RSA Encryption Tool Encrypt & Decrypt Messages

RSA Key Generation

RSA keys are generated by selecting two large prime numbers and computing their product (modulus). The public key consists of the modulus and public exponent (typically 65537), while the private key includes the modulus and private exponent derived from the primes.

• 512-bit: Weak, only for testing
• 1024-bit: Deprecated, avoid for production
• 2048-bit: Recommended minimum for production use
• 4096-bit: High security, slower performance

Encryption & Decryption

Encryption: Uses the public key to transform plaintext into ciphertext. The mathematical operation ensures that only the corresponding private key can decrypt the message.

Decryption: Uses the private key to recover the original plaintext from ciphertext. The asymmetric nature ensures secure communication without pre-shared secrets.

Do's

• Use 2048-bit or larger keys for production
• Use OAEP padding with SHA-256 for new applications
• Keep your private key secure and never share it
• Use hybrid encryption for messages larger than key size
• Rotate keys periodically according to your security policy
• Use this tool for testing and learning purposes
• Generate keys offline for highly sensitive production use

Don'ts

• Don't use 512-bit or 1024-bit keys in production
• Don't use PKCS1Padding for new applications (use OAEP)
• Don't encrypt large files directly with RSA (size limits apply)
• Don't share your private key with anyone
• Don't reuse the same key pair across different applications
• Don't use this tool for encrypting highly classified data
• Don't assume RSA alone provides message integrity (use signatures)