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/*
* (C) 2019 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/sodium.h>
#include <botan/secmem.h>
#include <botan/stream_cipher.h>
#include <botan/mac.h>
namespace Botan {
int Sodium::crypto_secretbox_xsalsa20poly1305(uint8_t ctext[],
const uint8_t ptext[],
size_t ptext_len,
const uint8_t nonce[],
const uint8_t key[])
{
if(ptext_len < 32)
return -1;
auto salsa = StreamCipher::create_or_throw("Salsa20");
salsa->set_key(key, crypto_secretbox_KEYBYTES);
salsa->set_iv(nonce, crypto_secretbox_NONCEBYTES);
secure_vector<uint8_t> auth_key(32);
salsa->write_keystream(auth_key.data(), auth_key.size());
salsa->cipher(ptext + 32, ctext + 32, ptext_len - 32);
auto poly1305 = MessageAuthenticationCode::create_or_throw("Poly1305");
poly1305->set_key(auth_key);
poly1305->update(ctext + 32, ptext_len - 32);
poly1305->final(ctext + 16);
clear_mem(ctext, 16);
return 0;
}
int Sodium::crypto_secretbox_xsalsa20poly1305_open(uint8_t ptext[],
const uint8_t ctext[],
size_t ctext_len,
const uint8_t nonce[],
const uint8_t key[])
{
if(ctext_len < crypto_box_curve25519xsalsa20poly1305_ZEROBYTES)
{
return -1;
}
auto salsa = StreamCipher::create_or_throw("Salsa20");
salsa->set_key(key, crypto_secretbox_KEYBYTES);
salsa->set_iv(nonce, crypto_secretbox_NONCEBYTES);
secure_vector<uint8_t> auth_key(32);
salsa->write_keystream(auth_key.data(), auth_key.size());
auto poly1305 = MessageAuthenticationCode::create_or_throw("Poly1305");
poly1305->set_key(auth_key);
poly1305->update(ctext + 32, ctext_len - 32);
secure_vector<uint8_t> computed = poly1305->final();
if(!constant_time_compare(computed.data(), ctext + 16, 16))
return -1;
salsa->cipher(ctext + 32, ptext + 32, ctext_len - 32);
clear_mem(ptext, 32);
return 0;
}
int Sodium::crypto_secretbox_detached(uint8_t ctext[], uint8_t mac[],
const uint8_t ptext[],
size_t ptext_len,
const uint8_t nonce[],
const uint8_t key[])
{
auto salsa = StreamCipher::create_or_throw("Salsa20");
salsa->set_key(key, crypto_secretbox_KEYBYTES);
salsa->set_iv(nonce, crypto_secretbox_NONCEBYTES);
secure_vector<uint8_t> auth_key(32);
salsa->write_keystream(auth_key.data(), auth_key.size());
salsa->cipher(ptext, ctext, ptext_len);
auto poly1305 = MessageAuthenticationCode::create_or_throw("Poly1305");
poly1305->set_key(auth_key);
poly1305->update(ctext, ptext_len);
poly1305->final(mac);
return 0;
}
int Sodium::crypto_secretbox_open_detached(uint8_t ptext[],
const uint8_t ctext[],
const uint8_t mac[],
size_t ctext_len,
const uint8_t nonce[],
const uint8_t key[])
{
auto salsa = StreamCipher::create_or_throw("Salsa20");
salsa->set_key(key, crypto_secretbox_KEYBYTES);
salsa->set_iv(nonce, crypto_secretbox_NONCEBYTES);
secure_vector<uint8_t> auth_key(32);
salsa->write_keystream(auth_key.data(), auth_key.size());
auto poly1305 = MessageAuthenticationCode::create_or_throw("Poly1305");
poly1305->set_key(auth_key);
poly1305->update(ctext, ctext_len);
secure_vector<uint8_t> computed_mac = poly1305->final();
if(!constant_time_compare(mac, computed_mac.data(), computed_mac.size()))
return -1;
salsa->cipher(ctext, ptext, ctext_len);
return 0;
}
}
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