Signature Malleability Check

Paste a Bitcoin address (or a transaction ID) to extract each input's ECDSA signature components — R, S, Z — and classify each signature as canonical (low-S, S ≤ n/2) or malleable (high-S). BIP-62 makes low-S the relay standard; a high-S signature can be replaced by its twin S′ = n − S, changing the transaction ID with no private key. Everything runs in your browser.

bitcoin
Enter a Bitcoin address or a 64-character transaction ID (TXID). Balance and stats load for every chain; the transaction graph loads where a keyless explorer is available.
newest for the address (exactly this many are scanned; a single TXID fetches just that one transaction)
Each signature is classified low-S (canonical) vs high-S (malleable) per BIP-62 — no parameters needed.
Balance 0 BTC
Received 0 BTC
TX 0 
Instructions:
1. Enter a Bitcoin address (recommended) or a 64-character TXID.
2. Every input's ECDSA signature is extracted and its S value is checked against the BIP-62 low-S rule (S ≤ n/2).
3. High-S signatures are flagged MALLEABLE and their canonical twin S′ = n − S is shown; low-S signatures are CANONICAL.
4. An internet connection is required to fetch transaction data from public block explorers.
Educational / read-only tool. Transaction data is fetched live from public block-explorer APIs (blockstream.info, with blockchain.info as a fallback). This tool only classifies each signature as canonical (low-S) or malleable (high-S) per BIP-62 — it recovers no keys and changes nothing on-chain. It demonstrates why non-canonical high-S signatures enable transaction-ID malleability (the SegWit / BIP-62 fix).