public Class DERParser

Class Inheritance

Imports

A bare minimum DER parser - just enough to be able to decode signatures and private keys

Field Summary

Modifier and Type	Field and Description
private final byte[]	lenBytes
public static final int	MAX_DER_VALUE_LENGTH Maximum size of data allowed by `readLength()` - it is a bit arbitrary since one can encode 32-bit length data, but it is good enough for the keys

Access	Constructor and Description
public	DERParser(byte... bytes)
public	DERParser(byte[] bytes, int offset, int len)
public	DERParser(InputStream s)

Modifier and Type	Method and Description
public BigInteger	readBigInteger()
public int	Returns: The length as integer readLength() Decode the length of the field.
public ASN1Object	readObject()

Inherited from java.io.FilterInputStream:: available close mark markSupported read read read reset skip

lenBytes	back to summary
private final byte[] lenBytes

MAX_DER_VALUE_LENGTH	back to summary
public static final int MAX_DER_VALUE_LENGTH Maximum size of data allowed by `readLength()` - it is a bit arbitrary since one can encode 32-bit length data, but it is good enough for the keys

DERParser	back to summary
public DERParser(byte... bytes)

DERParser	back to summary
public DERParser(byte[] bytes, int offset, int len)

DERParser	back to summary
public DERParser(InputStream s)

readBigInteger	back to summary
public BigInteger readBigInteger() throws IOException

readLength	back to summary
public int readLength() throws IOException Decode the length of the field. Can only support length encoding up to 4 octets. In BER/DER encoding, length can be encoded in 2 forms: Short form - One octet. Bit 8 has value "0" and bits 7-1 give the length. Long form - Two to 127 octets (only 4 is supported here). Bit 8 of first octet has value "1" and bits 7-1 give the number of additional length octets. Second and following octets give the length, base 256, most significant digit first. Returns:int The length as integer Exceptions IOException: If invalid format found

readLength

public int readLength() throws IOException

Decode the length of the field. Can only support length encoding up to 4 octets. In BER/DER encoding, length can be encoded in 2 forms:

Short form - One octet. Bit 8 has value "0" and bits 7-1 give the length.
Long form - Two to 127 octets (only 4 is supported here). Bit 8 of first octet has value "1" and bits 7-1 give the number of additional length octets. Second and following octets give the length, base 256, most significant digit first.

Returns:int

The length as integer

Exceptions

readObject	back to summary
public ASN1Object readObject() throws IOException