Composable Event Streaming Representation (CESR) Specification

CESR is a dual text-binary encoding format that enables seamless conversion between text and binary representations while maintaining data integrity and composability. It provides a unique solution for encoding both cryptographic primitives and general data types in a way that supports both human-readable text and compact binary transmission.

Key features:

• Text-binary concatenation composability
• Self-framing primitives for efficient stream processing
• Support for cryptographic material suites
• Interleaved serialization support for JSON, CBOR, and MGPK

The standard's core purpose is to provide:

1. A universal encoding format for cryptographic primitives and data
2. Efficient streaming capabilities in both text and binary domains
3. Support for complex data structures and protocols
4. Seamless interoperability between different serialization formats

Technical Specifications:

1. Purpose and Scope:

• Enables lossless round-trip conversion between text and binary representations
• Supports cryptographically agile encodings for primitives
• Facilitates protocol-based data serialization
• Covers electronically transmitted information

2. Key Technical Specifications:

• Uses Base64 URL-safe encoding for text representation
• Implements 24-bit alignment for composability
• Provides framing codes for type and size information
• Supports variable-length and fixed-length encodings

3. Implementation Requirements:

• Must support transformations between three domains:
  • Text (T)
  • Binary (B)
  • Raw binary (R)
• Must maintain concatenation composability
• Must implement self-framing primitives
• Must support standard code tables

4. Security Considerations:

• Supports cryptographic strength of 128 bits minimum
• Enables post-quantum security through digest-based hiding
• Provides cryptographic agility through version control
• Maintains integrity across transformations

5. Interoperability Features:

• Supports multiple serialization formats
• Enables stream processing and pipelining
• Provides version control mechanisms
• Allows for protocol extensibility

6. Current Adoption:

• Implemented in the KERI (Key Event Receipt Infrastructure) protocol
• Used in various cryptographic applications
• Supported by multiple programming languages
• Integrated with existing Base64 tooling

The standard is particularly notable for its ability to maintain data integrity while supporting both human-readable text formats and efficient binary transmission, making it well-suited for modern cryptographic applications and protocols.