diff options
Diffstat (limited to 'libjava/classpath/gnu/javax/crypto/mac/HMac.java')
| -rw-r--r-- | libjava/classpath/gnu/javax/crypto/mac/HMac.java | 195 |
1 files changed, 65 insertions, 130 deletions
diff --git a/libjava/classpath/gnu/javax/crypto/mac/HMac.java b/libjava/classpath/gnu/javax/crypto/mac/HMac.java index c1f97b54195..f0e588d1831 100644 --- a/libjava/classpath/gnu/javax/crypto/mac/HMac.java +++ b/libjava/classpath/gnu/javax/crypto/mac/HMac.java @@ -48,70 +48,51 @@ import java.util.HashMap; import java.util.Map; /** - * <p>The implementation of the <i>HMAC</i> (Keyed-Hash Message Authentication - * Code).</p> - * - * <p><i>HMAC</i> can be used in combination with any iterated cryptographic - * hash function. <i>HMAC</i> also uses a <i>secret key</i> for calculation and + * The implementation of the <i>HMAC</i> (Keyed-Hash Message Authentication + * Code). + * <p> + * <i>HMAC</i> can be used in combination with any iterated cryptographic hash + * function. <i>HMAC</i> also uses a <i>secret key</i> for calculation and * verification of the message authentication values. The main goals behind this - * construction are</p> - * + * construction are: * <ul> - * <li>To use, without modifications, available hash functions. In - * particular, hash functions that perform well in software, and for which - * code is freely and widely available.</li> - * - * <li>To preserve the original performance of the hash function without - * incurring a significant degradation.</li> - * - * <li>To use and handle keys in a simple way.</li> - * - * <li>To have a well understood cryptographic analysis of the strength of - * the authentication mechanism based on reasonable assumptions on the - * underlying hash function.</li> - * - * <li>To allow for easy replaceability of the underlying hash function in - * case that faster or more secure hash functions are found or required.</li> + * <li>To use, without modifications, available hash functions. In particular, + * hash functions that perform well in software, and for which code is freely + * and widely available.</li> + * <li>To preserve the original performance of the hash function without + * incurring a significant degradation.</li> + * <li>To use and handle keys in a simple way.</li> + * <li>To have a well understood cryptographic analysis of the strength of the + * authentication mechanism based on reasonable assumptions on the underlying + * hash function.</li> + * <li>To allow for easy replaceability of the underlying hash function in case + * that faster or more secure hash functions are found or required.</li> * </ul> - * - * <p>References:</p> - * + * <p> + * References: * <ol> - * <li><a href="http://www.ietf.org/rfc/rfc-2104.txt">RFC 2104</a>HMAC: - * Keyed-Hashing for Message Authentication.<br> - * H. Krawczyk, M. Bellare, and R. Canetti.</li> + * <li><a href="http://www.ietf.org/rfc/rfc-2104.txt">RFC 2104</a>HMAC: + * Keyed-Hashing for Message Authentication.<br> + * H. Krawczyk, M. Bellare, and R. Canetti.</li> * </ol> */ -public class HMac extends BaseMac implements Cloneable +public class HMac + extends BaseMac + implements Cloneable { - - // Constants and variables - // ------------------------------------------------------------------------- - public static final String USE_WITH_PKCS5_V2 = "gnu.crypto.hmac.pkcs5"; - private static final byte IPAD_BYTE = 0x36; - private static final byte OPAD_BYTE = 0x5C; - /** caches the result of the correctness test, once executed. */ private static Boolean valid; - protected int macSize; - protected int blockSize; - protected IMessageDigest ipadHash; - protected IMessageDigest opadHash; - protected byte[] ipad; - // Constructor(s) - // ------------------------------------------------------------------------- - /** - * <p>Trivial constructor for use by concrete subclasses.</p> + * Trivial constructor for use by concrete subclasses. * * @param underlyingHash the underlying hash algorithm instance. */ @@ -124,14 +105,6 @@ public class HMac extends BaseMac implements Cloneable ipadHash = opadHash = null; } - // Class methods - // ------------------------------------------------------------------------- - - // Instance methods - // ------------------------------------------------------------------------- - - // java.lang.Cloneable interface implementation ---------------------------- - public Object clone() throws CloneNotSupportedException { HMac result = (HMac) super.clone(); @@ -145,88 +118,65 @@ public class HMac extends BaseMac implements Cloneable return result; } - // implementation of abstract methods in BaseMac --------------------------- - public void init(Map attributes) throws InvalidKeyException, IllegalStateException { Integer ts = (Integer) attributes.get(TRUNCATED_SIZE); truncatedSize = (ts == null ? macSize : ts.intValue()); if (truncatedSize < (macSize / 2)) - { - throw new IllegalArgumentException("Truncated size too small"); - } + throw new IllegalArgumentException("Truncated size too small"); else if (truncatedSize < 10) - { - throw new IllegalArgumentException("Truncated size less than 80 bits"); - } + throw new IllegalArgumentException("Truncated size less than 80 bits"); // we dont use/save the key outside this method byte[] K = (byte[]) attributes.get(MAC_KEY_MATERIAL); if (K == null) { // take it as an indication to re-use previous key if set if (ipadHash == null) - { - throw new InvalidKeyException("Null key"); - } + throw new InvalidKeyException("Null key"); // we already went through the motions; ie. up to step #4. re-use underlyingHash = (IMessageDigest) ipadHash.clone(); return; } - // for HMACs used in key-derivation functions (e.g. PBKDF2) the key - // material need not be >= the (output) block size of the underlying - // algorithm + // for HMACs used in key-derivation functions (e.g. PBKDF2) the key material + // need not be >= the (output) block size of the underlying algorithm Boolean pkcs5 = (Boolean) attributes.get(USE_WITH_PKCS5_V2); if (pkcs5 == null) - { - pkcs5 = Boolean.FALSE; - } - if (K.length < macSize && !pkcs5.booleanValue()) - { - throw new InvalidKeyException("Key too short"); - } + pkcs5 = Boolean.FALSE; + if (K.length < macSize && ! pkcs5.booleanValue()) + throw new InvalidKeyException("Key too short"); if (K.length > blockSize) { - // (0) replace K with HASH(K) if K is larger than the hash's - // block size. Then pad with zeros until it is the correct - // size (the next `if'). + // (0) replace K with HASH(K) if K is larger than the hash's block size. + // Then pad with zeros until it is the correct size (the next `if'). underlyingHash.update(K, 0, K.length); K = underlyingHash.digest(); } if (K.length < blockSize) { - // (1) append zeros to the end of K to create a B byte string - // (e.g., if K is of length 20 bytes and B=64, then K will be - // appended with 44 zero bytes 0x00) + // (1) append zeros to the end of K to create a B byte string (e.g., if + // K is of length 20 bytes and B=64, then K will be appended with 44 + // zero bytes 0x00) int limit = (K.length > blockSize) ? blockSize : K.length; byte[] newK = new byte[blockSize]; System.arraycopy(K, 0, newK, 0, limit); K = newK; } - underlyingHash.reset(); opadHash = (IMessageDigest) underlyingHash.clone(); if (ipad == null) - { - ipad = new byte[blockSize]; - } - // (2) XOR (bitwise exclusive-OR) the B byte string computed in step - // (1) with ipad - // (3) append the stream of data 'text' to the B byte string resulting - // from step (2) + ipad = new byte[blockSize]; + // (2) XOR (bitwise exclusive-OR) the B byte string computed in step (1) + // with ipad + // (3) append the stream of data 'text' to the B byte string resulting from + // step (2) // (4) apply H to the stream generated in step (3) for (int i = 0; i < blockSize; i++) - { - // underlyingHash.update((byte)(K[i] ^ IPAD_BYTE)); - ipad[i] = (byte) (K[i] ^ IPAD_BYTE); - } + ipad[i] = (byte)(K[i] ^ IPAD_BYTE); for (int i = 0; i < blockSize; i++) - { - opadHash.update((byte) (K[i] ^ OPAD_BYTE)); - } - + opadHash.update((byte)(K[i] ^ OPAD_BYTE)); underlyingHash.update(ipad, 0, blockSize); ipadHash = (IMessageDigest) underlyingHash.clone(); K = null; @@ -245,28 +195,21 @@ public class HMac extends BaseMac implements Cloneable public byte[] digest() { if (ipadHash == null) - { - throw new IllegalStateException("HMAC not initialised"); - } - + throw new IllegalStateException("HMAC not initialised"); byte[] out = underlyingHash.digest(); - // (5) XOR (bitwise exclusive-OR) the B byte string computed in - // step (1) with opad + // (5) XOR (bitwise exclusive-OR) the B byte string computed in step (1) + // with opad underlyingHash = (IMessageDigest) opadHash.clone(); - // (6) append the H result from step (4) to the B byte string - // resulting from step (5) + // (6) append the H result from step (4) to the B byte string resulting from + // step (5) underlyingHash.update(out, 0, macSize); - // (7) apply H to the stream generated in step (6) and output - // the result + // (7) apply H to the stream generated in step (6) and output the result out = underlyingHash.digest(); // which also resets the underlying hash - // truncate and return if (truncatedSize == macSize) return out; - byte[] result = new byte[truncatedSize]; System.arraycopy(out, 0, result, 0, truncatedSize); - return result; } @@ -279,31 +222,25 @@ public class HMac extends BaseMac implements Cloneable IMac mac = new HMac(new MD5()); // use rfc-2104 test vectors String tv1 = "9294727A3638BB1C13F48EF8158BFC9D"; String tv3 = "56BE34521D144C88DBB8C733F0E8B3F6"; - byte[] k1 = new byte[] { 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, - 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, - 0x0B, 0x0B }; - byte[] k3 = new byte[] { (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, - (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, - (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, - (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, - (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, - (byte) 0xAA }; + byte[] k1 = new byte[] { + 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, + 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B, 0x0B }; + byte[] k3 = new byte[] { + (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, + (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, + (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, + (byte) 0xAA, (byte) 0xAA, (byte) 0xAA, (byte) 0xAA }; byte[] data = new byte[50]; for (int i = 0; i < 50;) - { - data[i++] = (byte) 0xDD; - } + data[i++] = (byte) 0xDD; HashMap map = new HashMap(); - // test vector #1 map.put(MAC_KEY_MATERIAL, k1); mac.init(map); mac.update("Hi There".getBytes("ASCII"), 0, 8); - if (!tv1.equals(Util.toString(mac.digest()))) - { - valid = Boolean.FALSE; - } + if (! tv1.equals(Util.toString(mac.digest()))) + valid = Boolean.FALSE; // test #2 is not used since it causes a "Key too short" exception @@ -311,10 +248,8 @@ public class HMac extends BaseMac implements Cloneable map.put(MAC_KEY_MATERIAL, k3); mac.init(map); mac.update(data, 0, 50); - if (!tv3.equals(Util.toString(mac.digest()))) - { - valid = Boolean.FALSE; - } + if (! tv3.equals(Util.toString(mac.digest()))) + valid = Boolean.FALSE; valid = Boolean.TRUE; } catch (Exception x) |
