BCRYPT_ECCKEY_BLOB Structure

The BCRYPT_ECCKEY_BLOB structure is used as a header for an elliptic curve public key or private keyBLOB in memory.

Syntax

typedef struct _BCRYPT_ECCKEY_BLOB {
    ULONG dwMagic;
    ULONG cbKey;
} BCRYPT_ECCKEY_BLOB, *PBCRYPT_ECCKEY_BLOB;

Members

dwMagic

Specifies the type of key this BLOB represents. The possible values for this member depend on the type of BLOB this structure represents. The following keys use the NIST 256-bit prime curve defined in FIPS 186-2.

Value Meaning
BCRYPT_ECDH_PUBLIC_P256_MAGIC The key is a 256 bit elliptic curve Diffie-Hellman public key.
BCRYPT_ECDH_PRIVATE_P256_MAGIC The key is a 256 bit elliptic curve Diffie-Hellman private key.
BCRYPT_ECDH_PUBLIC_P384_MAGIC The key is a 384 bit elliptic curve Diffie-Hellman public key.
BCRYPT_ECDH_PRIVATE_P384_MAGIC The key is a 384 bit elliptic curve Diffie-Hellman private key.
BCRYPT_ECDH_PUBLIC_P521_MAGIC The key is a 521 bit elliptic curve Diffie-Hellman public key.
BCRYPT_ECDH_PRIVATE_P521_MAGIC The key is a 521 bit elliptic curve Diffie-Hellman private key.
BCRYPT_ECDSA_PUBLIC_P256_MAGIC The key is a 256 bit elliptic curve DSA public key.
BCRYPT_ECDSA_PRIVATE_P256_MAGIC The key is a 256 bit elliptic curve DSA private key.
BCRYPT_ECDSA_PUBLIC_P384_MAGIC The key is a 384 bit elliptic curve DSA public key.
BCRYPT_ECDSA_PRIVATE_P384_MAGIC The key is a 384 bit elliptic curve DSA private key.
BCRYPT_ECDSA_PUBLIC_P521_MAGIC The key is a 521 bit elliptic curve DSA public key.
BCRYPT_ECDSA_PRIVATE_P521_MAGIC The key is a 521 bit elliptic curve DSA private key.

cbKey
The length, in bytes, of the key.

Remarks

This structure is used as a header for a larger buffer. An elliptic curve public key BLOB (BCRYPT_ECCPUBLIC_BLOB) has the following format in contiguous memory. The X and Y coordinates are unsigned integers encoded in big-endian format.

Example

BCRYPT_ECCKEY_BLOB
BYTE X[cbKey] // Big-endian.
BYTE Y[cbKey] // Big-endian.

An elliptic curve private key BLOB (BCRYPT_ECCPRIVATE_BLOB) has the following format in contiguous memory. The X and Y coordinates and d value are unsigned integers encoded in big-endian format.

Example

BCRYPT_ECCKEY_BLOB
BYTE X[cbKey] // Big-endian.
BYTE Y[cbKey] // Big-endian.
BYTE d[cbKey] // Big-endian.

Requirements

Header: Declared in bcrypt.h.

Library: Use bcrypt.lib.