A Canonical S-expression (or csexp) is a binary encoding form of a subset of general S-expression. It was designed for use in SPKI - to retain the power of S-expressions, while achieving the compactness of a binary form and maximizing the speed of parsing. An S-expression is composed of atoms, which are byte strings, and parentheses used to delimit lists or sub-lists. S-expressions are fully recursive.

PropertyValue
dbpprop:abstract
  • A Canonical S-expression (or csexp) is a binary encoding form of a subset of general S-expression. It was designed for use in SPKI - to retain the power of S-expressions, while achieving the compactness of a binary form and maximizing the speed of parsing. An S-expression is composed of atoms, which are byte strings, and parentheses used to delimit lists or sub-lists. S-expressions are fully recursive. Typically, S-expressions are encoded as text, with spaces delimiting atoms and quotation marks used to surround atoms that contain spaces. Atoms in a Canonical S-expression are encoded as length-prefixed byte strings. The length of the following byte string is expressed as an ASCII decimal number followed by a ":". The sexp (this "Canonical S-expression" has 5 atoms) becomes the csexp . There is no white space to be normalized - thus the adjective canonical - and the atoms can be any binary string. So, a cryptographic hash value or a public key modulus that would have to be encoded in base64 or some other printable encoding can be expressed in csexp as its binary bytes. Binary byte strings can represent various encodings. A csexp includes a non-S-expression construct for indicating the encoding of a string, when that encoding is not obvious. Any atom in csexp can be prefixed by a single atom in square brackets - such as "[4:JPEG]" or "[7:UNICODE]". Finally, an csexp as used in SPKI has one limitation compared to a full S-expression - that every list must start with an atom - and therefore there can be no empty lists. Typically, a list's first atom is treated as one treats an element name in XML.
dbpprop:hasPhotoCollection
dbpprop:reference
rdf:type
rdfs:comment
  • A Canonical S-expression (or csexp) is a binary encoding form of a subset of general S-expression. It was designed for use in SPKI - to retain the power of S-expressions, while achieving the compactness of a binary form and maximizing the speed of parsing. An S-expression is composed of atoms, which are byte strings, and parentheses used to delimit lists or sub-lists. S-expressions are fully recursive.
rdfs:label
  • Canonical S-expressions
owl:sameAs
skos:subject
foaf:page
is owl:sameAs of