Tesla Motors has published the liblithium cryptographic library, the key goals of which are compactness, low resource consumption, and portability. The library is initially developed with an eye to being able to run both on conventional CPUs and on DSP chips and microcontrollers, and is suitable for use in limited environments and in code called at early boot stages to verify digital signatures of embedded device firmware. The code is written in C (C99) and distributed under the Apache 2.0 license.
The library implements tools for streaming encryption and digital signatures based on the X25519 key agreement scheme (RFC 7748), the Gimli cryptographic permutation method and the Gimli-Hash hash function proposed by Daniel J. Bernstein and allowing to achieve high performance on low power hardware such as 8-bit microcontrollers. The implementation of X25519 digital signatures is based on code from the STROBE framework and differs from ed25519 signatures by using only βXβ coordinates when manipulating points on an elliptic curve, which can significantly reduce the code size required to create and verify signatures.
Source: opennet.ru