rc4.h File Reference

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Classes
struct	_RC4_CONTEXT

Typedefs
typedef struct _RC4_CONTEXT	RC4_CONTEXT

Functions
void	rc4_init (RC4_CONTEXT *a4i, const unsigned char *key, unsigned int keyLen)
void	rc4_crypt (RC4_CONTEXT *a4i, unsigned char *inoutString, unsigned int length)

Typedef Documentation

RC4_CONTEXT

typedef struct _RC4_CONTEXT RC4_CONTEXT

Function Documentation

rc4_crypt()

void rc4_crypt	(	RC4_CONTEXT *	a4i,
		unsigned char *	inoutString,
		unsigned int	length
	)

Definition at line 47 of file rc4.c.

{
    unsigned char *const s=a4i->state;
    unsigned int x = a4i->x;
    unsigned int y = a4i->y;
    unsigned int a, b;
 
    while(length--)
    {
        x = (x+1) & 0xff;
        a = s[x];
        y = (y+a) & 0xff;
        b = s[y];
        s[x] = b;
        s[y] = a;
        *inoutString++ ^= s[(a+b) & 0xff];
    }
 
    a4i->x = x;
    a4i->y = y;
}

Referenced by SystemFunction032().

rc4_init()

void rc4_init	(	RC4_CONTEXT *	a4i,
		const unsigned char *	key,
		unsigned int	keyLen
	)

Definition at line 25 of file rc4.c.

{
    unsigned int keyIndex = 0, stateIndex = 0;
    unsigned int i, a;
 
    a4i->x = a4i->y = 0;
 
    for (i=0; i<256; i++)
        a4i->state[i] = i;
 
    for (i=0; i<256; i++)
    {
        a = a4i->state[i];
        stateIndex += key[keyIndex] + a;
        stateIndex &= 0xff;
        a4i->state[i] = a4i->state[stateIndex];
        a4i->state[stateIndex] = a;
        if (++keyIndex >= keyLen)
            keyIndex = 0;
    }
}

Referenced by SystemFunction032().