Package javacard.security

Interface RSAPrivateKey

All Superinterfaces:

Key, PrivateKey

public interface RSAPrivateKey
extends PrivateKey

The RSAPrivateKey class is used to sign data using the RSA algorithm in its modulus/exponent form. It may also be used by the javacardx.crypto.Cipher class to encrypt/decrypt messages.

When both the modulus and exponent of the key are set, the key is initialized and ready for use.

See Also:

RSAPublicKey, RSAPrivateCrtKey, KeyBuilder, Signature, javacardx.crypto.Cipher, javacardx.crypto.KeyEncryption

Method Summary

Modifier and Type	Method	Description
short	getExponent(byte[] buffer, short offset)	Returns the private exponent value of the key in plain text.
short	getModulus(byte[] buffer, short offset)	Returns the modulus value of the key in plain text.
void	setExponent(byte[] buffer, short offset, short length)	Sets the private exponent value of the key.
void	setModulus(byte[] buffer, short offset, short length)	Sets the modulus value of the key.

Methods inherited from interface javacard.security.Key

clearKey, getSize, getType, isInitialized

Method Detail

setModulus

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

Sets the modulus value of the 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 modulus 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 modulus value is decrypted using the Cipher object.

Parameters:

buffer - the input buffer

offset - the offset into the input buffer at which the modulus value begins

length - the length of the modulus

Throws:

CryptoException - with the following reason code:

• CryptoException.ILLEGAL_VALUE if the input modulus data length is inconsistent with the implementation or if input data decryption is required and fails.

setExponent

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

Sets the private exponent value of the 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 exponent 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 exponent value is decrypted using the Cipher object.

Parameters:

buffer - the input buffer

offset - the offset into the input buffer at which the exponent value begins

length - the length of the exponent

Throws:

CryptoException - with the following reason code:

• CryptoException.ILLEGAL_VALUE if the input exponent data length is inconsistent with the implementation or if input data decryption is required and fails.

getModulus

short getModulus(byte[] buffer,
                 short offset)

Returns the modulus value of the key in plain text. 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 output buffer at which the modulus value starts

Returns:

the byte length of the modulus value returned

Throws:

CryptoException - with the following reason code:

• CryptoException.UNINITIALIZED_KEY if the modulus 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

getExponent

short getExponent(byte[] buffer,
                  short offset)

Returns the private exponent value of the key in plain text. 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 output buffer at which the exponent value begins

Returns:

the byte length of the private exponent value returned

Throws:

CryptoException - with the following reason code:

• CryptoException.UNINITIALIZED_KEY if the private exponent 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