Square has had a big 2012 so far — it relaunched its mobile payment app under a new brand, and its card reader hardware was recently beefed up with hardware encryption. Now, All Things D is reporting that Square is hoping for a valuation of up to $4 billion as it looks to raise a new round of capital. Negotiations are ongoing, but this would represent a pretty massive growth in valuation — only ten months ago, Square was valued at $1 billion as it raised $100 million in capital. Unsurprisingly, Square hasn't yet commented on this speculation. The mobile payment space is certainly starting to heat up — earlier in the year, PayPal announced its own competitor to Square, and Google Wallet continues to be a part of the company's Android strategy. We're still waiting for these services to gain more traction with consumers, and we imagine Square is hoping use some of that cash to continue to become more ubiquitous in the mobile payment game.