control = threshold(c->r1,c->r2,c->r3); c->r1 = clock r1(control,c->r1); c->r2 = clock r2(control,c->r2); c->r3 = clock r3(control,c->r3); return( (c->r1Ac->r2Ac->r3)&1);

/* Encrypts a buffer of len bytes. */

void a5 encrypt(a5 ctx *c, char *data, int len){

int i,j;

char t;

for(i=0;i<len;i++){

for(j=0;j<8;j++) t = t<<1 a5 step(c); data[i]A=t;

void a5 decrypt(a5 ctx *c, char *data, int len){ a5 encrypt(c,data,len);

void main(void){ a5 ctx c;

char data[100];

char key[] = {1,2,3,4,5,6,7,8};

int i,flag;

for(i=0;i<100;i++) data[i] = i;

a5 key(&c,key); a5 encrypt(&c,data,100);

a5 key(&c,key);

a5 decrypt(&c,data,1);

a5 decrypt(&c,data+1,99);

flag = 0;

for(i=0;i<100;i++) if(data[i]!=i)flag = 1; if(flag)printf("Decrypt failed\n"); else printf("Decrypt succeeded\n");

#undef SEAL DEBUG #define ALG OK 0

#define ALG NOTOK 1

#define WORDS PER SEAL CALL 1024

typedef struct {

unsigned long t[520]; /* 512 rounded up to a multiple of 5 + 5*/ unsigned long s[265]; /* 256 rounded up to a multiple of 5 + 5*/ unsigned long r[20]; /* 16 rounded up to multiple of 5 */ unsigned long counter; /* 32-bit synch value. */

unsigned long ks buf[WORDS PER SEAL CALL];

int ks pos; } seal ctx;

#defineROT2(x) (((x) >> 2) ((x) << 30))

#defineROT9(x) (((x) >> 9) ((x) << 23))

#defineROT8(x) (((x) >> 8) ((x) << 24))

#defineROT16(x) (((x) >> 16) ((x) << 16))

#defineROT24(x) (((x) >> 24) ((x) << 8))

#defineROT27(x) (((x) >> 27) ((x) << 5))

#defineWORD(cp) ((cp[0] << 24)(cp[1] << 16)(cp[2] << 8)(cp[3]))

#defineF1(x,y,z)(((x) & (y)) ((~(x)) & (z)))

#defineF2(x,y,z)((x)A(y)A(z))

#defineF3(x,y,z)(((x) & (y)) ((x) & (z)) ((y) & (z)))

#defineF4(x,y,z)((x)A(y)A(z))

int g(in, i, h) unsigned char *in; int i;

unsigned long *h;

unsigned long h0; unsigned long h1; unsigned long h2; unsigned long h3; unsigned long h4; unsigned long a; unsigned long b; unsigned long c; unsigned long d; unsigned long e; unsigned char *kp; unsigned long w[80]; unsigned long temp;

kp = in;

h0 = WORD(kp);kp += 4;

h1 = WORD(kp);kp += 4;

h2 = WORD(kp);kp += 4;

h3 = WORD(kp);kp += 4;

h4 = WORD(kp);kp += 4;

w[0] = i;

for (i=1;i<16;i++)

w[i] = 0;

for (i=16;i<80;i++)

w[i] = w[i-3]Aw[i-8]Aw[i-14]Aw[i-16];

a = h0;

b = h1;

c = h2;

d = h3;

e = h4;

for (i=0;i<20;i++) {

temp = ROT27(a) + F1(b, c, d) + e + w[i] + 0x5a827999; e = d; d = c;

c = ROT2(b);

b = a; a = temp;

for (i=20;i<40;i++) {

temp = ROT27(a) + F2(b, c, d) + e + w[i] + 0x6ed9eba1; e = d; d = c;

c = ROT2(b);

b = a; a = temp;

for (i=40;i<60;i++) {

temp = ROT27(a) + F3(b, c, d) + e + w[i] + 0x8f1bbcdc;

e = d; d = c;

c = ROT2(b);

b = a; a = temp;

for (i=60;i<80;i++) {

temp = ROT27(a) + F4(b, c, d) + e + w[i] + 0xca62c1d6;

e = d; d = c;

c = ROT2(b);

b = a; a = temp;

h[0] = h0+a; h[1] = h1+b; h[2] = h2+c; h[3] = h3+d; h[4] = h4+e;

return (ALG OK);

unsigned long gamma(a, i) unsigned char *a; int i;

unsigned long h[5];

(void) g(a, i/5, h); return h[i % 5];

int seal init(seal ctx *result, unsigned char *key)

unsigned long h[5];

for (i=0;i<510;i+=5)

g(key, i/5, &(result->t[i])); /* horrible special case for the end */

g(key, 510/5, h);

for (i=510;i<512;i++)

result->t[i] = h[i-510];

/* 0x1000 mod 5 is +1, so have horrible special case for the start */

g(key, (-1+0x1000)/5, h); for (i=0;i<4;i++)

result->s[i] = h[i+1]; for (i=4;i<254;i+=5)