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javacard.security
Interface ECKey

All Known Subinterfaces:
ECPrivateKey, ECPublicKey
public interface ECKey

The ECKey interface is the base interface for the EC algorithm's private and public key implementations. An EC private key implementation must also implement the ECPrivateKey interface methods. An EC public key implementation must also implement the ECPublicKey interface methods.

The equation of the curves for keys of type TYPE_EC_FP_PUBLIC or TYPE_EC_FP_PRIVATE is y^2 = x^3 + A * x + B. The equation of the curves for keys of type TYPE_EC_F2M_PUBLIC or TYPE_EC_F2M_PRIVATE is y^2 + x * y = x^3 + A * x^2 + B.

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

Version:
1.0
See Also:
ECPublicKey

Method Summary
 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.
 

Method Detail

setB

public void setB(byte[] buffer,
                 short offset,
                 short length)
          throws CryptoException
Sets the second coefficient of the curve of the key. For keys of type TYPE_EC_FP_PRIVATE or TYPE_EC_FP_PUBLIC, this is the value of B as an integer modulo the field specification parameter p, that is, an integer in the range 0 to p-1. For keys of type TYPE_EC_F2M_PRIVATE or TYPE_EC_F2M_PUBLIC, the bit representation of this value specifies a polynomial with binary coefficients which represents the value of B in the field. 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:

Parameters:
buffer - the input buffer
offset - the offset into the input buffer at which the coefficient value begins
length - the byte length of the coefficient value
Throws:
CryptoException - with the following reason codes:
  • CryptoException.ILLEGAL_VALUE if the input parameter data is inconsistent with the key length or if input data decryption is required and fails.

getA

public short getA(byte[] buffer,
                  short offset)
           throws CryptoException
Returns the first coefficient of the curve of the key. For keys of type TYPE_EC_FP_PRIVATE or TYPE_EC_FP_PUBLIC, this is the value of A as an integer modulo the field specification parameter p, that is, an integer in the range 0 to p-1. For keys of type TYPE_EC_F2M_PRIVATE or TYPE_EC_F2M_PUBLIC, the bit representation of this value specifies a polynomial with binary coefficients which represents the value of A in the field. The plain text 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 output buffer at which the coefficient value is to begin
Returns:
the byte length of the coefficient
Throws:
CryptoException - with the following reason code:
  • CryptoException.UNINITIALIZED_KEY if the coefficient of the curve of the key has not been successfully initialized since the time the initialized state of the key was set to false.
See Also:
Key

setFieldFP

public void setFieldFP(byte[] buffer,
                       short offset,
                       short length)
                throws CryptoException
Sets the field specification parameter value for keys of type TYPE_EC_FP_PRIVATE or TYPE_EC_FP_PUBLIC. The specified value is the prime p corresponding to the field GF(p). 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:

Parameters:
buffer - the input buffer
offset - the offset into the input buffer at which the parameter value begins
length - the byte length of the parameter value
Throws:
CryptoException - with the following reason codes:
  • CryptoException.ILLEGAL_VALUE if the input parameter data is inconsistent with the key length or if input data decryption is required and fails.
  • CryptoException.NO_SUCH_ALGORITHM if the key is neither of type TYPE_EC_FP_PUBLIC nor TYPE_EC_FP_PRIVATE.

setFieldF2M

public void setFieldF2M(short e1,
                        short e2,
                        short e3)
                 throws CryptoException
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). It is required for all ei where ei = {e1, e2, e3} that n > ei > 0.

Parameters:
e1 - the value of the first of the intermediate exponents of the pentanomial
e2 - the value of the second of the intermediate exponent of the pentanomial
e3 - the value of the third of the intermediate exponents
Throws:
CryptoException - with the following reason codes:
  • CryptoException.ILLEGAL_VALUE if the input parameters ei where ei = {e1, e2, e3} are not such that for all ei, n > ei > 0.
  • CryptoException.NO_SUCH_ALGORITHM if the key is neither of type TYPE_EC_F2M_PUBLIC nor TYPE_EC_F2M_PRIVATE.

getB

public short getB(byte[] buffer,
                  short offset)
           throws CryptoException
Returns the second coefficient of the curve of the key. For keys of type TYPE_EC_FP_PRIVATE or TYPE_EC_FP_PUBLIC, this is the value of B as an integer modulo the field specification parameter p, that is, an integer in the range 0 to p-1. For keys of type TYPE_EC_F2M_PRIVATE or TYPE_EC_F2M_PUBLIC, the bit representation of this value specifies a polynomial with binary coefficients which represents the value of B in the field. The plain text 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 output buffer at which the coefficient value is to begin
Returns:
the byte length of the coefficient
Throws:
CryptoException - with the following reason code:
  • CryptoException.UNINITIALIZED_KEY if the second coefficient of the curve of the key has not been successfully initialized since the time the initialized state of the key was set to false.
See Also:
Key

setFieldF2M

public void setFieldF2M(short e)
                 throws CryptoException
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). It is required that n > e > 0.

Parameters:
e - the value of the intermediate exponent of the trinomial
Throws:
CryptoException - with the following reason codes:
  • CryptoException.ILLEGAL_VALUE if the input parameter e is not such that 0 < e < n.
  • CryptoException.NO_SUCH_ALGORITHM if the key is neither of type TYPE_EC_F2M_PUBLIC nor TYPE_EC_F2M_PRIVATE.

setK

public void setK(short K)
Sets the cofactor of the order of the fixed point G of the curve. The cofactor need not be specified for the key to be initialized. However, the KeyAgreement algorithm type ALG_EC_SVDP_DHC requires that the cofactor, K, be initialized.

Parameters:
K - the value of the cofactor

getField

public short getField(byte[] buffer,
                      short offset)
               throws CryptoException
Returns the field specification parameter value of the key. For keys of type TYPE_EC_FP_PRIVATE or TYPE_EC_FP_PUBLIC, this is the value of the prime p corresponding to the field GF(p). For keys of type TYPE_EC_F2M_PRIVATE or TYPE_EC_F2M_PUBLIC, it is the value whose bit representation specifies the polynomial with binary coefficients used to define the arithmetic operations in the field GF(2^n) The plain text 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 output buffer at which the parameter value is to begin
Returns:
the byte length of the parameter
Throws:
CryptoException - with the following reason code:
  • CryptoException.UNINITIALIZED_KEY if the field specification parameter value of the key has not been successfully initialized since the time the initialized state of the key was set to false.
See Also:
Key

getG

public short getG(byte[] buffer,
                  short offset)
           throws CryptoException
Returns the fixed point of the curve. The point is represented as an octet string in compressed or uncompressed forms as per ANSI X9.62. The plain text 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 output buffer at which the point specification data is to begin
Returns:
the byte length of the point specificiation
Throws:
CryptoException - with the following reason code:
  • CryptoException.UNINITIALIZED_KEY if the fixed point of the curve of the key has not been successfully initialized since the time the initialized state of the key was set to false.
See Also:
Key

getK

public short getK()
           throws CryptoException
Returns the cofactor of the order of the fixed point G of the curve.

Returns:
the value of the cofactor
Throws:
CryptoException - with the following reason codes:
  • CryptoException.UNINITIALIZED_KEY if the cofactor of the order of the fixed point G of the curve of the key has not been successfully initialized since the time the initialized state of the key was set to false.
See Also:
Key

setG

public void setG(byte[] buffer,
                 short offset,
                 short length)
          throws CryptoException
Sets the fixed point of the curve. The point should be specified as an octet string as per ANSI X9.62. A specific implementation need not support the compressed form, but must support the uncompressed form of the point. 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:

Parameters:
buffer - the input buffer
offset - the offset into the input buffer at which the point specification begins
length - the byte length of the point specification
Throws:
CryptoException - with the following reason codes:
  • CryptoException.ILLEGAL_VALUE if the input parameter data format is incorrect, or if the input parameter data is inconsistent with the key length, or if input data decryption is required and fails.

setR

public void setR(byte[] buffer,
                 short offset,
                 short length)
          throws CryptoException
Sets the order of the fixed point G of the curve. 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.

Parameters:
buffer - the input buffer
offset - the offset into the input buffer at which the order begins
length - the byte length of the order
Throws:
CryptoException - with the following reason codes:
  • CryptoException.ILLEGAL_VALUE if the input parameter data is inconsistent with the key length, or if input data decryption is required and fails.

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.

getR

public short getR(byte[] buffer,
                  short offset)
           throws CryptoException
Returns the order of the fixed point G of the curve. The plain text 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 order begins
Returns:
the byte length of the order
Throws:
CryptoException - with the following reason code:
  • CryptoException.UNINITIALIZED_KEY if the order of the fixed point G of the curve of the key has not been successfully initialized since the time the initialized state of the key was set to false.
See Also:
Key

setA

public void setA(byte[] buffer,
                 short offset,
                 short length)
          throws CryptoException
Sets the first coefficient of the curve of the key. For keys of type TYPE_EC_FP_PRIVATE or TYPE_EC_FP_PUBLIC, this is the value of A as an integer modulo the field specification parameter p, that is, an integer in the range 0 to p-1. For keys of type TYPE_EC_F2M_PRIVATE or TYPE_EC_F2M_PUBLIC, the bit representation of this value specifies a polynomial with binary coefficients which represents the value of A in the field. 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:

Parameters:
buffer - the input buffer
offset - the offset into the input buffer at which the coefficient value begins
length - the byte length of the coefficient value
Throws:
CryptoException - with the following reason codes:
  • CryptoException.ILLEGAL_VALUE if the input parameter data is inconsistent with the key length or if input data decryption is required and fails.
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