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https://github.com/rdolbeau/VexRiscvBPluginGenerator.git
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126 lines
3.5 KiB
C
126 lines
3.5 KiB
C
#include "namespace.h"
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/*
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chacha.c version $Date: 2020/03/13 13:02:57 $
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D. J. Bernstein
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Romain Dolbeau
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Public domain.
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*/
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#include "ecrypt-sync.h"
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#include "api.h"
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//#include <arm_sve.h> // fixme: is there a specific include ?
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#include <stdio.h>
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#define ROUNDS 20
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#include "new_instructions_support_b.h"
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#define ROTATE(v,c) _rv32_rol(v,c)
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#define XOR(v,w) ((v) ^ (w))
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#define PLUS(v,w) (U32V((v) + (w)))
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#define PLUSONE(v) (PLUS((v),1))
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#define QUARTERROUND(a,b,c,d) \
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x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]),16); \
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x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]),12); \
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x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]), 8); \
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x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]), 7);
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static void salsa20_wordtobyte(u8 output[64],const u32 input[16])
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{
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u32 x[16];
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int i;
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for (i = 0;i < 16;++i) x[i] = input[i];
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for (i = ROUNDS;i > 0;i -= 2) {
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QUARTERROUND( 0, 4, 8,12)
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QUARTERROUND( 1, 5, 9,13)
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QUARTERROUND( 2, 6,10,14)
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QUARTERROUND( 3, 7,11,15)
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QUARTERROUND( 0, 5,10,15)
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QUARTERROUND( 1, 6,11,12)
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QUARTERROUND( 2, 7, 8,13)
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QUARTERROUND( 3, 4, 9,14)
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}
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for (i = 0;i < 16;++i) x[i] = PLUS(x[i],input[i]);
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for (i = 0;i < 16;++i) U32TO8_LITTLE(output + 4 * i,x[i]);
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}
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void crypto_stream_chacha20_dolbeau_rv32_ECRYPT_init(void)
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{
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return;
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}
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static const char sigma[16] = "expand 32-byte k";
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static const char tau[16] = "expand 16-byte k";
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void crypto_stream_chacha20_dolbeau_rv32_ECRYPT_keysetup(crypto_stream_chacha20_dolbeau_rv32_ECRYPT_ctx *x,const u8 *k,u32 kbits,u32 ivbits)
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{
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const char *constants;
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x->input[4] = U8TO32_LITTLE(k + 0);
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x->input[5] = U8TO32_LITTLE(k + 4);
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x->input[6] = U8TO32_LITTLE(k + 8);
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x->input[7] = U8TO32_LITTLE(k + 12);
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if (kbits == 256) { /* recommended */
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k += 16;
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constants = sigma;
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} else { /* kbits == 128 */
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constants = tau;
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}
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x->input[8] = U8TO32_LITTLE(k + 0);
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x->input[9] = U8TO32_LITTLE(k + 4);
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x->input[10] = U8TO32_LITTLE(k + 8);
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x->input[11] = U8TO32_LITTLE(k + 12);
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x->input[0] = U8TO32_LITTLE(constants + 0);
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x->input[1] = U8TO32_LITTLE(constants + 4);
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x->input[2] = U8TO32_LITTLE(constants + 8);
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x->input[3] = U8TO32_LITTLE(constants + 12);
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}
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void crypto_stream_chacha20_dolbeau_rv32_ECRYPT_ivsetup(crypto_stream_chacha20_dolbeau_rv32_ECRYPT_ctx *x,const u8 *iv)
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{
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x->input[12] = 0;
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x->input[13] = 0;
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x->input[14] = U8TO32_LITTLE(iv + 0);
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x->input[15] = U8TO32_LITTLE(iv + 4);
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}
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void crypto_stream_chacha20_dolbeau_rv32_ECRYPT_encrypt_bytes(crypto_stream_chacha20_dolbeau_rv32_ECRYPT_ctx *x_,const u8 *m,u8 *c_,u32 bytes)
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{
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u8 output[64];
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int i;
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u32* x = (u32*)&x_->input;
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u8* out = c_;
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if (!bytes) return;
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for (;;) {
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salsa20_wordtobyte(output,x);
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x[12] = PLUSONE(x[12]);
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if (!x[12]) {
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x[13] = PLUSONE(x[13]);
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/* stopping at 2^70 bytes per nonce is user's responsibility */
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}
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if (bytes <= 64) {
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for (i = 0;i < bytes;++i) out[i] = m[i] ^ output[i];
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return;
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}
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for (i = 0;i < 64;++i) out[i] = m[i] ^ output[i];
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bytes -= 64;
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out += 64;
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m += 64;
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}
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}
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void crypto_stream_chacha20_dolbeau_rv32_ECRYPT_decrypt_bytes(crypto_stream_chacha20_dolbeau_rv32_ECRYPT_ctx *x,const u8 *c,u8 *m,u32 bytes)
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{
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crypto_stream_chacha20_dolbeau_rv32_ECRYPT_encrypt_bytes(x,c,m,bytes);
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}
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void crypto_stream_chacha20_dolbeau_rv32_ECRYPT_keystream_bytes(crypto_stream_chacha20_dolbeau_rv32_ECRYPT_ctx *x,u8 *stream,u32 bytes)
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{
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u32 i;
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for (i = 0;i < bytes;++i) stream[i] = 0;
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crypto_stream_chacha20_dolbeau_rv32_ECRYPT_encrypt_bytes(x,stream,stream,bytes);
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}
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