javacard.security
Interface RSAPrivateKey

public abstract 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, Cipher, KeyEncryption

Method Summary

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

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

Sets the modulus value of the key. The plaintext 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.

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.

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.

setExponent

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

Sets the private exponent value of the key. The plaintext 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.

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.

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.

getModulus

public 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

getExponent

public 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