Key formats

  • JWK (JSON Web Key)
    • Used in JWT, OAuth, and other web security areas
    • Stores keys in a JSON format
    • {
    "kty": "EC",
    "d": "ld4HSs2CAT3q024_H5RX4WCEr08UyhkyTGHxqxmbL4I",
    "use": "sig",
    "crv": "P-256",
    "x": "fUjn_n2VJUk3aGHGtz1_aUhV2gGj6xg_bz5Bz0cBJ0o",
    "y": "FYuI2kDG8UPtVwJM2RxpK69wf3F-sAk5CAPMImxGB7k",
    "alg": "ES256"
}
  • RAW (Uncompressed/Compressed EC Point)
    • Usually stores the x, y coordinates, or just the private scalar
    • Used more for low-level cryptographic operations
  • DER (Distinguished Encoding Rules, ASN.1 format)
    • Used in X.509 certificates and PKCS#8 keys
    • Also in Java Keystores (JKS, PKCS#12)
    • Primary format in JCA (/BouncyCastle)
  • PEM (Base64-encoded DER with headers)
    • Text format that wraps DER (which makes it easier to handle in files)
    • Used in e.g. OpenSSL, TLS certificates, SSH keys
    • -----BEGIN EC PRIVATE KEY-----
(Base64-encoded data)
-----END EC PRIVATE KEY-----
HashingAdvanced Usage