Encryption Key Strength Estimator

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Encryption Key Strength Estimator

Estimates the effective security strength of encryption keys based on algorithm type, key length, and resistance to known attacks. Uses NIST SP 800-57 guidelines and current cryptanalytic estimates.

Algorithm Type

Symmetric (AES, 3DES, ChaCha20) RSA / Diffie-Hellman (Asymmetric) Elliptic Curve Cryptography (ECC) Hash-based (SHA, BLAKE2)

Key Length (bits)

56-bit (DES — legacy) 112-bit (3DES) 128-bit (AES-128) 192-bit (AES-192) 256-bit (AES-256)

Target Security Year

2024 (Current) 2030 2040 2050

Quantum Computer Threat

No (Classical computers only) Yes (Include Grover/Shor attack models)

Estimate Key Strength

Fill in the fields above and click Estimate Key Strength.

function updateKeyLengthOptions() { var algo = document.getElementById("enc-algorithm").value; var sel = document.getElementById("enc-keylength"); sel.innerHTML = "";

var options = { symmetric: [ [56, "56-bit (DES — legacy)"], [112, "112-bit (3DES)"], [128, "128-bit (AES-128)"], [192, "192-bit (AES-192)"], [256, "256-bit (AES-256)"] ], rsa: [ [512, "512-bit (broken)"], [1024, "1024-bit (deprecated)"], [2048, "2048-bit (minimum recommended)"], [3072, "3072-bit"], [4096, "4096-bit"], [7680, "7680-bit"], [15360,"15360-bit"] ], ecc: [ [160, "160-bit (P-160, legacy)"], [192, "192-bit (P-192)"], [224, "224-bit (P-224)"], [256, "256-bit (P-256 / secp256k1)"], [384, "384-bit (P-384)"], [521, "521-bit (P-521)"] ], hash: [ [128, "128-bit output (MD5 — broken)"], [160, "160-bit output (SHA-1 — deprecated)"], [224, "224-bit output (SHA-224)"], [256, "256-bit output (SHA-256)"], [384, "384-bit output (SHA-384)"], [512, "512-bit output (SHA-512)"] ] };

var list = options[algo]; for (var i = 0; i k operations for a k-bit key."; if (quantum === "yes") { // Grover's algorithm: O(2^(k/2)) quantum operations quantumBits = Math.floor(keyBits / 2); quantumNote = "Grover's algorithm reduces effective security to k/2 = " + quantumBits + " bits."; } } else if (algo === "rsa") { classicalBits = rsaSecurityBits(keyBits); algoNote = "RSA/DH security is governed by the General Number Field Sieve (GNFS). A " + keyBits + "-bit key provides ~" + classicalBits + " bits of security (NIST SP 800-57 Table 2)."; if (quantum === "yes") { // Shor's algorithm breaks RSA in polynomial time quantumBits = 0; quantumNote = "Shor's algorithm solves integer factorization in polynomial time — RSA/DH is completely broken by a sufficiently large quantum computer."; } } else if (algo === "ecc") { // Pollard-rho: O(2^(k/2)) classicalBits = Math.floor(keyBits / 2); algoNote = "ECC security relies on the Elliptic Curve Discrete Logarithm Problem (ECDLP). Pollard-rho gives ~k/2 bits of security for a k-bit curve."; if (quantum === "yes") { quantumBits = 0; quantumNote = "Shor's algorithm (adapted for ECDLP) breaks ECC in polynomial time on a quantum computer."; } } else { // hash // Collision resistance: output/2 (birthday attack) // Preimage resistance: output bits classicalBits = Math.floor(keyBits / 2); // collision (worst case) algoNote = "Hash collision resistance: birthday attack requires O(2n/2) operations for n-bit output → " + classicalBits + " bits. Preimage resistance = " + keyBits + " bits."; if (quantum === "yes") { // Grover halves preimage; BHT algorithm: O(2^(n/3)) for collisions quantumBits = Math.floor(keyBits / 3); quantumNote = "Quantum BHT (Brassard-Høyer-Tapp) collision attack: O(2n/3) → effective " + quantumBits + " bits. Grover reduces preimage to " + Math.floor(keyBits/2) + " bits."; } }

var effectiveBits = (quantum === "yes" && quantumBits !== undefined) ? quantumBits : classicalBits; var info = strengthLabel(effectiveBits); var ttb = timeToBreak(effectiveBits, year);

// Key entropy (bits of entropy in the key itself) var entropy = keyBits; // assuming truly random key

// Equivalent symmetric strength (NIST comparison) var equivSym = effectiveBits;

var html = ''; html += '### Grade: ' + info.grade + ' — ' + info.label + ' '; html += ''; html += 'Algorithm' + document.getElementById("enc-algorithm").options[document.getElementById("enc-algorithm").selectedIndex].text + ''; html += 'Key Length' + keyBits + ' bits'; html += 'Classical Security Strength' + classicalBits + ' bits'; if (quantum === "yes") { html += 'Post-Quantum Security Strength' + (quantumBits === 0 ? '0 bits (Broken)' : quantumBits + ' bits') + ''; } html += 'Effective Security Bits' + effectiveBits + ' bits'; html += 'Key Entropy' + entropy + ' bits (assuming random key)'; html += 'NIST Equivalent Symmetric Strength' + equivSym + '-bit'; html += 'Time-to-Break Estimate (' + year + ')' + ttb + ''; html += ''; html += 'Algorithm Note: ' + algoNote + '

'; if (quantum === "yes" && quantumNote) { html += 'Quantum Note: ' + quantumNote + '

'; } html += '';

document.getElementById("enc-result").innerHTML = html; }

// Initialize dropdown on load updateKeyLengthOptions();

#### Formulas Used

Symmetric (AES, ChaCha20): Security bits = Key length (k). Full key-space exhaustion requires 2k operations. Quantum (Grover): Effective bits = k / 2

RSA / Diffie-Hellman: Security governed by GNFS complexity: L[n, 1/3, 1.923] = e(1.923 + o(1))(ln n)1/3(ln ln n)2/3 NIST SP 800-57 Table 2 mapping: 2048-bit RSA ≈ 112-bit symmetric strength. Quantum (Shor): Polynomial time → 0 effective bits.

Elliptic Curve Cryptography (ECC): Security bits = k / 2 (Pollard-rho attack on ECDLP: O(√(2k)) = O(2k/2)) Quantum (Shor for ECDLP): Polynomial time → 0 effective bits.

Hash Functions: Collision resistance: n/2 bits (birthday attack: O(2n/2)) Preimage resistance: n bits Quantum collision (BHT): n/3 bits — O(2n/3) Quantum preimage (Grover): n/2 bits

Time-to-Break Model: Baseline (2024): ~260 operations/year at nation-state budget ($1B compute cluster). Moore's Law adjustment: +0.5 bits/year effective gain. Remaining security margin = Effective bits − (60 + 0.5 × years ahead)

#### Assumptions & References

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