code review 6208076: crypto/rsa: add SHA-224 hash prefix

src/pkg/crypto/rsa/pkcs1v15.go

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package rsa
 
 import (
         "crypto"
         "crypto/subtle"
         "errors"
@@ skipping 133 matching lines @@
 //   DigestInfo ::= SEQUENCE {
 //     digestAlgorithm AlgorithmIdentifier,
 //     digest OCTET STRING
 //   }
 // For performance, we don't use the generic ASN1 encoder. Rather, we
 // precompute a prefix of the digest value that makes a valid ASN1 DER string
 // with the correct contents.
 var hashPrefixes = map[crypto.Hash][]byte{
         crypto.MD5:       {0x30, 0x20, 0x30, 0x0c, 0x06, 0x08, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, 0x05, 0x00, 0x04, 0x10},
         crypto.SHA1:      {0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x0e, 0x03, 0x02, 0x1a, 0x05, 0x00, 0x04, 0x14},
+        crypto.SHA224:    {0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, 0x05, 0x00, 0x04, 0x1c},
         crypto.SHA256:    {0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20},
         crypto.SHA384:    {0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, 0x05, 0x00, 0x04, 0x30},
         crypto.SHA512:    {0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, 0x05, 0x00, 0x04, 0x40},
         crypto.MD5SHA1:   {}, // A special TLS case which doesn't use an ASN1 prefix.
         crypto.RIPEMD160: {0x30, 0x20, 0x30, 0x08, 0x06, 0x06, 0x28, 0xcf, 0x06, 0x03, 0x00, 0x31, 0x04, 0x14},
 }
 
 // SignPKCS1v15 calculates the signature of hashed using RSASSA-PKCS1-V1_5-SIGN from RSA PKCS#1 v1.5.
 // Note that hashed must be the result of hashing the input message using the
 // given hash function.
@@ skipping 69 matching lines @@
         hashLen = hash.Size()
         if inLen != hashLen {
                 return 0, nil, errors.New("crypto/rsa: input must be hashed message")
         }
         prefix, ok := hashPrefixes[hash]
         if !ok {
                 return 0, nil, errors.New("crypto/rsa: unsupported hash function")
         }
         return
 }