap()

void gpmp::RC4::byte_swap	(	uint8_t *	a,
		uint8_t *	b
	)

Definition at line 49 of file rc4.cpp.

                                              {
    uint8_t swapped = *a;
    swapped = *a;
    *a = *b;
    *b = swapped;
}

compute()

unsigned char * gpmp::RC4::compute	(	char *	key,
		char *	plaintext,
		unsigned char *	hashtext,
		int	swap_type
	)

Examples

rc4.cpp.

Definition at line 142 of file rc4.cpp.

                                                 {
    if (ciphertext == NULL) {
        throw std::runtime_error("[-] Error Allocating Memory");
    }
 
    // check for swap types 1-3
    if (0 <= swap_type && swap_type <= 2) {
        unsigned char S[BYTE_LIMIT];
        KSA(key, S, swap_type);
        PRGA(S, plaintext, ciphertext, swap_type);
    }
 
    else if (swap_type > 2) {
        throw std::runtime_error("[-] Invalid swap_type");
    }
 
    return ciphertext;
}

References BYTE_LIMIT.

Referenced by main().

KSA()

void gpmp::RC4::KSA	(	char *	key,
		unsigned char *	S,
		int	swap_type
	)

Definition at line 68 of file rc4.cpp.

                                                            {
    uint32_t len = strlen(key);
    int j = 0;
 
    for (int i = 0; i < BYTE_LIMIT; i++) {
        S[i] = i;
    }
 
    for (int i = 0; i < BYTE_LIMIT; i++) {
        j = (j + S[i] + key[i % len]) & BITS;
 
        // choose swap algorithm based off swap_type
        if (swap_type == 0) {
            XOR_swap(&S[i], &S[j]);
        } else if (swap_type == 1) {
            trad_swap(&S[i], &S[j]);
        } else if (swap_type == 2) {
            byte_swap(&S[i], &S[j]);
        }
    }
}

References BITS, and BYTE_LIMIT.

PRGA()

void gpmp::RC4::PRGA	(	unsigned char *	S,
		char *	plaintext,
		unsigned char *	ciphertext,
		int	swap_type
	)

Definition at line 90 of file rc4.cpp.

                                    {
    int i = 0;
    int j = 0;
 
    for (size_t n = 0, len = strlen(plaintext); n < len; n++) {
        i = (i + 1) & BITS;
        j = (j + S[i]) & BITS;
 
        // choose swap algorithm based off swap_type
        if (swap_type == 0) {
            XOR_swap(&S[i], &S[j]);
        } else if (swap_type == 1) {
            trad_swap(&S[i], &S[j]);
        } else if (swap_type == 2) {
            byte_swap(&S[i], &S[j]);
        }
 
        uint32_t rnd = S[(S[i] + S[j]) & BITS];
 
        ciphertext[n] = rnd ^ plaintext[n];
    }
}

References BITS.

store_hash()

std::string gpmp::RC4::store_hash	(	char *	plaintext,
		unsigned char *	hashtext,
		int	swap_type
	)

Examples

rc4.cpp.

Definition at line 117 of file rc4.cpp.

                                                                           {
    // length of our plaintext
    size_t len = strlen((char *)plaintext);
    // for snprintf declare a buffer
    char buffer[len + 1];
    size_t size = sizeof(buffer);
 
    // initialize empty string
    std::string stored_text = "";
 
    // traverse the hashtext appending each block to a string
    for (size_t index = 0; index < len; index++) {
        if (swap_type == 0) {
            snprintf(buffer, size, "|x%02hhx|", hashtext[index]);
        }
        // to format our hash to a string for future manipulation
        else {
            snprintf(buffer, size, "%02hhX", hashtext[index]);
        }
        // append the declared string
        stored_text += std::string(buffer);
    }
    return stored_text;
}

Referenced by main().

trad_swap()

void gpmp::RC4::trad_swap	(	unsigned char *	a,
		unsigned char *	b
	)

Definition at line 56 of file rc4.cpp.

                                                          {
    int swapped = *a;
    *a = *b;
    *b = swapped;
}

XOR_swap()

void gpmp::RC4::XOR_swap	(	unsigned char *	a,
		unsigned char *	b
	)

Definition at line 62 of file rc4.cpp.

                                                         {
    *a ^= *b;
    *b ^= *a;
    *a ^= *b;
}

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The documentation for this class was generated from the following files:

• include/openGPMP/nt/rc4.hpp
• modules/nt/rc4.cpp