+int CRYPTO_gcm128_decrypt_ctr32(GCM128_CONTEXT *ctx,
+ const unsigned char *in, unsigned char *out,
+ size_t len,ctr128_f stream)
+{
+ const union { long one; char little; } is_endian = {1};
+ unsigned int n, ctr;
+ size_t i;
+ u64 mlen = ctx->len.u[1];
+ void *key = ctx->key;
+#ifdef GCM_FUNCREF_4BIT
+ void (*gcm_gmult_p)(u64 Xi[2],const u128 Htable[16]) = ctx->gmult;
+# ifdef GHASH
+ void (*gcm_ghash_p)(u64 Xi[2],const u128 Htable[16],
+ const u8 *inp,size_t len) = ctx->ghash;
+# endif
+#endif
+
+ mlen += len;
+ if (mlen>((U64(1)<<36)-32) || (sizeof(len)==8 && mlen<len))
+ return -1;
+ ctx->len.u[1] = mlen;
+
+ if (ctx->ares) {
+ /* First call to decrypt finalizes GHASH(AAD) */
+ GCM_MUL(ctx,Xi);
+ ctx->ares = 0;
+ }
+
+ if (is_endian.little)
+ ctr = GETU32(ctx->Yi.c+12);
+ else
+ ctr = ctx->Yi.d[3];
+
+ n = ctx->mres;
+ if (n) {
+ while (n && len) {
+ u8 c = *(in++);
+ *(out++) = c^ctx->EKi.c[n];
+ ctx->Xi.c[n] ^= c;
+ --len;
+ n = (n+1)%16;
+ }
+ if (n==0) GCM_MUL (ctx,Xi);
+ else {
+ ctx->mres = n;
+ return 0;
+ }
+ }
+#if defined(GHASH) && !defined(OPENSSL_SMALL_FOOTPRINT)
+ while (len>=GHASH_CHUNK) {
+ GHASH(ctx,in,GHASH_CHUNK);
+ (*stream)(in,out,GHASH_CHUNK/16,key,ctx->Yi.c);
+ ctr += GHASH_CHUNK/16;
+ if (is_endian.little)
+ PUTU32(ctx->Yi.c+12,ctr);
+ else
+ ctx->Yi.d[3] = ctr;
+ out += GHASH_CHUNK;
+ in += GHASH_CHUNK;
+ len -= GHASH_CHUNK;
+ }
+#endif
+ if ((i = (len&(size_t)-16))) {
+ size_t j=i/16;
+
+#if defined(GHASH)
+ GHASH(ctx,in,i);
+#else
+ while (j--) {
+ size_t k;
+ for (k=0;k<16;++k) ctx->Xi.c[k] ^= in[k];
+ GCM_MUL(ctx,Xi);
+ in += 16;
+ }
+ j = i/16;
+ in -= i;
+#endif
+ (*stream)(in,out,j,key,ctx->Yi.c);
+ ctr += (unsigned int)j;
+ if (is_endian.little)
+ PUTU32(ctx->Yi.c+12,ctr);
+ else
+ ctx->Yi.d[3] = ctr;
+ out += i;
+ in += i;
+ len -= i;
+ }
+ if (len) {
+ (*ctx->block)(ctx->Yi.c,ctx->EKi.c,key);
+ ++ctr;
+ if (is_endian.little)
+ PUTU32(ctx->Yi.c+12,ctr);
+ else
+ ctx->Yi.d[3] = ctr;
+ while (len--) {
+ u8 c = in[n];
+ ctx->Xi.c[n] ^= c;
+ out[n] = c^ctx->EKi.c[n];
+ ++n;
+ }
+ }
+
+ ctx->mres = n;
+ return 0;
+}
+
+int CRYPTO_gcm128_finish(GCM128_CONTEXT *ctx,const unsigned char *tag,
+ size_t len)