【OpenSSL】使用SMIME/CMS发送签名和加密邮件
1，通信双方的证书生成
1.1生成根节点证书
openssl genrsa -out cakey.pem 2048
openssl req -new -key cakey.pem -subj "/CN=rootca.bitbaba.com" -out cacsr.pem
openssl x509 -req -in cacsr.pem -days 999 -signkey cakey.pem -out cacert.pem
1.2生成alice的证书
openssl genrsa -out alicekey.pem 2048
openssl req -new -key cakey.pem -subj "/emailAddress=imalice.freemail@gmail.com" -out alicecsr.pem
openssl x509 -req -in alicecsr.pem -days 999 -CA cacert.pem -CAKey cakey.pem -set_serial 01 -name "alice" -out alicecert.pem
openssl pkcs12 -export -in alicecert.pem -inkey alicekey.pem -certfile cacert.pem -out alice.p12
1.3生成bob的证书
openssl genrsa -out bobkey.pem 2048
openssl req -new -key bobkey.pem -subj "/emailAddress=iambob.freemail@gmail.com" -out bobcsr.pem
openssl x509 -req -in bobcsr.pem -days 999 -CA cacert.pem -CAkey cakey.pem -set_serial 02 -name "bob" -out bobcert.pem
openssl pkcs12 -export -in bobcert.pem -inkey bobkey.pem -certfile cacert.pem -out bob.p12
2，邮件签名
openssl smime -sign -in /tmp/msg.txt -signer alicecert.pem -inkey alicekey.pem -nocerts -nodetach -text -out /tmp/alicesigned.eml
提醒：
-nodetach 把信息原文也包含到base64块里面，而不是用mime格式的分隔符单独放置，比较容易保证信息不被邮件收发服务器重构，导致验证失败。
-nocerts 是一个可选选项，如果设置的话，alice的证书（公钥等）不会被包含到签名信息里面（base64块）
-signer 在签发邮件的时候，指定发送人的证书位置，这里指定alice的证书
3，签名验证
openssl smime -verify -in /tmp/alicesigned.eml -certfile alicecert.pem -CAfile cacert.pem
注意：
-signer 参数这个时候的意思：导出签发邮件的证书保存。所以要小心覆盖原有证书
-CAfile 设置信任的ca位置，否则验证不通过
-certfile 是一个可选选项，如果签名的时候指定了-nocerts，这里可以指定验证证书（alice），这样网络传输经济。
4，邮件加密
smime -encrypt -in /tmp/msg.txt -from imalice.freemail@gmail.com -to iambob.freemail@gmail.com -des3 -out /tmp/msg.eml bobcert.pem
5，邮件解密
openssl smime -decrypt -in /tmp/msg.eml -recip bobcert.pem -inkey bobkey.pem
6， 签名并加密
openssl smime -sign -in msg.txt -signer alicecert.pem -inkey alicekey.pem -nocerts -nodetach -text | openssl smime -encrypt -des3 -from imalice.freemail@gmail.com -to iambob.freemail@gmail.com -subject HiBob bobcert.pem
To: iambob.freemail@gmail.com
From: imalice.freemail@gmail.com
Subject: HiBob
MIME-Version: 1.0
Content-Disposition: attachment; filename="smime.p7m"
Content-Type: application/x-pkcs7-mime; smime-type=enveloped-data; name="smime.p7m"
Content-Transfer-Encoding: base64
MIIGKQYJKoZIhvcNAQcDoIIGGjCCBhYCAQAxggFmMIIBYgIBADBKMEUxCzAJBgNV
BAYTAkFVMRMwEQYDVQQIDApTb21lLVN0YXRlMSEwHwYDVQQKDBhJbnRlcm5ldCBX
aWRnaXRzIFB0eSBMdGQCAQMwDQYJKoZIhvcNAQEBBQAEggEAdmR6L5KWIhmIFBwj
UV2wxBb8S20+TH+ZsQ7NtHN/FucV+LMkRWsif03ExRqnsLwigQSXinigsOrgpovn
X8JpfiOQp3cg6KEyhX0+q2Ziiu4qRNZLCKoWXZ4oxyYORe8PT1R9NwSfnfVcHvec
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6p+2K5sZr749RvGuzmZuwd4WvAtPO/bgBks7sbR8mR7jXLZaq8Q/NHN913Jq5Pf2
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7，解密并验证
openssl smime -decrypt -in enc.eml -recip bobcert.pem -inkey bobkey.pem | openssl smime -verify -certfile alicecert.pem -CAfile cacert.pem
Content-Type: text/plain
Hello, World !
Verification successful
管道命令
openssl smime -sign -in msg.txt -signer alicecert.pem -inkey alicekey.pem -nocerts -nodetach -text | \
openssl smime -encrypt -des3 -from imalice.freemail@gmail.com -to iambob.freemail@gmail.com -subject HiBob bobcert.pem | \
openssl smime -decrypt -recip bobcert.pem -inkey bobkey.pem | \
openssl smime -verify -certfile alicecert.pem -CAfile cacert.pem
8，邮件发送
关于smtp客户端的例子
9，邮件接收
关于pop3的例子
备注：
1）关于cms的一些数据结构定义
子结构的详细定义可以参考：https://github.com/openssl/openssl/blob/master/crypto/cms/cms_lcl.h
struct CMS_ContentInfo_st {
ASN1_OBJECT *contentType;
union {
ASN1_OCTET_STRING *data;
CMS_SignedData *signedData;
CMS_EnvelopedData *envelopedData;
CMS_DigestedData *digestedData;
CMS_EncryptedData *encryptedData;
CMS_AuthenticatedData *authenticatedData;
CMS_CompressedData *compressedData;
ASN1_TYPE *other;
/* Other types ... */
void *otherData;
} d;
};
PKCS7的递推定义
/*-
Encryption_ID DES-CBC
Digest_ID MD5
Digest_Encryption_ID rsaEncryption
Key_Encryption_ID rsaEncryption
*/
typedef struct pkcs7_issuer_and_serial_st {
X509_NAME *issuer;
ASN1_INTEGER *serial;
} PKCS7_ISSUER_AND_SERIAL;
typedef struct pkcs7_signer_info_st {
ASN1_INTEGER *version; /* version 1 */
PKCS7_ISSUER_AND_SERIAL *issuer_and_serial;
X509_ALGOR *digest_alg;
STACK_OF(X509_ATTRIBUTE) *auth_attr; /* [ 0 ] */
X509_ALGOR *digest_enc_alg;
ASN1_OCTET_STRING *enc_digest;
STACK_OF(X509_ATTRIBUTE) *unauth_attr; /* [ 1 ] */
/* The private key to sign with */
EVP_PKEY *pkey;
} PKCS7_SIGNER_INFO;
DECLARE_STACK_OF(PKCS7_SIGNER_INFO)
DECLARE_ASN1_SET_OF(PKCS7_SIGNER_INFO)
typedef struct pkcs7_recip_info_st {
ASN1_INTEGER *version; /* version 0 */
PKCS7_ISSUER_AND_SERIAL *issuer_and_serial;
X509_ALGOR *key_enc_algor;
ASN1_OCTET_STRING *enc_key;
X509 *cert; /* get the pub-key from this */
} PKCS7_RECIP_INFO;
DECLARE_STACK_OF(PKCS7_RECIP_INFO)
DECLARE_ASN1_SET_OF(PKCS7_RECIP_INFO)
typedef struct pkcs7_signed_st {
ASN1_INTEGER *version; /* version 1 */
STACK_OF(X509_ALGOR) *md_algs; /* md used */
STACK_OF(X509) *cert; /* [ 0 ] */
STACK_OF(X509_CRL) *crl; /* [ 1 ] */
STACK_OF(PKCS7_SIGNER_INFO) *signer_info;
struct pkcs7_st *contents;
} PKCS7_SIGNED;
/*
* The above structure is very very similar to PKCS7_SIGN_ENVELOPE. How about
* merging the two
*/
typedef struct pkcs7_enc_content_st {
ASN1_OBJECT *content_type;
X509_ALGOR *algorithm;
ASN1_OCTET_STRING *enc_data; /* [ 0 ] */
const EVP_CIPHER *cipher;
} PKCS7_ENC_CONTENT;
typedef struct pkcs7_enveloped_st {
ASN1_INTEGER *version; /* version 0 */
STACK_OF(PKCS7_RECIP_INFO) *recipientinfo;
PKCS7_ENC_CONTENT *enc_data;
} PKCS7_ENVELOPE;
typedef struct pkcs7_signedandenveloped_st {
ASN1_INTEGER *version; /* version 1 */
STACK_OF(X509_ALGOR) *md_algs; /* md used */
STACK_OF(X509) *cert; /* [ 0 ] */
STACK_OF(X509_CRL) *crl; /* [ 1 ] */
STACK_OF(PKCS7_SIGNER_INFO) *signer_info;
PKCS7_ENC_CONTENT *enc_data;
STACK_OF(PKCS7_RECIP_INFO) *recipientinfo;
} PKCS7_SIGN_ENVELOPE;
typedef struct pkcs7_digest_st {
ASN1_INTEGER *version; /* version 0 */
X509_ALGOR *md; /* md used */
struct pkcs7_st *contents;
ASN1_OCTET_STRING *digest;
} PKCS7_DIGEST;
typedef struct pkcs7_encrypted_st {
ASN1_INTEGER *version; /* version 0 */
PKCS7_ENC_CONTENT *enc_data;
} PKCS7_ENCRYPT;
typedef struct pkcs7_st {
/*
* The following is non NULL if it contains ASN1 encoding of this
* structure
*/
unsigned char *asn1;
long length;
# define PKCS7_S_HEADER 0
# define PKCS7_S_BODY 1
# define PKCS7_S_TAIL 2
int state; /* used during processing */
int detached;
ASN1_OBJECT *type;
/* content as defined by the type */
/*
* all encryption/message digests are applied to the 'contents', leaving
* out the 'type' field.
*/
union {
char *ptr;
/* NID_pkcs7_data */
ASN1_OCTET_STRING *data;
/* NID_pkcs7_signed */
PKCS7_SIGNED *sign;
/* NID_pkcs7_enveloped */
PKCS7_ENVELOPE *enveloped;
/* NID_pkcs7_signedAndEnveloped */
PKCS7_SIGN_ENVELOPE *signed_and_enveloped;
/* NID_pkcs7_digest */
PKCS7_DIGEST *digest;
/* NID_pkcs7_encrypted */
PKCS7_ENCRYPT *encrypted;
/* Anything else */
ASN1_TYPE *other;
} d;
} PKCS7;
PKCS7 vs CMS
PKCS#7 is an old standard from RSA Labs, published later on as an "informational RFC". Then, a new versions was produced, as an "Internet standard", i.e. with the seal of approval from the powers-that-be at IETF; a new name was invented for that: CMS. Newer versions were subsequently defined: RFC 3369, RFC 3852, RFC 5652. You can consider CMS and PKCS#7 to both designate the same standard, which has several versions.
CMS (PKCS#7) is a format for applying encryption, signatures and/or integrity checks on arbitrary binary messages (which can be large). It can be nested. It is the basis for some protocols such as time stamping. It is also frequently (ab)used as a container for X.509 certificates: the SignedData type includes a field for a set of signatures (and that set can be empty), and also a field to store arbitrary X.509 certificates which are considered as "potentially useful" for whoever processes the object.
CMS is nominally backward compatible: there are version fields at various places, and a library which understands a version of CMS should be able to process messages from older versions; moreover, such a library should also produce messages which are compatible with other versions, inasmuch as it is feasible given the message contents. See section 5.1 for an example: the "version" fields are set to the minimal values which still make sense given what else is in the structure.
if (noout) {
if (print)
CMS_ContentInfo_print_ctx(out, cms, 0, NULL);
} else if (outformat == FORMAT_SMIME) {
if (to)
BIO_printf(out, "To: %s\n", to);
if (from)
BIO_printf(out, "From: %s\n", from);
if (subject)
BIO_printf(out, "Subject: %s\n", subject);
if (operation == SMIME_RESIGN)
ret = SMIME_write_CMS(out, cms, indata, flags);
else
ret = SMIME_write_CMS(out, cms, in, flags);
} else if (outformat == FORMAT_PEM)
ret = PEM_write_bio_CMS_stream(out, cms, in, flags);
else if (outformat == FORMAT_ASN1)
ret = i2d_CMS_bio_stream(out, cms, in, flags);
else {
BIO_printf(bio_err, "Bad output format for CMS file\n");
goto end;
}
else {
if (to)
BIO_printf(out, "To: %s\n", to);
if (from)
BIO_printf(out, "From: %s\n", from);
if (subject)
BIO_printf(out, "Subject: %s\n", subject);
if (outformat == FORMAT_SMIME) {
if (operation == SMIME_RESIGN)
SMIME_write_PKCS7(out, p7, indata, flags);
else
SMIME_write_PKCS7(out, p7, in, flags);
} else if (outformat == FORMAT_PEM)
PEM_write_bio_PKCS7_stream(out, p7, in, flags);
else if (outformat == FORMAT_ASN1)
i2d_PKCS7_bio_stream(out, p7, in, flags);
else {
BIO_printf(bio_err, "Bad output format for PKCS#7 file\n");
goto end;
}
2) smtp如何发送邮件
https://technet.microsoft.com/en-us/library/dd441082.aspx
https://tools.ietf.org/html/rfc821
https://tools.ietf.org/html/rfc2554
https://tools.ietf.org/html/rfc2821
http://tools.ietf.org/html/rfc5321
邮件如何在smtp服务器之间路由 http://en.wikipedia.org/wiki/MX_record
如何通过邮件地址后缀的domain来查询邮件服务器（smtp）的地址：nslookup -type=mx sina.com
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作者：开心乐源
来源：CSDN
原文：https://blog.csdn.net/hacode/article/details/43851927
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