/* This file is in the public domain. */

#include <des.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>

#include "algs.h"
#include "panic.h"
#include "verbose.h"
#include "alg-util.h"

typedef struct des3_state DES3_STATE;

struct des3_state {
  unsigned char key[24];
  unsigned char iv[8];
  int direction;
  } ;

static void *enc_3des_cbc_init_enc(const void *key, const void *iv)
{
 DES3_STATE *s;

 s = malloc(sizeof(DES3_STATE));
 if (s == 0) return(0);
 bcopy(key,&s->key[0],24);
 bcopy(iv,&s->iv[0],8);
 s->direction = ENCRYPT;
 if (VERB(CRYPTO))
  { int i;
    verb(CRYPTO,"3des-cbc %p: enc key=",(void *)s);
    for (i=0;i<24;i++) verb(CRYPTO,"%02x",((const unsigned char *)key)[i]);
    verb(CRYPTO," iv=");
    for (i=0;i<8;i++) verb(CRYPTO,"%02x",s->iv[i]);
    verb(CRYPTO,"\n");
  }
 return(s);
}

static void *enc_3des_cbc_init_dec(const void *key, const void *iv)
{
 DES3_STATE *s;

 s = malloc(sizeof(DES3_STATE));
 if (s == 0) return(0);
 bcopy(key,&s->key[0],24);
 bcopy(iv,&s->iv[0],8);
 s->direction = DECRYPT;
 if (VERB(CRYPTO))
  { int i;
    verb(CRYPTO,"3des-cbc %p: dec key=",(void *)s);
    for (i=0;i<24;i++) verb(CRYPTO,"%02x",((const unsigned char *)key)[i]);
    verb(CRYPTO," iv=");
    for (i=0;i<8;i++) verb(CRYPTO,"%02x",s->iv[i]);
    verb(CRYPTO,"\n");
  }
 return(s);
}

static void enc_3des_cbc_process(void *state, const void *in, void *out, int datalen)
{
 DES3_STATE *s;
 const unsigned char *ip;
 unsigned char *op;
 int len0;

 s = state;
 ip = in;
 op = out;
 if (datalen & 7) panic("misaligned length");
 if (VERB(CRYPTO))
  { int i;
    verb(CRYPTO,"3des-cbc %p\n in ",(void *)s);
    for (i=0;i<datalen;i++) verb(CRYPTO,"%02x",((const unsigned char *)in)[i]);
    verb(CRYPTO,"\n iv ");
    for (i=0;i<8;i++) verb(CRYPTO,"%02x",s->iv[i]);
    verb(CRYPTO,"\n");
    len0 = datalen;
  }
 switch (s->direction)
  { case ENCRYPT:
       while (datalen > 0)
	{ xor_block(&s->iv[0],ip,&s->iv[0],8);
	  des3(&s->iv[0],&s->iv[0],&s->key[0],ENCRYPT);
	  bcopy(&s->iv[0],op,8);
	  ip += 8;
	  op += 8;
	  datalen -= 8;
	}
       break;
    case DECRYPT:
       while (datalen > 0)
	{ unsigned char ib[8];
	  bcopy(ip,&ib[0],8);
	  des3(op,ip,&s->key[0],DECRYPT);
	  xor_block(&s->iv[0],op,op,8);
	  bcopy(ib,&s->iv[0],8);
	  ip += 8;
	  op += 8;
	  datalen -= 8;
	}
       break;
    default:
       panic("bad direction");
       break;
  }
 if (VERB(CRYPTO))
  { int i;
    verb(CRYPTO,"out ");
    for (i=0;i<len0;i++) verb(CRYPTO,"%02x",((unsigned char *)out)[i]);
    verb(CRYPTO,"\nniv ");
    for (i=0;i<8;i++) verb(CRYPTO,"%02x",s->iv[i]);
    verb(CRYPTO,"\n");
  }
}

static void *enc_3des_ctr_init(const void *key, const void *iv)
{
 DES3_STATE *s;

 s = malloc(sizeof(DES3_STATE));
 if (s == 0) return(0);
 bcopy(key,&s->key[0],24);
 bcopy(iv,&s->iv[0],8);
 if (VERB(CRYPTO))
  { int i;
    verb(CRYPTO,"3des-ctr %p: key=",(void *)s);
    for (i=0;i<24;i++) verb(CRYPTO,"%02x",s->key[i]);
    verb(CRYPTO," iv=");
    for (i=0;i<8;i++) verb(CRYPTO,"%02x",s->iv[i]);
    verb(CRYPTO,"\n");
  }
 return(s);
}

static void enc_3des_ctr_process(void *state, const void *in, void *out, int datalen)
{
 DES3_STATE *s;
 const unsigned char *ip;
 unsigned char *op;
 unsigned char *x;
 unsigned char xorbuf[8];
 int left;
 int i;

 s = state;
 ip = in;
 op = out;
 x = &s->iv[0];
 if (datalen & 7) panic("misaligned length");
 if (VERB(CRYPTO))
  { int i;
    verb(CRYPTO,"3des-ctr %p\n in",(void *)s);
    for (i=0;i<datalen;i++) verb(CRYPTO,"%s%02x",(i&7)?"":" ",ip[i]);
    verb(CRYPTO,"\n  x ");
    for (i=0;i<8;i++) verb(CRYPTO,"%02x",x[i]);
    verb(CRYPTO,"\n");
  }
 for (left=datalen;left>0;left-=8)
  { des3(&xorbuf[0],&x[0],&s->key[0],ENCRYPT);
    xor_block(&xorbuf[0],ip,op,8);
    i = 7;
    while (1)
     { if (i < 0) break;
       if (x[i] != 0xff)
	{ x[i] ++;
	  break;
	}
       x[i] = 0;
       i --;
     }
    ip += 8;
    op += 8;
  }
 if (VERB(CRYPTO))
  { int i;
    verb(CRYPTO,"out");
    for (i=0;i<datalen;i++) verb(CRYPTO,"%s%02x",(i&7)?"":" ",op[i-datalen]);
    verb(CRYPTO,"\n");
  }
}

static void enc_3des_done(void *state)
{
 free(state);
}

ENCALG encalg_3des_cbc
 = { "3des-cbc", 0, 8, 8, 24, 0,
     &enc_3des_cbc_init_enc,
     &enc_3des_cbc_init_dec,
     &enc_3des_cbc_process,
     &enc_3des_done };

ENCALG encalg_3des_ctr
 = { "3des-ctr", 0, 8, 8, 24, 0,
     &enc_3des_ctr_init,
     &enc_3des_ctr_init,
     &enc_3des_ctr_process,
     &enc_3des_done };