diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /lib/crypto/curve25519-hacl64.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | lib/crypto/curve25519-hacl64.c | 786 |
1 files changed, 786 insertions, 0 deletions
diff --git a/lib/crypto/curve25519-hacl64.c b/lib/crypto/curve25519-hacl64.c new file mode 100644 index 0000000000..c40e5d9132 --- /dev/null +++ b/lib/crypto/curve25519-hacl64.c @@ -0,0 +1,786 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT +/* + * Copyright (C) 2016-2017 INRIA and Microsoft Corporation. + * Copyright (C) 2018-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. + * + * This is a machine-generated formally verified implementation of Curve25519 + * ECDH from: <https://github.com/mitls/hacl-star>. Though originally machine + * generated, it has been tweaked to be suitable for use in the kernel. It is + * optimized for 64-bit machines that can efficiently work with 128-bit + * integer types. + */ + +#include <asm/unaligned.h> +#include <crypto/curve25519.h> +#include <linux/string.h> + +static __always_inline u64 u64_eq_mask(u64 a, u64 b) +{ + u64 x = a ^ b; + u64 minus_x = ~x + (u64)1U; + u64 x_or_minus_x = x | minus_x; + u64 xnx = x_or_minus_x >> (u32)63U; + u64 c = xnx - (u64)1U; + return c; +} + +static __always_inline u64 u64_gte_mask(u64 a, u64 b) +{ + u64 x = a; + u64 y = b; + u64 x_xor_y = x ^ y; + u64 x_sub_y = x - y; + u64 x_sub_y_xor_y = x_sub_y ^ y; + u64 q = x_xor_y | x_sub_y_xor_y; + u64 x_xor_q = x ^ q; + u64 x_xor_q_ = x_xor_q >> (u32)63U; + u64 c = x_xor_q_ - (u64)1U; + return c; +} + +static __always_inline void modulo_carry_top(u64 *b) +{ + u64 b4 = b[4]; + u64 b0 = b[0]; + u64 b4_ = b4 & 0x7ffffffffffffLLU; + u64 b0_ = b0 + 19 * (b4 >> 51); + b[4] = b4_; + b[0] = b0_; +} + +static __always_inline void fproduct_copy_from_wide_(u64 *output, u128 *input) +{ + { + u128 xi = input[0]; + output[0] = ((u64)(xi)); + } + { + u128 xi = input[1]; + output[1] = ((u64)(xi)); + } + { + u128 xi = input[2]; + output[2] = ((u64)(xi)); + } + { + u128 xi = input[3]; + output[3] = ((u64)(xi)); + } + { + u128 xi = input[4]; + output[4] = ((u64)(xi)); + } +} + +static __always_inline void +fproduct_sum_scalar_multiplication_(u128 *output, u64 *input, u64 s) +{ + output[0] += (u128)input[0] * s; + output[1] += (u128)input[1] * s; + output[2] += (u128)input[2] * s; + output[3] += (u128)input[3] * s; + output[4] += (u128)input[4] * s; +} + +static __always_inline void fproduct_carry_wide_(u128 *tmp) +{ + { + u32 ctr = 0; + u128 tctr = tmp[ctr]; + u128 tctrp1 = tmp[ctr + 1]; + u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU; + u128 c = ((tctr) >> (51)); + tmp[ctr] = ((u128)(r0)); + tmp[ctr + 1] = ((tctrp1) + (c)); + } + { + u32 ctr = 1; + u128 tctr = tmp[ctr]; + u128 tctrp1 = tmp[ctr + 1]; + u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU; + u128 c = ((tctr) >> (51)); + tmp[ctr] = ((u128)(r0)); + tmp[ctr + 1] = ((tctrp1) + (c)); + } + + { + u32 ctr = 2; + u128 tctr = tmp[ctr]; + u128 tctrp1 = tmp[ctr + 1]; + u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU; + u128 c = ((tctr) >> (51)); + tmp[ctr] = ((u128)(r0)); + tmp[ctr + 1] = ((tctrp1) + (c)); + } + { + u32 ctr = 3; + u128 tctr = tmp[ctr]; + u128 tctrp1 = tmp[ctr + 1]; + u64 r0 = ((u64)(tctr)) & 0x7ffffffffffffLLU; + u128 c = ((tctr) >> (51)); + tmp[ctr] = ((u128)(r0)); + tmp[ctr + 1] = ((tctrp1) + (c)); + } +} + +static __always_inline void fmul_shift_reduce(u64 *output) +{ + u64 tmp = output[4]; + u64 b0; + { + u32 ctr = 5 - 0 - 1; + u64 z = output[ctr - 1]; + output[ctr] = z; + } + { + u32 ctr = 5 - 1 - 1; + u64 z = output[ctr - 1]; + output[ctr] = z; + } + { + u32 ctr = 5 - 2 - 1; + u64 z = output[ctr - 1]; + output[ctr] = z; + } + { + u32 ctr = 5 - 3 - 1; + u64 z = output[ctr - 1]; + output[ctr] = z; + } + output[0] = tmp; + b0 = output[0]; + output[0] = 19 * b0; +} + +static __always_inline void fmul_mul_shift_reduce_(u128 *output, u64 *input, + u64 *input21) +{ + u32 i; + u64 input2i; + { + u64 input2i = input21[0]; + fproduct_sum_scalar_multiplication_(output, input, input2i); + fmul_shift_reduce(input); + } + { + u64 input2i = input21[1]; + fproduct_sum_scalar_multiplication_(output, input, input2i); + fmul_shift_reduce(input); + } + { + u64 input2i = input21[2]; + fproduct_sum_scalar_multiplication_(output, input, input2i); + fmul_shift_reduce(input); + } + { + u64 input2i = input21[3]; + fproduct_sum_scalar_multiplication_(output, input, input2i); + fmul_shift_reduce(input); + } + i = 4; + input2i = input21[i]; + fproduct_sum_scalar_multiplication_(output, input, input2i); +} + +static __always_inline void fmul_fmul(u64 *output, u64 *input, u64 *input21) +{ + u64 tmp[5] = { input[0], input[1], input[2], input[3], input[4] }; + { + u128 b4; + u128 b0; + u128 b4_; + u128 b0_; + u64 i0; + u64 i1; + u64 i0_; + u64 i1_; + u128 t[5] = { 0 }; + fmul_mul_shift_reduce_(t, tmp, input21); + fproduct_carry_wide_(t); + b4 = t[4]; + b0 = t[0]; + b4_ = ((b4) & (((u128)(0x7ffffffffffffLLU)))); + b0_ = ((b0) + (((u128)(19) * (((u64)(((b4) >> (51)))))))); + t[4] = b4_; + t[0] = b0_; + fproduct_copy_from_wide_(output, t); + i0 = output[0]; + i1 = output[1]; + i0_ = i0 & 0x7ffffffffffffLLU; + i1_ = i1 + (i0 >> 51); + output[0] = i0_; + output[1] = i1_; + } +} + +static __always_inline void fsquare_fsquare__(u128 *tmp, u64 *output) +{ + u64 r0 = output[0]; + u64 r1 = output[1]; + u64 r2 = output[2]; + u64 r3 = output[3]; + u64 r4 = output[4]; + u64 d0 = r0 * 2; + u64 d1 = r1 * 2; + u64 d2 = r2 * 2 * 19; + u64 d419 = r4 * 19; + u64 d4 = d419 * 2; + u128 s0 = ((((((u128)(r0) * (r0))) + (((u128)(d4) * (r1))))) + + (((u128)(d2) * (r3)))); + u128 s1 = ((((((u128)(d0) * (r1))) + (((u128)(d4) * (r2))))) + + (((u128)(r3 * 19) * (r3)))); + u128 s2 = ((((((u128)(d0) * (r2))) + (((u128)(r1) * (r1))))) + + (((u128)(d4) * (r3)))); + u128 s3 = ((((((u128)(d0) * (r3))) + (((u128)(d1) * (r2))))) + + (((u128)(r4) * (d419)))); + u128 s4 = ((((((u128)(d0) * (r4))) + (((u128)(d1) * (r3))))) + + (((u128)(r2) * (r2)))); + tmp[0] = s0; + tmp[1] = s1; + tmp[2] = s2; + tmp[3] = s3; + tmp[4] = s4; +} + +static __always_inline void fsquare_fsquare_(u128 *tmp, u64 *output) +{ + u128 b4; + u128 b0; + u128 b4_; + u128 b0_; + u64 i0; + u64 i1; + u64 i0_; + u64 i1_; + fsquare_fsquare__(tmp, output); + fproduct_carry_wide_(tmp); + b4 = tmp[4]; + b0 = tmp[0]; + b4_ = ((b4) & (((u128)(0x7ffffffffffffLLU)))); + b0_ = ((b0) + (((u128)(19) * (((u64)(((b4) >> (51)))))))); + tmp[4] = b4_; + tmp[0] = b0_; + fproduct_copy_from_wide_(output, tmp); + i0 = output[0]; + i1 = output[1]; + i0_ = i0 & 0x7ffffffffffffLLU; + i1_ = i1 + (i0 >> 51); + output[0] = i0_; + output[1] = i1_; +} + +static __always_inline void fsquare_fsquare_times_(u64 *output, u128 *tmp, + u32 count1) +{ + u32 i; + fsquare_fsquare_(tmp, output); + for (i = 1; i < count1; ++i) + fsquare_fsquare_(tmp, output); +} + +static __always_inline void fsquare_fsquare_times(u64 *output, u64 *input, + u32 count1) +{ + u128 t[5]; + memcpy(output, input, 5 * sizeof(*input)); + fsquare_fsquare_times_(output, t, count1); +} + +static __always_inline void fsquare_fsquare_times_inplace(u64 *output, + u32 count1) +{ + u128 t[5]; + fsquare_fsquare_times_(output, t, count1); +} + +static __always_inline void crecip_crecip(u64 *out, u64 *z) +{ + u64 buf[20] = { 0 }; + u64 *a0 = buf; + u64 *t00 = buf + 5; + u64 *b0 = buf + 10; + u64 *t01; + u64 *b1; + u64 *c0; + u64 *a; + u64 *t0; + u64 *b; + u64 *c; + fsquare_fsquare_times(a0, z, 1); + fsquare_fsquare_times(t00, a0, 2); + fmul_fmul(b0, t00, z); + fmul_fmul(a0, b0, a0); + fsquare_fsquare_times(t00, a0, 1); + fmul_fmul(b0, t00, b0); + fsquare_fsquare_times(t00, b0, 5); + t01 = buf + 5; + b1 = buf + 10; + c0 = buf + 15; + fmul_fmul(b1, t01, b1); + fsquare_fsquare_times(t01, b1, 10); + fmul_fmul(c0, t01, b1); + fsquare_fsquare_times(t01, c0, 20); + fmul_fmul(t01, t01, c0); + fsquare_fsquare_times_inplace(t01, 10); + fmul_fmul(b1, t01, b1); + fsquare_fsquare_times(t01, b1, 50); + a = buf; + t0 = buf + 5; + b = buf + 10; + c = buf + 15; + fmul_fmul(c, t0, b); + fsquare_fsquare_times(t0, c, 100); + fmul_fmul(t0, t0, c); + fsquare_fsquare_times_inplace(t0, 50); + fmul_fmul(t0, t0, b); + fsquare_fsquare_times_inplace(t0, 5); + fmul_fmul(out, t0, a); +} + +static __always_inline void fsum(u64 *a, u64 *b) +{ + a[0] += b[0]; + a[1] += b[1]; + a[2] += b[2]; + a[3] += b[3]; + a[4] += b[4]; +} + +static __always_inline void fdifference(u64 *a, u64 *b) +{ + u64 tmp[5] = { 0 }; + u64 b0; + u64 b1; + u64 b2; + u64 b3; + u64 b4; + memcpy(tmp, b, 5 * sizeof(*b)); + b0 = tmp[0]; + b1 = tmp[1]; + b2 = tmp[2]; + b3 = tmp[3]; + b4 = tmp[4]; + tmp[0] = b0 + 0x3fffffffffff68LLU; + tmp[1] = b1 + 0x3ffffffffffff8LLU; + tmp[2] = b2 + 0x3ffffffffffff8LLU; + tmp[3] = b3 + 0x3ffffffffffff8LLU; + tmp[4] = b4 + 0x3ffffffffffff8LLU; + { + u64 xi = a[0]; + u64 yi = tmp[0]; + a[0] = yi - xi; + } + { + u64 xi = a[1]; + u64 yi = tmp[1]; + a[1] = yi - xi; + } + { + u64 xi = a[2]; + u64 yi = tmp[2]; + a[2] = yi - xi; + } + { + u64 xi = a[3]; + u64 yi = tmp[3]; + a[3] = yi - xi; + } + { + u64 xi = a[4]; + u64 yi = tmp[4]; + a[4] = yi - xi; + } +} + +static __always_inline void fscalar(u64 *output, u64 *b, u64 s) +{ + u128 tmp[5]; + u128 b4; + u128 b0; + u128 b4_; + u128 b0_; + { + u64 xi = b[0]; + tmp[0] = ((u128)(xi) * (s)); + } + { + u64 xi = b[1]; + tmp[1] = ((u128)(xi) * (s)); + } + { + u64 xi = b[2]; + tmp[2] = ((u128)(xi) * (s)); + } + { + u64 xi = b[3]; + tmp[3] = ((u128)(xi) * (s)); + } + { + u64 xi = b[4]; + tmp[4] = ((u128)(xi) * (s)); + } + fproduct_carry_wide_(tmp); + b4 = tmp[4]; + b0 = tmp[0]; + b4_ = ((b4) & (((u128)(0x7ffffffffffffLLU)))); + b0_ = ((b0) + (((u128)(19) * (((u64)(((b4) >> (51)))))))); + tmp[4] = b4_; + tmp[0] = b0_; + fproduct_copy_from_wide_(output, tmp); +} + +static __always_inline void fmul(u64 *output, u64 *a, u64 *b) +{ + fmul_fmul(output, a, b); +} + +static __always_inline void crecip(u64 *output, u64 *input) +{ + crecip_crecip(output, input); +} + +static __always_inline void point_swap_conditional_step(u64 *a, u64 *b, + u64 swap1, u32 ctr) +{ + u32 i = ctr - 1; + u64 ai = a[i]; + u64 bi = b[i]; + u64 x = swap1 & (ai ^ bi); + u64 ai1 = ai ^ x; + u64 bi1 = bi ^ x; + a[i] = ai1; + b[i] = bi1; +} + +static __always_inline void point_swap_conditional5(u64 *a, u64 *b, u64 swap1) +{ + point_swap_conditional_step(a, b, swap1, 5); + point_swap_conditional_step(a, b, swap1, 4); + point_swap_conditional_step(a, b, swap1, 3); + point_swap_conditional_step(a, b, swap1, 2); + point_swap_conditional_step(a, b, swap1, 1); +} + +static __always_inline void point_swap_conditional(u64 *a, u64 *b, u64 iswap) +{ + u64 swap1 = 0 - iswap; + point_swap_conditional5(a, b, swap1); + point_swap_conditional5(a + 5, b + 5, swap1); +} + +static __always_inline void point_copy(u64 *output, u64 *input) +{ + memcpy(output, input, 5 * sizeof(*input)); + memcpy(output + 5, input + 5, 5 * sizeof(*input)); +} + +static __always_inline void addanddouble_fmonty(u64 *pp, u64 *ppq, u64 *p, + u64 *pq, u64 *qmqp) +{ + u64 *qx = qmqp; + u64 *x2 = pp; + u64 *z2 = pp + 5; + u64 *x3 = ppq; + u64 *z3 = ppq + 5; + u64 *x = p; + u64 *z = p + 5; + u64 *xprime = pq; + u64 *zprime = pq + 5; + u64 buf[40] = { 0 }; + u64 *origx = buf; + u64 *origxprime0 = buf + 5; + u64 *xxprime0; + u64 *zzprime0; + u64 *origxprime; + xxprime0 = buf + 25; + zzprime0 = buf + 30; + memcpy(origx, x, 5 * sizeof(*x)); + fsum(x, z); + fdifference(z, origx); + memcpy(origxprime0, xprime, 5 * sizeof(*xprime)); + fsum(xprime, zprime); + fdifference(zprime, origxprime0); + fmul(xxprime0, xprime, z); + fmul(zzprime0, x, zprime); + origxprime = buf + 5; + { + u64 *xx0; + u64 *zz0; + u64 *xxprime; + u64 *zzprime; + u64 *zzzprime; + xx0 = buf + 15; + zz0 = buf + 20; + xxprime = buf + 25; + zzprime = buf + 30; + zzzprime = buf + 35; + memcpy(origxprime, xxprime, 5 * sizeof(*xxprime)); + fsum(xxprime, zzprime); + fdifference(zzprime, origxprime); + fsquare_fsquare_times(x3, xxprime, 1); + fsquare_fsquare_times(zzzprime, zzprime, 1); + fmul(z3, zzzprime, qx); + fsquare_fsquare_times(xx0, x, 1); + fsquare_fsquare_times(zz0, z, 1); + { + u64 *zzz; + u64 *xx; + u64 *zz; + u64 scalar; + zzz = buf + 10; + xx = buf + 15; + zz = buf + 20; + fmul(x2, xx, zz); + fdifference(zz, xx); + scalar = 121665; + fscalar(zzz, zz, scalar); + fsum(zzz, xx); + fmul(z2, zzz, zz); + } + } +} + +static __always_inline void +ladder_smallloop_cmult_small_loop_step(u64 *nq, u64 *nqpq, u64 *nq2, u64 *nqpq2, + u64 *q, u8 byt) +{ + u64 bit0 = (u64)(byt >> 7); + u64 bit; + point_swap_conditional(nq, nqpq, bit0); + addanddouble_fmonty(nq2, nqpq2, nq, nqpq, q); + bit = (u64)(byt >> 7); + point_swap_conditional(nq2, nqpq2, bit); +} + +static __always_inline void +ladder_smallloop_cmult_small_loop_double_step(u64 *nq, u64 *nqpq, u64 *nq2, + u64 *nqpq2, u64 *q, u8 byt) +{ + u8 byt1; + ladder_smallloop_cmult_small_loop_step(nq, nqpq, nq2, nqpq2, q, byt); + byt1 = byt << 1; + ladder_smallloop_cmult_small_loop_step(nq2, nqpq2, nq, nqpq, q, byt1); +} + +static __always_inline void +ladder_smallloop_cmult_small_loop(u64 *nq, u64 *nqpq, u64 *nq2, u64 *nqpq2, + u64 *q, u8 byt, u32 i) +{ + while (i--) { + ladder_smallloop_cmult_small_loop_double_step(nq, nqpq, nq2, + nqpq2, q, byt); + byt <<= 2; + } +} + +static __always_inline void ladder_bigloop_cmult_big_loop(u8 *n1, u64 *nq, + u64 *nqpq, u64 *nq2, + u64 *nqpq2, u64 *q, + u32 i) +{ + while (i--) { + u8 byte = n1[i]; + ladder_smallloop_cmult_small_loop(nq, nqpq, nq2, nqpq2, q, + byte, 4); + } +} + +static void ladder_cmult(u64 *result, u8 *n1, u64 *q) +{ + u64 point_buf[40] = { 0 }; + u64 *nq = point_buf; + u64 *nqpq = point_buf + 10; + u64 *nq2 = point_buf + 20; + u64 *nqpq2 = point_buf + 30; + point_copy(nqpq, q); + nq[0] = 1; + ladder_bigloop_cmult_big_loop(n1, nq, nqpq, nq2, nqpq2, q, 32); + point_copy(result, nq); +} + +static __always_inline void format_fexpand(u64 *output, const u8 *input) +{ + const u8 *x00 = input + 6; + const u8 *x01 = input + 12; + const u8 *x02 = input + 19; + const u8 *x0 = input + 24; + u64 i0, i1, i2, i3, i4, output0, output1, output2, output3, output4; + i0 = get_unaligned_le64(input); + i1 = get_unaligned_le64(x00); + i2 = get_unaligned_le64(x01); + i3 = get_unaligned_le64(x02); + i4 = get_unaligned_le64(x0); + output0 = i0 & 0x7ffffffffffffLLU; + output1 = i1 >> 3 & 0x7ffffffffffffLLU; + output2 = i2 >> 6 & 0x7ffffffffffffLLU; + output3 = i3 >> 1 & 0x7ffffffffffffLLU; + output4 = i4 >> 12 & 0x7ffffffffffffLLU; + output[0] = output0; + output[1] = output1; + output[2] = output2; + output[3] = output3; + output[4] = output4; +} + +static __always_inline void format_fcontract_first_carry_pass(u64 *input) +{ + u64 t0 = input[0]; + u64 t1 = input[1]; + u64 t2 = input[2]; + u64 t3 = input[3]; + u64 t4 = input[4]; + u64 t1_ = t1 + (t0 >> 51); + u64 t0_ = t0 & 0x7ffffffffffffLLU; + u64 t2_ = t2 + (t1_ >> 51); + u64 t1__ = t1_ & 0x7ffffffffffffLLU; + u64 t3_ = t3 + (t2_ >> 51); + u64 t2__ = t2_ & 0x7ffffffffffffLLU; + u64 t4_ = t4 + (t3_ >> 51); + u64 t3__ = t3_ & 0x7ffffffffffffLLU; + input[0] = t0_; + input[1] = t1__; + input[2] = t2__; + input[3] = t3__; + input[4] = t4_; +} + +static __always_inline void format_fcontract_first_carry_full(u64 *input) +{ + format_fcontract_first_carry_pass(input); + modulo_carry_top(input); +} + +static __always_inline void format_fcontract_second_carry_pass(u64 *input) +{ + u64 t0 = input[0]; + u64 t1 = input[1]; + u64 t2 = input[2]; + u64 t3 = input[3]; + u64 t4 = input[4]; + u64 t1_ = t1 + (t0 >> 51); + u64 t0_ = t0 & 0x7ffffffffffffLLU; + u64 t2_ = t2 + (t1_ >> 51); + u64 t1__ = t1_ & 0x7ffffffffffffLLU; + u64 t3_ = t3 + (t2_ >> 51); + u64 t2__ = t2_ & 0x7ffffffffffffLLU; + u64 t4_ = t4 + (t3_ >> 51); + u64 t3__ = t3_ & 0x7ffffffffffffLLU; + input[0] = t0_; + input[1] = t1__; + input[2] = t2__; + input[3] = t3__; + input[4] = t4_; +} + +static __always_inline void format_fcontract_second_carry_full(u64 *input) +{ + u64 i0; + u64 i1; + u64 i0_; + u64 i1_; + format_fcontract_second_carry_pass(input); + modulo_carry_top(input); + i0 = input[0]; + i1 = input[1]; + i0_ = i0 & 0x7ffffffffffffLLU; + i1_ = i1 + (i0 >> 51); + input[0] = i0_; + input[1] = i1_; +} + +static __always_inline void format_fcontract_trim(u64 *input) +{ + u64 a0 = input[0]; + u64 a1 = input[1]; + u64 a2 = input[2]; + u64 a3 = input[3]; + u64 a4 = input[4]; + u64 mask0 = u64_gte_mask(a0, 0x7ffffffffffedLLU); + u64 mask1 = u64_eq_mask(a1, 0x7ffffffffffffLLU); + u64 mask2 = u64_eq_mask(a2, 0x7ffffffffffffLLU); + u64 mask3 = u64_eq_mask(a3, 0x7ffffffffffffLLU); + u64 mask4 = u64_eq_mask(a4, 0x7ffffffffffffLLU); + u64 mask = (((mask0 & mask1) & mask2) & mask3) & mask4; + u64 a0_ = a0 - (0x7ffffffffffedLLU & mask); + u64 a1_ = a1 - (0x7ffffffffffffLLU & mask); + u64 a2_ = a2 - (0x7ffffffffffffLLU & mask); + u64 a3_ = a3 - (0x7ffffffffffffLLU & mask); + u64 a4_ = a4 - (0x7ffffffffffffLLU & mask); + input[0] = a0_; + input[1] = a1_; + input[2] = a2_; + input[3] = a3_; + input[4] = a4_; +} + +static __always_inline void format_fcontract_store(u8 *output, u64 *input) +{ + u64 t0 = input[0]; + u64 t1 = input[1]; + u64 t2 = input[2]; + u64 t3 = input[3]; + u64 t4 = input[4]; + u64 o0 = t1 << 51 | t0; + u64 o1 = t2 << 38 | t1 >> 13; + u64 o2 = t3 << 25 | t2 >> 26; + u64 o3 = t4 << 12 | t3 >> 39; + u8 *b0 = output; + u8 *b1 = output + 8; + u8 *b2 = output + 16; + u8 *b3 = output + 24; + put_unaligned_le64(o0, b0); + put_unaligned_le64(o1, b1); + put_unaligned_le64(o2, b2); + put_unaligned_le64(o3, b3); +} + +static __always_inline void format_fcontract(u8 *output, u64 *input) +{ + format_fcontract_first_carry_full(input); + format_fcontract_second_carry_full(input); + format_fcontract_trim(input); + format_fcontract_store(output, input); +} + +static __always_inline void format_scalar_of_point(u8 *scalar, u64 *point) +{ + u64 *x = point; + u64 *z = point + 5; + u64 buf[10] __aligned(32) = { 0 }; + u64 *zmone = buf; + u64 *sc = buf + 5; + crecip(zmone, z); + fmul(sc, x, zmone); + format_fcontract(scalar, sc); +} + +void curve25519_generic(u8 mypublic[CURVE25519_KEY_SIZE], + const u8 secret[CURVE25519_KEY_SIZE], + const u8 basepoint[CURVE25519_KEY_SIZE]) +{ + u64 buf0[10] __aligned(32) = { 0 }; + u64 *x0 = buf0; + u64 *z = buf0 + 5; + u64 *q; + format_fexpand(x0, basepoint); + z[0] = 1; + q = buf0; + { + u8 e[32] __aligned(32) = { 0 }; + u8 *scalar; + memcpy(e, secret, 32); + curve25519_clamp_secret(e); + scalar = e; + { + u64 buf[15] = { 0 }; + u64 *nq = buf; + u64 *x = nq; + x[0] = 1; + ladder_cmult(nq, scalar, q); + format_scalar_of_point(mypublic, nq); + memzero_explicit(buf, sizeof(buf)); + } + memzero_explicit(e, sizeof(e)); + } + memzero_explicit(buf0, sizeof(buf0)); +} |