Bitcoin's new quantum defenses and 18.9M SOL cut

Bitcoin's new quantum defenses moved from theory toward practice this week: StarkWare tested a quantum-resistant mainnet transaction, Blockstream published a SHRINCS signature proposal, and Solana validators voted to curb issuance by 18.9 million SOL over six years—signaling progress on long-term security and near-term supply as markets weigh a renewed bull case.

The latest Fintech & Crypto Alerts roundup from Cointelegraph's Hodler's Digest highlights two parallel storylines. Developers are hardening Bitcoin against future quantum computers, while Solana's network is tightening inflation after a record transaction month.

Key Takeaways

• StarkWare's Avihu Levy spent a quantum-protected 10,000-satoshi output on Bitcoin mainnet using the Quantum Safe Bitcoin scheme.
• Blockstream researchers published a SHRINCS signature Bitcoin Improvement Proposal on August 27, slimming post-quantum signatures by roughly 13 times.
• Solana validators approved SGP-0002, doubling the disinflation rate to cancel 18.9 million SOL in future issuance.
• Bernstein analysts forecast Bitcoin could reclaim $125,000 and peak at $500,000 in 2029 under a bullish scenario.
• Michael Saylor signaled Strategy may resume corporate Bitcoin buying after a two-month pause.

What are Bitcoin's new quantum defenses?

Despite skepticism about how imminent the quantum threat is, two developments showed concrete progress. StarkWare researcher Avihu Levy tested an experimental quantum-resistant transaction on Bitcoin mainnet that protects outputs during the brief window when public keys are exposed in the mempool.

Onchain data shows StarkWSare spent a 10,000-satoshi output protected by Levy's Quantum Safe Bitcoin scheme. It combines hash-based one-time signatures with computational searches binding authorization to a specific transaction. Each transaction takes hours and costs $150 to $200, making it a last resort rather than a daily tool.

On August 27, Blockstream researchers published a Bitcoin Improvement Proposal to upgrade Bitcoin with the SHRINCS signature scheme. They reduced a large hash-based post-quantum signature by about 13.23 times, though SHRINCS signatures remain at least nine times larger than Bitcoin's existing signatures.

Blockstream Research's Jonas Nick called it "the first concrete proposal for a post-quantum signature scheme designed specifically for Bitcoin." Details are in the Cointelegraph Hodler's Digest.

Why did Solana validators vote to cut 18.9M SOL in issuance?

Solana validators approved proposal SGP-0002, known as Double Disinflation, to double the network's annual disinflation rate from 15% to 30%. The measure will reduce issuance by 18.9 million SOL over the next six years.

Participation reached 60.7% of eligible stake, with 67% support, 25.16% against, and 7.84% abstaining. Under the new schedule, Solana is expected to reach its 1.5% terminal inflation rate in about 2.8 years, compared with roughly 5.7 years previously.

The vote landed as Solana processed a record 4.2 billion transactions in July, up 13.5% from June, according to data from The Kobeissi Letter.

Could Bitcoin reach $500K this cycle?

Market momentum is building alongside the technical upgrades. BlocksBridge Consulting reported Bitcoin's 23% rally over the past week outpaced most AI-linked infrastructure stocks, while Bitcoin ETFs minted more than $3.3 billion in August—the strongest month since October 2025's all-time high.

Wall Street analysts at Bernstein predict a new four-year cycle is beginning. Their forecast suggests Bitcoin will reclaim $125,000 under both base and bull cases, peak at $300,000 in 2029 under the base case, or top $500,000 that year under a bullish scenario.

CryptoQuant CEO Ki Young Ju also flagged the first positive reading on CryptoQuant's Bull/Bear Market Cycle Indicator since early October, writing that "the Bitcoin bear cycle is over."

Is Strategy resuming Bitcoin buying?

Separately, Strategy's Michael Saylor posted "We're Back" on X, hinting the firm may resume Bitcoin purchases after a two-month pause focused on balance-sheet strength. Strategy built a $5.1 billion US dollar reserve and a $1.59 billion cash pool while pausing weekly accumulation.

The company holds more than 840,447 Bitcoin at an average cost near $75,385. With Bitcoin recovering past $80,000, Saylor's signal suggests dry powder may soon return to the asset class he champions most.