Add a function for parsing RFC 5280's "TBSCertificate".

net/data/parse_certificate_unittest/serial_number_21_octets_leading_0.pem

+$ openssl x509 -inform DER -text -noout < [CERTIFICATE]
+Certificate:
+    Data:
+        Version: 3 (0x2)
+        Serial Number:
+            d8:c3:7e:4d:87:f9:c8:c8:2b:af:26:ef:53:50:1d:f1:fc:f3:a5:20
+    Signature Algorithm: sha1WithRSAEncryption
+        Issuer: C=IT, ST=IT, O=Postecom S.p.A., OU=Servizi di Certificazione, CN=Postecom CS3
+        Validity
+            Not Before: Apr 17 14:34:23 2012 GMT
+            Not After : Apr 17 14:34:23 2013 GMT
+        Subject: C=IT, O=Poste Italiane S.p.A., OU=Postecom S.p.A., CN=mail.uniroma3.it
+        Subject Public Key Info:
+            Public Key Algorithm: rsaEncryption
+                Public-Key: (1024 bit)
+                Modulus:
+                    00:b4:62:c0:3a:48:45:cb:6a:44:5f:31:15:2e:4f:
+                    50:40:a4:6b:1f:f3:9c:69:e3:ad:d9:b6:0d:bf:cf:
+                    2e:09:a4:c9:94:a9:de:0b:03:30:a2:37:be:88:81:
+                    7f:fe:1b:17:9b:81:6b:0c:f5:f3:a3:f2:50:7c:cc:
+                    ee:6b:95:5e:98:6a:c0:03:bb:62:81:12:29:fb:ac:
+                    00:29:92:87:db:8c:5f:f9:eb:5b:29:f6:b4:35:4a:
+                    c3:a0:0c:83:38:b1:7d:76:f8:67:e9:db:15:f9:f4:
+                    16:03:61:d3:3e:e8:8c:0b:54:2e:fd:d4:84:3c:04:
+                    fe:8a:d2:7a:10:6f:59:aa:1f
+                Exponent: 65537 (0x10001)
+        X509v3 extensions:
+            X509v3 Basic Constraints: 
+                CA:FALSE
+            X509v3 Certificate Policies: 
+                Policy: 1.3.76.11.1.1.4.1
+                  CPS: http://postecert.poste.it/manualioperativi/
+
+            X509v3 Key Usage: critical
+                Digital Signature, Key Encipherment, Data Encipherment, Key Agreement
+            X509v3 Extended Key Usage: 
+                TLS Web Server Authentication, TLS Web Client Authentication
+            X509v3 Authority Key Identifier: 
+                DirName:/C=IE/O=Baltimore/OU=CyberTrust/CN=Baltimore CyberTrust Root
+                serial:07:27:52:62
+
+            X509v3 CRL Distribution Points: 
+
+                Full Name:
+                  URI:http://postecert.poste.it/postecomcs3/crl.crl
+
+    Signature Algorithm: sha1WithRSAEncryption
+         74:40:d4:35:ea:05:12:1f:b5:e7:2f:d8:2b:00:30:4c:32:2b:
+         a4:b0:35:55:74:cb:c0:03:56:ad:27:2c:5e:46:85:0a:93:4f:
+         3f:1e:93:d9:a6:de:3b:f5:54:41:60:6f:3a:81:99:48:96:e4:
+         52:b9:f7:39:90:7e:c7:b6:2f:4f:9b:bb:e6:e9:58:d1:25:4e:
+         0a:e3:3f:bb:ff:b1:7b:a1:d3:1e:86:29:62:8d:61:48:1b:10:
+         eb:22:a7:d2:05:8d:f9:a2:7e:d2:c5:1c:c3:2e:b8:b3:97:49:
+         bd:b9:f1:4c:1f:d6:d9:ca:71:5d:5b:85:66:3e:5f:25:00:ec:
+         af:50:48:35:a1:59:0d:62:2c:e0:a0:b2:b2:cb:d6:9b:7b:01:
+         5b:83:ee:f0:48:aa:6d:b6:10:37:96:db:56:aa:d8:4f:9e:e5:
+         2a:68:fb:8b:2d:8f:0e:c6:6a:88:2f:90:a6:f5:b2:bb:e0:be:
+         05:3e:f3:22:35:cc:0b:e5:e3:53:76:7d:fb:f8:7d:29:2c:3b:
+         f8:b6:75:44:c6:b1:8c:c4:24:81:14:86:8c:c4:dd:ff:a5:21:
+         d6:5a:ce:3a:be:1b:c1:94:ea:f7:67:10:8d:db:d1:47:ce:86:
+         10:7e:be:db:54:87:c2:67:8c:0e:aa:dd:87:9f:3d:12:dc:40:
+         32:68:f9:f4
+
+
+$ openssl asn1parse -i -inform DER < [CERTIFICATE]
+    0:d=0  hl=4 l=1054 cons: SEQUENCE          
+    4:d=1  hl=4 l= 774 cons:  SEQUENCE          
+    8:d=2  hl=2 l=   3 cons:   cont [ 0 ]        
+   10:d=3  hl=2 l=   1 prim:    INTEGER           :02
+   13:d=2  hl=2 l=  21 prim:   INTEGER           :D8C37E4D87F9C8C82BAF26EF53501DF1FCF3A520
+   36:d=2  hl=2 l=  13 cons:   SEQUENCE          
+   38:d=3  hl=2 l=   9 prim:    OBJECT            :sha1WithRSAEncryption
+   49:d=3  hl=2 l=   0 prim:    NULL              
+   51:d=2  hl=2 l= 111 cons:   SEQUENCE          
+   53:d=3  hl=2 l=  11 cons:    SET               
+   55:d=4  hl=2 l=   9 cons:     SEQUENCE          
+   57:d=5  hl=2 l=   3 prim:      OBJECT            :countryName
+   62:d=5  hl=2 l=   2 prim:      PRINTABLESTRING   :IT
+   66:d=3  hl=2 l=  11 cons:    SET               
+   68:d=4  hl=2 l=   9 cons:     SEQUENCE          
+   70:d=5  hl=2 l=   3 prim:      OBJECT            :stateOrProvinceName
+   75:d=5  hl=2 l=   2 prim:      UTF8STRING        :IT
+   79:d=3  hl=2 l=  24 cons:    SET               
+   81:d=4  hl=2 l=  22 cons:     SEQUENCE          
+   83:d=5  hl=2 l=   3 prim:      OBJECT            :organizationName
+   88:d=5  hl=2 l=  15 prim:      UTF8STRING        :Postecom S.p.A.
+  105:d=3  hl=2 l=  34 cons:    SET               
+  107:d=4  hl=2 l=  32 cons:     SEQUENCE          
+  109:d=5  hl=2 l=   3 prim:      OBJECT            :organizationalUnitName
+  114:d=5  hl=2 l=  25 prim:      UTF8STRING        :Servizi di Certificazione
+  141:d=3  hl=2 l=  21 cons:    SET               
+  143:d=4  hl=2 l=  19 cons:     SEQUENCE          
+  145:d=5  hl=2 l=   3 prim:      OBJECT            :commonName
+  150:d=5  hl=2 l=  12 prim:      UTF8STRING        :Postecom CS3
+  164:d=2  hl=2 l=  30 cons:   SEQUENCE          
+  166:d=3  hl=2 l=  13 prim:    UTCTIME           :120417143423Z
+  181:d=3  hl=2 l=  13 prim:    UTCTIME           :130417143423Z
+  196:d=2  hl=2 l=  98 cons:   SEQUENCE          
+  198:d=3  hl=2 l=  11 cons:    SET               
+  200:d=4  hl=2 l=   9 cons:     SEQUENCE          
+  202:d=5  hl=2 l=   3 prim:      OBJECT            :countryName
+  207:d=5  hl=2 l=   2 prim:      PRINTABLESTRING   :IT
+  211:d=3  hl=2 l=  30 cons:    SET               
+  213:d=4  hl=2 l=  28 cons:     SEQUENCE          
+  215:d=5  hl=2 l=   3 prim:      OBJECT            :organizationName
+  220:d=5  hl=2 l=  21 prim:      UTF8STRING        :Poste Italiane S.p.A.
+  243:d=3  hl=2 l=  24 cons:    SET               
+  245:d=4  hl=2 l=  22 cons:     SEQUENCE          
+  247:d=5  hl=2 l=   3 prim:      OBJECT            :organizationalUnitName
+  252:d=5  hl=2 l=  15 prim:      UTF8STRING        :Postecom S.p.A.
+  269:d=3  hl=2 l=  25 cons:    SET               
+  271:d=4  hl=2 l=  23 cons:     SEQUENCE          
+  273:d=5  hl=2 l=   3 prim:      OBJECT            :commonName
+  278:d=5  hl=2 l=  16 prim:      UTF8STRING        :mail.uniroma3.it
+  296:d=2  hl=3 l= 159 cons:   SEQUENCE          
+  299:d=3  hl=2 l=  13 cons:    SEQUENCE          
+  301:d=4  hl=2 l=   9 prim:     OBJECT            :rsaEncryption
+  312:d=4  hl=2 l=   0 prim:     NULL              
+  314:d=3  hl=3 l= 141 prim:    BIT STRING        
+  458:d=2  hl=4 l= 320 cons:   cont [ 3 ]        
+  462:d=3  hl=4 l= 316 cons:    SEQUENCE          
+  466:d=4  hl=2 l=   9 cons:     SEQUENCE          
+  468:d=5  hl=2 l=   3 prim:      OBJECT            :X509v3 Basic Constraints
+  473:d=5  hl=2 l=   2 prim:      OCTET STRING      [HEX DUMP]:3000
+  477:d=4  hl=2 l=  79 cons:     SEQUENCE          
+  479:d=5  hl=2 l=   3 prim:      OBJECT            :X509v3 Certificate Policies
+  484:d=5  hl=2 l=  72 prim:      OCTET STRING      [HEX DUMP]:3046304406072B4C0B010104013039303706082B06010505070201162B687474703A2F2F706F737465636572742E706F7374652E69742F6D616E75616C696F70657261746976692F
+  558:d=4  hl=2 l=  14 cons:     SEQUENCE          
+  560:d=5  hl=2 l=   3 prim:      OBJECT            :X509v3 Key Usage
+  565:d=5  hl=2 l=   1 prim:      BOOLEAN           :255
+  568:d=5  hl=2 l=   4 prim:      OCTET STRING      [HEX DUMP]:030203B8
+  574:d=4  hl=2 l=  29 cons:     SEQUENCE          
+  576:d=5  hl=2 l=   3 prim:      OBJECT            :X509v3 Extended Key Usage
+  581:d=5  hl=2 l=  22 prim:      OCTET STRING      [HEX DUMP]:301406082B0601050507030106082B06010505070302
+  605:d=4  hl=2 l= 111 cons:     SEQUENCE          
+  607:d=5  hl=2 l=   3 prim:      OBJECT            :X509v3 Authority Key Identifier
+  612:d=5  hl=2 l= 104 prim:      OCTET STRING      [HEX DUMP]:3066A15EA45C305A310B300906035504061302494531123010060355040A130942616C74696D6F726531133011060355040B130A43796265725472757374312230200603550403131942616C74696D6F7265204379626572547275737420526F6F74820407275262
+  718:d=4  hl=2 l=  62 cons:     SEQUENCE          
+  720:d=5  hl=2 l=   3 prim:      OBJECT            :X509v3 CRL Distribution Points
+  725:d=5  hl=2 l=  55 prim:      OCTET STRING      [HEX DUMP]:30353033A031A02F862D687474703A2F2F706F737465636572742E706F7374652E69742F706F737465636F6D6373332F63726C2E63726C
+  782:d=1  hl=2 l=  13 cons:  SEQUENCE          
+  784:d=2  hl=2 l=   9 prim:   OBJECT            :sha1WithRSAEncryption
+  795:d=2  hl=2 l=   0 prim:   NULL              
+  797:d=1  hl=4 l= 257 prim:  BIT STRING        
+-----BEGIN CERTIFICATE-----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=
+-----END CERTIFICATE-----
+
+
+-----BEGIN SIGNATURE-----
+dEDUNeoFEh+15y/YKwAwTDIrpLA1VXTLwANWrScsXkaFCpNPPx6T2abeO/VUQWBvOoGZSJbkUrn
+3OZB+x7YvT5u75ulY0SVOCuM/u/+xe6HTHoYpYo1hSBsQ6yKn0gWN+aJ+0sUcwy64s5dJvbnxTB
+/W2cpxXVuFZj5fJQDsr1BINaFZDWIs4KCyssvWm3sBW4Pu8EiqbbYQN5bbVqrYT57lKmj7iy2PD
+sZqiC+QpvWyu+C+BT7zIjXMC+XjU3Z9+/h9KSw7+LZ1RMaxjMQkgRSGjMTd/6Uh1lrOOr4bwZTq
+92cQjdvRR86GEH6+21SHwmeMDqrdh589EtxAMmj59A==
+-----END SIGNATURE-----
+
+$ openssl asn1parse -i -inform DER < [SIGNATURE ALGORITHM]
+    0:d=0  hl=2 l=  13 cons: SEQUENCE          
+    2:d=1  hl=2 l=   9 prim:  OBJECT            :sha1WithRSAEncryption
+   13:d=1  hl=2 l=   0 prim:  NULL              
+-----BEGIN SIGNATURE ALGORITHM-----
+MA0GCSqGSIb3DQEBBQUA
+-----END SIGNATURE ALGORITHM-----
+