Verify Schnorr Signature

WHAT IT DOES

Verify Schnorr Signature enables you to cryptographically verify Schnorr signatures on the secp256k1 elliptic curve following the BIP340 standard. Schnorr signatures are a modern alternative to ECDSA, offering linearity (enabling signature aggregation), simpler verification, and provable security. They are increasingly adopted in blockchain systems like Bitcoin's Taproot upgrade and various threshold signature schemes. The tool takes a message (text or hex), a Schnorr public key (33-byte compressed or 65-byte uncompressed), and a Schnorr signature (64 bytes, consisting of R and s components), and performs the verification algorithm to confirm the signature's authenticity. If the verification succeeds, the tool returns a valid result, confirming that the signature was generated by the private key corresponding to the provided public key and that the message has not been altered. This is essential for applications that require efficient signature verification, aggregate signatures, and compatibility with Bitcoin and other blockchain systems.

HOW TO USE

Connect your wallet using the BGWallet connector (required for context). Select the elliptic curve (secp256k1, the standard for Bitcoin and Ethereum). Choose the message format—"Text" for plain text messages or "Hex" for raw hex-encoded data. Enter the original message that was signed in the text area. Enter the Schnorr public key as a hex string with a 0x prefix—this is the public key that corresponds to the signer's private key and follows the BIP340 standard. Enter the Schnorr signature as a hex string with a 0x prefix—this is a 64-byte signature (32 bytes for R and 32 bytes for s). Click "Verify Schnorr Signature" to run the verification. The tool displays the message, public key, signature, and the verification result: a green "Valid" checkmark if the signature is authentic and a red "Invalid" X if it fails. The result includes a detailed explanation of the outcome, making it clear whether the signature was successfully verified or not.

TECHNICAL MECHANISM

This tool implements BIP340 Schnorr signature verification on the secp256k1 curve using the noble-secp256k1 cryptographic library. The verification algorithm follows the BIP340 specification: given a message m, a public key PK, and a signature (R, s), the verifier computes the challenge e = H(R || PK || m) and checks that s * G = R + e * PK. If this equation holds, the signature is valid; if not, the signature is invalid. The tool handles the elliptic curve point operations, including point addition, scalar multiplication, and the hash-to-challenge function. The public key can be provided in compressed (33 bytes) or uncompressed (65 bytes) format, and the signature must be 64 bytes (R and s components). The tool uses the noble-secp256k1 library for high-performance cryptographic operations, with all computation performed locally in the browser using WebAssembly for efficiency. No data is sent to external servers, ensuring that sensitive data remains private.

WHAT IT CANNOT SEE

This tool cannot verify that the signature was generated from a trusted private key—it only verifies mathematical correctness. It does not support all elliptic curve variants beyond secp256k1. The tool cannot verify aggregate signatures from multiple messages; it only verifies a single signature against a single message and public key. It does not support verification against on-chain registered public keys; you must provide the public key manually. The tool cannot guarantee that the public key or signature formatting is correct beyond basic hex validation. It does not support verification of signatures with non-standard Schnorr variants that deviate from BIP340. The tool cannot detect if the message was altered after signing; verification will fail if the message does not match the original signed data. It does not support hardware-assisted verification; all verification is done in software. The tool cannot verify signatures without the original message and public key provided; both are required for verification. It does not support verification of signatures with custom nonce generation schemes that differ from the BIP340 standard.

PLEASE NOTE

This tool is designed for developers and users working with Schnorr signatures on the secp256k1 curve, following the BIP340 standard used in Bitcoin's Taproot upgrade. The public key should be provided in compressed format (33 bytes, 66 hex characters with 0x prefix) or uncompressed format (65 bytes, 130 hex characters with 0x prefix). The signature must be 64 bytes (128 hex characters with 0x prefix), consisting of the R and s components. The message must match the original message that was signed exactly—even a single character difference will cause verification to fail. The tool uses BIP340-compatible verification, which is the standard for Schnorr signatures in the Bitcoin and blockchain ecosystem. Verification is performed locally using WebAssembly, ensuring that sensitive data is not transmitted to external servers. Always verify signatures from trusted sources using a reliable BIP340-compatible verification library before relying on them in production systems. The tool supports only secp256k1, which is the most widely adopted elliptic curve for blockchain applications. For aggregate signature verification or verification with custom Schnorr variants, consider using a dedicated cryptographic library.