Quantum computer code cracking
First of all, I seriously doubt that anyone would have a working quantum computer capable of doing anything useful in the foreseeable future (let's say 10 years). Even if someone does construct a "quantum computer", it will probably be quite useless, and it will take several years more until it can be used to, say, crack codes.

The quantum speedup for breaking symmetric encryption is quadratic: if a single decryption takes time $T$ and there are $N$ bits in the key (usually $N\geq128$ nowadays, unless you're using DES which has $N=56$), then a classical computer will take $2^NT_{\text{classic}}$ time while a quantum computer will take $O(2^{N/2}T_{\text{quantum}})$ time using Grover's algorithm (as far as I understand). In terms of real-world time, we expect $T_{\text{quantum}}$ to be several orders of magnitude larger than $T_{\text{classic}}$, at least at first. Decrypting $2^{64}$ blocks in "quantum speed" will take a lot of time, so quantum computing doesn't seem to break symmetric encryption, barring any weaknesses which enable one to use a smarter algorithm than the naive one.

The story is different for public-key encryption, though again, quantum computers capable of doing anything interesting are still far into the future. Shor's algorithm can be used to factor integers, thus breaking RSA. The algorithm also applies for the discrete log problem, even on elliptic curves. This is problematic for other public-key cryptosystems. You can check out this survey for some quantum-resistant protocols.