Interface ECPrivateKey

All Superinterfaces:

ECKey, Key, PrivateKey

public interface ECPrivateKey
extends PrivateKey, ECKey

The ECPrivateKey interface is used to generate signatures on data using the ECDSA (Elliptic Curve Digital Signature Algorithm) and to generate shared secrets using the ECDH (Elliptic Curve Diffie-Hellman) algorithm. An implementation of ECPrivateKey interface must also implement the ECKey interface methods.

When all components of the key (S, A, B, G, R, Field) are set, the key is initialized and ready for use. In addition, the KeyAgreement algorithm type ALG_EC_SVDP_DHC requires that the cofactor, K, be initialized.

The notation used to describe parameters specific to the EC algorithm is based on the naming conventions established in [IEEE P1363].

See Also:

• ECPublicKey
• KeyBuilder
• Signature
• javacardx.crypto.KeyEncryption
• KeyAgreement

Method Summary

Modifier and Type	Method	Description
short	getS(byte[] buffer, short offset)	Returns the value of the secret key in plaintext form.
void	setS(byte[] buffer, short offset, short length)	Sets the value of the secret key.

Methods inherited from interface ECKey

copyDomainParametersFrom, getA, getB, getField, getG, getK, getR, setA, setB, setFieldF2M, setFieldF2M, setFieldFP, setG, setK, setR

Modifier and Type	Method	Description
void	copyDomainParametersFrom(ECKey ecKey)	Copies the domain parameters from the specified ECKey instance into the domain parameters of this object instance.
short	getA(byte[] buffer, short offset)	Returns the first coefficient of the curve of the key.
short	getB(byte[] buffer, short offset)	Returns the second coefficient of the curve of the key.
short	getField(byte[] buffer, short offset)	Returns the field specification parameter value of the key.
short	getG(byte[] buffer, short offset)	Returns the fixed point of the curve.
short	getK()	Returns the cofactor of the order of the fixed point G of the curve.
short	getR(byte[] buffer, short offset)	Returns the order of the fixed point G of the curve.
void	setA(byte[] buffer, short offset, short length)	Sets the first coefficient of the curve of the key.
void	setB(byte[] buffer, short offset, short length)	Sets the second coefficient of the curve of the key.
void	setFieldF2M(short e)	Sets the field specification parameter value for keys of type TYPE_EC_F2M_PUBLIC or TYPE_EC_F2M_PRIVATE in the case where the polynomial is a trinomial, of the form x^n + x^e + 1 (where n is the bit length of the key).
void	setFieldF2M(short e1, short e2, short e3)	Sets the field specification parameter value for keys of type TYPE_EC_F2M_PUBLIC or TYPE_EC_F2M_PRIVATE in the case where the polynomial is a pentanomial, of the form x^n + x^e1 + x^e2 + x^e3 + 1 (where n is the bit length of the key).
void	setFieldFP(byte[] buffer, short offset, short length)	Sets the field specification parameter value for keys of type TYPE_EC_FP_PRIVATE or TYPE_EC_FP_PUBLIC.
void	setG(byte[] buffer, short offset, short length)	Sets the fixed point of the curve.
void	setK(short K)	Sets the cofactor of the order of the fixed point G of the curve.
void	setR(byte[] buffer, short offset, short length)	Sets the order of the fixed point G of the curve.

Methods inherited from interface Key

clearKey, getSize, getType, isInitialized

Modifier and Type	Method	Description
void	clearKey()	Clears the key and sets its initialized state to false.
short	getSize()	Returns the key size in number of bits.
byte	getType()	Returns the key interface type.
boolean	isInitialized()	Reports the initialized state of the key.

Method Details

setS

void setS(byte[] buffer,
 short offset,
 short length)
   throws CryptoException

Sets the value of the secret key. The plain text data format is big-endian and right-aligned (the least significant bit is the least significant bit of last byte). Input parameter data is copied into the internal representation.

Note:

• If the key object implements the javacardx.crypto.KeyEncryption interface and the Cipher object specified via setKeyCipher() is not null, the key value is decrypted using the Cipher object.

Parameters:

buffer - the input buffer

offset - the offset into the input buffer at which the secret value is to begin

length - the byte length of the secret value

Throws:

CryptoException - with the following reason code:

• CryptoException.ILLEGAL_VALUE if the length parameter is 0 or invalid or the input key data is inconsistent with the key length or if input data decryption is required and fails.

getS

short getS(byte[] buffer,
 short offset)
    throws CryptoException

Returns the value of the secret key in plaintext form. The data format is big-endian and right-aligned (the least significant bit is the least significant bit of last byte).

Parameters:

buffer - the output buffer

offset - the offset into the input buffer at which the secret value is to begin

Returns:

the byte length of the secret value

Throws:

CryptoException - with the following reason code:

• CryptoException.UNINITIALIZED_KEY if the value of the secret key has not been successfully initialized since the time the initialized state of the key was set to false.

See Also:

• Key