GPG Fingerprint Colon Formatter

Format a supplied v4 20-byte or v6 32-byte OpenPGP fingerprint as uppercase colon-separated hexadecimal byte pairs.

Description

An OpenPGP fingerprint identifies a key through a digest whose length depends on the key version.

An OpenPGP fingerprint identifies a key through a digest whose length depends on the key version. Presenting byte pairs with separators can make a supplied fingerprint easier to compare visually.^[1]

Format a supplied v4 20-byte or v6 32-byte OpenPGP fingerprint as uppercase colon-separated hexadecimal byte pairs.

When to use GPG Fingerprint Colon Formatter

Use this tool to format a supplied v4 20-byte or v6 32-byte OpenPGP fingerprint as uppercase colon-separated hexadecimal byte pairs.

Choose the text, counts, explicit reference time or format parameters requested by this tool. Follow the stated byte, epoch-time and randomness assumptions.

How to use GPG Fingerprint Colon Formatter and understand its results

Choose the text, counts, explicit reference time or format parameters requested by this tool. Follow the stated byte, epoch-time and randomness assumptions.
Enter hex using the field table and calculation rules, then run the tool.
Read fingerprint. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
hex	Fingerprint hexadecimal	string; maximum length: 64	Required

Enter exactly 40 or 64 ASCII hexadecimal characters, corresponding to 20-byte v4 or 32-byte v6 fingerprint layouts. The tool validates the length and characters, uppercases them and inserts colons between successive byte pairs. Original byte order is retained and no prefix is added.

fingerprint = uppercase hex grouped into colon-separated byte pairs

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
fingerprint	Colon-separated fingerprint	string

json

{
  "input": {
    "hex": "00112233445566778899aabbccddeeff00112233"
  },
  "output": {
    "fingerprint": "00:11:22:33:44:55:66:77:88:99:AA:BB:CC:DD:EE:FF:00:11:22:33"
  }
}

Limitations and assumptions

It does not calculate a fingerprint, inspect a key packet or establish trust and key ownership. The accepted length alone does not verify the version or provenance of the supplied digest. Spaces, colons and other fingerprint lengths are rejected.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Extremely large text inputs are rejected. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use SSH Key MD5-Style Fingerprint Formatter: Format a supplied 16-byte MD5 fingerprint as the lowercase colon-separated form used by SSH tooling. For a complementary task, use Random Hex Token Bits From Characters: Return the ideal uniform-random capacity of a hexadecimal token from its number of independently random characters.

References

GPG Fingerprint Colon Formatter — tool.io

Similar or alternative tools

SSH Key MD5-Style Fingerprint Formatter
Format a supplied 16-byte MD5 fingerprint as the lowercase colon-separated form used by SSH tooling.
Random Hex Token Bits From Characters
Return the ideal uniform-random capacity of a hexadecimal token from its number of independently random characters.