Convert between AES, RSA, and ECC key sizes to find equivalent security strength. Based on NIST SP 800-57 recommendations.
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Understanding the relationship between different encryption key sizes is crucial for designing secure systems. AES-128, RSA-2048, and ECC-256 all provide roughly 128-bit security, but their key sizes differ dramatically. Our calculator helps you convert between algorithms and understand the security implications.
Encryption strength is measured in 'security bits'—the number of operations an attacker would need to break the encryption. A 128-bit security level means 2^128 operations are required. Different algorithms achieve the same security level with vastly different key sizes: AES uses 128 bits, RSA needs 3072 bits, and ECC requires only 256 bits.
Key Size to Security Bits
AES: Security = Key Size | ECC: Security ≈ Key/2 | RSA: Security ≈ log₂(GNFS complexity)Ensure all components of your system provide equivalent security levels. A chain is only as strong as its weakest link.
Choose the most efficient algorithm for your use case. ECC provides the same security as RSA with much smaller keys and faster operations.
Plan upgrades from legacy algorithms. Know exactly what RSA key size matches your current AES configuration.
Verify your implementations meet minimum security requirements across all algorithm types.
Understand which algorithms are quantum-resistant and plan your migration to post-quantum cryptography.
When using RSA for key exchange and AES for data encryption, ensure both provide equivalent security. RSA-3072 + AES-128 both offer ~128-bit security.
Select cipher suites with balanced security. ECDHE-256 + AES-128-GCM provides consistent 128-bit security throughout the connection.
Determine master key sizes that will adequately protect derived session keys. Your key hierarchy should maintain consistent security levels.
Quickly assess whether cryptographic implementations across your organization meet minimum security thresholds.
Choose between RSA-2048, RSA-4096, or ECC-256 certificates based on actual security provided, not just key size numbers.
Identify which parts of your cryptographic infrastructure need migration to post-quantum algorithms.
RSA security depends on the difficulty of factoring large numbers, not brute force. The General Number Field Sieve (GNFS) algorithm can factor RSA moduli much faster than brute force. A 2048-bit RSA key provides only ~112 bits of security because GNFS requires roughly 2^112 operations to factor it.