RSA Public and Private Key Extraction & Verification

RSA Public and Private Key Extraction & Verification Tool

Process existing RSA public and private keys. Extract the corresponding public key from an RSA private key, or compare key parameters to determine whether a public key and private key belong to the same key pair. Useful for developers working with API integrations, server configuration, and key format conversion.

Key Features

• Extract RSA public keys: Import or paste an RSA private key to extract its corresponding public key without providing a separate public key.
• Verify RSA key pairs: Enter an RSA public key and private key to compare their modulus n and public exponent e and determine whether they belong to the same key pair.
• Export public keys in multiple formats: Supports seven output formats: PEM / SPKI, PKCS#1 PEM, OpenSSH, JWK, XML, SPKI DER Base64, and SPKI DER Hex.
• Key information detection: Displays the RSA key type, key size, input format, and public exponent.
• Text and file input: Paste key text directly or import PEM, KEY, PUB, DER, JSON, and TXT files.
• Local processing: Key parsing, extraction, verification, and format conversion are performed entirely in your browser. Keys are not uploaded to the server.

Supported Key Formats

The tool automatically detects supported RSA key formats, including PEM, DER, PKCS#1, PKCS#8, SPKI, OpenSSH, JWK, XML, and raw Base64 or Hex encodings. The actual structures that can be parsed depend on the key type and encoded content.

Public Key Export Formats

• PEM / SPKI: The commonly used X.509 SubjectPublicKeyInfo public key format, compatible with most development frameworks and cryptographic libraries.
• PKCS#1: An RSA-specific public key structure for systems that require the PKCS#1 format.
• OpenSSH: The SSH public key format used for server SSH public key configuration.
• JWK: JSON Web Key format for web applications, JWT, and related development scenarios.
• XML: The .NET RSA XML public key format.
• SPKI DER Base64: Raw Base64 encoding of SPKI DER binary data, without PEM headers or footers.
• SPKI DER Hex: Hexadecimal encoding of SPKI DER binary data.

How to Use

1. Paste key text or import a key file, then enter the RSA private key in the private key field.
2. Select "Extract Public Key" and click the action button to generate the corresponding public key.
3. Choose the required format from the output format dropdown, then copy or download the public key.
4. To verify a key pair, switch to "Verify Key Pair", enter both the public key and private key, and run the verification.
5. Check the result to see whether the keys match, and review details such as key size, public exponent, and input formats.

Limitations and Security Notes

This tool is designed only to detect, extract, verify, and convert existing RSA keys. It does not generate keys, perform encryption or decryption, create or verify digital signatures, or decrypt password-protected private keys. Encrypted private keys must be decrypted with tools such as OpenSSL before import. Unsupported inputs, including X.509 certificates, non-RSA keys, and PuTTY PPK files, will display relevant handling suggestions. The maximum file size is 1 MB.

All key parsing and processing take place locally in your browser. Key contents are never uploaded to the server. Keep your RSA private key secure and do not share it with others or enter it on untrusted websites.