PEM文件格式详细解析

PEM文件格式存档
Author：Roson sun sunxiao@tomonline-inc.com

Time：2006-4-11

1． 描述：

Openssl使用PEM(RFC 1421－1424)文档格式，如果使用其他语言包，则需要将此格式进行解码并将各个私公钥加入。

2． 说明：

a) 首先使用BASE64解码，如果是非ANSI TXT格式，需要做转换。

b) 一个RSA私钥包含一下信息（1024位）：

>openssl rsa -in key.pem -noout -text

modulus:

00:d5:00:b2:18:c3:04:d1:ac:80:c6:22:a0:cc:5c:

f1:c0:4a:83:95:e5:c9:88:ae:31:64:ab:e1:15:42:

de:1a:da:bc:f5:d2:05:05:74:9d:d3:86:94:9b:9d:

74:bb:e5:72:a4:b8:40:27:61:88:d4:ac:20:b0:2b:

1c:1e:d7:9b:43:c5:06:b6:3a:b4:42:f0:5a:22:38:

23:74:99:4a:50:f1:f1:54:11:5a:44:0b:40:cf:83:

8a:73:6c:34:15:98:0a:7d:cf:0e:e5:00:8d:07:40:

f7:7d:fb:3f:64:35:1b:5d:a3:40:a9:51:fa:92:7d:

34:ef:03:fe:e0:59:56:31:25

数量:128

publicExponent:

01:00:01

数量:3

privateExponent:

11:e2:a8:11:ba:36:6a:60:c0:c3:62:5e:fc:2a:05:

c6:ae:bb:13:d8:22:af:0e:69:69:59:a1:61:c6:a6:

9d:bc:a6:47:41:e6:58:09:ed:c2:b8:37:3c:45:e1:

6a:71:9e:c9:c4:0a:e7:03:a2:98:b1:07:61:a3:8d:

0d:ed:ee:c4:7f:ca:fe:7d:c1:2e:2f:ca:3d:16:81:

4f:bf:ad:6a:03:ca:d7:80:dc:57:03:fe:cf:1f:37:

05:8d:58:79:14:01:1f:66:42:e4:f1:b6:9d:f1:01:

37:12:f4:d8:15:c0:cc:9b:fc:ea:55:cb:2f:ba:46:

fd:17:11:7e:43:b5:d1:15

数量:128

prime1:

00:ed:a0:e8:25:cc:1c:aa:f5:44:e2:78:9e:54:2c:

1d:60:cb:8f:32:b3:68:6d:b3:1d:cd:a9:8c:2a:ca:

02:bc:7b:a7:8b:06:1d:fa:af:4f:8c:26:81:54:12:

ec:7d:92:20:77:85:ef:6e:06:a6:8b:9c:eb:ab:6a:

e6:a1:83:6d:a3

数量:64（去掉开头的0）

prime2:

00:e5:78:66:5a:84:22:51:78:2d:14:fc:5f:f8:4e:

45:5f:e3:b2:5e:5b:50:a4:f5:55:e0:f3:0e:98:2c:

52:61:c2:50:df:f4:b7:bc:6e:69:3e:99:ff:1c:50:

a8:89:05:7a:2b:25:91:56:a5:a6:8f:8a:ec:80:82:

fa:eb:09:c2:97

数量:64（去掉开头的0）

exponent1:

00:89:e6:26:d2:48:71:1a:84:db:44:d1:da:8f:de:

49:ee:32:33:17:a9:25:a1:03:a0:f8:08:bc:5e:d8:

7c:5e:05:24:65:79:57:4c:73:10:26:b4:f1:b8:68:

82:f5:1c:27:db:34:ce:8d:7b:2e:8b:36:b5:4c:f4:

ec:82:2e:53:21

数量:64（去掉开头的0）

exponent2:

6a:16:a6:e3:74:31:55:8f:04:f0:ad:d9:44:b8:13:

14:c8:f5:5e:f0:42:b1:71:07:5a:2f:a4:f0:af:95:

0a:c3:46:96:b3:d1:fa:58:e5:69:5e:d2:f5:e9:48:

71:c8:c9:79:87:2d:d1:6c:56:3c:08:d3:5c:7a:b1:

bc:d6:4f:53

数量:64

coefficient:

62:dd:3f:f4:c7:30:c7:77:5e:8c:ae:c8:11:c1:23:

b0:6d:7d:07:54:8f:e7:12:1d:e1:00:ad:70:55:12:

43:f6:6f:a9:d7:94:9d:33:15:66:16:2d:d1:76:13:

33:0d:ae:6f:e3:3f:46:4b:4a:78:14:02:2e:72:66:

59:0c:2d:6a

数量:64

c) 与C#中RSAParameter结构体对应表：

说明	PEM	RSAParameter
	Modulus	modulus
	Exponent	Exponent
	prime1	P
	exponent1	Q
	prime2	DP
	exponent2	DQ
	coefficient	InverseQ
	privateExponent	D

d) PEM偏移（1024位，以0为开始字符，十进制）

说明	PEM私钥	PEM公钥	长度
Modulus	11	29	128
PublicExponent	141	159	3
PrivateExponent	147	×	128
Prime1	278	×	64
Prime2	345	×	64
Exponent1	412	×	64
Exponent2	478	×	64
Coefficient	545	×	64

e) 例子程序（C＃）：

/// <summary>
/// 用得到的解码值来得到相应的Parameter（BASE64->RSAParameter）
/// </summary>
/// <param name="hashKey">源</param>
/// <param name="type">0私钥1公钥</param>

/// <returns></returns>

public RSAParameters getKeyPara(string hashKey,int type)
{
RSAParameters rsaP=new RSAParameters();
byte[] tmpKeyNoB64=Convert.FromBase64String(hashKey);
int pemModulus=128;
int pemPublicExponent=3;
int pemPrivateExponent=128;
int pemPrime1=64;
int pemPrime2=64;
int pemExponent1=64;
int pemExponent2=64;
int pemCoefficient=64;

byte[] arrPemModulus=new byte[128];
byte[] arrPemPublicExponent=new byte[3];
byte[] arrPemPrivateExponent=new byte[128];
byte[] arrPemPrime1=new byte[64];
byte[] arrPemPrime2=new byte[64];
byte[] arrPemExponent1=new byte[64];
byte[] arrPemExponent2=new byte[64];
byte[] arrPemCoefficient=new byte[64];

if(type==0)//私钥
{
//Modulus
for(int i=0;i<pemModulus;i++)
{
arrPemModulus[i]=tmpKeyNoB64[11+i];
}
rsaP.Modulus=arrPemModulus;

//PublicExponent
for(int i=0;i<pemPublicExponent;i++)
{
arrPemPublicExponent[i]=tmpKeyNoB64[141+i];
}
rsaP.Exponent=arrPemPublicExponent;

//PrivateExponent
for(int i=0;i<pemPrivateExponent;i++)
{
arrPemPrivateExponent[i]=tmpKeyNoB64[147+i];
}
rsaP.D=arrPemPrivateExponent;

//Prime1
for(int i=0;i<pemPrime1;i++)
{
arrPemPrime1[i]=tmpKeyNoB64[278+i];
}
rsaP.P=arrPemPrime1;

//Prime2
for(int i=0;i<pemPrime2;i++)
{
arrPemPrime2[i]=tmpKeyNoB64[345+i];
}
rsaP.Q=arrPemPrime2;

//Exponent1
for(int i=0;i<pemExponent1;i++)
{
arrPemExponent1[i]=tmpKeyNoB64[412+i];
}
rsaP.DP=arrPemExponent1;

//Exponent2
for(int i=0;i<pemExponent2;i++)
{
arrPemExponent2[i]=tmpKeyNoB64[478+i];
}
rsaP.DQ=arrPemExponent2;

//Coefficient
for(int i=0;i<pemCoefficient;i++)
{
arrPemCoefficient[i]=tmpKeyNoB64[545+i];
}
rsaP.InverseQ=arrPemCoefficient;
}
else//公钥
{
for(int i=0;i<pemModulus;i++)
{
arrPemModulus[i]=tmpKeyNoB64[29+i];
}
rsaP.Modulus=arrPemModulus;

for(int i=0;i<pemPublicExponent;i++)
{
arrPemPublicExponent[i]=tmpKeyNoB64[159+i];
}
rsaP.Exponent=arrPemPublicExponent;

}

return rsaP;
}