{
  "name": "Post-quantum and classical key & signature sizes (bytes)",
  "source": "crypto-sizes.tools",
  "generated": "2026-09-23",
  "units": "bytes",
  "citation": [
    "FIPS 203 (ML-KEM)",
    "FIPS 204 (ML-DSA)",
    "FIPS 205 (SLH-DSA)",
    "Falcon/FN-DSA",
    "classical: standard encodings"
  ],
  "license": "CC-BY-4.0",
  "records": [
    {
      "algorithm": "ML-KEM-512",
      "type": "KEM",
      "nist_level": 1,
      "public_key_bytes": 800,
      "ciphertext_bytes": 768,
      "private_key_bytes": 1632,
      "classical": false,
      "standard": "FIPS 203"
    },
    {
      "algorithm": "ML-KEM-768",
      "type": "KEM",
      "nist_level": 3,
      "public_key_bytes": 1184,
      "ciphertext_bytes": 1088,
      "private_key_bytes": 2400,
      "classical": false,
      "standard": "FIPS 203"
    },
    {
      "algorithm": "ML-KEM-1024",
      "type": "KEM",
      "nist_level": 5,
      "public_key_bytes": 1568,
      "ciphertext_bytes": 1568,
      "private_key_bytes": 3168,
      "classical": false,
      "standard": "FIPS 203"
    },
    {
      "algorithm": "X25519 (classical)",
      "type": "KEM",
      "nist_level": 1,
      "public_key_bytes": 32,
      "ciphertext_bytes": 32,
      "private_key_bytes": 32,
      "classical": true,
      "standard": "RFC 7748"
    },
    {
      "algorithm": "ECDH P-256 (classical)",
      "type": "KEM",
      "nist_level": 1,
      "public_key_bytes": 64,
      "ciphertext_bytes": 64,
      "private_key_bytes": 32,
      "classical": true,
      "standard": "SEC1"
    },
    {
      "algorithm": "RSA-2048 (classical)",
      "type": "KEM",
      "nist_level": 1,
      "public_key_bytes": 256,
      "ciphertext_bytes": 256,
      "private_key_bytes": 1190,
      "classical": true,
      "standard": "PKCS#1"
    },
    {
      "algorithm": "RSA-3072 (classical)",
      "type": "KEM",
      "nist_level": 1,
      "public_key_bytes": 384,
      "ciphertext_bytes": 384,
      "private_key_bytes": 1770,
      "classical": true,
      "standard": "PKCS#1"
    },
    {
      "algorithm": "ML-DSA-44",
      "type": "signature",
      "nist_level": 2,
      "public_key_bytes": 1312,
      "signature_bytes": 2420,
      "private_key_bytes": 2560,
      "classical": false,
      "standard": "FIPS 204"
    },
    {
      "algorithm": "ML-DSA-65",
      "type": "signature",
      "nist_level": 3,
      "public_key_bytes": 1952,
      "signature_bytes": 3309,
      "private_key_bytes": 4032,
      "classical": false,
      "standard": "FIPS 204"
    },
    {
      "algorithm": "ML-DSA-87",
      "type": "signature",
      "nist_level": 5,
      "public_key_bytes": 2592,
      "signature_bytes": 4627,
      "private_key_bytes": 4896,
      "classical": false,
      "standard": "FIPS 204"
    },
    {
      "algorithm": "Falcon-512 (FN-DSA)",
      "type": "signature",
      "nist_level": 1,
      "public_key_bytes": 897,
      "signature_bytes": 666,
      "private_key_bytes": 1281,
      "classical": false,
      "standard": "draft"
    },
    {
      "algorithm": "Falcon-1024 (FN-DSA)",
      "type": "signature",
      "nist_level": 5,
      "public_key_bytes": 1793,
      "signature_bytes": 1280,
      "private_key_bytes": 2305,
      "classical": false,
      "standard": "draft"
    },
    {
      "algorithm": "SLH-DSA-128s",
      "type": "signature",
      "nist_level": 1,
      "public_key_bytes": 32,
      "signature_bytes": 7856,
      "private_key_bytes": 64,
      "classical": false,
      "standard": "FIPS 205"
    },
    {
      "algorithm": "SLH-DSA-128f",
      "type": "signature",
      "nist_level": 1,
      "public_key_bytes": 32,
      "signature_bytes": 17088,
      "private_key_bytes": 64,
      "classical": false,
      "standard": "FIPS 205"
    },
    {
      "algorithm": "SLH-DSA-192s",
      "type": "signature",
      "nist_level": 3,
      "public_key_bytes": 48,
      "signature_bytes": 16224,
      "private_key_bytes": 96,
      "classical": false,
      "standard": "FIPS 205"
    },
    {
      "algorithm": "SLH-DSA-256s",
      "type": "signature",
      "nist_level": 5,
      "public_key_bytes": 64,
      "signature_bytes": 29792,
      "private_key_bytes": 128,
      "classical": false,
      "standard": "FIPS 205"
    },
    {
      "algorithm": "Ed25519 (classical)",
      "type": "signature",
      "nist_level": 1,
      "public_key_bytes": 32,
      "signature_bytes": 64,
      "private_key_bytes": 32,
      "classical": true,
      "standard": "RFC 8032"
    },
    {
      "algorithm": "ECDSA P-256 (classical)",
      "type": "signature",
      "nist_level": 1,
      "public_key_bytes": 64,
      "signature_bytes": 72,
      "private_key_bytes": 32,
      "classical": true,
      "standard": "SEC1"
    },
    {
      "algorithm": "RSA-2048 (classical)",
      "type": "signature",
      "nist_level": 1,
      "public_key_bytes": 256,
      "signature_bytes": 256,
      "private_key_bytes": 1190,
      "classical": true,
      "standard": "PKCS#1"
    },
    {
      "algorithm": "RSA-3072 (classical)",
      "type": "signature",
      "nist_level": 1,
      "public_key_bytes": 384,
      "signature_bytes": 384,
      "private_key_bytes": 1770,
      "classical": true,
      "standard": "PKCS#1"
    }
  ]
}