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Crypto Math: Modular Multiplicative Inverse
x402
Crypto Math: Modular Multiplicative Inverse is a paid API for AI agents from crypto-math.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).
Computes the modular multiplicative inverse of a mod m, or returns the GCD proving no inverse exists when gcd(a,m) > 1.
Price / call$0.02
Success—
StatusUnknown
How this service works
Modular multiplicative inverse of a mod m, or the gcd that proves none exists.
Output
Returns a JSON object with a 'result' field containing the modular inverse (in decimal, hex, and bit-length), a 'gcd' field (null if gcd=1, otherwise the GCD value showing why no inverse exists), a 'verdict' string, a human-readable 'summary', and optional 'check' and 'reasons' fields. The 'degraded' flag indicates if the result is partial.
Example use cases
RSA private exponent computation
“I need to find the modular inverse of my public exponent e=65537 mod phi(n), where phi(n) is 7905853580. That will be my RSA private exponent d — can you compute it?”
Elliptic curve scalar inversion
“For a secp256k1 point scalar operation I need the modular inverse of 0x3f2d1a9b mod the curve order 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141. Can you compute that?”
Checking invertibility before cryptographic step
“Before I proceed with my protocol, I need to know: does 42 have a modular inverse mod 100? If not, give me the GCD that shows why it's impossible.”
Technical details
Endpoint
GEThttps://crypto-math.x402tookit.com/mod-inverse?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to compute a modular multiplicative inverse for cryptographic or number-theoretic purposes — especially for RSA key derivation, elliptic curve scalar inversion, or any modular arithmetic where you also want confirmation that the inverse is valid (gcd=1). It handles both decimal and 0x hex inputs and explicitly returns the GCD when no inverse exists, making it useful for pre-flight checks in cryptographic protocols.
Side effects
- Missing required parameter 'a' or 'mod' returns an error
- Modulus less than 2 is rejected as invalid
- Non-integer or malformed hex input causes a parse error
- When gcd(a,m) > 1, no inverse exists and the response returns the GCD instead of a result
- Very large integers may exceed bit-size limits
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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