diff options
Diffstat (limited to 'core/src/main/java/org/spongycastle/crypto/signers/RSADigestSigner.java')
| -rw-r--r-- | core/src/main/java/org/spongycastle/crypto/signers/RSADigestSigner.java | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/crypto/signers/RSADigestSigner.java b/core/src/main/java/org/spongycastle/crypto/signers/RSADigestSigner.java new file mode 100644 index 00000000..2fe248e4 --- /dev/null +++ b/core/src/main/java/org/spongycastle/crypto/signers/RSADigestSigner.java @@ -0,0 +1,240 @@ +package org.spongycastle.crypto.signers; + +import java.io.IOException; +import java.util.Hashtable; + +import org.spongycastle.asn1.ASN1Encoding; +import org.spongycastle.asn1.ASN1ObjectIdentifier; +import org.spongycastle.asn1.DERNull; +import org.spongycastle.asn1.nist.NISTObjectIdentifiers; +import org.spongycastle.asn1.pkcs.PKCSObjectIdentifiers; +import org.spongycastle.asn1.teletrust.TeleTrusTObjectIdentifiers; +import org.spongycastle.asn1.x509.AlgorithmIdentifier; +import org.spongycastle.asn1.x509.DigestInfo; +import org.spongycastle.asn1.x509.X509ObjectIdentifiers; +import org.spongycastle.crypto.AsymmetricBlockCipher; +import org.spongycastle.crypto.CipherParameters; +import org.spongycastle.crypto.CryptoException; +import org.spongycastle.crypto.DataLengthException; +import org.spongycastle.crypto.Digest; +import org.spongycastle.crypto.Signer; +import org.spongycastle.crypto.encodings.PKCS1Encoding; +import org.spongycastle.crypto.engines.RSABlindedEngine; +import org.spongycastle.crypto.params.AsymmetricKeyParameter; +import org.spongycastle.crypto.params.ParametersWithRandom; +import org.spongycastle.util.Arrays; + +public class RSADigestSigner + implements Signer +{ + private final AsymmetricBlockCipher rsaEngine = new PKCS1Encoding(new RSABlindedEngine()); + private final AlgorithmIdentifier algId; + private final Digest digest; + private boolean forSigning; + + private static final Hashtable oidMap = new Hashtable(); + + /* + * Load OID table. + */ + static + { + oidMap.put("RIPEMD128", TeleTrusTObjectIdentifiers.ripemd128); + oidMap.put("RIPEMD160", TeleTrusTObjectIdentifiers.ripemd160); + oidMap.put("RIPEMD256", TeleTrusTObjectIdentifiers.ripemd256); + + oidMap.put("SHA-1", X509ObjectIdentifiers.id_SHA1); + oidMap.put("SHA-224", NISTObjectIdentifiers.id_sha224); + oidMap.put("SHA-256", NISTObjectIdentifiers.id_sha256); + oidMap.put("SHA-384", NISTObjectIdentifiers.id_sha384); + oidMap.put("SHA-512", NISTObjectIdentifiers.id_sha512); + oidMap.put("SHA-512/224", NISTObjectIdentifiers.id_sha512_224); + oidMap.put("SHA-512/256", NISTObjectIdentifiers.id_sha512_256); + + oidMap.put("MD2", PKCSObjectIdentifiers.md2); + oidMap.put("MD4", PKCSObjectIdentifiers.md4); + oidMap.put("MD5", PKCSObjectIdentifiers.md5); + } + + public RSADigestSigner( + Digest digest) + { + this(digest, (ASN1ObjectIdentifier)oidMap.get(digest.getAlgorithmName())); + } + + public RSADigestSigner( + Digest digest, + ASN1ObjectIdentifier digestOid) + { + this.digest = digest; + this.algId = new AlgorithmIdentifier(digestOid, DERNull.INSTANCE); + } + + /** + * @deprecated + */ + public String getAlgorithmName() + { + return digest.getAlgorithmName() + "withRSA"; + } + + /** + * initialise the signer for signing or verification. + * + * @param forSigning + * true if for signing, false otherwise + * @param parameters + * necessary parameters. + */ + public void init( + boolean forSigning, + CipherParameters parameters) + { + this.forSigning = forSigning; + AsymmetricKeyParameter k; + + if (parameters instanceof ParametersWithRandom) + { + k = (AsymmetricKeyParameter)((ParametersWithRandom)parameters).getParameters(); + } + else + { + k = (AsymmetricKeyParameter)parameters; + } + + if (forSigning && !k.isPrivate()) + { + throw new IllegalArgumentException("signing requires private key"); + } + + if (!forSigning && k.isPrivate()) + { + throw new IllegalArgumentException("verification requires public key"); + } + + reset(); + + rsaEngine.init(forSigning, parameters); + } + + /** + * update the internal digest with the byte b + */ + public void update( + byte input) + { + digest.update(input); + } + + /** + * update the internal digest with the byte array in + */ + public void update( + byte[] input, + int inOff, + int length) + { + digest.update(input, inOff, length); + } + + /** + * Generate a signature for the message we've been loaded with using the key + * we were initialised with. + */ + public byte[] generateSignature() + throws CryptoException, DataLengthException + { + if (!forSigning) + { + throw new IllegalStateException("RSADigestSigner not initialised for signature generation."); + } + + byte[] hash = new byte[digest.getDigestSize()]; + digest.doFinal(hash, 0); + + try + { + byte[] data = derEncode(hash); + return rsaEngine.processBlock(data, 0, data.length); + } + catch (IOException e) + { + throw new CryptoException("unable to encode signature: " + e.getMessage(), e); + } + } + + /** + * return true if the internal state represents the signature described in + * the passed in array. + */ + public boolean verifySignature( + byte[] signature) + { + if (forSigning) + { + throw new IllegalStateException("RSADigestSigner not initialised for verification"); + } + + byte[] hash = new byte[digest.getDigestSize()]; + + digest.doFinal(hash, 0); + + byte[] sig; + byte[] expected; + + try + { + sig = rsaEngine.processBlock(signature, 0, signature.length); + expected = derEncode(hash); + } + catch (Exception e) + { + return false; + } + + if (sig.length == expected.length) + { + return Arrays.constantTimeAreEqual(sig, expected); + } + else if (sig.length == expected.length - 2) // NULL left out + { + int sigOffset = sig.length - hash.length - 2; + int expectedOffset = expected.length - hash.length - 2; + + expected[1] -= 2; // adjust lengths + expected[3] -= 2; + + int nonEqual = 0; + + for (int i = 0; i < hash.length; i++) + { + nonEqual |= (sig[sigOffset + i] ^ expected[expectedOffset + i]); + } + + for (int i = 0; i < sigOffset; i++) + { + nonEqual |= (sig[i] ^ expected[i]); // check header less NULL + } + + return nonEqual == 0; + } + else + { + return false; + } + } + + public void reset() + { + digest.reset(); + } + + private byte[] derEncode( + byte[] hash) + throws IOException + { + DigestInfo dInfo = new DigestInfo(algId, hash); + + return dInfo.getEncoded(ASN1Encoding.DER); + } +} |