This is last one i've actively coded:
Crypteria5.c Cipher
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define ull unsigned long long
#define ll long long int
#define ui unsigned int
#define lu unsigned long
#define li long int
#define ch char
#define uc unsigned char
#define chp char*
#define ucp unsigned char*
#define stdargs int argc,char **argv
//==DEBUG
#define thisline ;printf("%d,",__LINE__) ;
//debug scan,print number of last executed line
//==ASM
#define rdt(timer) ;asm volatile("rdtsc\n\t":"=A"(timer)) ;
// unsigned long long timer
//==Bitutil//byte rotate left/right
#define brol(value,shift) ((value << shift) | (value >> (8 - shift)))
#define getbit(byte,place) (byte&(1<<place))
#define delbit(byte,place) (byte&(0xFF^(1<<place)))
//get 2chunks of byte
#define byte04(bt) bt&0xc0
//chunk[11000000]
#define byte14(bt) bt&0x30
//chunk[00110000]
#define byte24(bt) bt&0xc
//chunk[00001100]
#define byte34(bt) bt&0x3
//chunk[00000011]
//erase 2chunks of byte
#define byte40(bt) bt&0x3f
//chunk[00111111]
#define byte41(bt) bt&0xcf
//chunk[11001111]
#define byte42(bt) bt&0xf3
//chunk[11110011]
#define byte43(bt) bt&0xfc
//chunk[11111100]
//get 1bit from byte
#define gbit0(bt) bt&0x80
#define gbit1(bt) bt&0x40
#define gbit2(bt) bt&0x20
#define gbit3(bt) bt&0x10
#define gbit4(bt) bt&0x8
#define gbit5(bt) bt&0x4
#define gbit6(bt) bt&0x2
#define gbit7(bt) bt&0x1
//erase 1 bit from byte
#define cbit0(bt) bt&0x7f
#define cbit1(bt) bt&0xbf
#define cbit2(bt) bt&0xdf
#define cbit3(bt) bt&0xef
#define cbit4(bt) bt&0xf7
#define cbit5(bt) bt&0xfb
#define cbit6(bt) bt&0xfd
#define cbit7(bt) bt&0xfe
//==File IO
#define fseekend(file) ;fseek(file,0,SEEK_END) ;
#define fseekstart(file) ;fseek(file,0,SEEK_SET) ;
#define rfp(pointer,filename) ;FILE* pointer=fopen(filename,"rb") ;
#define srfp(pointer2,file) ;FILE* pointer2=fopen(file,"rb") ;if(!pointer2){printf("%s",file) ;perror("<=srfp:") ;exit(1) ;}
#define wfp(pointer,filename) ;FILE* pointer=fopen(filename,"wb") ;
#define swfp(pointer2,file) ;FILE* pointer2=fopen(file,"wb") ;if(!pointer2){printf("%s",file) ;perror("<=swfp:") ;exit(1) ;}
#define fsize(name,rsize) ;srfp(temp_1,name) ;fseekend(temp_1) ;rsize=ftell(temp_1) ;fclose(temp_1)
#define rdf(pointer3,name,rsize) ;srfp(temp_2,name) ;fseekend(temp_2) ;li rsize=ftell(temp_2) ;rewind(temp_2) ;uc* pointer3=malloc(rsize) ;fread(pointer3,1,rsize,temp_2) ;fclose(temp_2) ;
#define wrf(pointer,name,size) ;swfp(temp_3,name) ;fwrite(pointer,1,size,temp_3) ;fclose(temp_3) ;
#define SYNTAX ;printf("Syntax : %s inputfile password [-decode]\n .ecf files are encrypted, .src files are decrypted",argv[0]) ;
inline uc rndbyte(void){ull tmp ;rdt(tmp) ;uc a,c,b,d ;a=tmp&0xFF ;d=a%5 ;if(d< ;3){d++ ;}rdt(tmp) ;b=tmp&0xFF ;d=(d*(b%5))^a ;if(d> ;10){d-=10 ;} ;rdt(tmp) ;c=tmp&0xFF ;if(d&1){return a^b^c ;}else{return b^c^a ;}}
void main(stdargs){
if(argc<3){SYNTAX ;return ;};
rdf(input,argv[1],inpsize) ;
int pwlen=strlen(argv[2]) ;
if(pwlen<8){printf("Password too short!\n") ;exit(1) ;}
uc pwshift=((pwlen%256)^(argv[2][0])) ;
chp outputname=malloc(512) ;
sprintf(outputname,"%s%s",argv[1],argv[3]?".src":".ecf") ;
printf("%s '%s' to '%s'",argv[3]?"Decoding":"Encoding",argv[1],outputname) ;
swfp(output,outputname) ;
li loop=0 ;
li gapbyte=0 ;
uc bitarr[8] ;
uc bitpos,byten,curgap,curgaph,s1,s2,endbyte ;
if(!argv[3]){for(loop=0 ;loop<inpsize ;loop++){
curgap=argv[2][loop%pwlen] ;
s2=((pwshift++)^curgap)%8 ;
curgaph=(brol(curgap,s2))%(((pwshift++)%16)+16) ;
for(gapbyte=0 ;gapbyte< (curgaph) ;gapbyte++){
fputc(rndbyte(),output) ;} ;
for(bitpos=0 ;bitpos< 8 ;bitpos++){
s2=((pwshift++)^curgap)%8 ;
s1=(brol(curgap,s2))%8 ;
s1+=((pwshift++)|curgap) ;
s1%=8 ;
bitarr[bitpos]=((getbit(input[loop],(7-bitpos)))|(delbit(rndbyte(),(7-bitpos))))^(brol(curgap,s1))^((s1+s2)*(s1-s2)) ;
fputc(brol(bitarr[bitpos],(8-s1)),output) ;
}}}else{
while(1){
if(gapbyte==pwlen){gapbyte=0 ;} ;
curgap=argv[2][gapbyte++] ;
s2=((pwshift++)^curgap)%8 ;
loop+=((brol(curgap,s2))%(((pwshift++)%16)+16)) ;
if(loop> inpsize){break ;} ;
endbyte=0 ;
for(bitpos=0 ;bitpos< 8 ;bitpos++){
s2=((pwshift++)^curgap)%8 ;
bitarr[bitpos]=input[loop++] ;
s1=(brol(curgap,s2))%8 ;
s1+=((pwshift++)|curgap) ;
s1%=8 ;
byten=(brol(bitarr[bitpos],s1))^(brol(curgap,s1))^((s1+s2)*(s1-s2)) ;
endbyte|=(getbit(byten,(7-bitpos))) ;}
fputc(endbyte,output) ;}}}