diff --git a/chacha20.h b/chacha20.h new file mode 100644 index 0000000..9095a6e --- /dev/null +++ b/chacha20.h @@ -0,0 +1,174 @@ +/* define SLOWGRAPH_IMPL */ + +#ifndef SLOWCRYPT_CHACHA20_H +#define SLOWCRYPT_CHACHA20_H + +#include + +#ifndef SLOWCRYPT_CHACHA20_FUNC +#define SLOWCRYPT_CHACHA20_FUNC /**/ +#endif + +typedef struct { + uint32_t state[16]; +} slowcrypt_chacha20; + +/* + * initialize state, run 20 iterations, serialize, xor data inplace + * + * does NOT zeroize states! zeroize manually when done. + */ +SLOWCRYPT_CHACHA20_FUNC void +slowcrypt_chacha20_block(slowcrypt_chacha20 state[2], char const key[32], + uint32_t block_ctr, char const nonce[12], + char data[64]); + +/* call this to zero out memory */ +SLOWCRYPT_CHACHA20_FUNC void +slowcrypt_chacha20_deinit(slowcrypt_chacha20 *state); + +SLOWCRYPT_CHACHA20_FUNC void slowcrypt_chacha20_init(slowcrypt_chacha20 *state, + char const key[32], + uint32_t block_ctr, + char const nonce[12]); + +SLOWCRYPT_CHACHA20_FUNC void +slowcrypt_chacha20_serialize(char buf[64], slowcrypt_chacha20 const *state); + +SLOWCRYPT_CHACHA20_FUNC void +slowcrypt_chacha20_serialize_xor(char buf[64], slowcrypt_chacha20 const *state); + +SLOWCRYPT_CHACHA20_FUNC void slowcrypt_chacha20_run(slowcrypt_chacha20 *state, + slowcrypt_chacha20 *swap, + int num_rounds); + +SLOWCRYPT_CHACHA20_FUNC uint32_t slowcrypt_chacha20_read_ul32(char const *buf); + +SLOWCRYPT_CHACHA20_FUNC void slowcrypt_chacha20_write_ul32(char *buf, + uint32_t val); + +#define SLOWCRYPT_CHACHA20_LAST32(n, bits) (((uint32_t)(n)) >> (32 - (bits))) + +#define SLOWCRYPT_CHACHA20_ROL32(n, by) \ + ((((uint32_t)(n)) << (by)) | SLOWCRYPT_CHACHA20_LAST32((n), (by))) + +#define SLOWCRYPT_CHACHA20_QROUND(state, a, b, c, d) \ + do { \ + state[a] += state[b]; \ + state[d] ^= state[a]; \ + state[d] = SLOWCRYPT_CHACHA20_ROL32(state[d], 16); \ + \ + state[c] += state[d]; \ + state[b] ^= state[c]; \ + state[b] = SLOWCRYPT_CHACHA20_ROL32(state[b], 12); \ + \ + state[a] += state[b]; \ + state[d] ^= state[a]; \ + state[d] = SLOWCRYPT_CHACHA20_ROL32(state[d], 8); \ + \ + state[c] += state[d]; \ + state[b] ^= state[c]; \ + state[b] = SLOWCRYPT_CHACHA20_ROL32(state[b], 7); \ + } while (0) + +#ifdef SLOWCRYPT_CHACHA20_IMPL + +SLOWCRYPT_CHACHA20_FUNC void +slowcrypt_chacha20_deinit(slowcrypt_chacha20 *state) { + int i; + for (i = 0; i < 16; i++) + *(volatile int *)&state->state[i] = 0; +} + +SLOWCRYPT_CHACHA20_FUNC uint32_t slowcrypt_chacha20_read_ul32(char const *buf) { + uint32_t o = (uint32_t)((uint8_t const *)buf)[0]; + o |= (uint32_t)((uint8_t const *)buf)[1] << 8; + o |= (uint32_t)((uint8_t const *)buf)[2] << 16; + o |= (uint32_t)((uint8_t const *)buf)[3] << 24; + return o; +} + +SLOWCRYPT_CHACHA20_FUNC void slowcrypt_chacha20_write_ul32(char *buf, + uint32_t val) { + ((uint8_t *)buf)[0] = (uint8_t)(val & 0xFF); + ((uint8_t *)buf)[1] = (uint8_t)((val >> 8) & 0xFF); + ((uint8_t *)buf)[2] = (uint8_t)((val >> 16) & 0xFF); + ((uint8_t *)buf)[3] = (uint8_t)((val >> 24) & 0xFF); +} + +SLOWCRYPT_CHACHA20_FUNC void slowcrypt_chacha20_init(slowcrypt_chacha20 *state, + char const key[32], + uint32_t block_ctr, + char const nonce[12]) { + int i; + state->state[0] = 0x61707865; + state->state[1] = 0x3320646e; + state->state[2] = 0x79622d32; + state->state[3] = 0x6b206574; + for (i = 0; i < 8; i++) + state->state[4 + i] = slowcrypt_chacha20_read_ul32(&key[i * 4]); + state->state[12] = block_ctr; + for (i = 0; i < 3; i++) + state->state[13 + i] = slowcrypt_chacha20_read_ul32(&nonce[i * 4]); +} + +SLOWCRYPT_CHACHA20_FUNC void +slowcrypt_chacha20_serialize(char buf[64], slowcrypt_chacha20 const *state) { + int i; + for (i = 0; i < 16; i++) + slowcrypt_chacha20_write_ul32(&buf[i * 4], state->state[i]); +} + +SLOWCRYPT_CHACHA20_FUNC void +slowcrypt_chacha20_serialize_xor(char buf[64], + slowcrypt_chacha20 const *state) { + char swp[4]; + int i, j; + + for (i = 0; i < 16; i++) { + slowcrypt_chacha20_write_ul32(swp, state->state[i]); + for (j = 0; j < 4; j++) + buf[i * 4 + j] ^= swp[j]; + } +} + +SLOWCRYPT_CHACHA20_FUNC void slowcrypt_chacha20_run(slowcrypt_chacha20 *state, + slowcrypt_chacha20 *swap, + int num_rounds) { + int i; + + for (i = 0; i < 16; i++) + swap->state[i] = state->state[i]; + + for (i = 0; i < num_rounds; i++) { + if (i % 2 == 0) { + /* column round */ + SLOWCRYPT_CHACHA20_QROUND(state->state, 0, 4, 8, 12); + SLOWCRYPT_CHACHA20_QROUND(state->state, 1, 5, 9, 13); + SLOWCRYPT_CHACHA20_QROUND(state->state, 2, 6, 10, 14); + SLOWCRYPT_CHACHA20_QROUND(state->state, 3, 7, 11, 15); + } else { + /* diagonal round */ + SLOWCRYPT_CHACHA20_QROUND(state->state, 0, 5, 10, 15); + SLOWCRYPT_CHACHA20_QROUND(state->state, 1, 6, 11, 12); + SLOWCRYPT_CHACHA20_QROUND(state->state, 2, 7, 8, 13); + SLOWCRYPT_CHACHA20_QROUND(state->state, 3, 4, 9, 14); + } + } + + for (i = 0; i < 16; i++) + state->state[i] += swap->state[i]; +} + +SLOWCRYPT_CHACHA20_FUNC void +slowcrypt_chacha20_block(slowcrypt_chacha20 state[2], char const key[32], + uint32_t block_ctr, char const nonce[12], + char data[64]) { + slowcrypt_chacha20_init(state, key, block_ctr, nonce); + slowcrypt_chacha20_run(state, &state[1], 20); + slowcrypt_chacha20_serialize_xor(data, state); +} + +#endif + +#endif diff --git a/chacha20/nostd0.c b/chacha20/nostd0.c new file mode 100644 index 0000000..3495a3e --- /dev/null +++ b/chacha20/nostd0.c @@ -0,0 +1,63 @@ +#define SLOWCRYPT_CHACHA20_IMPL +#include "../chacha20.h" + +static char key[] = { + 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, + 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, + 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, +}; + +static char nonce[] = { + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x4a, 0x00, 0x00, 0x00, 0x00, +}; + +static char text[] = + "Ladies and Gentlemen of the class of '99: If I could offer you only one " + "tip for the future, sunscreen would be it."; + +static char expected[] = { + 0x6E, 0x2E, 0x35, 0x9A, 0x25, 0x68, 0xF9, 0x80, 0x41, 0xBA, 0x07, 0x28, + 0xDD, 0x0D, 0x69, 0x81, 0xE9, 0x7E, 0x7A, 0xEC, 0x1D, 0x43, 0x60, 0xC2, + 0x0A, 0x27, 0xAF, 0xCC, 0xFD, 0x9F, 0xAE, 0x0B, 0xF9, 0x1B, 0x65, 0xC5, + 0x52, 0x47, 0x33, 0xAB, 0x8F, 0x59, 0x3D, 0xAB, 0xCD, 0x62, 0xB3, 0x57, + 0x16, 0x39, 0xD6, 0x24, 0xE6, 0x51, 0x52, 0xAB, 0x8F, 0x53, 0x0C, 0x35, + 0x9F, 0x08, 0x61, 0xD8, 0x07, 0xCA, 0x0D, 0xBF, 0x50, 0x0D, 0x6A, 0x61, + 0x56, 0xA3, 0x8E, 0x08, 0x8A, 0x22, 0xB6, 0x5E, 0x52, 0xBC, 0x51, 0x4D, + 0x16, 0xCC, 0xF8, 0x06, 0x81, 0x8C, 0xE9, 0x1A, 0xB7, 0x79, 0x37, 0x36, + 0x5A, 0xF9, 0x0B, 0xBF, 0x74, 0xA3, 0x5B, 0xE6, 0xB4, 0x0B, 0x8E, 0xED, + 0xF2, 0x78, 0x5E, 0x42, 0x87, 0x4D, +}; + +int main(int argc, char **argv) { + slowcrypt_chacha20 state[2]; + char buf[64]; + int i, j, blksz; + uint32_t ctr = 1; + + (void)argc; + (void)argv; + + for (i = 0; i < (int)(sizeof(text) - 1); i += 64) { + blksz = (sizeof(text) - 1) - i; + if (blksz > 64) + blksz = 64; + + for (j = 0; j < blksz; j++) { + buf[j] = text[i + j]; + } + + slowcrypt_chacha20_block(state, key, ctr, nonce, buf); + ctr++; + + for (j = 0; j < blksz; j++) + if (buf[j] != expected[i + j]) + return 1; + } + + slowcrypt_chacha20_deinit(&state[0]); + slowcrypt_chacha20_deinit(&state[1]); + for (i = 0; i < 64; i++) + buf[i] = 0; + + return 0; +}