/**
* Sets the algorithm used for computing the digest.
*
* @param alg the algorithm name
*/
public void setAlgorithm(String alg) {
try {
currentAlgorithm = MessageDigest.getInstance(alg);
digest.setText("");
} catch (NoSuchAlgorithmException e) {
digest.setText("" + e);
}
}
/**
* Calculates the hash of the certificate known as the "thumbprint" and returns it as a string
* representation.
*
* @param cert The certificate to hash.
* @param algorithm The hash algorithm to use.
* @return The SHA-1 hash of the certificate.
* @throws CertificateException
*/
private static String getThumbprint(X509Certificate cert, String algorithm)
throws CertificateException {
MessageDigest digest;
try {
digest = MessageDigest.getInstance(algorithm);
} catch (NoSuchAlgorithmException e) {
throw new CertificateException(e);
}
byte[] encodedCert = cert.getEncoded();
StringBuilder sb = new StringBuilder(encodedCert.length * 2);
Formatter f = new Formatter(sb);
try {
for (byte b : digest.digest(encodedCert)) f.format("%02x", b);
} finally {
f.close();
}
return sb.toString();
}
