Package javacard.security

Interface RSAPublicKey

All Superinterfaces:

Key, PublicKey

public interface RSAPublicKey
extends PublicKey

The RSAPublicKey is used to verify signatures on signed data using the RSA algorithm. It may also 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:

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

Method Summary

Modifier and Type	Method	Description
short	getExponent(byte[] buffer, short offset)	Returns the public 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 public 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 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.

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 byte 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 public 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.

Notes:

• All implementations must support exponent values up to 4 bytes in length. Implementations may also support exponent values greater than 4 bytes in length.
• 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 byte 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 or if the implementation does not support the specified exponent length.

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 input 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 public 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 public exponent returned

Throws:

CryptoException - with the following reason code:

• CryptoException.UNINITIALIZED_KEY if the public 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