diff options
Diffstat (limited to 'mobile/android/services/src/main/java/org/mozilla/gecko/browserid/ASNUtils.java')
-rw-r--r-- | mobile/android/services/src/main/java/org/mozilla/gecko/browserid/ASNUtils.java | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/ASNUtils.java b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/ASNUtils.java new file mode 100644 index 000000000..b032067c5 --- /dev/null +++ b/mobile/android/services/src/main/java/org/mozilla/gecko/browserid/ASNUtils.java @@ -0,0 +1,82 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +package org.mozilla.gecko.browserid; + + +/** + * Java produces signature in ASN.1 format. Here's some hard-coded encoding and decoding + * code, courtesy of a comment in + * <a href="http://stackoverflow.com/questions/10921733/how-sign-method-of-the-digital-signature-combines-the-r-s-values-in-to-array">http://stackoverflow.com/questions/10921733/how-sign-method-of-the-digital-signature-combines-the-r-s-values-in-to-array</a>. + */ +public class ASNUtils { + /** + * Decode two short arrays from ASN.1 bytes. + * @param input to extract. + * @return length 2 array of byte arrays. + */ + public static byte[][] decodeTwoArraysFromASN1(byte[] input) throws IllegalArgumentException { + if (input == null) { + throw new IllegalArgumentException("input must not be null"); + } + if (input.length <= 3) + throw new IllegalArgumentException("bad length"); + if (input[0] != 0x30) + throw new IllegalArgumentException("bad encoding"); + if ((input[1] & ((byte) 0x80)) != 0) + throw new IllegalArgumentException("bad length encoding"); + if (input[2] != 0x02) + throw new IllegalArgumentException("bad encoding"); + if ((input[3] & ((byte) 0x80)) != 0) + throw new IllegalArgumentException("bad length encoding"); + byte rLength = input[3]; + if (input.length <= 5 + rLength) + throw new IllegalArgumentException("bad length"); + if (input[4 + rLength] != 0x02) + throw new IllegalArgumentException("bad encoding"); + if ((input[5 + rLength] & (byte) 0x80) !=0) + throw new IllegalArgumentException("bad length encoding"); + byte sLength = input[5 + rLength]; + if (input.length != 6 + sLength + rLength) + throw new IllegalArgumentException("bad length"); + byte[] rArr = new byte[rLength]; + byte[] sArr = new byte[sLength]; + System.arraycopy(input, 4, rArr, 0, rLength); + System.arraycopy(input, 6 + rLength, sArr, 0, sLength); + return new byte[][] { rArr, sArr }; + } + + /** + * Encode two short arrays into ASN.1 bytes. + * @param first array to encode. + * @param second array to encode. + * @return array. + */ + public static byte[] encodeTwoArraysToASN1(byte[] first, byte[] second) throws IllegalArgumentException { + if (first == null) { + throw new IllegalArgumentException("first must not be null"); + } + if (second == null) { + throw new IllegalArgumentException("second must not be null"); + } + byte[] output = new byte[6 + first.length + second.length]; + output[0] = 0x30; + if (4 + first.length + second.length > 255) + throw new IllegalArgumentException("bad length"); + output[1] = (byte) (4 + first.length + second.length); + if ((output[1] & ((byte) 0x80)) != 0) + throw new IllegalArgumentException("bad length encoding"); + output[2] = 0x02; + output[3] = (byte) first.length; + if ((output[3] & ((byte) 0x80)) != 0) + throw new IllegalArgumentException("bad length encoding"); + System.arraycopy(first, 0, output, 4, first.length); + output[4 + first.length] = 0x02; + output[5 + first.length] = (byte) second.length; + if ((output[5 + first.length] & ((byte) 0x80)) != 0) + throw new IllegalArgumentException("bad length encoding"); + System.arraycopy(second, 0, output, 6 + first.length, second.length); + return output; + } +} |