Chilkat RSASSA-PSS signature problem with Powerbuilder 9.0.3 and Powerbuilder 12.6 - rsa

Question

We use Chilkat to sign HTTP requests in our Powerbuilder 9.0.3 application (and also powerbuilder 12.6) but it's like the signature generated by Chilkat is not accepted by the API of Isabel (we already have contacted Isabel and they guess that there is a parameters issue in the signature algorithm).
The documentation of the Isabel API (https://documentation.ibanity.com/http-signature)say that we have to use the RSASSA-PSS signature algorithm with the following parameters.
Hash algorithm: SHA-256
Mask generation function: MGF1 Mask
generation algorithm: SHA-256
Salt length: 32 bytes (= 256 bits, same as the hash length)
Trailer field: 1
and so we have set the chilkat Rsa component like this:
loo_Rsa = create oleobject
li_rc = loo_Rsa.ConnectToNewObject("Chilkat_9_5_0.Rsa")
loo_Rsa.DebugLogFilePath = "c:\tmp\rsa.log"
loo_Rsa.VerboseLogging=1
li_Success=loo_Rsa.ImportPrivateKeyObj(loo_Privkey)
if li_Success <> 1 then
ls_error = "Error importPrivateKey: "+loo_Rsa.LastErrorText
destroy loo_Rsa
goto ee_error
end if
// Use RSA-PSS by setting OaepPadding = 1
loo_Rsa.OaepPadding = 1
loo_Rsa.OaepHash = "SHA-256"
loo_Rsa.EncodingMode = "base64"
ls_Signature = loo_Rsa.SignStringENC(ls_signing_string,"SHA-256")
Based on the Isabel documentation do you think we have correctly set the RSA parameters in Chilkat or we have miss something ? (we have also tried with LittleEndian = 0 but we receive the same error from the Isabel API).
For your information here is the log of chilkat :
In the log i see that Chilkat add sometime the character 3D after the characters "=" in the signing string, is it normal ? (in the log below i put the characters 3D in bold)
ImportPrivateKeyObj:
DllDate: Feb 12 2018
ChilkatVersion: 9.5.0.72
UnlockPrefix: BEWANB.CB1042019
Architecture: Little Endian; 32-bit
Language: ActiveX
VerboseLogging: 1
toPrivKeyXml:
toRsaPrivateKeyXml:
toRsaPkcs1PrivateKeyDer:
(leaveContext)
DecodeToAsn:
(leaveContext)
(leaveContext)
(leaveContext)
importPrivateKey:
loadAnyString:
loadAnyXml:
loadAnyXml:
(leaveContext)
(leaveContext)
(leaveContext)
(leaveContext)
Success.
(leaveContext 15ms)
SignStringENC:
DllDate: Feb 12 2018
ChilkatVersion: 9.5.0.72
UnlockPrefix: BEWANB.CB1042019
Architecture: Little Endian; 32-bit
Language: ActiveX
VerboseLogging: 1
hashAlgorithm: SHA-256
charset: windows-1252
Component successfully unlocked using purchased unlock code.
inputBytesQP: (request-target): get /isabel-connect/account-reports?offset=3D0&size=3D100=
\nhost: api.ibanity.com\ndigest: SHA-512=3Dz4PhNX7vuL3xVChQ1m2AB9Yg5AULVxXc=
g/SpIdNs6c5H0NE8XYXysP+DGNKHfuwvY7kxvUdBeoGlODJ6+SfaPg=3D=3D\n(created): 16=
15285438\nauthorization: Bearer access_token_1615285439
hashAndSign:
modulus_bitlen: 2048
hashBytes: 070D CF6B 85D6 ACE2 971F 20B3 29A0 439A
FE36 9394 0D1C 10E7 513B 1447 F04D 39B2
padAndSignHash:
keyType: Private
hashInSize: 32
padding: PSS
hashAlg: SHA-256
pss_encode:
emLen: 256
autoSelectedSaltLen: 32
(leaveContext)
(leaveContext 31ms)
byteOrder: LittleEndian
(leaveContext 47ms)
signature: Te3sMFkvo26Mi5pkLsB8AwAJYynlB3xKU1Dy2AyPS4GlF1fUgTU4k5dU3mSu2dkJEbvmkUd+aPuwo+51AyNarcD7vGtFp/ze3vjCB87lZ+qrzDquEpVUNOb6tOq467odIeGPAsj4b9sa6JsdXciEGKPIZgC8+7zojm87f2MdAVVkDXTwFq7nmI+Q5czGlswLpihYn4VF+5ateKDInl1TdiekujmBh5ffkZAE43LZQX4UWIhqqlak7p2P9GyhF9n3RQRZ55Tp25vOWgPdnwz90OKnQR5aWtcHoVY+JuIl0VX49UFELU+L/Xz9tOGnilA7UcKElWMXVzcEqo3KLcGUWQ==
Success.
(leaveContext 47ms)
ImportPrivateKeyObj:
DllDate: Feb 12 2018
ChilkatVersion: 9.5.0.72
UnlockPrefix: BEWANB.CB1042019
Architecture: Little Endian; 32-bit
Language: ActiveX
VerboseLogging: 1
toPrivKeyXml:
toRsaPrivateKeyXml:
toRsaPkcs1PrivateKeyDer:
(leaveContext)
DecodeToAsn:
(leaveContext)
(leaveContext)
(leaveContext)
importPrivateKey:
loadAnyString:
loadAnyXml:
loadAnyXml:
(leaveContext)
(leaveContext)
(leaveContext)
(leaveContext)
Success.
(leaveContext 31ms)
SignStringENC:
DllDate: Feb 12 2018
ChilkatVersion: 9.5.0.72
UnlockPrefix: BEWANB.CB1042019
Architecture: Little Endian; 32-bit
Language: ActiveX
VerboseLogging: 1
hashAlgorithm: SHA-256
charset: windows-1252
Component successfully unlocked using purchased unlock code.
inputBytesQP: (request-target): get /isabel-connect/account-reports?offset=3D0&size=3D100=
\nhost: api.ibanity.com\ndigest: SHA-512=3Dz4PhNX7vuL3xVChQ1m2AB9Yg5AULVxXc=
g/SpIdNs6c5H0NE8XYXysP+DGNKHfuwvY7kxvUdBeoGlODJ6+SfaPg=3D=3D\n(created): 16=
15287272\nauthorization: Bearer access_token_1615287272
hashAndSign:
modulus_bitlen: 2048
hashBytes: B22B C9AF 7041 43E4 1CFE 5898 C88C C9CE
95FC B536 AC75 1F21 996C 7E7A 7B19 80EF
padAndSignHash:
keyType: Private
hashInSize: 32
padding: PSS
hashAlg: SHA-256
pss_encode:
emLen: 256
autoSelectedSaltLen: 32
(leaveContext)
(leaveContext 31ms)
byteOrder: LittleEndian
(leaveContext 31ms)
signature: 0b/fLp4xbSaGqrH7HXsP8bRuhtr9xo7oPiY1+ryhVuR4vDCdCRFc2As6RX2SazS2T2MK4P966TX1rr5Qx2VnDYN0JL6ZnZAiR/P+ILP19bJN9+f6Jv1nfmgSOUB/stxeLKNlibeMXaR6+heX/ccGY807r8MdEk3hGFwlkK611GjrHoNTH+vge2ReQo8lKBaVP1QIHCvwXUVS39GdABHFLxTQ8La514YX8qruJp6i69lDfCvh4P9rOl5pebMwknyEjJ2rs0D40MUU8z+hM5bm+hSD100S7Ww9sDwObitn4FftR60fee/f3vf9qCv0wkBTBbVP8DTR4vbpKxv/oUNXFQ==
Success.
(leaveContext 31ms)
and we receive this errors from the Isabel API:
{"errors":[{"code":"invalidSignature","detail":"The HTTP signature could not be verified. Please refer to https://documentation.ibanity.com/http-signature","meta":{}}]}
Here is also the original signing string:
(request-target): get /isabel-connect/account-reports?offset=0&size=100\nhost: api.ibanity.com\ndigest: SHA-512=z4PhNX7vuL3xVChQ1m2AB9Yg5AULVxXcg/SpIdNs6c5H0NE8XYXysP+DGNKHfuwvY7kxvUdBeoGlODJ6+SfaPg==\n(created): 1615287272\nauthorization: Bearer access_token_1615287272
Thank in advance for any help or suggestion.
Regards.
Guy

Answer 1

I created some examples, and will create a few more here: https://www.example-code.com/powerbuilder/ibanity.asp

Answer 2

It's working fine now, in fact base on Chlikat example i change the way i build the Signing string: i was using a string variable in place of Chilkat StringBuilder
in place of this
// Step 4 - Build the signing string
ls_signing_string = "(request-target): "+ls_request_target+'\n'+&
"host: api.ibanity.com\n"+&
"digest: "+ls_digest+"\n"+&
"(created): "+ls_created+"\n"+&
"authorization: "+"Bearer "+is_token_isabel
...
ls_Signature = loo_Rsa.SignStringENC(ls_signing_string,"SHA-256")
i should use this
// Step 4 - Build the signing string
oleobject loo_SbSigningString
loo_SbSigningString = create oleobject
li_rc = loo_SbSigningString.ConnectToNewObject("Chilkat_9_5_0.StringBuilder")
loo_SbSigningString.Append("(request-target): ")
loo_SbSigningString.AppendLine(ls_Request_target,0)
loo_SbSigningString.Append("host: ")
loo_SbSigningString.AppendLine("api.ibanity.com",0)
loo_SbSigningString.Append("digest: ")
loo_SbSigningString.AppendLine(ls_digest,0)
loo_SbSigningString.Append("(created): ")
loo_SbSigningString.AppendLine(ls_Created,0)
loo_SbSigningString.Append("authorization: Bearer "+is_token_isabel)
..
ls_Signature = loo_Rsa.SignStringENC(loo_SbSigningString.GetAsString(),"sha-256")