ecdsa_brainpoolP256r1tls13_sha256
ecdsa_brainpoolP256r1tls13_sha256 is ECDSA on the Brainpool P-256 curve for TLS 1.3. Only OpenSSL clients offer it.
What it is
ecdsa_brainpoolP256r1tls13_sha256 (code 0x081A) is a TLS 1.3 signature scheme defined in RFC 8734. It uses ECDSA on brainpoolP256r1, one of the Brainpool curves, with SHA-256. Brainpool curves were designed as an alternative to the NIST curves, with parameters derived in a documented way to avoid doubts about how they were chosen.
They are mostly used where a security policy asks for them. The tls13 part of the name exists because RFC 8734 defines new code points for TLS 1.3, separate from how Brainpool curves were negotiated in TLS 1.2.
Public web certificates almost never use Brainpool curves, so mainstream browsers have little reason to support them. RFC 8734 also defines brainpoolP384r1 and brainpoolP512r1 variants.
RFC 8734 also adds Brainpool groups for TLS 1.3 key exchange, which none of our measured clients offer.
Who sends it
Measured on 2026-10-25 against our own test server: sent by 5 of 11 clients. Position counts from 1 and ignores GREASE values.
Why it matters for fingerprinting
Python requests, httpx, Node.js fetch and Guzzle send it 9th, followed by the brainpoolP384r1 and brainpoolP512r1 variants. Debian curl, macOS curl, curl_cffi, curl-impersonate and Go net/http do not.
Check whether your client sends it
Open the test from your browser, or call it from your script, and look for ecdsa_brainpoolP256r1tls13_sha256 in the TLS details.
Run the TLS fingerprint test