Browse All TLS Extensions

ec_point_formats

TLS Extension Code: 11

Extension Details

Extension Name
ec_point_formats
Extension Code (Decimal)
11
Extension Code (Hex)
0x000B
RFC Reference
RFC 8422

What is ec_point_formats?

The EC Point Formats extension specifies which elliptic curve point formats the client can parse. The most common format is "uncompressed" (0x00), where both X and Y coordinates are sent. Other formats include "ansiX962_compressed_prime" (0x01) and "ansiX962_compressed_char2" (0x02), which reduce bandwidth by sending only the X coordinate and a sign bit. However, most implementations only support uncompressed format due to patent concerns and complexity. This extension is defined in RFC 8422 and is used in TLS 1.2 and earlier (deprecated in TLS 1.3).

Role in JA3 Fingerprinting

How This Extension Affects Fingerprinting

The ec_point_formats extension is part of the TLS Client Hello packet that JA3 analyzes to create a unique fingerprint of your browser or HTTP client.

JA3 Construction: JA3 concatenates TLS parameters including extensions in a specific format:
TLS_VERSION,CIPHERS,EXTENSIONS,CURVES,POINT_FORMATS

Different browsers and HTTP clients support different sets of TLS extensions, making this a key differentiator in fingerprinting. The presence, absence, or order of extensions like ec_point_formats can reveal:

  • Browser type and version (Chrome, Firefox, Safari, Edge)
  • Operating system (Windows, macOS, Linux, Android, iOS)
  • HTTP library (curl, Python requests, Go http.Client, Node.js)
  • Bot detection - automated tools often have distinctive extension sets

Test Your TLS Configuration

See if your browser or HTTP client includes the ec_point_formats extension in its TLS handshake:

Test Your JA3 Fingerprint

The JA3 tool will show all TLS extensions your client advertises, including ec_point_formats.

Browser & Client Support

Modern Browser Support:

  • Chrome/Edge: Full support for ec_point_formats
  • Firefox: Full support for ec_point_formats
  • Safari: Full support for ec_point_formats

HTTP Client Libraries:

  • curl: Support varies by OpenSSL/LibreSSL version
  • Python requests: Limited TLS extension control
  • curl_cffi: Can mimic browser TLS configurations
  • Scrapfly API: Automatically matches real browser TLS fingerprints

Related TLS Resources

TLS Extensions
Testing Tools

Technical References