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Convert OpenSSH public key to RFC 4716 (SSH2) format
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/** | |
* Convert OpenSSH to RFC 4716 (SSH2) format [https://tools.ietf.org/html/rfc4716] | |
* | |
* @author KaushikTheDeveloper | |
* Created on Mar 08, 2018 | |
*/ | |
public class Ssh2Converter { | |
private static final int MAX_LINE_LENGTH = 70; | |
private static final String BEGIN_MARKER = "---- BEGIN SSH2 PUBLIC KEY ----\n"; | |
private static final String END_MARKER = "---- END SSH2 PUBLIC KEY ----"; | |
private static final String STANDARD_COMMENT = "Comment: \"2048-bit RSA, converted from OpenSSH"; | |
private static final String ADDITIONAL_COMMENT = " \\\nfor %s\"\n"; | |
private static final String NEW_LINE = "\n"; | |
private StringBuilder ssh2PublicKey; | |
Ssh2Converter() { | |
ssh2PublicKey = new StringBuilder(); | |
} | |
/** | |
* Convert Openssh to SSH2 (RFC 4716 compliant) | |
* | |
* @param opensshKey : the public key in openssh format | |
* @return SSH2 public key | |
*/ | |
public String convert(String opensshKey) { | |
try { | |
ssh2PublicKey.append(BEGIN_MARKER); | |
String[] opensshSplit = opensshKey.split(" "); | |
appendComment(opensshSplit); | |
appendHash(opensshSplit[1]); | |
ssh2PublicKey.append(END_MARKER); | |
return ssh2PublicKey.toString(); | |
} catch (Exception e) { | |
e.printStackTrace(); | |
return null; | |
} | |
} | |
/** | |
* Append the required comment | |
* If comment was provided in openssh : | |
* - Append Standard comment + Additional comment provided ;true | |
* - Append Standard comment + close the double quotes ;false | |
* | |
* @param opensshSplit : openssh key split by whitespace | |
*/ | |
private void appendComment(String[] opensshSplit) { | |
ssh2PublicKey.append(STANDARD_COMMENT); | |
// comment is available in the openssh key | |
if (opensshSplit.length == 3) { | |
ssh2PublicKey.append(String.format(ADDITIONAL_COMMENT, opensshSplit[2])); | |
} else { | |
ssh2PublicKey.append("\"\n"); | |
} | |
} | |
/** | |
* Append the hash of the OpenSSH key | |
* GUIDELINE : each line in the body MUST NOT be longer than 72 8-bit bytes excluding line termination characters | |
* => Split the body at 70 chars and wrap to next line | |
* | |
* @param hash : OpenSSH Public Key Body | |
*/ | |
private void appendHash(String hash) { | |
int index = 0; | |
while (index < hash.length()) { | |
ssh2PublicKey.append( | |
hash.substring(index, Math.min(index + MAX_LINE_LENGTH, hash.length())) | |
); | |
ssh2PublicKey.append(NEW_LINE); | |
index += MAX_LINE_LENGTH; | |
} | |
} | |
} | |
/** | |
* Driver function : | |
* - With comment in OpenSSH public key | |
* - Without comment in OpenSSH public key | |
* | |
* Example key taken from [https://tools.ietf.org/html/rfc4716] | |
*/ | |
class DriverFunction { | |
public static void main(String[] args) { | |
final String opensshKey1 = "ssh-rsa " + | |
"AAAAB3NzaC1yc2EAAAABIwAAAIEA1on8gxCGJJWSRT4uOrR13mUaUk0hRf4RzxSZ1zRbYY" + | |
"Fw8pfGesIFoEuVth4HKyF8k1y4mRUnYHP1XNMNMJl1JcEArC2asV8sHf6zSPVffozZ5TT4" + | |
"SfsUu/iKy9lUcCfXzwre4WWZSXXcPff+EHtWshahu3WzBdnGxm5Xoi89zcE=" + | |
" me@example.com"; | |
final String expected1 = "---- BEGIN SSH2 PUBLIC KEY ----\n" + | |
"Comment: \"2048-bit RSA, converted from OpenSSH \\\n" + | |
"for me@example.com\"\n" + | |
"AAAAB3NzaC1yc2EAAAABIwAAAIEA1on8gxCGJJWSRT4uOrR13mUaUk0hRf4RzxSZ1zRbYY\n" + | |
"Fw8pfGesIFoEuVth4HKyF8k1y4mRUnYHP1XNMNMJl1JcEArC2asV8sHf6zSPVffozZ5TT4\n" + | |
"SfsUu/iKy9lUcCfXzwre4WWZSXXcPff+EHtWshahu3WzBdnGxm5Xoi89zcE=\n" + | |
"---- END SSH2 PUBLIC KEY ----"; | |
final String result1 = new Ssh2Converter().convert(opensshKey1); | |
if (!expected1.equals(result1)) | |
throw new RuntimeException("Assertion Failed"); | |
final String opensshKey2 = "ssh-rsa " + | |
"AAAAB3NzaC1yc2EAAAABIwAAAIEA1on8gxCGJJWSRT4uOrR13mUaUk0hRf4RzxSZ1zRbYY" + | |
"Fw8pfGesIFoEuVth4HKyF8k1y4mRUnYHP1XNMNMJl1JcEArC2asV8sHf6zSPVffozZ5TT4" + | |
"SfsUu/iKy9lUcCfXzwre4WWZSXXcPff+EHtWshahu3WzBdnGxm5Xoi89zcE="; | |
final String expected2 = "---- BEGIN SSH2 PUBLIC KEY ----\n" + | |
"Comment: \"2048-bit RSA, converted from OpenSSH\"\n" + | |
"AAAAB3NzaC1yc2EAAAABIwAAAIEA1on8gxCGJJWSRT4uOrR13mUaUk0hRf4RzxSZ1zRbYY\n" + | |
"Fw8pfGesIFoEuVth4HKyF8k1y4mRUnYHP1XNMNMJl1JcEArC2asV8sHf6zSPVffozZ5TT4\n" + | |
"SfsUu/iKy9lUcCfXzwre4WWZSXXcPff+EHtWshahu3WzBdnGxm5Xoi89zcE=\n" + | |
"---- END SSH2 PUBLIC KEY ----"; | |
final String result2 = new Ssh2Converter().convert(opensshKey2); | |
if (!expected2.equals(result2)) | |
throw new RuntimeException("Assertion Failed"); | |
} | |
} | |
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i forgot the p in excemption