Description
Inspect DER INTEGER content sign and redundant prefix.
ASN.1 encodings separate identifiers, lengths and contents, with DER applying stricter canonical forms than BER. One leading octet or terminal-bit check covers only part of the complete value.
Inspect DER INTEGER content sign and redundant prefix.
When to use this tool
Use DER Integer Leading Sign Octet when inspecting a stated ASN.1 field or canonical-content condition.
How to use the tool and how it works
- Enter bytes. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read negative, redundantPrefix. Inspect negative, redundantPrefix before interpreting the associated values.
Inspect DER INTEGER content sign and redundant prefix. Require nonempty byte-range content; sign is the first high bit, and redundantPrefix detects unnecessary leading 00 or FF octets relative to the next sign bit.1
DER constrains primitive encodings, including canonical value representation. Inspecting the supplied value octets does not establish a complete valid ASN.1 element.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| bytes | Octet values, each from 0 through 255, in the stated byte order. | Required. Array of safe integer; maximum items 256. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| negative | Negative | Required. Boolean. |
| redundantPrefix | Redundant Prefix | Required. Boolean. |
{
"input": {
"bytes": [
0,
128
]
},
"output": {
"negative": false,
"redundantPrefix": false
}
}Limitations and assumptions
- No integer magnitude, tag/length or complete DER object is decoded or validated.
- 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 an ASN.1 schema and complete BER/DER parser for nested values, canonicality and application meaning.
References
Similar or alternative tools
- DER Boolean Value Octet
Decode one canonical DER BOOLEAN content octet.
- DER Bitstring Unused Bit Count
Check BIT STRING unused-tail-bit consistency.