132 lines
3.4 KiB
C
132 lines
3.4 KiB
C
/*
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* Copyright 2023 The Tongsuo Project Authors. All Rights Reserved.
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*
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* Licensed under the Apache License 2.0 (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://github.com/Tongsuo-Project/Tongsuo/blob/master/LICENSE.txt
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*/
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/* zuc_128_eea3 cipher implementation */
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#include "cipher_zuc_eea3.h"
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static int zuc_128_eea3_initiv(PROV_CIPHER_CTX *vctx);
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static int zuc_128_eea3_initkey(PROV_CIPHER_CTX *vctx, const uint8_t *key,
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size_t keylen)
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{
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PROV_ZUC_EEA3_CTX *ctx = (PROV_ZUC_EEA3_CTX *)vctx;
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ZUC_KEY *zk = &ctx->ks.ks;
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zk->k = key;
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zuc_128_eea3_initiv(vctx);
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return 1;
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}
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static int zuc_128_eea3_initiv(PROV_CIPHER_CTX *vctx)
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{
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PROV_ZUC_EEA3_CTX *ctx = (PROV_ZUC_EEA3_CTX *)vctx;
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ZUC_KEY *zk = &ctx->ks.ks;
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uint32_t count;
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uint32_t bearer;
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uint32_t direction;
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unsigned char *iv = &vctx->oiv[0];
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/*
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* This is a lazy approach: we 'borrow' the 'iv' parameter
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* to use it as a place of transfer the EEA3 iv params -
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* count, bearer and direction.
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*
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* count is 32 bits, bearer is 5 bits and direction is 1
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* bit so we read the first 38 bits of iv. And the whole
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* iv is set to 5 bytes (40 bits).
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*/
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/* IV is a 'must' */
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if (!vctx->iv_set || !zk->k)
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return 0;
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count = ((long)iv[0] << 24) | (iv[1] << 16) | (iv[2] << 8) | iv[3];
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bearer = (iv[4] & 0xF8) >> 3;
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direction = (iv[4] & 0x4) >> 2;
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zk->iv[0] = (count >> 24) & 0xFF;
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zk->iv[1] = (count >> 16) & 0xFF;
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zk->iv[2] = (count >> 8) & 0xFF;
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zk->iv[3] = count & 0xFF;
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zk->iv[4] = ((bearer << 3) | ((direction & 1) << 2)) & 0xFC;
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zk->iv[5] = zk->iv[6] = zk->iv[7] = 0;
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zk->iv[8] = zk->iv[0];
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zk->iv[9] = zk->iv[1];
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zk->iv[10] = zk->iv[2];
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zk->iv[11] = zk->iv[3];
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zk->iv[12] = zk->iv[4];
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zk->iv[13] = zk->iv[5];
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zk->iv[14] = zk->iv[6];
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zk->iv[15] = zk->iv[7];
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zk->keystream_len = 0;
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zk->inited = 0;
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ZUC_init(zk);
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return 1;
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}
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static int zuc_128_eea3_cipher(PROV_CIPHER_CTX *vctx, unsigned char *out,
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const unsigned char *in, size_t inl)
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{
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PROV_ZUC_EEA3_CTX *ctx = (PROV_ZUC_EEA3_CTX *)vctx;
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ZUC_KEY *zk = &ctx->ks.ks;
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unsigned int i, k, n, num = vctx->num;
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if (num >= zk->keystream_len && !ZUC_generate_keystream(zk))
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return 0;
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n = zk->L * sizeof(uint32_t);
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/*
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* EEA3 is based on 'bits', but we can only handle 'bytes'.
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*
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* So we choose to output a final whole byte, even if there are some
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* bits at the end of the input. Those trailing bits in the last byte
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* should be discarded by caller.
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*/
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for (i = 0; i < inl; i++) {
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k = num + i;
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if (k >= zk->keystream_len) {
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if (!ZUC_generate_keystream(zk))
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return 0;
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}
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out[i] = in[i] ^ zk->keystream[k % n];
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}
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/* num always points to next key byte to use */
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vctx->num += inl;
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return 1;
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}
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static void zuc_128_eea3_cleanup(PROV_ZUC_EEA3_CTX *ctx)
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{
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ZUC_destroy_keystream(&ctx->ks.ks);
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}
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static const PROV_CIPHER_HW_ZUC_EEA3 zuc_128_eea3_hw = {
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{ zuc_128_eea3_initkey, zuc_128_eea3_cipher },
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zuc_128_eea3_initiv,
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zuc_128_eea3_cleanup
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};
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const PROV_CIPHER_HW *ossl_prov_cipher_hw_zuc_128_eea3(size_t keybits)
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{
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return (PROV_CIPHER_HW *)&zuc_128_eea3_hw;
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}
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