我有一个 PKCS#5 加密的 PKCS#8 RSA 私钥存储在磁盘文件中（最初由 SSLPlus 生成，大约在 1997 年），例如：
-----BEGIN ENCRYPTED PRIVATE KEY-----
MIICmDAaBgkqhkiG9w0BBQMwDQQIybM2XFqx4EwCAQUEggJ4MKg/NE+L6NJgbOf4
...
8QnGu4R7lFlweH/VAK8n0L75h3q2g62MKLJqmKLtAILNve4zymnO+LVZ4Js=
-----END ENCRYPTED PRIVATE KEY-----
为此，我需要获取一个 Java Key 对象，然后我可以将其与匹配的证书一起添加到 KeyStore。私钥使用 100 字节的二进制密钥加密。
证书对象的创建很简单，但我似乎无法弄清楚如何从上述 Base64 编码的 PKCS#5 密钥到解密的 PKCS#8 RSA 私钥。在这一点上，我受到了阻碍，因为 SecretKeyFactory.generateSecret() 调用失败：
InvalidKeySpecException: Password is not ASCII
现在，密码确实不是 ASCII，在最严格的意义上是 0x00 到 0x7F，但是 PBEWithMD5AndDES 算法应该接受从 0x00 到 0xFF 的字符值。
谁能告诉我如何从 Base64 编码的值到我可以添加到密钥库的 Key 对象？
结论
使用 Java 发布的 PBEKey 只接受 ASCII 值在 0x20<=char<=0x7E 范围内的密码。通过制作我自己的 BinaryPBEKey 解决了我的非 ASCII 密码的这个问题，它允许从 0x00 到 0xFF 的字节值（见下文）。
我遇到的后续问题是我的 PKCS#8 数据未正确编码（显然是早期 SSL 实现的常见错误），因为 PKCS#1 数据需要包装在 ASN.1 八位字节字符串中。我编写了一个简单的修补程序来处理我的密钥，这些密钥的长度在 512 到 4096 位之间（见下文）。
私钥解码器
private PrivateKey readPrivateKey(File inpfil) throws IOException, GeneralSecurityException {
String[] pbeb64s; // PBE ASN.1 data base-64 encoded
byte[] pbedta; // PBE ASN.1 data in bytes
EncryptedPrivateKeyInfo pbeinf; // PBE key info
PBEParameterSpec pbeprm; // PBE parameters
Cipher pbecph; // PBE decryption cipher
byte[] pk8dta; // PKCS#8 ASN.1 data in bytes
KeyFactory pk8fac=KeyFactory.getInstance("RSA"); // PKCS#8 key factory for decoding private key from ASN.1 data.
pbeb64s=readDataBlocks(inpfil,"ENCRYPTED PRIVATE KEY");
if(pbeb64s.length!=1) { throw new GeneralSecurityException("The keystore '"+inpfil+"' contains multiple private keys"); }
pbedta=base64.decode(pbeb64s[0]);
log.diagln(" - Read private key data");
pbeinf=new EncryptedPrivateKeyInfo(pbedta);
pbeprm=(PBEParameterSpec)pbeinf.getAlgParameters().getParameterSpec(PBEParameterSpec.class);
pbecph=Cipher.getInstance(pbeinf.getAlgName());
pbecph.init(Cipher.DECRYPT_MODE,pbeDecryptKey,pbeprm);
pk8dta=pbecph.doFinal(pbeinf.getEncryptedData());
log.diagln(" - Private Key: Algorithm= "+pbeinf.getAlgName()+", Iterations: "+pbeprm.getIterationCount()+", Salt: "+Base16.toString(pbeprm.getSalt()));
pk8dta=patchKeyData(inpfil,pk8dta);
return pk8fac.generatePrivate(new PKCS8EncodedKeySpec(pk8dta));
}
二进制PBEKey
import java.io.*;
import java.security.*;
import java.security.spec.*;
import java.util.*;
import javax.crypto.*;
import javax.crypto.spec.*;
class BinaryPBEKey
extends Object
implements SecretKey
{
private final byte[] key;
/**
* Creates a PBE key from a given binary key.
*
* @param key The key.
*/
BinaryPBEKey(byte[] key) throws InvalidKeySpecException {
if(key==null) { this.key=new byte[0]; }
else { this.key=(byte[])key.clone(); }
Arrays.fill(key,(byte)0);
}
public byte[] getEncoded() {
return (byte[])key.clone();
}
public String getAlgorithm() {
return "PBEWithMD5AndDES";
}
public String getFormat() {
return "RAW";
}
/**
* Calculates a hash code value for the object.
* Objects that are equal will also have the same hashcode.
*/
public int hashCode() {
int ret=0;
for(int xa=1; xa<this.key.length; xa++) { ret+=(this.key[xa]*xa); }
return (ret^=getAlgorithm().toLowerCase().hashCode());
}
public boolean equals(Object obj) {
if(obj==this ) { return true; }
if(obj.getClass()!=getClass()) { return false; }
BinaryPBEKey oth=(BinaryPBEKey)obj;
if(!(oth.getAlgorithm().equalsIgnoreCase(getAlgorithm()))) {
return false;
}
byte[] othkey=oth.getEncoded();
boolean ret =Arrays.equals(key,othkey);
Arrays.fill(othkey,(byte)0);
return ret;
}
public void destroy() {
Arrays.fill(this.key,(byte)0);
}
/**
* Ensure that the password bytes of this key are zeroed out when there are no more references to it.
*/
protected void finalize() throws Throwable {
try { destroy(); } finally { super.finalize(); }
}
PKCS#8 补丁
/**
* Patch the private key ASN.1 data to conform to PKCS#8.
* <p>
* The SSLPlus private key is not properly encoded PKCS#8 - the PKCS#1 RSAPrivateKey should have been wrapped
* inside an OctetString, thus:
* <pre>
* SSLPlus Encoding:
* 0 30 627: SEQUENCE {
* 4 02 1: INTEGER 0
* 7 30 13: SEQUENCE {
* 9 06 9: OBJECT IDENTIFIER rsaEncryption (1 2 840 113549 1 1 1)
* 20 05 0: NULL
* : }
* 22 30 605: SEQUENCE {
* 26 02 1: INTEGER 0
* 29 02 129: INTEGER
* : 00 CA 72 B8 D1 B8 8E B9 39 C0 92 C1 4C 53 B4 F4
* ...
*
* PKCS#8 Encoding
* 0 30 631: SEQUENCE {
* 4 02 1: INTEGER 0
* 7 30 13: SEQUENCE {
* 9 06 9: OBJECT IDENTIFIER rsaEncryption (1 2 840 113549 1 1 1)
* 20 05 0: NULL
* : }
* ==> 22 04 609: OCTET STRING, encapsulates {
* 26 30 605: SEQUENCE {
* 30 02 1: INTEGER 0
* 33 02 129: INTEGER
* : 00 CA 72 B8 D1 B8 8E B9 39 C0 92 C1 4C 53 B4 F4
* ...
* </pre>
*
* Hex Dumps (1K key, space padded for clarity):
* Before : 30 820271 020100300D06092A864886F70D0101010500 30 82025B ... A228
* After : 30 820275 020100300D06092A864886F70D0101010500 04 82025F 30 82025B ... A228
* ^^^^^^ ^^^^^^
* Add 4 for later 0482xxxx Original total + 4 - 22 (equals the key length of 025B+4)
*/
private byte[] patchKeyData(File inpfil, byte[] asndta) throws IOException, GeneralSecurityException { // except it really doesn't throw an exception
ByteArrayOutputStream patdta=new ByteArrayOutputStream();
int orglen=decodeAsnLength(inpfil,asndta,1);
patdta.write(asndta,0,1); // original leader type
patdta.write(encodeAsnLength(inpfil,(orglen+4))); // new total length
patdta.write(asndta,4,(22-4)); // bit between total length an where octet-string wrapper needs to be inserted
patdta.write(0x04); // octet-string type
patdta.write(encodeAsnLength(inpfil,(orglen+4-22))); // octet-string length (key data type+key data length+key data)
patdta.write(asndta,22,asndta.length-22); // private key data
return patdta.toByteArray();
}
private int decodeAsnLength(File inpfil, byte[] asndta, int ofs) throws GeneralSecurityException {
if((asndta[ofs]&0xFF)==0x82) { return (((asndta[ofs+1]&0x000000FF)<< 8)|((asndta[ofs+2]&0x000000FF))); }
else { throw new GeneralSecurityException("The private key in file '"+inpfil+"' is not supported (ID="+Base16.toString(asndta,0,4)+")"); }
}
private byte[] encodeAsnLength(File inpfil, int len) throws GeneralSecurityException {
if(len>=0x0100 && len<=0xFFFF) { return new byte[]{ (byte)0x82,(byte)((len>>>8)&0x000000FF),(byte)len }; }
else { throw new GeneralSecurityException("The new length of "+len+" for patching the private key in file '"+inpfil+"' is out of range"); }
}