mtstickney/oe-encode

An implementation of Progress' ENCODE() function in Common Lisp.

Introduction

This is a port of Pieter van Ginkel’s C# implementation of the ENCODE() hash function from Progress OpenEdge. To paraphrase Pieter: Progress has declined to make the algorithm for ENCODE() public, which is problematic when working with legacy systems (particularly where it’s been used to hash user passwords). This implementation provides a compatible implementation of the hash function.

API

(hash-bytes bytes)

Usage:

(hash-bytes #(1 2 3 4))
;=> #(97 98 109 99 97 110 106 67 108 106 102 120 113 77 76 119)

HASH-BYTES takes a sequence of (unsigned-byte 8) and returns a (vector (unsigned-byte 8) 16) that is the bytes of the resulting hash.

(hash-string string &key encoding)

Usage:

(hash-string "foo" :encoding :utf-8)
;=> #(108 97 99 100 107 71 106 117 108 105 106 99 108 110 97 97)

HASH-STRING uses HASH-BYTES to hash the input string after encoding it with the specified encoding. If :encoding is not supplied, :iso-8559-1 is used.

(hash-string->string string &key in-encoding out-encoding)

Usage:

(oe-encode:hash-string->string "foo" :in-encoding :utf-8 :out-encoding :utf-8)
;=> "lacdkGjulijclnaa"

HASH-STRING->STRING works like HASH-STRING but decodes the result result into a string before returning it – the Progress API operates on and returns strings, so this is likely to be the most convenient function for working with existing data. :in-encoding is used to encode the input before hashing and defaults to :iso-8559-1, :out-encoding is used to decode the resulting hash bytes as a string and defaults to the value of :in-encoding.

Note that the ENCODE() algorithm ensures that output bytes are always in the range of alphabetic ASCII characters, so output encodings that are ASCII-compatible are preferrable.