Proquints: Readable, Spellable, and Pronounceable Identifiers

Introduction Proquints encode binary data as alternating consonant-vowel letters grouped into five-letter syllables, yielding identifiers that are readable, spellable, and pronounceable. The idea and specific letter tables were first described by Daniel Shawcross Wilkerson in 2009 (). This document does not claim originality for the concept; it reformulates and formalizes the description for archival purposes. While multiple schemes exist for encoding network addresses and other binary data, Proquints aim to provide a unique blend of human-reabability, accessibility, and long-term usability. They reduce transcription errors, are friendlier for non-technical users, and offer mnemonic qualities that can help in educational or operational contexts. Although they may not replace all existing representations, Proquints can serve as a complementary format that improves clarity in documentation, user interfaces, and spoken communication, particularly where accuracy and inclusivity matter.

Requirements Language 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 BCP 14 [] [] when, and only when, they appear in all capitals, as shown here.

Format A proquint encodes data in 16-bit blocks. Each block maps to a five-letter syllable of the form CVCVC (Consonant-Vowel-Consonant-Vowel-Consonant). The mapping tables are fixed: Consonants (indices 0..15):

b d f g h j k l m n p r s t v z

Vowels (indices 0..3):

a i o u

Encoding

Split the input byte string into 16-bit words (big-endian). If the number of bytes is odd, an implementation MAY pad a single zero byte to complete the final word; if padding is used, applications MUST define how the original length is recovered.
For each 16-bit word, map bits 15-12 to the first consonant, bits 11-10 to the first vowel, bits 9-6 to the second consonant, bits 5-4 to the second vowel, and bits 3-0 to the final consonant.
Concatenate syllables. Hyphens MAY be inserted between syllables for readability; decoders MUST ignore hyphens.

Decoding Decoders MUST reverse the mapping in . Each five-letter syllable maps to one 16-bit value using the same tables and bit ordering. Hyphens, if present, MUST be ignored.

Encoding and Decoding Specification

Letter Tables and Indices Proquint encodes each 16-bit word as five letters in the pattern CVCVC (Consonant–Vowel–Consonant–Vowel–Consonant). The mapping tables and indices are fixed and normative. Consonant table (index 0..15): Vowel table (index 0..3):

Bit Layout Each 16-bit input value (bits 15..0, most significant bit first) MUST be mapped to letters in this order: first consonant (C1) bits 11..10 -> first vowel (V1) bits 9.. 6 -> second consonant(C2) bits 5.. 4 -> second vowel (V2) bits 3.. 0 -> third consonant (C3) ]]> Encoders MUST process input as an ordered sequence of 16-bit words formed from the input octet string in network byte order (big-endian): octet[i] contributes bits 15..8 and octet[i+1] contributes bits 7..0 of the word. If the input contains an odd number of octets, encoders MAY pad a single zero octet to complete the final 16-bit word; applications using padding MUST specify how the original length is recovered. Encoders MAY insert ASCII hyphens (0x2D) between syllables for readability. Decoders MUST ignore hyphens.

Encoding Algorithm (Pseudocode) > 12) & 0xF] v1 = vowels [(w >> 10) & 0x3] c2 = consonants[(w >> 6) & 0xF] v2 = vowels [(w >> 4) & 0x3] c3 = consonants[(w ) & 0xF] syllable = c1 + v1 + c2 + v2 + c3 out += syllable // optional readability: insert '-' between syllables // e.g., if not last: out += '-' return out ]]>

Decoding Algorithm (Pseudocode) > 8) & 0xFF ) out.append( w & 0xFF ) return out ]]> Decoders MUST accept input in either case (upper/lower) and MUST reject any character not in the defined consonant/vowel sets (after stripping hyphens). If applications use padding on encode, they MUST specify how to remove any trailing zero octet introduced solely for padding.

Normalization Encoders SHOULD produce lowercase output. Decoders MUST treat input as case-insensitive and MUST ignore ASCII hyphens (0x2D). Encoders and decoders MUST use the tables and ordering defined in and . Substituting letters or re-ordering bits is not Proquint and will not interoperate.

Test Vectors The following vectors are derived directly from this specification and can be used to verify independent implementations. babab 0xFFFF -> zvzuz 0x1234 -> damuh 0xF00D -> zabat 0xBEEF -> ruroz # Two words (32-bit), big-endian byte order: bytes: 0x12 0x34 0xF0 0x0D words: 0x1234, 0xF00D pq: damuh-zabat (with hyphen) or damuhzabat (without) # Raw ASCII example ("F3r41OutL4w"), # UTF-8 bytes, zero-padded to even length: ASCII: 46 33 72 34 31 4F 75 74 4C 34 77 Pad: 00 Words: 0x4633 0x7234 0x314F 0x7574 0x4C34 0x7700 PQ: himug-lamud-kudaz-lijuh-hubuh-lisab (hyphens optional) ]]> Implementations MUST reproduce these outputs exactly.

Error Handling Decoders MUST fail input that: (1) contains characters outside the defined tables (after hyphen removal); (2) has length not divisible by 5 letters; or (3) violates the CVCVC pattern. Error signaling is application-specific but MUST reject invalid input rather than attempt to guess.

Security Considerations Proquint is a presentation encoding. It provides no confidentiality, integrity, or authentication services. It does not add or remove entropy, and it MUST NOT be used as a cryptographic transform.

IANA Considerations This document has no IANA actions.

Acknowledgments The author thanks Daniel Shawcross Wilkerson for originating the proquint concept and publishing the initial specification in 2009 ().