Description
Check canonical pad bits in one standard Base64 quartet.
Encoded representations separate alphabet symbols, numerical digit values, byte grouping and tail padding. Recognizing one symbol or pad-bit pattern is not full payload decoding, and different alphabet variants can assign different values.
Check canonical pad bits in one standard Base64 quartet.
When to use this tool
Use Decoding: Base64 Final Quartet Pad Bits Check when inspecting one stated alphabet, group or padding component.
How to use the tool and how it works
- Enter quartet. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read result. Expand result to inspect the returned fields.
Check canonical pad bits in one standard Base64 quartet. Require its local four-character alphabet/padding pattern; count trailing equals, inspect low four or two bits accordingly and return decodedByteCount = 3-pads.1
Canonical Base-N encodings require unused pad bits to be zero; alphabet membership alone does not establish canonical encoding.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| quartet | Quartet | Required. Text. Implementation limit: 8192 Unicode code points and 16384 UTF-16 code units. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| result | Returned object; expand its named members below. | Required. Object. |
| result.padCharacters | Pad Characters | Calculated result member: number. |
| result.canonicalPadBits | Unused bits are zero; this does not decode a complete Base64 stream. | Calculated result member: boolean. |
| result.decodedByteCount | Decoded Byte Count | Calculated result member: number. |
{
"input": {
"quartet": "Zh=="
},
"output": {
"result": {
"padCharacters": 2,
"canonicalPadBits": false,
"decodedByteCount": 1
}
}
}Limitations and assumptions
- A false canonical flag is a successful result; line handling, URL alphabet and complete streams are outside scope.
- Outputs are nested inside result. Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
Alternative or Complementary methods
Use the complete codec matching the required alphabet and canonicality rules for real encoded data.
References
Similar or alternative tools
- Decoding: Base32 Final Symbol Pad Bits Check
Check Base32 final-symbol canonicality under an explicit tail count.
- Base64 Sextet Padding Mask
Inspect unused low bits of a Base64 tail sextet.