Pyderasn

Strict and fast ASN.1 DER/CER/BER library for Python

PyDERASN – strict and fast ASN.1 DER/CER/BER library for Python

• BER/CER/DER decoding, strict DER validation, DER/CER encoding
• Basic ASN.1 data types X.208 BOOLEAN, INTEGER, BIT STRING, OCTET STRING, NULL, OBJECT IDENTIFIER, ENUMERATED, all strings, UTCTime, GeneralizedTime, CHOICE, ANY, SEQUENCE OF, SET OF
• Size constraints checking
• Working with sequences as high level data objects with ability to unmarshall them
• Aimed to be complaint with X.690-201508
• Streaming decoding and encoding capabilities, allowing working with very small memory footprint
• Python 3.5+ compatibility
• Automatic decoding of DEFINED BY fields
• Ability to know exact decoded objects offset and lengths in the binary
• Ability to allow BER-encoded data with knowing if any of specified field has either DER or BER encoding or possibly indefinite-length encoding
• Ability to use mmap-ed files, memoryviews, iterators, 2-pass DER encoding mode and CER encoder dealing with the writer, giving ability to create huge ASN.1 encoded files with very little memory footprint
• Ability to decode files in event generation mode, without the need to keep all the data and decoded structures in the memory
• slots, copy.copy friendliness
• Workability with pickle
• Cython compatibility
• Descriptive errors, with decode paths
• Pretty printer and command-line decoder, that could conveniently replace utilities like either dumpasn1 or openssl asn1parse