static int
aead_cipher_encrypt(cipher_ctx_t *cipher_ctx,
uint8_t *c,
size_t *clen,
uint8_t *m,
size_t mlen,
uint8_t *ad,
size_t adlen,
uint8_t *n,
uint8_t *k)
{
int err = CRYPTO_OK;
unsigned long long long_clen = 0;
size_t nlen = cipher_ctx->cipher->nonce_len;
size_t tlen = cipher_ctx->cipher->tag_len;
switch (cipher_ctx->cipher->method) {
case AES256GCM: // Only AES-256-GCM is supported by libsodium.
if (cipher_ctx->aes256gcm_ctx != NULL) { // Use it if availble
err = crypto_aead_aes256gcm_encrypt_afternm(c, &long_clen, m, mlen,
ad, adlen, NULL, n,
(const aes256gcm_ctx *)cipher_ctx->aes256gcm_ctx);
*clen = (size_t)long_clen; // it's safe to cast 64bit to 32bit length here
break;
}
// Otherwise, just use the mbedTLS one with crappy AES-NI.
case AES192GCM:
case AES128GCM:
err = mbedtls_cipher_auth_encrypt(cipher_ctx->evp, n, nlen, ad, adlen,
m, mlen, c, clen, c + mlen, tlen);
*clen += tlen;
break;
case CHACHA20POLY1305IETF:
err = crypto_aead_chacha20poly1305_ietf_encrypt(c, &long_clen, m, mlen,
ad, adlen, NULL, n, k);
*clen = (size_t)long_clen;
break;
#ifdef FS_HAVE_XCHACHA20IETF
case XCHACHA20POLY1305IETF:
err = crypto_aead_xchacha20poly1305_ietf_encrypt(c, &long_clen, m, mlen,
ad, adlen, NULL, n, k);
*clen = (size_t)long_clen;
break;
#endif
default:
return CRYPTO_ERROR;
}
return err;
}
/*
Public GCM encrypt function. This will just perform the encryption. The
tag should be fetched with psAesGetGCMTag
*/
void psAesEncryptGCM(psAesGcm_t *ctx, const unsigned char *pt, unsigned char *ct, uint32_t len)
{
unsigned long long ciphertext_len;
unsigned char *resultEncryption;
resultEncryption = psMalloc(NULL, len + sizeof(ctx->Tag));
/* libsodium will put the (cipher text and the tag) in the result, */
crypto_aead_aes256gcm_encrypt_afternm(resultEncryption, &ciphertext_len,
(const unsigned char *) pt, (unsigned long long) len,
(const unsigned char *) ctx->Aad, (unsigned long long) ctx->AadLen,
NULL, (const unsigned char *) ctx->IV,
(crypto_aead_aes256gcm_state *) &(ctx->libSodiumCtx));
/* Copy the authentication tag in context to be able to retrieve it later */
memcpy(ctx->Tag, (resultEncryption + len), sizeof(ctx->Tag));
/* Copy the ciphertext in destination */
memcpy(ct, resultEncryption, len);
psFree(resultEncryption, NULL);
}
