RSA Signature Generator & Verifier
RSA Signature Generator & Verifier: Computes SHA-256 digest of data, applies RSA private key signing exponent, and verifies signature with public key.
About this rsa signature generator & verifier
RSA Signature Generator & Verifier — browser-based utility.
How this tool works
Implements client-side RSA Signature Generator & Verifier operations. Computes SHA-256 digest of data, applies RSA private key signing exponent, and verifies signature with public key specifically designed for an api developer signs a payload with an rsa private key and verifies the digital signature with the public key.
- Key Derivation & CSPRNG Nonce Generation: Derives cryptographic keys from passphrases via PBKDF2 with random salts and generates unique IV nonces.
- Authenticated Encryption (AEAD): Encrypts plaintext blocks and computes an authentication tag to protect against ciphertext tampering.
- Container Formatting: Packages salt, IV, ciphertext, and auth tag into standardized Base64 or JSON envelopes.
- Decryption & Tamper Verification: Verifies the authentication tag before decrypting; throws immediate integrity errors if data was modified.
Worked example
Scenario: An API developer signs a payload with an RSA private key and verifies the digital signature with the public key.
Sample input:
Processing: Computes SHA-256 digest of data, applies RSA private key signing exponent, and verifies signature with public key.
Illustrative output:
Limits and verification
Never reuses an Initialization Vector (IV) with the same key (IV reuse in GCM mode destroys authenticity and leaks plaintext). Passphrases cannot be recovered if lost, as no backdoor or recovery key exists.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Enter, paste, or select your input data into the RSA Signature Generator & Verifier workspace controls.
- Review available parameter fields, units, formats, or options configured for your task.
- Click the action button or observe immediate live calculations rendered in your browser runtime.
- Inspect the resulting output and any diagnostic messages, then copy or download the result if needed.
Frequently asked questions
What keys does RSA Sign Verify require?+
Sign requires privateJwk from the RSA key generator signing pair. Verify requires the matching signing publicJwk and base64 signature.
What did the browser fixture verify?+
A newly generated signingPrivateJwk signed message abc and returned an RSASSA-PKCS1-v1_5-SHA256 signature.
Can RSA-OAEP encryption keys sign messages?+
No. The generator exposes a separate RSASSA-PKCS1-v1_5 signing pair. Encryption JWKs have different key operations and are not substitutes.
What can invalidate verification?+
Changing message bytes, using another public key, altering base64 signature data, or selecting a mismatched algorithm makes verification fail.