Are the banks quantum-safe? We checked 44 of them.

A bank login recorded today can be decrypted once a large quantum computer exists. The defence that exists now is post-quantum key exchange, which a server either offers or does not. We looked at every public server of 44 large banks to see which do.

What we did

For each bank we took every hostname that appears in the public certificate logs, added the common service names under each domain, kept the ones that resolve to a public address, and opened a TLS 1.3 handshake offering only hybrid ML-KEM key exchange. A server that completes it is protected. One that does not is still relying on key exchange that NIST has scheduled for retirement: deprecated after 2030, disallowed after 2035.

This is the outside view. We cannot see internal systems, and a hostname tells you what a server is called, not what traffic it carries. Both limits are on the board itself.

What we found

• 30,729 hostnames known across the 44 banks. 5,031 of them answered on port 443.
• 2,811 of those servers, 56%, already use post-quantum key exchange.
• 346 of the unprotected servers are production login, API, payment or developer hosts, the ones to fix first.
• One bank protects every server it runs: Goldman Sachs, 20 of 20.
• Grades: one A, 27 B, 16 C. No D or F.

The best of the rest: Wells Fargo (95), TD (94), Charles Schwab and Danske Bank (92), Citizens and BNP Paribas (90). At the bottom: UBS (4 of 100 servers protected), Fifth Third (5 of 104), BNY (34 of 194), State Street and American Express (36).

Size is not the problem. Bank of America has 4,628 known hostnames and 177 reachable servers, 64 of them protected; Truist has 206 reachable servers and protects 174. The difference is whether somebody owns the question.

Why it matters to a bank now

EU financial entities are required under DORA's technical standard to keep an encryption policy that follows developments in cryptanalysis and to manage keys through their whole lifecycle (Delegated Regulation 2024/1774, Articles 6 and 7). The first thing that policy needs is an inventory of where the cryptography is. For public servers, this board is that inventory, built from the outside, and it is re-scanned every week.

A bank can get the same scan for its own domains and its suppliers, privately, with a signed report its auditor can verify. The first scan is free.