Zcash (CRYPTO: ZEC) has bounced 45% from last week's $300 low to $437 after developers proposed an upgrade to fix the counterfeiting bug, while XRP (CRYPTO: XRP) attempts a fragile recovery after falling nearly 19% last week. Ironwood Proposal Would Let Anyone Verify Zcash Supply Is Clean Developers from Shielded Labs, the Zcash Foundation, and the Zcash Open Development Lab proposed creating a new privacy pool using repaired code.