Picotls is a TLS 1.3 implementation written in C.
At the moment, the library implements draft-22 of the specification, including support 0-RTT resumption using PSK or PSK-DHE.
Primary goal of the project is to create a fast, tiny TLS 1.3 implementation that can be used with the HTTP/2 protocol stack and possibly the upcoming QUIC stack of the H2O HTTP/2 server.
Picotls only implements the communination protocol; cryptographic operations are delegated to cryptographic engines. At the moment, minicrypto binding (uses cifra and micro-ecc) and openssl binding are provided.
License and algorithms supported by the bindings are as follows:
|Binding||License||Key Exchange||Certificate||AEAD cipher|
|minicrypto||CC0 / 2-clause BSD||secp256r1, x25519||ECDSA (P256)1||AES-128-GCM|
|OpenSSL||OpenSSL||secp256r1||RSA, ECDSA (P256)||AES-128-GCM|
Note 1: Minicrypto binding is capable of signing a handshake using the certificate's key, but cannot verify a signature sent by the peer.
If you have cloned picotls from git then ensure that you have initialised the submodules:
% git submodule init % git submodule update
Build using cmake:
% cmake . % make % make check
A dedicated documentation for using picotls with Visual Studio can be found in WindowsPort.md.
Developer documentation should be available on the wiki.
Using the cli command
Run the test server (at 127.0.0.1:8443):
% ./cli -c /path/to/certificate.pem -k /path/to/private-key.pem 127.0.0.1 8443
Connect to the test server:
% ./cli 127.0.0.1 8443
% ./cli -s session-file 127.0.0.1 8443
The session-file is read-write. The cli server implements a single-entry session cache. The cli server sends NewSessionTicket when it first sends application data after receiving ClientFinished.
% ./cli -s session-file -e 127.0.0.1 8443
-e option is used, client first waits for user input, and then sends CLIENT_HELLO along with the early-data.
The software is provided under the MIT license. Note that additional licences apply if you use the minicrypto binding (see above).