HMAC Two-Hash-Call Counter
Conceptual two hash-function invocations per HMAC message (inner and outer), not compression-block counts or performance prediction.
Description
Count conceptual inner and outer hash applications for a number of HMAC messages.
The HMAC construction conceptually applies an inner hash and an outer hash per authenticated message. Counting these applications is different from counting a hash function's compression blocks.1
When to use this tool
Count conceptual inner and outer hash applications for a number of HMAC messages. Use it when the input measurements and conventions below match the operation you need.
- Prepare messageCount, respecting the measurement basis and boundaries below.
- Compare the worked example with your intended operation before reusing its result.
How to use the tool and how it works
- Enter every field in the input table using the stated units and exact supported selector spelling where applicable.
- Run the tool. Correct input errors before interpreting an output.
- Read the result fields below; use accompanying flags and the stated sign, boundary or model convention when interpreting a number.
For a nonnegative integer message count, the tool returns twice that count as the conceptual hash-call total.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| messageCount | Message count. | Integer; from 0 to 1000000000 inclusive |
| Output field | Interpretation |
|---|---|
| result | Object containing the following named result fields. |
| result.conceptualHashInvocations | Conceptual hash invocations; use the stated units and sign convention. |
{
"input": {
"messageCount": 3
},
"output": {
"result": {
"conceptualHashInvocations": 6
}
}
}Limitations and assumptions
- Key preprocessing, reusable precomputed states, message length and implementation costs are omitted. The number is not a benchmark, a compression-call count or a security analysis.
- Every declared field is required and unexpected fields are rejected. Numeric inputs must be finite; input errors are distinct from a valid false result or an explicitly qualified output.
- Extremely large inputs and nonfinite or excessively large outputs are rejected. List positions reported by the tool use zero-based indices unless stated otherwise.
Alternative or Complementary methods
Use the applicable protocol specification and a reviewed implementation for real verification, hashing or key management. A format label, probability model or tentative text mapping does not replace that operation. Compare the scope of the nearby tools below before substituting one.
References
-
RFC 2104, Section 2: Definition of HMAC — RFC Editor
-
Tool behavior and example: HMAC Two-Hash-Call Counter — tool.io
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