de.profhenry.sshsig.core

Class SshPublicKeyEncoder

java.lang.Object

de.profhenry.sshsig.core.SshPublicKeyEncoder

public class SshPublicKeyEncoder
extends Object

Encoder for public keys in SSH format.

This encoder returns a blob containing the SSH public key as specified in the SSH protocol.
The second column of a SSH public key file contains this blob (base64 encoded).

Author:

profhenry

Constructor Summary

Constructors

Constructor and Description
SshPublicKeyEncoder()

Method Summary

Modifier and Type	Method and Description
protected byte[]	encodeDsaPublicKey(DSAPublicKey aDsaPublicKey) Encodes a DSA public key.
protected byte[]	encodeEd25519PublicKey(PublicKey aPublicKey) Encodes a ED25519 public key.
byte[]	encodePublicKey(PublicKey aPublicKey) Encodes a public key in SSH format.
protected byte[]	encodeRsaPublicKey(RSAPublicKey aRsaPublicKey) Encodes a RSA public key.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SshPublicKeyEncoder

public SshPublicKeyEncoder()

Method Detail

encodePublicKey

public byte[] encodePublicKey(PublicKey aPublicKey)
                       throws SshSignatureException

Encodes a public key in SSH format.

Parameters:

aPublicKey - a public key

Returns:

the encoded public key

Throws:

SshSignatureException - in case the public key could no be encoded

encodeDsaPublicKey

protected final byte[] encodeDsaPublicKey(DSAPublicKey aDsaPublicKey)

Encodes a DSA public key.

According to RTC 4253 the DSA public key encoding is

• the key format identifier (ssh-dss)
• prime (p)
• subprime (q)
• base (g)
• public key (y)

Parameters:

aDsaPublicKey - the DSA public key

Returns:

the encoded DSA public key

encodeRsaPublicKey

protected final byte[] encodeRsaPublicKey(RSAPublicKey aRsaPublicKey)

Encodes a RSA public key.

According to RTC 4253 the RSA public key encoding is

• the key format identifier (ssh-rsa)
• RSA public exponent (e)
• RSA modulus (n)

Parameters:

aRsaPublicKey - the RSA public key

Returns:

the encoded RSA public key

encodeEd25519PublicKey

protected byte[] encodeEd25519PublicKey(PublicKey aPublicKey)
                                 throws SshSignatureException

Encodes a ED25519 public key.

According to RFC 8709 the ED25519 public key encoding is

• the key format identifier (ssh-ed25519)
• the public key (A)

NOTE:
Since we are compiling against a JDK8 which has no support for ED25519 we are not able to provide a proper encoding method :-/.
For the case the public key has the X.509 format we can extract the required 32 bytes from the X.509 encoding.

Parameters:

aPublicKey - the ED25519 public key

Returns:

the encoded ED25519 key

Throws:

SshSignatureException - in case key is not in X.509 format