RSA Decrypt

RSA Decrypt performs RSA-OAEP asymmetric decryption by using a private key to recover the original plaintext from ciphertext that was encrypted with the corresponding public key. RSA-OAEP (Optimal Asymmetric Encryption Padding) with SHA-256 is the recommended RSA encryption scheme per PKCS#1 v2.1 and is widely used for key encapsulation, secure message exchange, and protecting small sensitive payloads. All decryption operations run locally using the browser's Web Crypto API, meaning your private key and plaintext never leave your device. This tool is ideal for testing RSA implementations and verifying key pair correctness.

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How to Use

Paste your RSA private key in PEM format (the block starting with -----BEGIN RSA PRIVATE KEY----- or -----BEGIN PRIVATE KEY-----) into the private key field. Paste the Base64-encoded ciphertext produced by RSA-OAEP encryption into the ciphertext field. Click Decrypt to invoke the Web Crypto API and recover the original plaintext. The decrypted result is displayed in the output panel. If decryption fails, verify that the private key matches the public key used for encryption and that the hash algorithm settings agree.

Common Use Cases

• •Decrypting test ciphertexts produced by the RSA Encrypt tool to verify that a generated key pair functions correctly end-to-end
• •Recovering symmetric encryption keys or session tokens that were RSA-OAEP encrypted for a hybrid encryption scheme
• •Debugging RSA decryption failures in development by testing key pairs and ciphertexts independently of application code
• •Verifying that an RSA private key correctly decrypts messages before integrating it into a production key management system
• •Demonstrating asymmetric decryption in hands-on cryptography workshops where learners encrypt and then decrypt their own messages

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