1# libder 2 3## What is libder? 4 5libder is a small library for encoding/decoding DER-encoded objects. It is 6expected to be able to decode any BER-encoded buffer, and an attempt to 7re-encode the resulting tree would apply any normalization expected by a DER 8decoder. The author's use is primarily to decode/encode ECC keys for 9interoperability with OpenSSL. 10 11The authoritative source for this software is located at 12https://git.kevans.dev/kevans/libder, but it's additionally mirrored to 13[GitHub](https://github.com/kevans91/libder) for user-facing interactions. 14Pull requests and issues are open on GitHub. 15 16## What is libder not? 17 18libder is not intended to be a general-purpose library for working with DER/BER 19specified objects. It may provide some helpers for building more primitive 20data types, but libder will quickly punt on anything even remotely complex and 21require the library consumer to supply it as a type/payload/size triple that it 22will treat as relatively opaque (modulo some encoding normalization rules that 23can be applied without deeply understanding the data contained within). 24 25libder also doesn't do strict validation of what it reads in today, for better 26or worse. e.g., a boolean may occupy more than one byte and libder will happily 27present it to the application in that way. It would be normalized on 28re-encoding to 0xff or 0x00 depending on whether any bits are set or not. 29