Encrypt RSA: Key & Text Cipher

MODEX

O aplikaciji

ENCRYPT RSA — ASYMMETRIC ENCRYPTION TOOL

A clean, fast RSA encryption and decryption tool built for developers, security professionals, students, and anyone who needs to work with asymmetric cryptography on mobile.

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WHAT IT DOES
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Generate RSA key pairs — 1024, 2048, or 4096-bit key sizes
Encrypt any plaintext message using a public key
Decrypt RSA ciphertext using your private key
Import and export keys in PEM format (PKCS#1 and PKCS#8 supported)
Copy encrypted output directly to clipboard
OAEP and PKCS#1 v1.5 padding modes
Base64-encoded output for easy transport

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HOW RSA WORKS
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RSA is asymmetric encryption — you encrypt with a public key, decrypt with a private key. The public key can be shared openly with anyone. Only the private key holder can decrypt. This is the cryptographic foundation behind HTTPS, SSH authentication, code signing certificates, and secure email (PGP/S/MIME). RSA-2048 is the current industry standard; RSA-4096 is used where maximum security is required.

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USE CASES
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Secure message exchange — encrypt with recipient's public key, only they can decrypt
Key exchange verification — confirm RSA key pairs are correctly matched
Development and testing — verify RSA implementations in backend systems or APIs
Security education — learn and demonstrate asymmetric cryptography hands-on
Encrypting sensitive strings — for configuration secrets, API keys, or private data
PEM key inspection — import and examine RSA keys from certificates or SSH configs

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KEY SIZES EXPLAINED
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1024-bit — legacy only, not recommended for security-critical uses
2048-bit — current industry standard, recommended for most applications
4096-bit — maximum security, used in high-assurance environments

Larger key sizes are more secure but slower to generate and process. For most use cases, RSA-2048 provides the right balance.

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FULLY OFFLINE
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All key generation, encryption, and decryption happens entirely on your device. No keys, no plaintext, no ciphertext, and no operation data ever leaves your phone. No internet connection required. No server involved. Ever.

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PEM FORMAT SUPPORT
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Import existing RSA keys from PEM files — useful for working with keys generated by OpenSSL, SSH-keygen, or your backend infrastructure. Export generated keys as PEM-formatted text for use in other systems.

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PRIVACY
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No account. No analytics. No data collection of any kind. GDPR-compliant.

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RSA vs AES — WHICH TO USE
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RSA is asymmetric — two different keys (public and private). Use RSA when you need to send encrypted data to someone without sharing a secret key first. The recipient shares their public key openly; only they can decrypt with their private key.

AES is symmetric — one shared key encrypts and decrypts. Use AES when both parties already share a secret key, or when encrypting data for yourself. AES is faster for large data; RSA is slower but solves the key distribution problem.

In practice, most secure systems use both: RSA to exchange an AES key, then AES for the data. This is exactly how HTTPS works.

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DEVELOPER WORKFLOW
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Generate a key pair on-device → export the public key → share it with a counterpart → receive encrypted payload → decrypt with your private key on this device. The entire workflow runs offline, on your phone, without any server or cloud service involved.

Whether you're learning cryptography, testing an implementation, or encrypting something that genuinely needs to stay private — Encrypt RSA gives you a clean, reliable, offline tool that does exactly what it says.

By Modex Apps.

Što je novo

April 2026 update!

RSA-4096 key generation is now 3× faster on all devices.

New: PKCS#8 encrypted private key export with passphrase protection.

Improved PEM parser — handles non-standard key formats from OpenSSL, SSH-keygen, and real-world tools.

Better clipboard handling for large key strings and PEM blocks.

UI improvements — better readability for long key material.

Encrypt RSA — offline, private, reliable.