BlockSize; remainder != 0 { var carry uint64 c.offset, carry = bits.Add64(c.offset, BlockSize-remainder, 0) if carry != 0 { panic("crypto/aes: counter overflow") } } } // XORKeyStreamAt behaves like XORKeyStream but keeps no state, and instead // seeks into the keystream by the given bytes offset from the start (ignoring // any XORKetStream calls). This allows for random access into the keystream, up // to 16 EiB from the start. func (c *CTR) XORKeyStreamAt(dst, src []byte, offset uint64) { if len(dst)...