gistfile1.c

    if (key)
        { do {
#ifdef BSAES_CAPABLE
        if (BSAES_CAPABLE)
            {
            AES_set_encrypt_key(key,ctx->key_len*8,&gctx->ks);
            CRYPTO_gcm128_init(&gctx->gcm,&gctx->ks,
                    (block128_f)AES_encrypt);
            gctx->ctr = (ctr128_f)bsaes_ctr32_encrypt_blocks;
            break;
            }
        else
#endif
#ifdef VPAES_CAPABLE
        if (VPAES_CAPABLE)
            {
            vpaes_set_encrypt_key(key,ctx->key_len*8,&gctx->ks);
            CRYPTO_gcm128_init(&gctx->gcm,&gctx->ks,
                    (block128_f)vpaes_encrypt);
            gctx->ctr = NULL;
            break;
            }
        else
#endif
        (void)0;    /* terminate potentially open 'else' */

        AES_set_encrypt_key(key, ctx->key_len * 8, &gctx->ks);
        CRYPTO_gcm128_init(&gctx->gcm, &gctx->ks, (block128_f)AES_encrypt);
#ifdef AES_CTR_ASM
        gctx->ctr = (ctr128_f)AES_ctr32_encrypt;
#else
        gctx->ctr = NULL;
#endif
        } while (0);