1. Introduction
1. Introduction
JSON Web Signature (JWS) represents content secured with digital signatures or Message Authentication Codes (MACs) using JSON-based [RFC7159] data structures. The JWS cryptographic mechanisms provide integrity protection for an arbitrary sequence of octets. See Section 10.5 for a discussion on the differences between digital signatures and MACs.
Two closely related serializations for JWSs are defined. The JWS Compact Serialization is a compact, URL-safe representation intended for space-constrained environments such as HTTP Authorization headers and URI query parameters. The JWS JSON Serialization represents JWSs as JSON objects and enables multiple signatures and/or MACs to be applied to the same content. Both share the same cryptographic underpinnings.
Cryptographic algorithms and identifiers for use with this specification are described in the separate JSON Web Algorithms (JWA) [JWA] specification and an IANA registry defined by that specification. Related encryption capabilities are described in the separate JSON Web Encryption (JWE) [JWE] specification.
Names defined by this specification are short because a core goal is for the resulting representations to be compact.
1.1 Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in "Key words for use in RFCs to Indicate Requirement Levels" [RFC2119]. The interpretation should only be applied when the terms appear in all capital letters.
BASE64URL(OCTETS) denotes the base64url encoding of OCTETS, per Section 2.
UTF8(STRING) denotes the octets of the UTF-8 [RFC3629] representation of STRING, where STRING is a sequence of zero or more Unicode [UNICODE] characters.
ASCII(STRING) denotes the octets of the ASCII [RFC20] representation of STRING, where STRING is a sequence of zero or more ASCII characters.
The concatenation of two values A and B is denoted as A || B.